Preparation method of stir-fried gualou seed with improved storage quality based on extract of leaves of soursop

Abstract

The application provides a preparation method of stir-fried gualouzi with improved storage quality based on a leaf extract of Bacopa monnieri, and relates to the field of food. The preparation method comprises the steps of steam pretreatment, microwave enzyme inactivation, composite antioxidant treatment, stir-frying, cooling and vacuum deoxygenation packaging. The application adopts a comprehensive preservation method, which comprises three means of steam-microwave enzyme inactivation, smearing of natural antioxidants and vacuum deoxygenation packaging, and establishes a multiple protection system from enzyme activity inhibition, oxidation reaction blocking to external oxygen isolation, thereby establishing a comprehensive quality protection measure for the stir-fried gualouzi product. Through the above three means, which are connected and supplemented to each other, the shelf life of the product is significantly prolonged on the basis of ensuring food safety, and the storage quality is effectively improved. The application breaks through the limitation of a single preservation method, provides an effective solution for prolonging the shelf life of stir-fried gualouzi and maintaining the flavor and nutritional value thereof, and has important popularization and application value.

Description

Technical Field

[0001] This invention relates to the food industry, specifically to a method for preparing roasted Trichosanthes kirilowii seeds based on Sacha indica leaf extract to improve storage quality. Background Technology

[0002] Trichosanthes seeds ( Trichosanthes kirilowii The seed is a type of Trichosanthes kirilowii that can be used to process snack foods. Trichosanthes kirilowii Maxim ) and double-sided Trichosanthes kirilowii ( T.rosthornii Harms The mature seeds of Trichosanthes kirilowii can be processed into roasted seeds, traditionally known as fried nuts and seeds. In recent years, the market share of nuts and seeds has continued to grow, and consumers have placed higher demands on their quality. Trichosanthes kirilowii seeds are rich in oil and protein, with an oil content as high as 50% to 60%, of which unsaturated fatty acids account for more than 90%. Notably, Trichosanthes kirilowii seeds also contain a rare polyunsaturated fatty acid—cucurbitacinic acid, with a structure of octadecanoic acid (9,11,13 cis-trans-cis conjugated structure). However, the high unsaturated fatty acid content of Trichosanthes kirilowii seeds makes them prone to rancidity during processing and storage, leading to a rancid taste, flavor deterioration, and a decline in nutritional value, severely limiting their shelf life. Therefore, developing efficient preservation technologies is a key prerequisite for promoting the industrialization of roasted Trichosanthes kirilowii seed processing.

[0003] However, products rich in unsaturated fatty acids, such as roasted trichosanthes seeds, generally face the following challenges in preservation: First, single preservation methods are insufficient to address the complex oxidative rancidity pathways, resulting in limited and short-lived preservation effects; second, over-reliance on synthetic antioxidants contradicts market demands for health benefits; and finally, the lack of a comprehensive preservation solution across the entire supply chain, from processing to packaging, leads to unstable product storage quality and a short shelf life. Existing technologies include roasting processes for trichosanthes seeds, but these primarily focus on imparting a specific flavor through soaking in broth, neglecting the seed's shelf life and storage quality.

[0004] Therefore, how to effectively extend the shelf life of roasted Trichosanthes kirilowii seeds and improve their storage quality has become an urgent problem to be solved by those skilled in the art. Summary of the Invention

[0005] The purpose of this invention is to overcome the defect that roasted Trichosanthes kirilowii seeds are prone to oxidation and rancidity, resulting in a rancid taste. By combining steam-microwave enzyme inactivation, treatment with compound natural antioxidants, and vacuum deoxygenation packaging, a comprehensive preservation method is developed to improve the preservation effect of roasted Trichosanthes kirilowii seeds through their synergistic effect. This provides a preparation method that effectively extends the shelf life of roasted Trichosanthes kirilowii seeds and improves their storage quality.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] In a first aspect, the present invention provides a method for preparing roasted Trichosanthes kirilowii seeds with improved storage quality based on Sacha indica leaf extract, comprising the following steps: S1. The seeds of Trichosanthes kirilowii are first steam-pretreated, then microwave-sterilized to remove enzymes, and then cooled to room temperature; S2. Dissolve rosemary extract and sacha in water to prepare a composite antioxidant solution. Apply the composite antioxidant solution evenly to the surface of the Trichosanthes kirilowii seeds obtained in step S1 and dry. S3. Stir-fry the Trichosanthes kirilowii seeds obtained in step S2 and then cool them. S4. Place the roasted Trichosanthes seeds obtained in step S3 together with the deoxidizer in a packaging bag and vacuum pack them.

[0008] Furthermore, in step S1, the Trichosanthes seeds are screened before steam pretreatment to remove bad seeds.

