Red flesh apple-pear composite cloudy juice and a preparation method thereof

Abstract

The application discloses a kind of red meat apple-pear composite turbid juice and preparation method thereof, belong to food processing production field.The preparation method includes: after cutting red meat apple piece, 0.1-0.35 g / 100mL L-cysteine is soaked 10 minutes color protection, after cutting pear piece, 0.1-0.2 g / 100mL EDTA-2Na is soaked 10 minutes color protection;After being broken and beating up respectively, filter and mix according to volume ratio 1-4:1;0.005-0.025 g / 100mL vitamin C and 0.03-0.08 g / 100mL sodium carboxymethyl cellulose are added, and after homogenization, ultra-high pressure sterilization is carried out, and it is obtained immediately.The application is prepared by the integrated application of differential color protection treatment, optimization of compounding ratio, the synergistic compounding of vitamin C and sodium carboxymethyl cellulose, and the composite turbid juice has bright color, stable system, rich nutrition, without adding exogenous sucrose, and has broad market application prospect.

Description

Technical Field

[0001] This invention belongs to the field of food processing and production, specifically relating to a red-fleshed apple-pear compound cloudy juice and its preparation method. Background Technology

[0002] Red-fleshed apples and pears are rich in various nutrients, including high-quality protein, dietary fiber, anthocyanins, polyphenols, vitamin C, vitamin E, various B vitamins, and trace elements such as potassium, calcium, and zinc. Not only do they complement each other in flavor and have a sweet taste, but they also possess excellent health benefits due to their rich content of natural antioxidants, making them a unique fruit combination with great development potential. Red-fleshed apples are brightly colored, and pears are crisp and juicy. As high-quality fruit and vegetable resources, they are currently mainly consumed fresh, with relatively few processed products. There is an urgent need to develop new compound beverages to broaden the industrial chain and increase product added value.

[0003] Red-fleshed apple-pear blended cloudy juice is a key area for its deep processing. Currently, this type of beverage faces three major challenges: First, the blended cloudy juice is prone to browning. During processing, red-fleshed apples and pears are susceptible to enzymatic and non-enzymatic browning due to factors such as temperature, oxygen, and enzyme activity. This not only damages the product's vibrant color and reduces sensory quality but also leads to the loss of active nutrients like anthocyanins and polyphenols. Second, the blended cloudy juice system has poor stability, easily exhibiting separation phenomena such as layering, sedimentation, and flocculation. This affects product uniformity and drinking experience, potentially leading to consumer skepticism about product quality. Third, fruit and vegetable blended cloudy beverages suffer from limited variety and severe flavor homogenization, lacking innovative products and failing to meet diverse market demands, thus hindering the large-scale development of the red-fleshed apple-pear blended beverage industry. These problems severely limit the industrialization and promotion of blended cloudy juice, hindering the in-depth development and utilization of specialty fruit and vegetable resources.

[0004] As living standards continue to improve, consumers are paying increasing attention to the health attributes of beverages. When making purchases, they not only focus on taste but also emphasize the health benefits of natural, low-sugar, and additive-free products. Traditional beverages on the market generally contain large amounts of sucrose, and long-term consumption of high-sugar drinks increases the risk of metabolic syndrome and other diseases. Natural, low-sugar, high-nutrition, and additive-free products have become the mainstream development trend in the beverage industry. Summary of the Invention

