High-quality physalis pubescens concentrated juice, preparation method thereof and physalis pubescens compound beverage containing high-quality physalis pubescens concentrated juice

Abstract

The invention discloses high-quality physalis pubescens concentrated juice, a preparation method thereof and a physalis pubescens compound beverage containing the high-quality physalis pubescens concentrated juice, and relates to the technical field of food engineering. The preparation method comprises composite enzymolysis before concentration, a color protection process in an enzymolysis process, a clarification process before concentration and a concentration process. In the process optimization process, evaluation is carried out by taking the juice yield, the browning degree, the light transmittance and the high concentration efficiency as evaluation indexes, and a good preparation process is obtained. Besides, the prepared physalis pubescens concentrated juice and raspberry juice are mixed, meanwhile, cane sugar, citric acid and a stabilizer CNC-Na are added, the physalis pubescens-raspberry compound juice is prepared, the physalis pubescens-raspberry compound juice is good in color and luster state and sour and sweet in taste, the physalis pubescens and raspberries are coordinated in taste, the tissue state is uniform and stable, and layering and foreign matter are avoided.

Description

Technical Field

[0001] This invention relates to the field of food engineering technology, and in particular to a high-quality concentrated juice of Physalis alkekengi, its preparation method, and a Physalis alkekengi compound beverage containing the same. Background Technology

[0002] Physalis alkekengi ( Physalis Pubescens Physalis (also known as ground cherry or lantern fruit) is an annual herbaceous plant belonging to the genus Physalis in the Solanaceae family. Its stem is erect with many branches, reaching a height of about 30-60 cm. The entire plant is densely covered with downy hairs, hence the name "hairy" ground cherry. During its summer flowering period, it produces small, pale yellow, bell-shaped flowers. After flowering, the calyx swells into a lantern-shaped membranous sac, enclosing the spherical fruit, thus resembling a lantern, hence its other name, lantern fruit. The ripe fruit of Physalis is golden yellow and can be eaten directly. It has a sweet and slightly sour taste and is rich in vitamin C, carotenoids, minerals, and other nutrients. Furthermore, Physalis is rich in flavonoids and polyphenols, and has a long history of use in traditional Chinese medicine for clearing heat and detoxifying, relieving sore throat, protecting eyesight, promoting digestion, and aiding in lowering blood sugar and blood lipids. Physalis is widely distributed in temperate and subtropical regions worldwide, and in China, it is mainly found in Heilongjiang, Jilin, Liaoning, and Jiangsu provinces. Besides being eaten directly, the fruit of the hairy urchin can be made into drinks such as juice, vinegar, and wine, or into fast food snacks such as canned goods and dried fruit.

[0003] There are many types of processed wild groundcherry products, the most common being wild groundcherry juice, canned wild groundcherry, and wild groundcherry berry vinegar. Processing wild groundcherry juice into concentrated juice can reduce transportation costs. Furthermore, because the concentrated juice has a low water content, microbial growth is inhibited, thus extending its shelf life.

[0004] Current research on wild physalis mainly focuses on its active substances, while there is relatively little research on the processing technology of its concentrated juice, and its processing potential still needs to be explored in depth.

[0005] Physalis concentrate can be used to produce fruit juices, jams, ice cream, and other products. It can also be added to milk to produce fiber-rich fruit-based beverages, such as blended milk and yogurt. However, due to a lack of relevant processing technology support, the variety of physalis concentrate products produced is limited, restricting consumer choice. Research into its processing technology can promote the emergence of more deep-processed physalis products and contribute to the development of physalis concentrate and related industries. Summary of the Invention

[0006] In view of this, the purpose of this invention is to provide a high-quality concentrated juice of Physalis alkekengi, its preparation method, and a Physalis alkekengi compound beverage containing it. This invention uses fresh Physalis alkekengi as raw material, studies the enzymatic hydrolysis, color protection, and clarification processes during its juice processing, and investigates the effects of different concentration methods on the content of major components and volatile compounds in the Physalis alkekengi juice. After analysis and comparison, vacuum concentration was selected to prepare the concentrated juice of Physalis alkekengi. Finally, the Physalis alkekengi juice was blended with raspberry juice to obtain a novel Physalis alkekengi compound beverage. This invention can provide a certain reference for the preparation process of Physalis alkekengi juice and concentrated juice, and offer new ideas for the development of novel Physalis alkekengi products.

[0007] To achieve the above objectives, the technical solution of the present invention is as follows: In a first aspect, the present invention provides a method for preparing high-quality concentrated physalis extract, comprising the following steps: S1. Extract juice from the hairy berry to obtain hairy berry pulp; S2. Add a color-protecting agent to the obtained physalis pulp, and then add a compound enzyme for enzymatic hydrolysis to obtain physalis enzymatic hydrolysate; The color-protecting agent includes citric acid, EDTA, and tea polyphenols; the amount of citric acid used is 0.15-0.21% of the weight of the citric acid pulp, the amount of EDTA used is 0.04-0.06% of the weight of the citric acid pulp, and the amount of tea polyphenols used is 0.06-0.10% of the weight of the citric acid pulp. The compound enzyme is obtained by combining pectinase and cellulase, and the amount of the compound enzyme is 0.2~0.4g / L; the mixing ratio of pectinase and cellulase is 1~2∶1; during enzymatic hydrolysis, the temperature is 45~55℃, the time is 1.5~2.5h, and the pH is 4~5. S3. Clarify the hydrolysate of *Physalis alkekengi* to obtain *Physalis alkekengi* juice; The clarification process includes adding chitosan to the enzymatic hydrolysate of *Physalis alkekengi*, wherein the amount of chitosan used is 0.02-0.04% of the weight of the enzymatic hydrolysate of *Physalis alkekengi*; the clarification time is 60-80 min, and the clarification temperature is 40-50℃. S4. The obtained sourdough juice is concentrated under vacuum to obtain concentrated sourdough juice; During vacuum concentration, the temperature is 50~60℃ and the vacuum degree is -90kPa~-100kPa.

[0008] In the concentration of wild sago juice, enzymatic hydrolysis, color protection, clarification, and concentration are key processes affecting the sensory quality and retention rate of active substances. Existing research often uses single-type enzymes for enzymatic hydrolysis of wild sago juice, while this invention uses a compound enzyme treatment. Results show that the compound enzyme treatment significantly improves juice yield and promotes the dissolution of effective components compared to single-enzyme treatment. High-temperature enzyme inactivation is a common color protection method in fruit and vegetable processing, but high temperatures can destroy some heat-sensitive components in wild sago juice, leading to nutrient loss. This invention uses a compound color protectant to treat wild sago juice, protecting both its color and the content of browning-related substances. Furthermore, this invention systematically compares the retention effects of two concentration methods—vacuum concentration and electromagnetic heating concentration—on the sensory, physicochemical, and flavor indicators of wild sago juice, ultimately determining a set of key vacuum concentration technologies integrating enzymatic hydrolysis, color protection, and clarification process parameters.

[0009] Furthermore, in step S1, the sour berries are fresh sour berries that are free from rot, surface damage, and impurities; the juicing is performed using a juicer with a power of 200-300W and a juicing time of 2-5 minutes.

[0010] Further, in step S2, the enzymatic hydrolysis is performed at a temperature of 50°C for 132 minutes, at a pH of 4.54, and the amount of the complex enzyme used is 0.32 g / L.

[0011] Furthermore, in step S2, The mixing ratio of pectinase to cellulase is 1.5:1; In the color-protecting agent, the amount of citric acid is 0.207% of the weight of the citric acid pulp, the amount of EDTA is 0.051% of the weight of the citric acid pulp, and the amount of tea polyphenols is 0.083% of the weight of the citric acid pulp.

[0012] Further, in step S3, the amount of chitosan used is 0.033% of the weight of the physalin hydrolysate; the clarification time is 74 min; and the clarification temperature is 47°C.

[0013] Furthermore, in step S4, the vacuum concentration temperature is 55°C, and the concentration endpoint is when the soluble solids content of the slurry reaches 50 °Brix.

[0014] In a second aspect, the present invention provides a concentrated extract of physalis prepared by any of the methods described above.

[0015] In a third aspect, the present invention provides a compound beverage of Physalis alkekengi, comprising raspberry juice, sucrose, sodium citrate, sodium carboxymethyl cellulose, and the above-mentioned Physalis alkekengi concentrate; wherein the mixing volume ratio of the Physalis alkekengi concentrate to the raspberry juice is 2:5~10, the amount of sucrose is 6~7% of the weight of the Physalis alkekengi concentrate, the amount of citric acid is 0.05~0.2% of the weight of the Physalis alkekengi concentrate, and the amount of sodium carboxymethyl cellulose is 0.1~0.3% of the weight of the Physalis alkekengi concentrate.