[0009] Further, in step S1, the steam pretreatment conditions are: steam temperature of 70~95 ℃ and time of 3~8 min; preferably, steam temperature of 90~95 ℃ and time of 5~7 min; more preferably, steam temperature of 90 ℃ and time of 5 min.

[0010] Further, in step S1, the microwave enzyme inactivation conditions are: power of 600~1000 W, frequency of 2200~2600 MHz, and time of 10~40 s; preferably, power of 800~900 W, frequency of 2450~2600 MHz, and time of 20~30 s; more preferably, power of 800 W, frequency of 2450 MHz, and time of 20 s.

[0011] Furthermore, in step S2, the mass ratio of rosemary extract to sacha inca leaf extract is 1~2:1, preferably 1~1.5:1, and more preferably 1.5:1.

[0012] Further, in step S2, based on the mass of Trichosanthes kirilowii seeds, the amount of rosemary extract is 0.2~0.5 g / kg, and the amount of Sacha inchi leaf extract is 0.1~0.4 g / kg; preferably, the amount of rosemary extract is 0.3~0.4 g / kg, and the amount of Sacha inchi leaf extract is 0.2~0.3 g / kg; more preferably, the amount of rosemary extract is 0.3 g / kg, and the amount of Sacha inchi leaf extract is 0.2 g / kg.

[0013] Furthermore, in step S2, the amount of water added is 5% to 6% of the mass of the Trichosanthes kirilowii seeds, preferably 5.5% to 6%, and more preferably 6%.

[0014] Furthermore, in step S2, the drying temperature is 25~35 ℃, preferably 30~35 ℃, and more preferably 30 ℃.

[0015] Furthermore, in step S2, the Sacha indica leaf extract is a water extract of Sacha indica leaves.

[0016] Furthermore, the preparation method of the Sacha indica leaf extract includes the following steps: taking Sacha indica leaves, washing them, adding water, extracting them by stirring in a boiling water bath, separating the solid and liquid, filtering the separated extract, and freeze-drying the obtained filtrate to obtain the Sacha indica leaf extract.

[0017] Furthermore, the ratio of Sacha involucrata leaves to water, expressed in g / mL, is 1:10 to 30, preferably 1:20 to 22, and more preferably 1:20.

[0018] Furthermore, the boiling water bath extraction time is 2 to 4 hours, preferably 3 to 4 hours, and more preferably 3 hours.

[0019] Further, the solid-liquid separation conditions are: centrifugation at 3000–5000 rpm for 10–20 min; preferably, centrifugation at 4000–4500 rpm for 15–18 min; more preferably, centrifugation at 4000 rpm for 15 min.

[0020] Further, a microporous membrane with a pore size of 0.20 to 0.45 μm is used for filtration; preferably, a microporous membrane with a pore size of 0.30 to 0.45 μm is used for filtration; more preferably, a microporous membrane with a pore size of 0.45 μm is used for filtration.

[0021] Further, the freeze-drying conditions are: temperature -60 to -30 ℃, time 24 to 72 h; preferably, temperature -48 to -40 ℃, time 48 to 52 h; more preferably, temperature -48 ℃, time 48 h.

[0022] Furthermore, the freeze-dried Sacha indica leaf extract is stored at 2–8 °C; preferably, the freeze-dried Sacha indica leaf extract is stored at 4–6 °C; more preferably, the freeze-dried Sacha indica leaf extract is stored at 4 °C.

[0023] Further, in step S3, the Trichosanthes kirilowii seeds and roasted sand are mixed at a mass ratio of 1 to 2:1 and then roasted; preferably, the Trichosanthes kirilowii seeds and roasted sand are mixed at a mass ratio of 1.5 to 2:1 and then roasted; more preferably, the Trichosanthes kirilowii seeds and roasted sand are mixed at a mass ratio of 1.5:1 and then roasted.

[0024] Further, in step S3, the frying temperature is 140~180 ℃ and the frying time is 30~50 min; preferably, the frying temperature is 160~170 ℃ and the frying time is 30~40 min; more preferably, the frying temperature is 160 ℃ and the frying time is 40 min.

[0025] Furthermore, in step S3, the Trichosanthes seeds are immediately separated from the fried sand after the frying is completed.

[0026] Furthermore, in step S3, after the roasting is completed, the Trichosanthes seeds are spread out to cool.

[0027] Furthermore, in step S4, the deoxidizer is an iron-based deoxidizer.

[0028] Further, in step S4, the mass ratio of the deoxidizer to the roasted Trichosanthes kirilowii seeds is 2:70~150, preferably 2:100~120, and more preferably 2:100.