[0005] To address the various problems in existing technologies for processing red-fleshed apple-pear compound cloudy juice, such as insufficient browning control, difficulty in balancing stability and taste, reliance on exogenous sucrose for a single flavor, and quality damage during sterilization, this invention provides a red-fleshed apple-pear compound cloudy juice and its preparation method. Through differentiated color-protecting treatment, optimized compound ratios, synergistic compounding of stabilizers and quality improvers, and the integrated application of non-thermal sterilization technology, the aim is to prepare a compound cloudy juice with vibrant color, stable system, natural flavor, and rich nutrition, meeting consumers' demand for healthy, natural, and additive-free beverages, while simultaneously promoting the industrialization of deep processing of specialty fruits such as red-fleshed apples.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a method for preparing a red-fleshed apple-pear compound cloudy juice, comprising the following steps: (1) Cut red apples into pieces and soak them in an L-cysteine ​​aqueous solution with a concentration of (0.1-0.35) g / 100 mL for 10 minutes for color protection treatment. Cut pears into pieces and soak them in an EDTA-2Na aqueous solution with a concentration of (0.1-0.2) g / 100 mL for 10 minutes for color protection treatment. (2) The red-fleshed apples and pears after color protection treatment are crushed, pulped, and filtered to obtain red-fleshed apple juice and pear juice; (3) Mix red apple juice and pear juice at a volume ratio of (1-4):1 to obtain a composite juice base; (4) Add vitamin C at a concentration of (0.005-0.025) g / 100 mL and sodium carboxymethyl cellulose at a concentration of (0.03-0.08) g / 100 mL to the composite turbid juice base, stir evenly and then perform homogenization treatment; (5) The homogenized compound turbid juice was sterilized under ultra-high pressure to obtain red-fleshed apple-pear compound turbid juice.

[0007] The red-fleshed apple-pear compound cloudy juice of the present invention is made by adding pear juice to red-fleshed apple juice, which enriches the taste of the beverage and increases the nutritional value of the product.

[0008] Preferably, the preparation method includes the following steps: (1) Cut red apples into pieces and soak them in a 0.25 g / 100 mL L-cysteine ​​aqueous solution for 10 minutes for color protection treatment. Cut pears into pieces and soak them in a 0.15 g / 100 mL EDTA-2Na aqueous solution for 10 minutes for color protection treatment. (2) The red-fleshed apples and pears after color protection treatment are crushed, pulped, and filtered to obtain red-fleshed apple juice and pear juice; (3) Mix red apple juice and pear juice at a volume ratio of 2:1 to obtain a composite juice base; (4) Add vitamin C at a concentration of 0.015 g / 100 mL and sodium carboxymethyl cellulose at a concentration of 0.07 g / 100 mL to the composite turbid juice base, stir evenly and then homogenize. (5) The homogenized compound turbid juice was sterilized under ultra-high pressure to obtain red-fleshed apple-pear compound turbid juice.

[0009] The filtration in step (2) uses an 80-100 mesh screen; the homogenization process in step (4) is carried out at a pressure of 20-25 MPa.

[0010] The ultra-high pressure sterilization process in step (5) is performed at a pressure of 400-600 MPa, a holding time of 4-6 minutes, and a temperature of 20-30℃.

[0011] In a second aspect, the present invention provides the application of the above-described method in improving the suspension stability and / or browning inhibition rate of turbid juice.

[0012] In a third aspect, the present invention provides a method for improving the suspension stability and browning inhibition rate of red-fleshed apple-pear composite turbid juice, comprising the steps of the above-described preparation method.

[0013] In a fourth aspect, the present invention provides a red-fleshed apple-pear composite cloudy juice, which is prepared by the above method.

[0014] Compared with the prior art, the present invention has the following beneficial effects: (1) This invention employs differentiated color-protecting treatment schemes targeting the different browning mechanisms of red-fleshed apples and pears: red-fleshed apples are soaked in 0.25 g / 100 mL L-cysteine ​​for 10 minutes, and pears are soaked in 0.15 g / 100 mL EDTA-2Na for 10 minutes. This differentiated color-protecting strategy overcomes the shortcomings of a single color-protecting agent in taking into account the two raw materials, effectively inhibiting both enzymatic and non-enzymatic browning, significantly reducing the browning degree of cloudy juice, and maintaining the bright color of the product.