[0016] In this invention, the preparation of the physalis compound beverage includes: physalis concentrate → reconstitution with water → clarifying physalis juice → blending → stabilizer → homogenization → sterilization → bottling → finished product; Mix appropriate amounts of wild sago, raspberry juice, sucrose, and citric acid in a certain proportion, add a stabilizer, homogenize for 1 min in a homogenizer, sterilize at 90 ℃ for 10 min, and then bottle to obtain the wild sago-raspberry compound beverage product.

[0017] Furthermore, the mixing ratio of the ground cherry concentrate to the raspberry juice is 2:8.3, the amount of sucrose used is 6.6% of the weight of the ground cherry concentrate, the amount of citric acid used is 0.12% of the weight of the ground cherry concentrate, and the amount of sodium carboxymethyl cellulose used is 0.2% of the weight of the ground cherry concentrate.

[0018] The beneficial effects of this invention include at least the following: (1) The preparation method of concentrated physalis juice provided by the present invention, through process optimization, can better protect the polyphenol, reducing sugar and ascorbic acid content of physalis juice, and significantly improve the total polyphenol content, VC content, reducing sugar content and total carotenoid content in physalis juice; it can effectively protect the browning-related components in physalis juice and improve the light transmittance of physalis juice. The obtained concentrated juice of wild sourdough contains 55 kinds of volatile flavor substances, including 13 kinds of esters, 15 kinds of alcohols, 11 kinds of aldehydes, 6 kinds of ketones, 3 kinds of acids, 1 kind of ether, 2 kinds of thioethers, 1 kind of terpene and 3 kinds of other substances. This study provides a novel preparation process for the development of raw hygroscopic plants, which can be commercialized.

[0019] (2) This invention creates a novel perilla-raspberry compound juice beverage. The perilla-raspberry compound juice under the optimal formula has a good color and state, a sweet and sour taste, a harmonious flavor of perilla and raspberry, and a uniform and stable texture without layering or foreign matter. It provides a certain reference for the development of perilla concentrate series products. Attached Figure Description

[0020] Figure 1 This is a technology roadmap.

[0021] Figure 2The effect of different ratios of pectinase and cellulase on juice yield.

[0022] Figure 3 The figure shows the optimized results of the compound enzyme hydrolysis conditions. (A) Hydrolysis temperature, (B) Hydrolysis time, (C) Amount of compound enzyme added, (D) Hydrolysis pH.

[0023] Figure 4 To observe the cell wall morphology of *Syzygium buergerianum* before and after enzymatic hydrolysis. (A) SEM image before enzymatic hydrolysis, (B) SEM image after enzymatic hydrolysis.

[0024] Figure 5 The results of single-factor experiments on the color protection process of citric acid pulp are as follows: (A) Amount of citric acid added, (B) Amount of EDTA added, (C) Amount of tea polyphenols added.

[0025] Figure 6 The results of single-factor experiments on the clarification process are as follows: (A) Chitosan addition amount, (B) Clarification temperature, (C) Clarification time.

[0026] Figure 7 This refers to the viscosity change during the concentration process.

[0027] Figure 8 The effect of concentration method on the physicochemical properties of crude sour pulp. (A) Total phenol content, (B) Vitamin C content, (C) Reducing sugar content, (D) Browning degree.

[0028] Figure 9 This is a two-dimensional spectrum of volatile components in crude acid slurry. In the figure, group (ST) represents crude acid slurry without concentration treatment, group (VHC) represents vacuum concentration group, and group (TC) represents electromagnetic heating concentration group.

[0029] Figure 10 This is a comparison chart of TC1 and VHC1.

[0030] Figure 11 This is a fingerprint spectrum of volatile substances.

[0031] Figure 12 PLS-DA analysis chromatogram of volatile flavor compounds. (A) Scores of crude sour juice from different concentration methods: ST group: freshly squeezed crude sour juice, VHC group: vacuum concentration group, TC group: electromagnetic heating concentration group; (B) Results of displacement test.

[0032] Figure 13 The effect of sodium carboxymethyl cellulose on the centrifugation rate of the precipitate. Detailed Implementation

[0033] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0034] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0035] The following specific embodiments illustrate the solution proposed in this invention: Example 1 Optimization of the compound enzymatic hydrolysis process before concentration of citric acid pulp 1.1 The enzymatic hydrolysis process of wild sour plum is as follows: fresh wild sour plum → juicer pulping → enzymatic hydrolysis → wild sour plum pulp → gauze filtration → centrifugation → supernatant → physicochemical index determination.

[0036] 1.2 Preparation of saffron berry pulp: Select fresh saffron berries that are free from rot, surface damage and impurities, wash them and put them into a juicer to extract the juice. The juicer power is 250 W and the juicing time is 2 min.

[0037] 1.3 Screening of the ratio of complex enzymes 100 mL of sageberry pulp was placed in a 250 mL Erlenmeyer flask, and pectinase and cellulase were added in ratios of 1:4, 2:3, 1:1, 3:2, and 4:1, respectively, with a total enzyme concentration of 0.2 g / L. The mixture was then thoroughly stirred and shaken, and placed in a 45°C water bath for enzymatic hydrolysis for 1.5 hours. After the reaction was complete, the juice was cooled to room temperature, and the juice yield was measured to determine the optimal ratio of pectinase to cellulase in the enzyme mixture.

[0038] The juice yield was determined as follows: 30 g of the *Phyllostachys edulis* pulp was placed in a 50 mL centrifuge tube, centrifuged at 4500 r / min for 15 min, filtered through 200-mesh gauze, and the supernatant was collected and its mass was measured. The juice yield was calculated using the following formula: The results are as follows Figure 2As shown, the juice yield of *Physalis alkekengi* increased with the increase of the ratio of pectinase to cellulase. The juice yield peaked at 76.64 ± 0.43% when the ratio reached 3:2. Further increasing the ratio of the combined enzymes significantly reduced the juice yield (p < 0.05). This may be because the amount of pectinase was close to saturation, while the amount of cellulase was reduced to a low level, resulting in insufficient degradation of the *Physalis alkekengi* cell walls, thus directly reducing the juice yield. Therefore, the ratio of pectinase to cellulase should ultimately be controlled between 1:1 and 4:2.

[0039] 1.4 Determination of Enzymatic Hydrolysis Conditions for Compound Enzymes The initial selection of compound enzyme addition amount as 0.2 g / L, compound enzyme hydrolysis time as 1.5 h, hydrolysis temperature as 45 ℃, and pH adjustment to 4.0 as the basic conditions were as follows: with juice yield as the evaluation index, the effects of compound enzyme addition amount, pectinase hydrolysis time, hydrolysis temperature and hydrolysis pH value on the juice yield of wild sour plum were investigated.

[0040] like Figure 3 As shown in Figure A, when the enzymatic hydrolysis temperature is between 40 ℃ and 50 ℃, the juice yield of *Physalis alkekengi* is positively correlated with temperature (p < 0.05), reaching a peak of 76.75 ± 0.59% at 50 ℃. However, once the enzymatic hydrolysis temperature exceeds 50 ℃, the juice yield decreases significantly (p < 0.05). This phenomenon can be attributed to the effect of temperature on enzyme activity. Specifically, enzyme activity is inhibited at low temperatures, which is not conducive to the effective binding of the enzyme and substrate, thus leading to a decrease in juice yield; while high temperatures may cause enzyme denaturation and inactivation, which is also not conducive to increasing the juice yield. Based on the above analysis, the temperature of the enzymatic hydrolysis reaction should be controlled between 45 ℃ and 55 ℃.

[0041] like Figure 3 As shown in Figure B, the juice yield of *Physalis alkekengi* continuously increased with prolonged enzymatic hydrolysis time (p < 0.05), showing rapid growth in the 0.5 h to 2 h range. However, after 2 h, the growth trend of the juice yield slowed down, showing no significant change (p > 0.05). This indicates that the reaction between the complex enzyme and the *Physalis alkekengi* pulp was nearly complete at this point, with most of the cell structure destroyed and intracellular components fully released. Therefore, the juice yield no longer significantly increased over time. Furthermore, excessively long enzymatic hydrolysis times may lead to enzyme inactivation and the decomposition of certain unstable components in the juice. Therefore, the enzymatic hydrolysis time of *Physalis alkekengi* should be selected within the range of 1.5 h to 2.5 h.

[0042] like Figure 3As shown in Figure C, the juice yield of *Pyracantha fortuneana* increased with the increase of the amount of compound enzyme added (p < 0.05). When the amount of compound enzyme added reached 0.3 g / L, the growth trend of juice yield slowed down (p > 0.05). This indicates that the amount of compound enzyme in *Pyracantha fortuneana* pulp had reached saturation at this point, and the substrate concentration was no longer the limiting factor for the reaction rate. Therefore, even if the amount of enzyme was increased, the increase in juice yield was not significant. In addition, excessive use of enzyme may have a negative impact on juice quality. Based on the above analysis, considering the factors of juice yield, cost, and quality, the final selection of the compound enzyme addition range was 0.2 g / L-0.4 g / L.