[0029] Further, in step S4, the vacuum packaging conditions are: pressure of 0.05~0.25 MPa, evacuation time of 10~15 s, and cooling time after heat sealing of 1~5 s; preferably, pressure of 0.10~0.20 MPa, evacuation time of 10~13 s, and cooling time after heat sealing of 3~4 s; more preferably, pressure of 0.10 MPa, evacuation time of 13 s, and cooling time after heat sealing of 3 s.

[0030] Secondly, the present invention provides roasted Trichosanthes kirilowii seeds obtained according to the preparation method described above.

[0031] This invention employs a comprehensive preservation method in the preparation of roasted Trichosanthes kirilowii seeds, combining steam-microwave enzyme inactivation, treatment with compound natural antioxidants, and vacuum deoxygenation packaging. First, in the raw material pretreatment stage, enzyme inactivation is key to inhibiting enzymatic oxidation. Microwave enzyme inactivation, as a highly efficient heat treatment method, can rapidly and uniformly inactivate endogenous enzymes such as lipases by causing vigorous molecular movement and heat generation within the material, offering a high potential advantage. However, for high-fat materials like Trichosanthes kirilowii seeds, microwave treatment alone can easily lead to localized oxidation of unsaturated fatty acids or scorching of the seed surface due to excessively high localized instantaneous temperature rises, affecting the product's color and flavor. Steam treatment can provide a mild and uniform humid heat environment, which is beneficial for the uniform denaturation of enzyme proteins, but its use alone often requires a long time and consumes a lot of energy. This invention combines steam pretreatment with microwave enzyme inactivation, utilizing the synergistic effect of its humid heat and rapid volumetric heating to efficiently and gently inactivate enzymes in Trichosanthes kirilowii seed raw materials.

[0032] Secondly, applying a compound natural antioxidant before roasting is an effective strategy to combat the oxidation of oils in Trichosanthes kirilowii seeds. Compared to synthetic antioxidants such as tert-butylhydroquinone (TBHQ), butylated hydroxytoluene (BHT), and butylated hydroxyanisole (BHA), using natural antioxidants such as rosemary extract is more in line with health-conscious consumer trends. The scientific compounding of rosemary extract and Sacha indica leaf extract can leverage the synergistic effect of different components to enhance antioxidant efficacy. To date, how to screen and construct highly efficient compound natural antioxidants for Trichosanthes kirilowii seeds, a raw material rich in cucurbitacin and other special unsaturated fatty acids, remains a research gap. Sacha indica, a perennial woody vine of the Euphorbiaceae family, contains abundant polyphenols, flavonoids, saponins, and other active substances in its leaf water extract, exhibiting certain antioxidant potential. Currently, there are no research reports on its application in roasting Trichosanthes kirilowii seeds, a food with a special oil system rich in high levels of unsaturated fatty acids, to improve its storage stability.

[0033] Third, packaging technology is the last line of defense in preventing external oxygen, moisture, and light from entering the product, ensuring its storage quality. Compared to ordinary packaging, vacuum packaging effectively removes most of the oxygen inside the packaging. Furthermore, introducing an oxygen absorber further adsorbs residual oxygen and oxygen that slowly seeps in later, creating a dynamic and continuous ultra-low oxygen environment, which theoretically can delay oxidation to the greatest extent. Currently, most roasted Trichosanthes kirilowii seed products on the market use ordinary packaging, whose oxygen-barrier effect cannot meet the needs of long-term storage.

[0034] The technical solution of this invention has the following advantages: The method for preparing roasted Trichosanthes kirilowii seeds provided by this invention employs comprehensive preservation measures during the preparation process. It utilizes a combination of steam-microwave enzyme inactivation, application of natural antioxidants (rosemary extract and Sacha indica leaf extract), and vacuum deoxygenation packaging to construct a multi-layered protection system that inhibits enzyme activity, blocks oxidation reactions, and isolates external oxygen. This establishes a comprehensive quality protection measure for roasted Trichosanthes kirilowii seed products. First, the use of saturated steam pretreatment combined with microwave enzyme inactivation can quickly and uniformly deactivate the enzymes inside the Trichosanthes kirilowii seeds that are prone to spoilage. Second, the application of a natural antioxidant composed of rosemary extract and Sacha indica leaf extract effectively neutralizes free radicals that can cause rancidity of oils during storage through the synergistic effect of multiple components, continuously protecting the quality of the Trichosanthes kirilowii seeds. Finally, the vacuum packaging with an oxygen absorber not only removes most of the air inside the bag, but the oxygen absorber also continuously absorbs residual and subsequently introduced trace amounts of oxygen, creating a near-oxygen-free environment. By employing these three interconnected and complementary methods, the rancidity of roasted Trichosanthes kirilowii seeds can be effectively prevented from different levels. This significantly slows down the rise in key oxidation indicators such as peroxide value, acid value, and malondialdehyde, effectively maintains the stability of fatty acid value and moisture content, and preserves the crisp texture and rich nutrition for a long time. Ultimately, while ensuring food safety, this significantly extends the shelf life of the product and effectively improves its storage quality.