[0015] (2) This invention optimizes the mixing ratio of red apple juice and pear juice, determining that a volume ratio of 2:1 is the optimal ratio. At this ratio, the sweet flavor of the pear juice perfectly balances the tartness of the red apple, achieving a pleasantly sweet and sour flavor without the need for added exogenous sucrose, which aligns with the healthy consumption trend of "natural, low-sugar, and additive-free".

[0016] (3) This invention is the first to apply sodium carboxymethyl cellulose (CMC) and vitamin C in combination to red apple-pear compound cloudy juice, and the two produce a significant synergistic effect: the combined use increases the suspension stability by 58 percentage points (from 32% to 90%), which is greater than the sum of the individual increases (38+14=52 percentage points); the browning inhibition rate (87%) is greater than the sum of the individual inhibition rates (22%+61%=83%); and the anthocyanin retention rate (92%) is significantly better than that of CMC alone (53%) or vitamin C alone (71%). This compounding scheme achieves a simultaneous improvement in physical and chemical stability, realizing a technical effect of 1+1>2.

[0017] (4) The preparation method provided by the present invention is simple in process, clear in parameters, and easy to industrialize. It makes full use of the characteristic resources of red apples and pears, provides a new technical path for the deep processing of red apples, and has broad market application prospects. Attached Figure Description

[0018] Figure 1 The effect of L-cysteine ​​on the color-preserving effect of cloudy juice from red-fleshed apples.

[0019] Figure 2 The effect of the ratio of red-fleshed apple turbid juice to pear turbid juice on the sensory quality of red-fleshed apple-pear composite turbid juice.

[0020] Figure 3 The effect of CMC concentration on the stability of red-fleshed apple-pear complex turbid juice.

[0021] Figure 4 Effects of vitamin C content on the sensory quality of red-fleshed apple-pear compound cloudy juice. Detailed Implementation

[0022] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0023] The specific embodiments of the present invention will be described in further detail below with reference to examples. The following detailed descriptions are illustrative and intended to provide further explanation of this application, rather than limiting the scope of the invention.

[0024] The raw materials used in the examples are: red-fleshed apples; pears (Akizuki pears); L-cysteine, EDTA-2Na, sodium carboxymethyl cellulose (CMC), and vitamin C (Vc), all of which are food grade.

[0025] Example 1: Optimization Experiment of Key Process Parameters 1. Screening of color-protecting agent (L-cysteine) concentration in red-fleshed apples Wash, core, and cut fresh red-fleshed apples into pieces. Soak them in L-cysteine ​​aqueous solutions with concentrations of 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, and 0.35% (w / v) at room temperature for 10 minutes. Use the non-color-protecting treatment (0%) as a blank control.

[0026] After the color-protecting treatment, the red-fleshed apple chunks are crushed, pulped, and filtered to obtain red-fleshed apple juice.

[0027] The turbid juice was stored at 4°C in the dark for 7 days, and the browning degree (OD) was measured. 420 The higher the degree of browning, the more severe the browning.

[0028] The test results showed that as the L-cysteine ​​concentration increased from 0.1% to 0.25%, the absorbance value continuously decreased, indicating a gradual increase in color-protecting effect. The absorbance value reached its lowest point at 0.25%, representing the optimal color-protecting effect. When the concentration continued to increase to 0.3%, the absorbance value increased instead of decreasing, and further increased at 0.35%. This "decreasing then increasing" trend indicates that there is an optimal concentration window for L-cysteine's color-protecting effect on red-fleshed apples. Too low a concentration results in insufficient color protection; too high a concentration may produce new color substances or promote non-enzymatic browning due to the chemical properties of L-cysteine ​​itself (such as the oxidation of sulfhydryl groups or interactions with other components), thus weakening the color-protecting effect. Therefore, 0.25% was determined to be the optimal color-protecting concentration of L-cysteine. Figure 1 ).

[0029] 2. Screening of the blending ratio of red apple cloudy juice and pear cloudy juice Red-fleshed apples were treated with 0.25% (w / v) L-cysteine ​​aqueous solution and pears were treated with 0.15% (w / v) EDTA-2Na aqueous solution, as determined in Experiment 1, to prepare cloudy juices of red-fleshed apples and pears, respectively.