[0043] like Figure 3 As shown in Figure D, when the enzymatic hydrolysis pH is in the range of 3.5 to 4.5, the juice yield of *Physalis alkekengi* increases with increasing pH (p < 0.05); however, within the pH range of 4.5 to 5.5, the juice yield decreases with increasing pH (p < 0.05). This phenomenon can be attributed to the negative impact of extreme pH values ​​on enzyme activity, leading to a decrease in the reaction efficiency between the enzyme and the substrate, and thus a decrease in the juice yield. The complex enzyme consists of pectinase and cellulase, with optimal pH ranges of 3.0 to 6.0 and 4.0 to 5.5, respectively. At an enzymatic hydrolysis pH of 4.5, the juice yield of *Physalis alkekengi* reached a peak of 78.13%, indicating that the complex enzyme exhibits optimal activity under this pH condition. Therefore, 4.5 was selected as the pH condition for complex enzymatic hydrolysis.

[0044] 1.5 Response surface methodology optimization experiment for the composite enzymatic hydrolysis process Based on the results of the single-factor experiments, the amount of compound enzyme added (A), enzymatic hydrolysis pH (B), and enzymatic hydrolysis time (C) were used as experimental variables, and the juice yield of raw sour pulp was used as the response value. The Design-Expert13 software was used to analyze the variables and optimize the process conditions. The experimental factor level design is shown in Table 1.

[0045] Table 1 Response Surface Experimental Level Design

[0046] Table 2 Response Surface Experiment Results

[0047] Analysis of the results in Table 2 shows that the main factors affecting the juice yield of wild sourdough are, in descending order: the amount of compound enzyme added (A), the pH of enzymatic hydrolysis (B), and the enzymatic hydrolysis time (C). Specifically, A, B, C, BC, and A... 2 B 2 C 2The effects on the juice yield of wild groundcherry were all significant. After removing insignificant terms, the resulting regression equation was: Y = 82.32 + 0.685A + 0.3637B + 0.1537C + 0.1675AB - 0.0925AC - 0.185BC - 1.83A 2 -2.48B 2 -1.37C 2 .

[0048] Based on the regression model, the optimal juice yield of wild sourdough reached its maximum (82.403%) when the compound enzyme dosage was 0.319 g / L, the hydrolysis pH was 4.539, and the hydrolysis time was 2.022 h. For operational feasibility, the optimal conditions were modified to: compound enzyme dosage 0.32 g / L, hydrolysis pH 4.54, and hydrolysis time 132 min. A verification experiment was conducted under these conditions, repeated three times, yielding a measured juice yield of 82.21 ± 1.25%.

[0049] 1.6 Effect of enzymatic hydrolysis on the quality of crude sour pulp juice The optimized enzymatic hydrolysis process was used to treat the aralia elata pulp, and the content of various nutrients in the aralia elata juice obtained after filtration and centrifugation was determined. The aralia elata juice obtained without enzymatic hydrolysis was used as a control group. The relevant data are shown in Table 3.

[0050] Table 3. Effects of enzymatic hydrolysis on the content of major nutrients in crude sour pulp.

[0051] Note: Different letters in the same row indicate that the differences in the same indicator among different groups are statistically significant (p < 0.05).

[0052] As shown in Table 3, the contents of total phenols, vitamin C, reducing sugars, and carotenoids in the juice of *Physalis alkekengi* after enzymatic hydrolysis were significantly higher than those obtained by direct crushing (p < 0.05). This indicates that pectinase and cellulase decomposed the pectin and cellulose components in the cell walls of *Physalis alkekengi* during enzymatic hydrolysis, effectively disrupting its cell structure and allowing for better dissolution of nutrients. Based on the comparison of nutrient content in *Physalis alkekengi* juice after single and combined enzymatic hydrolysis, it can be concluded that the combined enzymatic hydrolysis process has a good effect on promoting the release of effective components in *Physalis alkekengi*. Compared with *Physalis alkekengi* juice treated with single enzymatic hydrolysis, the combined enzymatic hydrolysis technology demonstrates its advantages in improving the nutritional content of *Physalis alkekengi* juice.

[0053] like Figure 4 The changes in cell wall morphology in *Syzygium buergerianum* under complex enzymatic hydrolysis were observed under scanning electron microscopy at a magnification of 10,000x and a scale bar of 5 micrometers. Figure 4As shown, in untreated *Physalis alkekengi* juice, the cell wall structure remains intact and continuous, with tightly packed cellulose microfibrils and a uniformly distributed, amorphous pectin layer. However, after enzymatic hydrolysis, large areas of cell wall fracture and voids appear, the cellulose microfibrils become loose, and the pectin layer degrades, exhibiting a discontinuous or fragmented state. This is because pectinase and cellulase decompose pectin, cellulose, and hemicellulose in the cell wall, thereby disrupting the *Physalis alkekengi* cell wall structure. Electron microscopy results indicate that the addition of the complex enzyme can effectively promote the release of nutrients from *Physalis alkekengi* cells.

[0054] 1.7 Conclusion Enzymatic hydrolysis is an important technique for improving the juice yield of fruits and vegetables. This invention uses a combination of pectinase and cellulase to perform enzymatic hydrolysis on *Physalis alkekengi*, resulting in a 18.49±0.39% increase in juice yield.

[0055] This invention investigated the optimal enzymatic hydrolysis pH and added cellulase to treat wild sour pulp juice using a combined enzymatic hydrolysis method. Compared with the final experimental results, this experiment not only saved 45% of the enzymatic hydrolysis time but also increased the wild sour pulp juice yield by 3.83%. Furthermore, the content of vitamin C and reducing sugars in the wild sour pulp juice after combined enzymatic hydrolysis was significantly higher than that of single enzymatic hydrolysis treatment. In this embodiment, the content of reducing sugars, vitamin C, and total phenols in the wild sour pulp juice after combined enzymatic hydrolysis was also significantly increased. Compared with the unhydrolyzed group, the total polyphenol content in the wild sour pulp juice treated with combined enzymatic hydrolysis increased by 22.5±0.23%, vitamin C content increased by 29.2±0.31%, reducing sugar content increased by 38.4±0.27%, and total carotenoid content increased by 15.4±0.11%.

[0056] Example 2 Optimization of color protection process during enzymatic hydrolysis of crude acid pulp 2.1 Color protection process Fresh ground cherry → pulping → color-protecting agent → optimal enzymatic hydrolysis process → fruit pulp → gauze filtration → centrifugation → supernatant → physicochemical property determination 2.2 Single-factor experimental design for color protection process of sour pulp juice Fresh, intact, and disease-free wild sorrel pulp was selected, screened, washed, and drained before being crushed in a juicer for 2 minutes. Color-protecting agents were added to the obtained wild sorrel pulp at the following amounts: citric acid 0.05%, 0.1%, 0.15%, 0.2%, 0.25%; EDTA 0.02%, 0.03%, 0.04%, 0.05%, 0.06%; and tea polyphenols 0.04%, 0.06%, 0.08%, 0.10%, 0.12%. Enzymatic hydrolysis was then performed. Immediately after enzymatic hydrolysis, the wild sorrel pulp juice was extracted for various physicochemical tests. The control group received the same enzymatic hydrolysis treatment without any color-protecting agents. Browning degree (OD) was used as the metric. 420 To determine the experimental indicators, the effects of different amounts of color-protecting agent added on browning during the processing of raw sour pulp were studied.

[0057] Determination of browning degree: After filtering the crude acid pulp through 200-mesh gauze, it was centrifuged at 5000 r / min for 15 min at 4℃. Distilled water was used as a blank control. The OD value of the crude acid pulp was measured at 420 nm. OD420nm represents the browning degree of the crude acid pulp. 420 The larger the nm value, the more severe the browning. In response surface methodology, for the convenience of data statistical processing, the degree of browning is converted into the browning index, which is expressed as the reciprocal of the degree of browning.

[0058] Browning index = 1 / browning degree OD 420 like Figure 5 As shown in Figure A, the browning degree of the fermented fruit juice showed a significant decreasing trend with increasing citric acid content (p < 0.05). However, once the content reached 0.2%, further increases in citric acid content did not significantly change the browning degree (p > 0.05). The reason for this is that the citric acid content in the juice was already close to saturation at this point, leaving few oxidase active sites to compete with polyphenols, thus increasing its concentration had no significant effect on browning degree. Therefore, the amount of citric acid added should be controlled within the range of 0.15%–0.20%.

[0059] like Figure 5 As shown in Figure B, it can be observed that the browning degree of wild marmalade decreases with increasing EDTA addition (p < 0.05). When the EDTA addition reaches 0.05%, further increases in its dosage do not significantly change the browning degree of the wild marmalade juice (p > 0.05). This may be because the EDTA content in the juice is close to saturation at this point, and there are no longer sufficient metal ions that can act as cofactors for polyphenol oxidase to form chelates with EDTA. Therefore, further increasing the EDTA addition has little effect on maintaining color. Therefore, the optimal range for EDTA addition is determined to be 0.04%–0.06%.