[0035] This invention overcomes the limitations of single preservation methods and provides an effective solution for extending the shelf life of roasted Trichosanthes kirilowii seeds and maintaining their flavor and nutritional value, and has important promotion and application value. Attached Figure Description

[0036] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0037] Figure 1 This is a comparison chart of the changes in POV of roasted Trichosanthes kirilowii seeds under different treatments in Experiment Example 2 of this invention over 20 days; Figure 2 This is a comparison chart of the changes in AV of roasted Trichosanthes kirilowii seeds under different treatments over 20 days in Experimental Example 2 of this invention; Figure 3 This is a comparison chart showing the changes in fatty acid values ​​of roasted Trichosanthes kirilowii seeds under different treatments over 20 days in Experimental Example 2 of this invention; Figure 4 This is a comparison chart showing the changes in moisture content of roasted Trichosanthes kirilowii seeds under different treatments over 20 days in Experimental Example 2 of this invention.

[0038] Note: Figures 1-4 Different letters indicate significant differences between groups (P < 0.05), while identical or overlapping letters indicate no significant differences between groups. Detailed Implementation

[0039] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.

[0040] The Sacha involucrata leaf extract used in the examples and comparative examples was prepared according to the following steps: Sacha involucrata leaves were washed and water was added at a material-to-liquid ratio of 1:20 (w / v, i.e., g / mL). The extract was stirred in a boiling water bath for 3 h. The extract was then centrifuged at 4000 rpm for 15 min. The supernatant was filtered through a 0.45 μm microporous membrane. The filtrate was freeze-dried at -48 ℃ for 48 h and stored at 4 ℃ for later use.

[0041] Where specific experimental steps or conditions are not specified in the embodiments, they can be performed according to the conventional experimental steps or conditions described in the literature in this field. All raw materials or instruments used are commercially available conventional products, including but not limited to those used in the embodiments of this application.

[0042] Example 1 This embodiment provides a method for preparing roasted Trichosanthes kirilowii seeds, the specific steps of which are as follows: S1. Preliminary screening of raw materials and steam-microwave enzyme inactivation: Trichosanthes seeds are preliminarily screened to remove unqualified seeds. The screened Trichosanthes seeds are placed in a portable high-pressure steam sterilizer (DSX-24L-I, Shanghai Shenan Medical Instrument Factory) and treated with saturated steam at 90℃ for 5 min. Immediately afterwards, the pre-treated Trichosanthes seeds are transferred to a microwave oven (G80F23CN1L-SD(S0), Guangdong Galanz Microwave Oven Appliances Manufacturing Co., Ltd.) and treated with 800 W power and 2450 MHz frequency for 20 s to inactivate enzymes. After microwave enzyme inactivation, the Trichosanthes seeds are spread out to cool to room temperature. S2. Application and drying of compound antioxidant: Based on the mass of the screened Trichosanthes kirilowii seeds, weigh 0.3 g / kg of rosemary extract and 0.2 g / kg of Sacha indica leaf extract, dissolve them in water (the amount of water added is 6% of the mass of the screened Trichosanthes kirilowii seeds) to prepare a compound antioxidant solution, and evenly spray and apply the compound antioxidant solution to the surface of the Trichosanthes kirilowii seeds treated in step S1 to ensure that the surface of the seeds is fully covered. Then, place the treated Trichosanthes kirilowii seeds in a 30 ℃ hot air oven until the surface is dry. S3, Sand Roasting and Cooling: The Trichosanthes seeds processed in step S2 are mixed with clean roasting sand (roasting sand for roasting) preheated to 160 ℃ at a mass ratio of 1.5:1. The mixture is then roasted continuously at 160 ℃ for 40 minutes on a multi-functional induction cooker (C21-WK2102, Guangdong Midea Home Appliances Manufacturing Co., Ltd.). During the roasting process, the mixture is turned at a constant speed to ensure even heating. After roasting, the Trichosanthes seeds are immediately sieved to separate them from the roasting sand. The roasted Trichosanthes seeds are then quickly spread out and cooled to room temperature. S4. Packaging: The roasted Trichosanthes seeds processed in step S3 are screened a second time to remove defective products such as cracked or burnt seeds. 200 g of qualified product is weighed and placed together with 4 g of iron-based deoxidizer into a packaging bag. A vacuum packaging machine (DZQ400-1D, Shanghai Sanlian Packaging Machinery Co., Ltd.) is used to evacuate air for 13 s under a vacuum pressure of 0.1 MPa, followed by heat sealing for 3 s to complete the packaging.