[0030] Pear juice and red apple juice were mixed in volume ratios of 2:1, 1:1, 1:2, 1:3, and 1:4, respectively.

[0031] Twenty trained sensory evaluators conducted sensory evaluations of the product's color, aroma, taste, and overall acceptability.

[0032] The results showed that the highest overall sensory score was achieved when the ratio of pear juice to red apple juice was 1:2. At this ratio, the vibrant color of the red apple was fully displayed, and the sweet flavor of the pear juice perfectly balanced the tartness of the red apple, resulting in a pleasantly sweet and sour taste with harmonious flavors. Therefore, a ratio of 1:2 for pear juice to red apple juice was determined to be the optimal blending ratio. Figure 2 ).

[0033] 3. Screening of sodium carboxymethyl cellulose (CMC) addition amount Prepare red-fleshed apple-pear mixed cloudy juice under the optimal conditions determined in Experiments 1 and 2 (the ratio of pear cloudy juice to red-fleshed apple cloudy juice is 1:2).

[0034] Add 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, and 0.08% (w / v) of CMC respectively.

[0035] After homogenization, the turbid juice was allowed to stand at 4°C for 14 days, and the suspension stability (%) was determined. The method for determining suspension stability was as follows: a certain amount of turbid juice was placed in a centrifuge tube and centrifuged at 3000 rpm for 10 minutes. The percentage of the height of the suspended layer to the total liquid surface was measured after centrifugation. The higher the suspension stability, the more stable the system is and the less likely it is to separate into layers and precipitate.

[0036] Depend on Figure 3 As can be seen, the suspension stability continuously increased with the increase of CMC addition from 0.03% to 0.07%, indicating that CMC has a significant effect on stabilizing the suspension of the complex turbid juice. When the addition was further increased to 0.08%, the suspension stability decreased slightly. Therefore, 0.07% was determined to be the optimal addition amount of CMC.

[0037] 4. Screening of Vitamin C (Vc) Addition Amount The composite cloudy juice was prepared according to the aforementioned optimal conditions (color protection 0.25% L-cysteine ​​+ 0.15% EDTA-2Na, the ratio of pear cloudy juice to red apple cloudy juice was 1:2, CMC 0.07%).

[0038] Add 0.005%, 0.010%, 0.015%, 0.020%, and 0.025% (w / v) of vitamin C respectively.

[0039] Twenty sensory evaluators scored the product’s color, aroma, taste, and overall acceptability.

[0040] The scoring results show that Vitamin C not only has antioxidant and color-protecting effects, but also regulates the sweet and sour taste of the complex cloudy juice. When the Vitamin C addition amount is 0.015%, the overall sensory score is the highest, with vibrant color, rich aroma, and a balanced sweet and sour taste. Too low an addition amount (<0.010%) results in insufficient acidity and a bland flavor; too high an addition amount (>0.020%) results in excessive acidity, masking the natural flavor of the fruit. Therefore, 0.015% is determined to be the optimal addition amount of Vitamin C. Figure 4 ).

[0041] Example 2: Preparation of red-fleshed apple-pear compound cloudy juice (1) Select fully ripe, fresh, free from mold, insect holes, abnormal flavor, and uniform and plump red-fleshed apples and pears, and wash them repeatedly with running drinking water to remove surface dirt and residue.

[0042] (2) Quickly remove the core from the washed red apple and cut it into pieces about 1-2 cm thick. 3 Immediately immerse the small pieces in a 0.25% (w / v) L-cysteine ​​aqueous solution until completely submerged, and soak at room temperature for 10 minutes. After soaking, drain off the surface liquid.

[0043] Quickly remove the core from the washed pear and cut it into pieces about 1-2 cm in size. 3 Immediately immerse the small pieces in a 0.15% (w / v) EDTA-2Na (disodium ethylenediaminetetraacetate) aqueous solution until completely submerged, and soak at room temperature for 10 minutes. After soaking, drain off the surface liquid.