[0060] like Figure 5 As shown in Figure C, the browning degree of the wild marmalade decreased with increasing tea polyphenol content (p < 0.05). When the tea polyphenol content reached 0.08%, further increases in its concentration did not significantly change the browning degree of the wild marmalade (p > 0.05). This phenomenon can be attributed to the fact that the concentration of tea polyphenols in the juice was close to saturation, and the polyphenol oxidase in the juice was essentially inactivated, with no further polyphenol oxidase reacting with the tea polyphenols. Therefore, further increasing the amount of tea polyphenols added no longer significantly improved the color-protecting effect. Thus, the recommended range for tea polyphenol addition is 0.06%–0.10%.

[0061] 2.3 Response Surface Design for Color Protection Process of Acid Pulp Based on the single-factor experimental results of the three color-protecting agents, the addition amounts of citric acid (A), EDTA (B), and tea polyphenols (C) were used as experimental factors, and the browning index of the crude acid pulp was used as the response variable. Design-Expert 13 software was employed to analyze the results and optimize the process conditions. The level codes for the experimental factors are detailed in Table 4.

[0062] Table 4 Response Surface Factor Levels and Coding

[0063] Table 5 Response Surface Design Schemes and Results

[0064] Analysis of the data in Table 5 showed that the regression model exhibited extremely high statistical significance (P < 0.0001), and the correction coefficient R0 was [value missing]. 2 =0.9920, indicating that the regression equation has extremely high goodness of fit and reliability. Therefore, this model is suitable for analyzing and predicting the browning degree changes of raw pulp under different amounts of color-protecting agent.

[0065] The results showed that the main factors affecting the browning index of wild marmalade were, in descending order, EDTA addition (C), tea polyphenol addition (A), and citric acid addition (B). Factors A, B, and C, and their interaction terms AB, BC, and A... 2 B 2 C 2 The effects on the browning index were all significant. After removing non-significant terms, the resulting regression equation was: Y = 3.04 + 0.0267A + 0.0154B + 0.0356C + 0.0370AB + 0.0095AC - 0.0322BC - 0.1191A 2 -0.0559B 2 -0.1114C 2 .

[0066] Based on the regression analysis model, when the addition amount of citric acid was set to 0.207%, EDTA to 0.051%, and tea polyphenols to 0.083%, the browning index reached its peak value of 3.046. Three repeated verification experiments conducted under these conditions yielded an average measured value of 3.025 for the browning index.

[0067] 2.4 Effects of Composite Color-Protecting Agents on Physicochemical Properties of Brush Pulp This invention treats raw sour pulp with an optimized level of color-protecting agent and measures the content of physicochemical indicators related to browning in the treated raw sour pulp. By comparing the treated raw sour pulp with the optimal dosage of a single color-protecting agent, and using raw sour pulp without added color-protecting agent as a control group, the protective effect of the color-protecting agent on browning-related components in raw sour pulp was investigated. Detailed data are shown in Table 6.

[0068] Table 6. Changes in physicochemical properties of raw sour pulp after treatment with different color-protecting agents

[0069] Note: Different letters in the same column indicate that the differences in the same indicator among different groups are statistically significant (p < 0.05).

[0070] Based on the data presented in Table 6, it can be observed that the addition of color-protecting agents effectively inhibited the oxidation of phenolic compounds and ascorbic acid in the raw sour pulp, thus significantly slowing down the browning phenomenon. Among the three color-protecting agents, tea polyphenols showed the best protective effect against phenolic compounds and browning, while citric acid showed the best protective effect against ascorbic acid (p < 0.05). This may be because tea polyphenols have strong antioxidant properties, which can directly protect phenolic substances and inhibit enzymatic browning; while citric acid and vitamin C have a synergistic antioxidant effect, which can directly enhance the stability of vitamin C. In addition, the composite color-protecting agent was significantly better than the single type of color-protecting agent in protecting the total phenol and ascorbic acid content in the raw sour pulp (p < 0.05).

[0071] 2.5 Conclusion The tea polyphenols selected in this invention have strong antioxidant properties and can effectively inhibit the oxidative decomposition of ascorbic acid, thereby inhibiting the non-enzymatic browning reaction of Physalis martensii. Simultaneously, the multiple composite color-protecting agents exhibit a synergistic effect, demonstrating significantly better protection against browning and total phenolic content in seedless white grape juice compared to single-type color-protecting agents.

[0072] This embodiment uses citric acid, EDTA, and tea polyphenols to treat the color of raw sour pulp, and studies the protective effects of different amounts and ratios of color-protecting agents on the browning degree and related physicochemical indicators during the processing of raw sour pulp. The results show that the browning degree OD of the raw sour pulp juice after enzymatic hydrolysis following composite color protection is significantly reduced. 420 The browning degree value (OD) of directly enzymatically hydrolyzed crude acid pulp was only 0.331 ± 0.14. 420 The value reached 0.612±0.09, and the color protection effectively protected the total phenol and vitamin C content in the malt pulp.

[0073] With the addition of 0.207% citric acid, 0.051% EDTA, and 0.083% tea polyphenols, the browning degree value (OD) of the crude acid pulp juice under this process was [not specified]. 420 It reached its lowest point, at 0.331 ± 0.14, while the browning value OD of the unprotected group was... 420 The value was 0.612±0.09, and the color protection effect was improved by 84.89±0.96%. The changes in the content of browning-related components in the color-protected and untreated crude pulp were also compared. The results showed that in the composite color-protected group, the total phenol content increased by 16.8±0.21%, and the ascorbic acid content increased by 19.9±0.27%.

[0074] Example 3 Optimization of the clarification process before concentration of crude sour pulp 3.1 Clarification Process Flow Fruit pulp after enzymatic hydrolysis and color protection treatment → clarification → gauze filtration → centrifugation → supernatant → transmittance measurement 3.2 Single-factor experimental design for clarification process After color protection and enzymatic hydrolysis, the effects of different chitosan dosages, clarification temperatures, and clarification times on the clarification effect of crude acid pulp were investigated under the basic conditions of 0.02% chitosan dosage, clarification temperature of 40 ℃, and clarification time of 50 min.

[0075] Transmittance determination: The transmittance T (%) of the raw acid juice was measured at 625 nm using a spectrophotometer after centrifugation at 4500 rpm for 15 min. Distilled water was used as a blank control. The experiment was repeated 3 times and the average value was taken.

[0076] like Figure 6As shown in Figure A, with the gradual increase of chitosan addition, the transmittance of the crude acid juice significantly increased (p < 0.05). When the chitosan addition reached 0.03%, the transmittance of the crude acid juice reached its maximum of 83.9%. However, with further increases in chitosan addition, the transmittance of the crude acid juice decreased (p < 0.05). This phenomenon may be because excessive chitosan will not adsorb the colloids, and some chitosan will dissolve in the clear crude acid juice, causing the originally clear juice to become cloudy again. In conclusion, the optimal range for chitosan addition is 0.02%-0.04%.

[0077] Figure 6 B shows the effect of clarification temperature on the transmittance of chitosan pulp. The results indicate that the transmittance of chitosan pulp continuously increases with increasing clarification temperature (p < 0.05). The transmittance reaches its peak at 45 ℃, at 83.6%. Further increases in temperature lead to a decrease in transmittance (p < 0.05). This is attributed to the fact that at lower temperatures, the chitosan molecules move more slowly, resulting in lower binding speed and efficiency with impurities; while at higher temperatures, proteins and sugars are damaged, and the desorption rate accelerates, leading to a decrease in transmittance. Therefore, a clarification temperature range of 40 ℃–50 ℃ was chosen.

[0078] Depend on Figure 6 As shown in Figure C, the transmittance of the physalis juice increased with time (p < 0.05). The transmittance reached its peak at 84.7% after 70 minutes of clarification. Further increases in transmittance with clarification time were no longer significant (p > 0.05). This may be because the juice contains negatively charged substances such as pectin. When chitosan reacts with these negatively charged substances, it forms flocs. The settling of these flocs takes time, and once settling is complete, the transmittance of the juice no longer changes significantly. Additionally, excessively long clarification times may lead to the loss of nutrients in the juice. Therefore, a chitosan clarification time of 60-80 minutes was chosen.

[0079] 3.3 Response surface methodology for clarification process Based on the results of single-factor experiments, chitosan addition (A), clarification temperature (B), and clarification time (C) were used as experimental factors, and the transmittance of the crude acid pulp was used as the response index. Response surface methodology was employed. The experimental design and data processing were completed using Design-Expert 13 software. The experimental factors and their level codes are detailed in Table 7.

[0080] Table 7 Response Surface Factor Levels and Coding

[0081] The experimental design and results of the clarification response surface methodology are shown in Table 8.