[0043] Comparative Example 1 This comparative example provides a method for preparing roasted Trichosanthes kirilowii seeds. The specific steps are the same as in Example 1, except that in step S2, 0.2 g / kg of Sacha indica leaf extract is replaced with 0.2 g / kg of tea polyphenols.

[0044] Comparative Example 2 This comparative example provides a method for preparing roasted Trichosanthes kirilowii seeds. The specific steps are the same as in Example 1, except that the steam pretreatment and microwave enzyme inactivation steps are omitted in step S1.

[0045] Comparative Example 3 This comparative example provides a method for preparing roasted Trichosanthes kirilowii seeds. The specific steps are the same as in Example 1, except that step S2 is omitted.

[0046] Comparative Example 4 Commercially available roasted Trichosanthes kirilowii seeds (manufacturer: Anhui Youyu Kuayue Food Development Co., Ltd.) are produced using uninactivated enzymes, without added antioxidants, and in ordinary packaging.

[0047] Experimental Example 1: Antioxidant Activity of Compound Antioxidants I. Experimental Objective The purpose of this experiment is to compare the preservation effects of different combinations of compound antioxidants on Trichosanthes kirilowii seeds.

[0048] Peroxide value (POV) and acid value (AV) are core indicators for assessing the quality of oils and fats. POV reflects the initial degree of oxidation of oils and fats; its products further decompose, leading to rancidity and flavor degradation. AV reflects the degree of hydrolytic rancidity of oils and fats, measuring the content of free fatty acids. These two indicators are closely related to the cracking and oxidative stability of oils and fats, and are key parameters for evaluating the deterioration of oil and fat quality.

[0049] Trichosanthes kirilowii seeds are rich in oil, with unsaturated fatty acids accounting for over 90%. During storage, they are highly susceptible to lipid rancidity, leading to increased POV and AV and a decline in quality. This is a key issue restricting the development of its products. To verify the antioxidant efficacy of a compound antioxidant on Trichosanthes kirilowii seeds, an accelerated oxidation experiment was conducted using pure oil extracted from the seeds. This method eliminates interference from other components such as protein and cellulose in the seeds, thus providing a more sensitive and direct reflection of the effect of the antioxidant formulation on lipid rancidity.

[0050] II. Experimental Methods Five groups of Trichosanthes seed oil samples were prepared for the experiment, each supplemented with a compound antioxidant: Group A (0.3 g / kg rosemary extract + 0.2 g / kg sacha indica leaf extract), Group B (0.3 g / kg rosemary extract + 0.2 g / kg tea polyphenols), Group C (0.3 g / kg rosemary extract + 0.2 g / kg licorice antioxidant), Group D (0.3 g / kg rosemary extract + 0.2 g / kg gallic acid), and Group E (0.3 g / kg rosemary extract + 0.2 g / kg theaflavins). The unit g / kg refers to the amount of the corresponding antioxidant added per kg of Trichosanthes seed oil. Trichosanthes seed oil without any added antioxidants served as a blank control. All samples were subjected to accelerated oxidation at 55 ℃ for 7 days, and their antioxidant effects were evaluated by monitoring POV and AV.

[0051] POV determination method: Refer to GB 5009.227-2023 "National Food Safety Standard - Determination of Peroxide Value in Food" for determination. Weigh 2 g of sample oil into a 250 mL Erlenmeyer flask, add 30 mL of chloroform-glacial acetic acid solution (chloroform:glacial acetic acid = 2:3, v / v), and shake until the oil dissolves. Add 1 mL of saturated potassium iodide solution (1.6 g / mL), tighten the cap, shake, and place in the dark for 3 min. Remove the Erlenmeyer flask from the dark, add 100 mL of water, shake well, and immediately titrate with sodium thiosulfate standard solution (0.002 mol / L) until a pale yellow color appears. Add 1 mL of starch indicator, continue titrating and shaking until the blue color disappears as the endpoint. Perform a blank control simultaneously. The formula for calculating POV is as follows:

[0052] In the formula, V is the volume of sodium thiosulfate solution consumed in the titration (mL); V0 is the volume of sodium thiosulfate solution consumed in the blank titration (mL); c is the concentration of sodium thiosulfate solution used in the titration (mol / L); 0.1269 is the mass of iodine equivalent to 1.00 mL of sodium thiosulfate titration solution [c(Na2S2O3)=1.000 mol / L] (g / mmol); m is the sample weight (g); and 100 is the conversion factor for 100 g of sample.