[0044] (3) The red-fleshed apple pieces and pear pieces after color protection treatment are crushed and pulped to obtain coarse red-fleshed apple juice and coarse pear juice respectively. The coarse red-fleshed apple juice and coarse pear juice are filtered through an 80-100 mesh sieve to remove fruit residue and obtain fine and uniform red-fleshed apple juice and pear juice.

[0045] (4) Mix the red apple juice and pear juice thoroughly at a volume ratio of 2:1 to obtain a composite juice base.

[0046] (5) Add 0.015% (w / v) vitamin C and 0.07% (w / v) carboxymethyl cellulose (CMC) to the compound turbid juice base and stir evenly. Homogenize under 25 MPa pressure to further refine the pulp particles and improve the stability of the system.

[0047] (6) The homogenized compound turbid juice is filled into sealed containers and sterilized using ultra-high pressure (HPP) technology: processing pressure 500 MPa, holding time 5 minutes, and temperature controlled at 25℃. After sterilization, the final product is obtained - red-fleshed apple-pear compound turbid juice.

[0048] Comparative Example 1: No Differentiation in Color Protection Treatment The difference from Example 2 is that after mixing red-fleshed apples and pears, they are soaked in 0.25% L-cysteine ​​color-protecting solution for 10 minutes, and the remaining steps are the same as in Example 2.

[0049] Testing revealed that the final product showed obvious browning within 24 hours of sterilization, with a decrease in L value (brightness), a significant reduction in a value (redness), and an anthocyanin retention rate of 75%.

[0050] The sweet flavor of the pear is slightly affected by L-cysteine, resulting in a faint sulfurous taste.

[0051] Comparative Example 2: CMC used alone (without Vitamin C) The difference from Example 2 is that only 0.015% Vc is added, and CMC is not added. The remaining steps are the same as in Example 2.

[0052] Comparative Example 3: VC used alone in a conventional manner (without CMC) The difference from Example 2 is that only 0.07% CMC is added, and no Vc is added; the rest of the steps are the same as in Example 2.

[0053] Comparative Example 4: The difference from Example 2 is that CMC and Vc are not added, but the rest of the steps are the same as in Example 2.

[0054] Experimental Example 1: The browning inhibition rate, suspension stability, and anthocyanin retention rate of the red-fleshed apple-pear composite turbid juice prepared in Example 2 and Comparative Examples 2-4 were tested. Among them: Browning inhibition rate: Using Comparative Example 4 (without CMC and without Vc) as a blank control, the browning inhibition rate of each group relative to the blank control was calculated. Browning degree is expressed as OD. 420 The browning inhibition rate (%) is expressed as: (OD) 420 Blank - OD 420 (sample) / OD 420 100% blank.

[0055] Suspension stability: determined according to the method described in Example 1, expressed as the percentage of the height of the suspended layer to the total liquid surface height after centrifugation at 3000 rpm for 10 minutes.

[0056] Anthocyanin retention rate (%) = (Anthocyanin content in the sample after storage / Initial anthocyanin content) × 100% The test results are shown in Table 1.

[0057] Table 1: Effects of different treatments on the quality of red-fleshed apple-pear blended turbid juice As shown in Table 1, compared with the blank control (Comparative Example 4), adding CMC alone (Comparative Example 2) can improve the suspension stability by 38 percentage points (from 32% to 70%), and adding Vc alone (Comparative Example 3) can improve the suspension stability by 14 percentage points (from 32% to 46%), with the sum of the individual improvements being 52 percentage points; while the combination of CMC and Vc (Example 2) can improve the suspension stability by 58 percentage points (from 32% to 90%), and the combined improvement is significantly greater than the sum of the individual improvements, indicating that the two have a synergistic effect in improving the physical stability of the system.