[0082] Table 8 Response Surface Design Schemes and Results

[0083] Multinomial regression was performed on the data in Table 8 using Design-Expert 13. The regression model showed extremely high significance (P < 0.0001), and the correction coefficient R0 was [value missing]. 2 =0.9853, the regression equation shows a high goodness of fit and confidence, indicating that the model is suitable for analyzing and predicting clarification effects.

[0084] The results showed that the main factors affecting the transmittance of bovine marmalade were, in descending order, clarification time (C), clarification temperature (B), and chitosan addition (A), with factors A, B, C, AC, BC, and A being the most significant. 2 B 2 C 2 The effects on transmittance were all significant. After removing insignificant terms, the resulting regression equation was: Y = 89.08 + 0.7500A + 0.8875B + 1.06C + 0.4500AB + 1.20AC + 1.62BC - 2.30A 2 -2.18B 2 -2.73C 2 .

[0085] Based on regression model analysis, the transmittance reached its maximum value of 89.553% when the chitosan addition was 0.033%, the clarification temperature was 46.866 ℃, and the clarification time was 73.712 min. Considering the practicality of the experimental operation, the optimal conditions were appropriately adjusted: chitosan addition of 0.033%, clarification temperature of 47 ℃, and clarification time of 74 min. In the verification experiment conducted under these conditions, after three repetitions and averaging, the transmittance was measured to be 89.2 ± 0.72%. This measured value falls within the response surface prediction interval, verifying the accuracy of the regression model's prediction of the experimental results.

[0086] 3.4 Conclusion In this embodiment, chitosan was selected as the clarifying agent. Furthermore, the investigation of clarification temperature and clarification time further explored the optimal process conditions for clarifying phytosan.

[0087] Chitosan was used to clarify crude acid pulp, and the effects of different chitosan addition amounts, clarification temperatures, and clarification times on the transmittance of the crude acid pulp were investigated. Single-factor experiments were conducted to determine the optimal range of each factor, and a response surface methodology was designed based on this to determine the optimal clarification process parameters: chitosan addition amount of 0.033%, clarification temperature of 47℃, and clarification time of 74 min. Under these conditions, the transmittance of the crude acid pulp reached its peak at 89.2±0.72%, an increase of 32.5±0.56% compared to the untreated crude acid pulp. The chitosan clarifier used in this embodiment showed good clarification effect and is simple to operate and easy to apply in practice, providing a certain reference for the research of crude acid pulp clarification technology.

[0088] Example 4 Optimization of the concentration process of sour pulp juice 4.1 Concentration Process Flow Sour pulp juice → Concentration → Concentrated juice → Reconstitution with water → Reduced juice → Physicochemical index testing 4.2 Screening of Concentration Methods (1) Determination of the concentration endpoint At room temperature (23 °C), the crude acid slurry was concentrated to 40°Brix to 70°Brix using a vacuum rotary evaporator (55 °C, 90 kPa~100 kPa, 120 r / min). The sampling interval was 5°Brix. The samples were retained at 4 °C, and the viscosity change was detected using a rheometer.

[0089] Viscosity was measured using an AR1500 rheometer in rheological mode under a 60 mm, 2 ° cone plate at a temperature of 25 °C and a shear rate of (10–80) s⁻¹. —1 The results showed that at a shear rate of 50 s —1 Viscosity at that time.

[0090] like Figure 7 As shown, the viscosity of the crude acid slurry increases continuously with the progress of concentration. When the crude acid slurry is concentrated to 55 °Brix, its viscosity increases dramatically, from 0.8446 Pa·s at 50 °Brix to 2.025 Pa·s, an increase of 58.3%. At this point, the crude acid slurry already has a certain viscosity, and its fluidity has clearly decreased to a low level. Excessively high juice viscosity increases the difficulty of equipment cleaning, leading to resource waste. Simultaneously, the viscosity change coefficient of the material is large during the concentrated juice production process, which places higher demands on the parameters of the production equipment, thus increasing production difficulty. To avoid these problems, the soluble solids content corresponding to a significant change in juice viscosity can be determined as the concentration endpoint. Therefore, the concentration endpoint is set when the soluble solids content of the crude acid slurry reaches 50 °Brix.

[0091] (2) Screening of concentration parameters Vacuum concentration group: The crude sour juice was concentrated using a rotary evaporator (70 kPa~90 kPa, 50 r / min). Concentrated crude sour juices at 20°Brix, 30°Brix, 40°Brix, 50°Brix, and 60°Brix were collected and stored at -4 ℃. Various physicochemical indicators were tested within 24 hours. Before testing, the juice was diluted with distilled water to the same Brix level as the original juice.

[0092] Electromagnetic heating concentration group: The crude sour slurry was concentrated using an open electromagnetic pot. The concentrated crude sour slurry was taken at 20°Brix, 30°Brix, 40°Brix, 50°Brix and 60°Brix respectively. The storage and testing methods were the same as those for the vacuum concentration group.

[0093] The temperature gradients of the vacuum rotary evaporator were set to 45 ℃, 55 ℃, and 65 ℃; the power gradients of the induction cooker were set to 600 W, 800 W, and 1000 W. Color and concentration efficiency were used as the measurement indicators to investigate the concentration conditions of crude acid pulp. Concentration efficiency refers to the time required to concentrate 1 L of sample to a certain concentration; color is represented by the total color difference ΔE*.

[0094] Table 9. Effect of vacuum concentration temperature on total color difference and concentration efficiency

[0095] Note: Columns with different superscript letters indicate statistical significance (p < 0.05) within the same group. The same applies below.

[0096] Table 9 shows a positive correlation between the concentration efficiency and concentration temperature in the vacuum concentration group; that is, higher temperatures lead to higher concentration efficiency. Specifically, the concentration efficiency at 60 ℃ is higher than that at 55 ℃, and 55 ℃ is higher than that at 50 ℃ (p < 0.05). However, the color difference in the vacuum concentration group also shows an increasing trend with increasing temperature, indicating that lower temperatures are more beneficial for preserving the color of the juice. Specifically, 50 ℃ is better than 55 ℃, and 55 ℃ is better than 60 ℃ (p < 0.05). Considering both concentration efficiency and juice color preservation, 55 ℃ was ultimately determined to be the optimal processing temperature for the vacuum concentration group.

[0097] Table 10 Effect of vacuum concentration temperature on total color difference and efficiency

[0098] During the heating process in an induction cooker, higher power results in a faster temperature rise. Data in Table 10 shows a positive correlation between concentration efficiency and power during thermal concentration; concentration efficiency increases with increasing power (p < 0.05). Specifically, the concentration efficiency at 1000 W is higher than at 800 W, and 800 W is higher than 600 W. Furthermore, the color difference of the crude sour pulp is significantly affected by temperature and concentration time (p < 0.05), with the color difference protection effect ranked as follows: 600 W is better than 800 W, and 800 W is better than 1000 W. Considering both concentration efficiency and the color difference protection effect of the crude sour pulp, 800 W was ultimately determined to be the optimal power choice for the thermal concentration process.

[0099] (3) Effect of concentration method on the physicochemical properties of concentrated crude sour pulp juice Phenolic compounds are widely found in various fruits and vegetables, and have a significant impact on the flavor, color, and antioxidant capacity of fruits. They include flavonoids, tannins, phenolic acids, quinones, and anthocyanins. Figure 8 As shown in Figure A, compared with the control group that had not undergone concentration treatment, the total phenol content in both concentration treatment groups decreased with increasing concentration (p < 0.05). The vacuum concentration group showed better retention of phenolic substances than the thermal concentration group at all concentration levels (p < 0.05). This is because, at the same concentration level, the vacuum concentration temperature is lower than the electromagnetic heating temperature, resulting in relatively less damage to the molecular structure of phenols, which are heat-sensitive substances.

[0100] Depend on Figure 8 As shown in Figure B, the vitamin C (VC) content in both groups of reconstituted malt extract showed a continuous decreasing trend as the concentration process progressed (p < 0.05). At different concentration levels, the VC content in the malt extract from the hot-concentrated group was lower than that from the vacuum-concentrated group (p < 0.05). The reason for this is that although the hot concentration method has higher concentration efficiency and shorter concentration time, the concentration temperature continuously increases over time during the concentration process. VC is easily destroyed under heat, typically starting the degradation reaction at 60℃, and the higher the temperature and the longer the heating time, the faster the degradation rate. Furthermore, VC easily decomposes into dehydroascorbic acid and other derivatives under light conditions. Therefore, the loss of VC content in the vacuum-concentrated group may be largely due to its longer concentration time.

[0101] In concentrated wild physalis juice, the sugar content not only affects the sensory quality and microbial inhibition of the product, but is also closely related to color changes during the concentration process. Figure 8As shown in Figure C, the reducing sugar content in both groups of concentrates decreased with increasing concentration (p < 0.05), which may be due to some reducing sugars participating in the Maillard reaction. Before reaching a concentration of 40 °Brix, the reducing sugar content in the hot concentration group was significantly higher than that in the vacuum concentration group (p < 0.05), presumably because the faster rate of hot concentration shortened the duration of the Maillard reaction, thus reducing the total consumption of reducing sugars. After reaching a concentration of 40 °Brix, the reducing sugar content in the vacuum concentration group was significantly higher than that in the hot concentration group (p < 0.05), indicating that as the temperature of the hot concentration group increased, more reducing sugars participated in the Maillard browning reaction, resulting in a significantly lower reducing sugar content than the vacuum concentration group.