[0053] The method for determining AV is as follows: Refer to GB 5009.229-2016, "National Food Safety Standard - Determination of Acid Value in Food". Weigh 1.5 g of sample oil into a 150 mL Erlenmeyer flask, add 50-60 mL of diethyl ether-isopropanol mixture (ether:isopropanol = 1:1, v / v), mix well to dissolve the oil, then add 3-4 drops of phenolphthalein indicator and shake thoroughly. After shaking well, titrate with potassium hydroxide ethanol standard solution (0.01 mol / L) until a faint pink color appears and there is no obvious fading within 15 seconds. Perform a blank control simultaneously. The formula for calculating AV is as follows:

[0054] In the formula, V is the volume of potassium hydroxide ethanol solution consumed in the titration (mL); V0 is the volume of potassium hydroxide ethanol solution consumed in the blank titration (mL); c is the concentration of the potassium hydroxide ethanol solution used in the titration (mol / L); 56.1 is the molar mass of potassium hydroxide (g / mol); and m is the sample weight (g).

[0055] III. Experimental Results Table 1. Inhibitory effects of different compound antioxidants on rancidity of Trichosanthes kirilowii seed oil.

[0056] As shown in Table 1, the POV and AV of the blank control group increased sharply within 7 days, with increases of 242.47% and 142.91%, respectively, confirming that Trichosanthes kirilowii seed oil is extremely unstable during storage and suffers from severe rancidity. Among all the compound formulations, combination A, consisting of 0.3 g / kg rosemary extract and 0.2 g / kg Sacha indica leaf extract, exhibited unexpectedly superior anti-rancidity effects, with a POV increase of only 13.44% and an AV increase of only 1.90%. In conclusion, the specific ratio of Sacha indica leaf extract and rosemary extract provided by this invention is significantly superior to the compound formulation of rosemary extract with other common natural antioxidants in inhibiting the rancidity of Trichosanthes kirilowii seed oil, producing an unexpected antioxidant stabilizing effect.

[0057] Experiment Example 2: Accelerated Storage Experiment I. Experimental Methods To study the storage stability of the roasted Trichosanthes kirilowii seeds prepared in Example 1, an accelerated storage experiment at 35 °C for 20 days was conducted. The POV, AV, malondialdehyde content, fatty acid value and moisture content of the roasted Trichosanthes kirilowii seed samples were measured on days 0 and 20, respectively. At the same time, the roasted Trichosanthes kirilowii seeds in Comparative Examples 1 to 4 were used as control samples for the determination.

[0058] 1. Methods for determining POV See Experiment Example 1.

[0059] 2. Methods for measuring AV See Experiment Example 1.

[0060] 3. Method for determining malondialdehyde content The determination was performed according to GB 5009.181-2016, "National Food Safety Standard - Determination of Malondialdehyde in Food". Accurately transfer 0.1 mL, 0.5 mL, 1.0 mL, 1.5 mL, and 2.5 mL of the malondialdehyde standard working solution into 10 mL volumetric flasks. Dilute to volume with a trichloroacetic acid mixture (containing 75 g / L trichloroacetic acid and 1 g / L disodium ethylenediaminetetraacetate) to prepare concentrations of 0.01 μg / mL, 0.05 μg / mL, 0.10 μg / mL, 0.15 μg / mL, and 0.25 μg / mL, respectively. Prepare fresh for each use. Transfer 5 mL of the above standard series solutions into test tubes, add 5 mL of thiobarbituric acid solution (0.02 mol / L), stopper, mix well, and place in a 90 ℃ water bath for 30 min. Remove and cool to room temperature. Plotting the mass concentration of the standard series solutions on the x-axis and the absorbance values ​​on the y-axis, the standard curve was obtained as y = 5.7489x + 0.0229 (R²). 2 =0.9977).

[0061] Weigh 5 g of crushed Trichosanthes kirilowii seeds and place them in a 100 mL stoppered conical flask. Add 50 mL of a trichloroacetic acid mixture (containing 75 g / L trichloroacetic acid and 1 g / L disodium ethylenediaminetetraacetate), shake well, stopper, and place in a 50 ℃ magnetically stirred water bath for 30 min. Remove and cool to room temperature, then filter and collect the filtrate. Transfer 5 mL of the filtrate to a test tube. Take another 5 mL of the trichloroacetic acid mixture (containing 75 g / L trichloroacetic acid and 1 g / L disodium ethylenediaminetetraacetate) as a sample blank, add 5 mL of thiobarbituric acid solution (0.02 mol / L), stopper, mix well, and place in a 90 ℃ water bath for 30 min. Remove and cool to room temperature. The formula for calculating MDA is as follows:

[0062] In the formula, c is the concentration of the sample solution obtained from the standard curve, in μg / mL; V is the total volume of the mixed solution, in mL; m is the sample weight, in g; and 1000 is the conversion factor.