[0058] Regarding browning inhibition, CMC alone had a browning inhibition rate of 22%, and Vc alone had a rate of 61%, with the sum of the two being 83%. The browning inhibition rate of the combination was as high as 87%, which was also higher than the sum of the two, further confirming the existence of a synergistic effect.

[0059] Regarding anthocyanin retention, CMC alone increased the retention rate by 18 percentage points (from 35% to 53%), and Vitamin C alone increased it by 36 percentage points (from 35% to 71%), with the sum of their individual increases being 54 percentage points. The combined use of CMC and Vitamin C increased the retention rate by 57 percentage points (from 35% to 92%), indicating that the combination of CMC and Vitamin C can achieve a better protective effect than either of them alone.

[0060] Therefore, the combination of CMC and Vc in this invention is not a simple superposition of functions, but rather a comprehensive improvement in the quality of the compound turbid juice through the synergy of physical stability and chemical protection.

[0061] The above description is merely a preferred embodiment of this application and is not intended to limit the application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications made within the spirit and principles of this application are not permitted. Equivalent substitutions and improvements should all be included within the scope of protection of this application.

Claims

1. A method for preparing a red-fleshed apple-pear composite cloudy juice, characterized in that, Includes the following steps: (1) Cut red apples into pieces and soak them in an L-cysteine ​​aqueous solution with a concentration of (0.1-0.35) g / 100 mL for 10 minutes for color protection treatment. Cut pears into pieces and soak them in an EDTA-2Na aqueous solution with a concentration of (0.1-0.2) g / 100 mL for 10 minutes for color protection treatment. (2) After color protection treatment, the red-fleshed apples and pears are crushed, pulped, and filtered to obtain red-fleshed apple juice and pear juice. (3) Mix red apple juice and pear juice at a volume ratio of (1-4):1 to obtain a composite juice base; (4) Add vitamin C at a concentration of (0.005-0.025) g / 100 mL and sodium carboxymethyl cellulose at a concentration of (0.03-0.08) g / 100 mL to the composite turbid juice base, stir evenly and then perform homogenization treatment; (5) The homogenized compound turbid juice was sterilized under ultra-high pressure to obtain red-fleshed apple-pear compound turbid juice.

2. The preparation method according to claim 1, characterized in that, Includes the following steps: (1) Cut red apples into pieces and soak them in a 0.25 g / 100 mL L-cysteine ​​aqueous solution for 10 minutes for color protection treatment. Cut pears into pieces and soak them in a 0.15 g / 100 mL EDTA-2Na aqueous solution for 10 minutes for color protection treatment. (2) The red-fleshed apples and pears after color protection treatment are crushed, pulped, and filtered to obtain red-fleshed apple juice and pear juice; (3) Mix red apple juice and pear juice at a volume ratio of 2:1 to obtain a composite juice base; (4) Add vitamin C at a concentration of 0.015 g / 100 mL and sodium carboxymethyl cellulose at a concentration of 0.07 g / 100 mL to the composite turbid juice base, stir evenly and then homogenize. (5) The homogenized compound turbid juice was sterilized under ultra-high pressure to obtain red-fleshed apple-pear compound turbid juice.

3. The preparation method according to claim 1, characterized in that, The filtration in step (2) uses an 80-100 mesh screen; the homogenization process in step (4) is carried out at a pressure of 20-25 MPa.

4. The preparation method according to claim 1, characterized in that, The ultra-high pressure sterilization process in step (5) is performed at a pressure of 400-600 MPa, a holding time of 4-6 minutes, and a temperature of 20-30℃.

5. The application of the method according to any one of claims 1-4 in improving the suspension stability and / or browning inhibition rate of turbid juice.

6. A method for improving the suspension stability and browning inhibition rate of red-fleshed apple-pear composite turbid juice, characterized in that, This includes the preparation method described in any one of claims 1-4.

7. A red-fleshed apple-pear composite cloudy juice, characterized in that, The red-fleshed apple-pear composite turbid juice is prepared by the method described in any one of claims 1-4.

Images