[0102] Depend on Figure 8 As shown in D, the browning degree increased in both concentration groups, with the increase in browning degree in the hot concentration group being significantly greater than that in the vacuum concentration group (p < 0.05). The reason for this is that during hot concentration, the concentration temperature continuously rises over time. High temperatures induce more chemical reactions in the crude acid pulp, including Maillard reactions of reducing sugars, caramelization of sugars during heating and concentration, and thermal oxidation of phenols and their derivatives, producing more brown substances and thus increasing browning degree. In contrast, the temperature remains stable during vacuum concentration, resulting in a relatively smaller change in browning degree.

[0103] 4.3 Analysis of volatile flavor compounds in crude sourdough before and after concentration (1) Preparation of raw sour pulp sample At room temperature (23 °C), the crude sour pulp juice was concentrated to 50 ° Brix using a vacuum rotary evaporator (55 °C, 90 kPa~100 kPa, 120 r / min) and an induction cooker (800 W), respectively. Water was immediately added to restore it to the original Brix of the crude sour pulp juice. Three copies of each sample were prepared and sealed and stored at 4 °C.

[0104] Samples obtained by vacuum concentration of styrax juice are denoted as VHC1, VHC2, and VHC3, while samples obtained by electromagnetic heating concentration are denoted as TC1, TC2, and TC3. Unconcentrated styrax juice serves as the control group, denoted as ST1, ST2, and ST3.

[0105] (2) GC-IMS instrument parameters and analysis methods Six mL of crude acid slurry was weighed and placed in a 20 mL headspace vial, and reacted in an oven at 65 °C for 50 min. Gas chromatography was performed using an HP-5 column. The initial program temperature for IMS was 40 °C, increased to 120 °C at a rate of 10 °C / min after 5 min, then increased to 210 °C at a rate of 20 °C / min, and finally increased to 230 °C at a rate of 2 °C / min. The retention indices (RIs) of each volatile compound were calculated using the C4-C9 ketones as external standards. Qualitative analysis was performed by comparing the RIs and drift times (Dt) with the NIST and IMS databases. Quantitative analysis of volatile compounds was performed by calculating the peak volume of the selected signal peaks.

[0106] (3) Two-dimensional spectral analysis of volatile components Volatile substances in *Physalis alkekengi* were analyzed using GC-IMS technology. Two-dimensional spectra were plotted using the Reporter plugin within the VOCal software. Figure 9 The vertical axis in the graph represents the retention time of volatile components, and the horizontal axis represents the migration time. The red vertical line represents the normalized reaction ion peak (RIP). Each point to the right of the RIP peak corresponds to the ion peak of a specific volatile substance. The ion peak intensity is displayed using color, with red and white representing the intensity of the peak, i.e., the amount present. Figure 9 As shown, compared with the ST (untreated) group, the number and intensity of ion peaks in the VHC (vacuum concentration) group and TC (electromagnetic heating concentration) group decreased, indicating that the concentration process caused the loss of volatile compounds in the slurry.

[0107] To visually compare the differences in ion peak changes between the two concentration groups, VHC1 was selected as the reference. A two-dimensional top view was plotted after subtracting the reference value from TC1. See details below. Figure 10 In the graph after deduction, white indicates that the concentration of volatile compounds is consistent with the reference, red indicates that the concentration of the substance is higher than the reference, and blue indicates that it is lower than the reference. For example... Figure 10 As shown, within the retention time range of 400-800 seconds, the TC group has more and darker spots, with some spots appearing blue, indicating a higher abundance of volatile compounds in this range. However, within the 200-400 second range, most spots in the TC group are blue, with a few red, indicating a higher content of most volatile compounds in the VHC group within this range. Overall, the colors and numbers of spots in the two samples are significantly different, suggesting a preliminary assessment that the types and amounts of volatile substances lost due to different concentration methods differ.

[0108] (4) Qualitative analysis and fingerprint analysis of volatile substances Based on the NIST and IMS databases, and combined with the retention index, retention time, and migration time of substances detected by GC-IMS, the volatile substances in three groups of maltose slurry samples were qualitatively identified. A total of 63 peaks were detected in the three groups of samples, including haploids and dimers of 13 volatile compounds, therefore the total number of volatile flavor compounds was 50. These included 11 alcohols, 14 esters, 7 aldehydes, 4 ketones, 3 carboxylic acids, 2 ethers, 5 thioethers, 1 terpene, and 3 other substances.

[0109] To more concretely and intuitively demonstrate the differences in volatile compounds in crude acid slurry treated by different concentration methods, a fingerprint spectrum of volatile compounds was constructed using the Gallery Plot plugin in VOCal software. Figure 11 Each row represents a sample, each sample group is repeated 3 times, and each column represents the signal peak of the same compound in different samples. The redder the color, the higher the content of the substance in the sample.

[0110] Depend on Figure 11 It is known that untreated phytic acid pulp contains higher levels of alcohols and esters, which give it its unique fruity and sweet aroma. In regions A and B, the ion peak intensities of volatile substances are higher in both concentration groups, indicating compounds newly generated or whose content increases during the concentration process. In region A, the four substances—4-methyl-3-penten-2-one, 4-ketoisophorone, butyraldehyde, and 2,3-butanedione—are present in higher amounts in the VHC group than in the TC group, suggesting that these four substances are generated in greater quantities during vacuum concentration. In region B, the six substances—trans-dibutenal, ethyl formate, 2-methyl-1-propanol, 3-methylbutyraldehyde, ethyl trans-dibutenate, and 1,2-dimethoxyethane—are present in higher amounts in the TC group, indicating that electromagnetic heating concentration produces more of these substances. In regions C and D, the ion peak intensities of substances in the ST group are higher, suggesting that these substances are lost to varying degrees during the two concentration processes. The substances in region C include 2-hexenal, diethyl sulfide, 1,1-diethoxyethane, 1-pentanol, 1-hydroxy-2-propanone, trans-dipentenal, 1,2-propanediol, 3-methyl-1-pentanol, and acetic acid. The higher levels of these volatile substances in the VHC group indicate better retention during vacuum concentration. In region D, the higher levels of trans-diheptenal, propyl butyrate, and benzaldehyde in the TC group suggest less loss of these substances during electromagnetic heating concentration. Substances outside these four regions exhibit extremely low or undetectable ion peak intensities, indicating significant or complete loss of these substances.

[0111] Overall, both thermal concentration processes resulted in the loss of significant amounts of volatile compounds in the raw sourdough. The types of volatile compounds lost were essentially the same in both concentration methods, but vacuum concentration showed an advantage in retaining a wider range of volatile substances. Furthermore, the types of newly generated volatile compounds were also very similar in both thermal concentration processes. This is likely because both methods rely on heating to evaporate moisture from the material, and the high temperatures generated during concentration lead to the formation of new volatile substances. The electromagnetic heating concentration group produced a higher amount of most volatile substances, and the formation of these new substances may affect the flavor of the raw sourdough. Therefore, it is concluded that vacuum heating concentration is more effective in preserving the original flavor of the raw sourdough.

[0112] (5) PLS-DA analysis of volatile flavor compounds To specifically identify volatile compounds whose content varies significantly during the concentration process, a PLS-DA model was used to analyze the differences in the main volatile components of crude sour pulp. The model's independent variable fit index R0 was used. 2 X is 0.957, and the dependent variable fit index R0 is... 2 Y is 0.993, Q 2 R is 0.972. 2 Q 2 A value greater than 0.5 indicates that the model fit is acceptable, and the closer it is to 1, the stronger the predictive ability. Figure 12 A shows the PLS-DA dispersion plots of volatile substances in maize pulp from different treatment groups. It can be seen that the distances between samples within the same group are small, while the distances between samples from different groups differ significantly. This indicates that the experimental results have good discrimination, and there are clear differences in flavor among the groups. To verify whether the model is overfitting, the Y matrix variable was randomly permuted 200 times to perform a permutation test on the model. Figure 12 B), the verification results show that R 2 =0.527, Q 2 =-0.113, R 2 Q 2 The original values ​​are all higher than the simulated values, and Q 2 The intersection of the regression line and the vertical axis is less than 0, indicating that the model data has not overfitted and has reliable predictive ability. It can be used for the identification and analysis of different concentration methods of koji.