[0063] 4. Methods for determining fatty acid value The determination was performed according to GB / T 5510-2011 "Grain and Oil Inspection: Determination of Fatty Acid Values ​​in Grains and Oilseeds". 10 g of crushed Trichosanthes kirilowii seeds were weighed and placed in a 250 mL Erlenmeyer flask. 50 mL of petroleum ether (boiling range 60-90 ℃) was added, the flask was stoppered, mixed thoroughly, and stirred for 10 min. After standing, the filtrate was collected by filtration. 25 mL of the filtrate was placed in an Erlenmeyer flask, 75 mL of 50% ethanol solution was added, and the mixture was shaken well. 4-5 drops of phenolphthalein indicator were added, and titration was performed with potassium hydroxide ethanol standard solution (0.01 mol / L) until the lower ethanol layer turned a faint pink. A blank control was prepared using 25 mL of petroleum ether instead of the filtrate. The formula for calculating the fatty acid value is as follows:

[0064] In the formula, V1 is the volume of potassium hydroxide ethanol solution consumed in the titration of the filtrate, in mL; V0 is the volume of potassium hydroxide ethanol solution consumed in the blank titration, in mL; c is the concentration of potassium hydroxide ethanol solution, in mol / L; m is the sample mass, in g; and w is the sample moisture content.

[0065] 5. Methods for determining moisture content The moisture content (MC) was determined according to GB 5009.3-2016, "National Food Safety Standard - Determination of Moisture in Food". First, the aluminum box was dried in an oven at 100-105 ℃. An appropriate amount of Trichosanthes kirilowii seeds was weighed, and the seed shells were separated using seed tongs. The seeds were then placed in the dried aluminum box and dried again in an oven at 100-105 ℃ until constant weight. The formula for calculating the moisture content (MC) is as follows:

[0066] In the formula, m1 is the mass of the aluminum box and the sample (g); m2 is the mass of the aluminum box and the dried sample (g); m3 is the mass of the aluminum box (g); and 100 is the unit conversion factor.

[0067] II. Experimental Results 1. Accelerate the change of POV during storage During a 20-day accelerated storage experiment at 35 ℃, the changes in POV of roasted Trichosanthes kirilowii seeds in each group were as follows: Figure 1 As shown in the figure. The results show that in Example 1, which uses the comprehensive preservation method of the present invention, the POV increased by only 12.41%, far lower than that of other groups, indicating that it has the most significant inhibitory effect on the initial oxidation of oils. The increases in Comparative Example 1 (replacing Sacha involucrata leaf extract with tea polyphenols), Comparative Example 2 (without enzyme inactivation), and Comparative Example 3 (without antioxidant coating) were 17.58%, 23.03%, and 27.43%, respectively, indicating that the addition of steam-microwave enzyme inactivation and compound natural antioxidants can effectively delay the increase in POV. However, the POV value of Comparative Example 4 (commercially available) increased by as much as 138.46%, indicating that ordinary packaging cannot effectively prevent oxidation, and the product has generated a large number of oxidation products, resulting in a significant decline in quality. In summary, the present invention, through the synergistic effect of steam-microwave enzyme inactivation, compound antioxidants, and vacuum deoxygenation packaging, can effectively block the initial stage of oil oxidation, thereby providing a fundamental guarantee for the flavor stability of roasted Trichosanthes kirilowii seeds.

[0068] 2. Accelerate the changes in AV during storage In a 20-day accelerated storage experiment at 35 ℃, the changes in AV of each group of roasted Trichosanthes kirilowii seeds were as follows: Figure 2 As shown in the figure. The results showed that the AV of Example 1 group increased by only 0.05 mg / g, the smallest increase, at 43.67%. In contrast, the increases in Comparative Examples 1, 2, and 3 were higher, at 57.50%, 71.46%, and 83.43%, respectively. This proves that both steam-microwave enzyme inactivation and the compound antioxidant can effectively delay the increase in AV. Comparative Example 4 showed a significant increase in AV of 0.60 mg / g, an increase of 264.23%, indicating a marked deterioration in its quality. In summary, this invention, through the synergistic effect of steam-microwave enzyme inactivation, compound antioxidants, and vacuum deoxygenation packaging, can effectively inhibit the increase in AV of roasted Trichosanthes kirilowii seeds during storage and slow down the hydrolytic rancidity process of the oil.

[0069] 3. Accelerate the change in malondialdehyde content during storage. Table 2. Changes in MDA in roasted Trichosanthes kirilowii seeds under different treatments over 20 days.

[0070] Malonaldehyde (MDA), a C3 aldehyde, is produced from the peroxidation of polyunsaturated fatty acids and is a key product in the oxidation process of oils and fats. Changes in its content directly reflect the oxidative stability of food; a lower MDA value or a slower growth rate indicates a less severe degree of oxidation and better preservation of food quality.