[0113] The VIP value (variable influence on projection) reflects the degree of contribution of each variable to the model. A larger VIP value indicates greater difference in a particular volatile component among samples. Using VIP > 1 as the screening criterion, 14 key biomarkers were selected, arranged from largest to smallest VIP value: trans-dibutenoic acid, trans-dipentenal, benzaldehyde, 2-hexenal, propyl butyrate, 1,2-dimethoxyethane, 4-methyl-3-penten-2-one, butyraldehyde, 4-ketoisophorone, 3-methyl-1-pentanol, 2,3-butanedione, diethyl sulfide, acetic acid, and 1,1-diethoxyethane. The key biomarkers selected by the difference analysis all fell within the significantly different regions ABCD in the fingerprint analysis, indicating that the PLS-DA model can effectively identify and distinguish crude acid pulp treated by different concentration methods.

[0114] Among the key biomarkers, trans-dibutenoic acid (DDI) was the volatile compound with the largest difference in content among the three sample groups. Its content decreased after vacuum concentration but increased after electromagnetic heating concentration. This increase in DDI resulted in a more acidic taste in the concentrated bovine pulp obtained through electromagnetic heating. During both concentration processes, the contents of 4-methyl-3-penten-2-one, 4-ketoisophorone, butyraldehyde, 2,3-butanedione, and 1,2-dimethoxyethane all increased. These substances impart the unique tobacco, sweet, and creamy aromas to the concentrated bovine pulp. The loss of other biomarkers, such as 2-hexenal, diethyl sulfide, 1,1-diethoxyethane, trans-dipentenal, 3-methyl-1-pentanol, acetic acid, propyl butyrate, and benzaldehyde, resulted in a certain loss of the unique fruity and sweet aromas of the bovine pulp.

[0115] 4.4 Conclusion This embodiment selects electromagnetic heating concentration and vacuum heating concentration to treat crude acid slurry, and compares the effects of the two concentration methods on the content of the main components and volatile components of crude acid slurry. The main difference between the two thermal concentration technologies is that electromagnetic heating concentration has a continuously rising temperature over time, resulting in higher concentration efficiency and lower equipment cost; vacuum concentration, on the other hand, creates a low-pressure environment to lower the boiling point of the liquid, allowing concentration to be carried out at lower temperature conditions, but its concentration efficiency is relatively lower.

[0116] This embodiment uses thermal concentration and vacuum heating concentration to treat bovine sour pulp juice, comparing the effects of different concentration methods on the content of its main components and volatile substances. The bovine sour pulp juice was concentrated to different degrees of whiteness, then reconstituted with water to the original juice whiteness, followed by measurement and comparative analysis of physicochemical indicators. Ultimately, it was found that vacuum concentration has a better effect on protecting the content of the main components and volatile substances in the bovine sour pulp juice. This embodiment aims to explore a more suitable concentration method for processing bovine sour pulp juice.

[0117] To achieve high concentration efficiency and minimize the impact of concentration on the physicochemical properties and flavor of wild sour pulp, this embodiment analyzed and compared the effects of vacuum heating and electromagnetic heating on the quality of wild sour pulp, and determined the parameters of the concentration process. The results showed that the optimal heating temperature for the vacuum concentration group was 55 ℃, the optimal power for the electromagnetic heating group was 800 W, and the optimal concentration endpoint was 50 °Brix. The concentration method significantly affected the stability of the physicochemical properties of the concentrated wild sour pulp. Vacuum concentration better preserved the total phenols, reducing sugars, and ascorbic acid content of the wild sour pulp, and the wild sour pulp obtained through vacuum concentration had lower browning.

[0118] Analysis of volatile components revealed that different concentration methods affected the types and contents of volatile substances in the crude sour pulp. A total of 50 volatile compounds were detected in the three crude sour pulp samples, including 11 alcohols, 14 esters, 7 aldehydes, 4 ketones, 3 carboxylic acids, 2 ethers, 5 thioethers, 1 terpene, and 3 other substances. Ten of these compounds were newly generated during the concentration process or their content increased, while the remaining compounds were lost to varying degrees during concentration. Trans-butenoic acid (TDI) showed the largest difference in content among the three groups of samples; its content decreased after vacuum concentration but increased after electromagnetic heating concentration. This substance can be used to distinguish between the two concentration methods.

[0119] Compared to unconcentrated wild sourdough, both concentration groups produced new volatile compounds, with the vacuum concentration group showing a lower amount than the electromagnetic heating concentration group. This indicates that vacuum concentration has less impact on the original flavor of wild sourdough. Furthermore, the vacuum heating concentration group lost fewer types and amounts of existing volatile substances than the electromagnetic heating concentration group, suggesting that vacuum heating concentration is more effective at preserving the original volatile compounds in wild sourdough. In conclusion, vacuum heating concentration is more suitable for the production of concentrated wild sourdough.

[0120] Example 5 Preparation of Physalis alkekengi compound beverage 5.1 Preparation process of Physalis alkekengi-Raspberry composite beverage concentrated crude sour juice → reconstitution with water → clarified crude sour juice → blending → stabilizer → homogenization → sterilization → bottling → finished product Mix appropriate amounts of wild sago, raspberry juice, sucrose, and citric acid in a certain proportion, add a stabilizer, homogenize for 1 min in a homogenizer, sterilize at 90 ℃ for 10 min, and then bottle to obtain the wild sago-raspberry compound beverage product.

[0121] 5.2 Sensory Evaluation Criteria for Physalis-Raspberry Compound Beverage Referring to GB7101-2022 "National Food Safety Standard for Beverages," and considering the sensory characteristics of groundcherry and raspberries, the compound fruit juice was evaluated from four aspects: color, taste, aroma, and state, with a total score of 100 points. The sensory scoring criteria are shown in Table 11. Before the formal sensory evaluation, the team members received systematic training, clarifying the standard levels for sensory index evaluation and related precautions to ensure the objectivity and consistency of the evaluation results. In the sensory scores of the tested samples, the highest and lowest scores were removed, and then the average value was calculated.

[0122] Table 11 Sensory Rating Table

[0123] 5.3 Effect of the ratio of marzipan juice to raspberry juice on the sensory quality of the compound beverage Experiments were conducted with five ratios of physalis juice to raspberry juice: 2:5, 2:6, 2:7, 2:8, and 2:9, to evaluate the impact of different ratios on the sensory quality of the compound beverage.

[0124] Table 12 Effect of the ratio of purslane juice to raspberry juice on sensory evaluation

[0125] As shown in Table 12, with the increase in the proportion of raspberry juice added, its flavor in the compound fruit juice became more pronounced, initially masked by the flavor of groundcherry juice, and eventually exhibiting a unique astringent taste. The color of the compound fruit juice also changed from purplish-black to bright purplish-red. When the ratio of groundcherry to raspberry juice was 2:8, the compound fruit juice exhibited a purplish-red color, and the flavors of both groundcherry and raspberry were moderate. At this ratio, the compound fruit juice displayed typical aromas of groundcherry and raspberry, and the two flavors blended very harmoniously.

[0126] 5.4 Effect of Sucrose Addition on Sensory Quality of Compound Beverages Five gradients of sucrose addition were set at 2%, 4%, 6%, 8%, and 10% to investigate their effects on the sensory quality of compound beverages.

[0127] The sweetness of sucrose can, to some extent, mask the sourness and bitterness of compound fruit juices. As shown in Table 13, there is a significant correlation between the sensory evaluation of the *Physalis alkekengi*-raspberry compound beverage and the amount of sucrose added. The sensory score peaks when the sucrose addition is 6%. However, when the sucrose addition exceeds 6%, the beverage becomes unpalatable due to excessive sweetness; conversely, if the sucrose addition is below 6%, the insufficient sweetness results in an overly prominent sour taste, similarly affecting the drinking experience.

[0128] Table 13 Effect of sucrose addition on sensory evaluation

[0129] 5.5 Effect of Citric Acid Addition on Sensory Quality of Compound Beverages Five gradients of citric acid addition were set at 0.05%, 0.10%, 0.15%, 0.20%, and 0.25% to investigate its effect on the sensory quality of the compound beverage.

[0130] Table 14 Effect of Citric Acid Addition on Sensory Evaluation

[0131] Adding appropriate amounts of citric acid can significantly reduce the astringency of blended fruit juices. Its mechanism involves the following aspects: First, citric acid can lower the pH value of the juice, altering the chemical properties of astringent substances such as tannins in an acidic environment. Second, citric acid has the property of chelating metal ions, forming chelates with those metal ions that bind to astringent substances and enhance astringency, thereby reducing the production of astringent substances. Furthermore, adjusting the sugar-acid ratio of blended fruit juices with citric acid can create a unique sweet and sour flavor. According to Table 14, the sensory score of the blended beverage reaches its highest level when the added citric acid is 0.10%. However, excessive addition of citric acid will lead to excessively high acidity in the blended fruit juice, thus affecting the quality of the final product.

[0132] 5.6 Response Surface Methodology Experiment for Beverage Formulation and Process Research Based on the results of the single-factor experiments, a response surface methodology was designed to determine the optimal formulation using the proportion of physalis raspberry juice added (A), the amount of sucrose added (B), and the amount of citric acid added (C) as experimental factors, and sensory scores as the response values. The level codes for the experimental factors are detailed in Table 15.

[0133] Table 15 Response Surface Factor Levels and Coding

[0134] Table 16 Response Surface Design Schemes and Results

[0135] Using Design-Expert 13, a multinomial regression was performed on the data in Table 6-8. The regression model showed extremely high statistical significance (P < 0.0001), and the adjusted R-squared value was [value missing]. 2 The value reached 0.9776, indicating that the regression equation has extremely high goodness of fit and reliability. Therefore, this model is suitable for analyzing and predicting sensory ratings.

[0136] The results showed that the main influencing factors on the sensory score of the compound fruit juice were, in descending order, the amount of citric acid added (C), the amount of sucrose added (B), and the ratio of purslane juice to raspberry juice (A). Factors A, B, C, AB, and A...2 B 2 C 2 The effects on the sensory scores of the compound fruit juice were all statistically significant. After removing non-significant terms, the resulting regression equation was: Y = 83.26 + 1.18A + 1.20B + 1.40C + 2.12AB + 0.025AC + 0.725BC - 2.72A 2 -3.67B 2 -2.37C 2 .

[0137] Based on regression model analysis, the sensory score reached its highest value of 83.871 when the mixing ratio of wild privet juice to raspberry juice was 2:8.334, the added sucrose was 6.588%, and the added citric acid was 0.117%. Considering the practicality of the experimental operation, the optimal conditions were appropriately adjusted: the mixing ratio of wild privet juice to raspberry juice was 2:8.3, the added sucrose was 6.6%, and the added citric acid was 0.12%. In the verification experiment conducted under these conditions, after three repetitions and averaging, the measured sensory score was 83.2. This value falls within the response surface prediction interval, verifying the accuracy of the regression model's prediction of the experimental results.

[0138] 5.7 Research on Beverage Stabilization Technology The effect of different amounts of sodium carboxymethyl cellulose (0.10%, 0.15%, 0.20%, 0.25%, 0.30%) on the stability of the marmalade-raspberry compound beverage was investigated using centrifugal sedimentation rate as an indicator.

[0139] Sodium carboxymethyl cellulose (CMC-Na) is a cellulose ether compound, a hydrophilic colloid, possessing excellent water solubility and molecular compatibility. This substance is widely used in the food and pharmaceutical industries as a stabilizer, emulsifier, and thickener. Figure 13 As shown, when the addition amount of CMC-Na is between 0.10% and 0.20%, the centrifugal sedimentation rate of the compound fruit juice gradually decreases with increasing CMC-Na addition (p < 0.05). When the addition amount reaches 0.20%, the centrifugal sedimentation rate drops to its lowest point, indicating that CMC-Na has the best stabilizing effect on the compound fruit juice at this addition amount. However, if the addition amount of CMC-Na continues to increase, the centrifugal sedimentation rate shows an upward trend (p < 0.05). It is speculated that the reason is that excessive CMC-Na causes the interfacial membrane, which was originally dominated by proteins, to become dominated by CMC-Na, thereby weakening the interfacial strength and thus increasing the centrifugal sedimentation rate of the compound fruit juice. Therefore, the optimal addition amount of CMC-Na is determined to be 0.20%.

[0140] 5.7 Quality Assessment of Physalis alkekengi-Raspberry Compound Beverage (1) Sensory evaluation of compound beverages Sensory analysis was performed on the optimized formula of the physalis-raspberry compound beverage, and the results are shown in Table 17 below.

[0141] Table 17 Sensory Evaluation of Physalis-Raspberry Compound Beverage

[0142] (2) Results of physicochemical index determination Table 18 Results of Physicochemical Indicators of Compound Beverages

[0143] 5.8 Conclusion This embodiment studied the formulation optimization of the *Physalis alkekengi*-raspberry composite beverage using sensory evaluation as an indicator, and examined the specific effects of the stabilizer through centrifugal sedimentation rate, which can provide a certain reference for future research on *Physalis alkekengi* related composite beverages.

[0144] This embodiment investigated the changes in sensory scores and specific sensory characteristics of a compound fruit juice containing *Physalis alkekengi* and raspberry juice under different addition ratios, sucrose amounts, and citric acid amounts. Single-factor experiments were conducted to determine the optimal range for each component's addition, and a response surface methodology was designed to optimize the compound fruit juice formulation. The response surface results showed that the sensory score reached its highest value of 83.2 when the mixing ratio of *Physalis alkekengi* juice to raspberry juice was 2:8.3, the sucrose addition was 6.6%, and the citric acid addition was 0.12%. Using the centrifugal sedimentation rate of the compound fruit juice as an indicator, the optimal addition amount of the stabilizer CMC-Na was determined to be 0.20%. Finally, the sensory evaluation of the compound beverage obtained after process optimization was performed. The *Physalis alkekengi*-raspberry compound fruit juice with the optimal formulation exhibited good color and texture, a sweet and sour taste, harmonious flavors of *Physalis alkekengi* and raspberry, and a uniform and stable texture without layering or foreign matter.

[0145] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0146] The sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0147] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for preparing high-quality concentrated physalis juice, characterized in that, Includes the following steps: S1. Extract juice from the hairy berry to obtain hairy berry pulp; S2. Add a color-protecting agent to the obtained physalis pulp, and then add a compound enzyme for enzymatic hydrolysis to obtain physalis enzymatic hydrolysate; The color-protecting agent includes citric acid, EDTA, and tea polyphenols; the amount of citric acid used is 0.15-0.21% of the weight of the citric acid pulp, the amount of EDTA used is 0.04-0.06% of the weight of the citric acid pulp, and the amount of tea polyphenols used is 0.06-0.10% of the weight of the citric acid pulp. The compound enzyme is obtained by combining pectinase and cellulase, and the amount of the compound enzyme is 0.2~0.4g / L; the mixing ratio of pectinase and cellulase is 1~2∶1; during enzymatic hydrolysis, the temperature is 45~55℃, the time is 1.5~2.5h, and the pH is 4~5. S3. Clarify the hydrolysate of *Physalis alkekengi* to obtain *Physalis alkekengi* juice; The clarification process includes adding chitosan to the enzymatic hydrolysate of *Physalis alkekengi*, wherein the amount of chitosan used is 0.02-0.04% of the weight of the enzymatic hydrolysate of *Physalis alkekengi*; the clarification time is 60-80 min, and the clarification temperature is 40-50℃. S4. The obtained sourdough juice is concentrated under vacuum to obtain concentrated sourdough juice; During vacuum concentration, the temperature is 50~60℃ and the vacuum degree is -90kPa~-100kPa.

2. The preparation method according to claim 1, characterized in that, In step S1, the sour berries are fresh sour berries that are free from rot, surface damage, and impurities; the juicing is carried out using a juicer with a power of 200~300W and a juicing time of 2~5 minutes.

3. The preparation method according to claim 1, characterized in that, In step S2, the enzymatic hydrolysis is performed at a temperature of 50°C for 132 minutes, at a pH of 4.54, and the amount of the complex enzyme used is 0.32 g / L.

4. The preparation method according to claim 1, characterized in that, In step S2, The mixing ratio of pectinase to cellulase is 1.5:1; In the color-protecting agent, the amount of citric acid is 0.207% of the weight of the citric acid pulp, the amount of EDTA is 0.051% of the weight of the citric acid pulp, and the amount of tea polyphenols is 0.083% of the weight of the citric acid pulp.

5. The preparation method according to claim 1, characterized in that, In step S3, the amount of chitosan used is 0.033% of the weight of the physalin hydrolysate; the clarification time is 74 min; and the clarification temperature is 47℃.

6. The preparation method according to claim 1, characterized in that, In step S4, the vacuum concentration temperature is 55°C, and the concentration endpoint is when the soluble solids content of the slurry reaches 50 °Brix.

7. The concentrated juice of maltose syrup prepared by any one of the methods described in claims 1 to 6.

8. A compound beverage of Physalis alkekengi, characterized in that, The mixture includes raspberry juice, sucrose, sodium citrate, sodium carboxymethyl cellulose, and the concentrated physalis juice as described in claim 7; the volume ratio of the concentrated physalis juice to the raspberry juice is 2:5~10, the amount of sucrose used is 6~7% of the weight of the concentrated physalis juice, the amount of citric acid used is 0.05~0.2% of the weight of the concentrated physalis juice, and the amount of sodium carboxymethyl cellulose used is 0.1~0.3% of the weight of the concentrated physalis juice.

9. The *Physalis alkekengi* compound beverage according to claim 8, characterized in that, The mixing ratio of the ground privet concentrate to the raspberry juice is 2:8.3, the amount of sucrose used is 6.6% of the weight of the ground privet concentrate, the amount of citric acid used is 0.12% of the weight of the ground privet concentrate, and the amount of sodium carboxymethyl cellulose used is 0.2% of the weight of the ground privet concentrate.

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