[0071] Table 2 shows the changes in MDA of roasted Trichosanthes kirilowii seeds in each group during a 20-day accelerated storage experiment at 35 °C. The results show that Example 1, using the comprehensive preservation method of this invention, had an MDA growth rate of only 9.78% and the lowest final content among all groups, demonstrating the best oxidation inhibition effect. Secondly, Comparative Example 1 (with Sacha inchi leaf extract replaced by tea polyphenols) showed an MDA growth rate of 15.35%, indicating that tea polyphenols were far less effective than the Sacha inchi leaf extract used in this invention in inhibiting MDA. Comparative Example 2 (without enzyme inactivation) and Comparative Example 3 (without antioxidant application) showed growth rates of 16.01% and 27.19%, respectively, indicating that omitting either the steam-microwave enzyme inactivation or the natural antioxidant step would significantly reduce the preservation effect. Furthermore, Comparative Example 4 (commercially available) showed a sharp increase in MDA content of 355.84%, indicating a very serious oxidation problem. In summary, this invention, through the synergistic effect of steam-microwave enzyme inactivation, compound antioxidants, and vacuum deoxygenation packaging, can effectively inhibit the formation of MDA, stabilize the oxidation level of Trichosanthes kirilowii seeds at an extremely low level, and achieve unexpected preservation results.

[0072] 4. Accelerate the change in fatty acid value during storage. Fatty acid value reflects the degree of deterioration in the quality of seed products and is another important factor in evaluating the quality of seed products.

[0073] During a 20-day accelerated storage experiment at 35 ℃, the changes in fatty acid values ​​of roasted Trichosanthes kirilowii seeds in each group were as follows: Figure 3 As shown in the figure. The results showed that during the entire storage period, the fatty acid value of Example 1 increased by only 0.76 mg / 100g, an increase of less than 7%, demonstrating the best stability. The fatty acid value of Comparative Example 1 (with Sacha inca leaf extract replaced by tea polyphenols) increased by 1.29 mg / 100g within 20 days. The increase in Comparative Example 2 (without enzyme inactivation) was similar to that of Comparative Example 1, indicating that the combination of compound antioxidants and vacuum deoxygenation packaging played an important role in controlling the increase in fatty acid value. However, the fatty acid value of Comparative Example 4 (commercially available) increased sharply, reaching 3.01 times that of Example 1 by day 20, indicating that its internal oils had undergone severe hydrolytic rancidity. In summary, the present invention, through the synergistic effect of steam-microwave enzyme inactivation, compound antioxidants, and vacuum deoxygenation packaging, can effectively inhibit the increase in fatty acid value of roasted Trichosanthes kirilowii seeds during storage, thereby delaying the occurrence of hydrolytic rancidity.

[0074] 5. Accelerate the change in moisture content during storage. Moisture content is a key indicator affecting the textural stability and shelf life of food (especially roasted nuts and seeds). Appropriate moisture content helps maintain the crisp texture of food, while excessive moisture can lead to hydrolysis or oxidation of nuts, thereby altering the physicochemical properties of the food and causing quality deterioration such as softening and rancidity.

[0075] During a 20-day accelerated storage experiment at 35 ℃, the changes in moisture content of roasted Trichosanthes kirilowii seeds in each group were as follows: Figure 4 As shown in the figure. The results showed that the moisture content of Example 1 (using comprehensive preservation methods), Comparative Example 1 (replacing sacha inophyllum leaf extract with tea polyphenols), and Comparative Example 2 (without enzyme inactivation) all showed a slight decreasing trend after 20 days of storage. This may be because microwave treatment changed the microstructure of Trichosanthes kirilowii seeds, making it easier for internal moisture to escape during storage, thus better maintaining the crisp texture. Among them, the moisture content of Example 1 fluctuated the least throughout the storage period, showing the most ideal stability. In contrast, the moisture content of Control Group 3 (without antioxidant coating) and Comparative Example 4 (commercially available) increased significantly during the 20-day storage period, especially Comparative Example 4, indicating that the moisture barrier performance of ordinary packaging is insufficient and cannot effectively prevent the product from absorbing moisture. In summary, the present invention, through the synergistic effect of steam-microwave enzyme inactivation, compound antioxidants, and vacuum deoxygenation packaging, helps to maintain the crisp texture of roasted Trichosanthes kirilowii seeds and avoid the deterioration of taste.

[0076] Experiment Example 3: Sensory Evaluation I. Experimental Methods Ten trained students (5 males and 5 females) were selected to conduct sensory evaluations of roasted Trichosanthes kirilowii seeds (Example 1, Comparative Examples 1-4) stored at 35 ℃ for 20 days. The scoring criteria are shown in Table 3.

[0077] Table 3 Sensory Evaluation Criteria for Roasted Trichosanthes Seeds

[0078] II. Experimental Results Table 4 Sensory Evaluation Scores

[0079] As shown in Table 4, the roasted Trichosanthes kirilowii seeds prepared using the method provided by this invention (Example 1) exhibited significantly better overall sensory quality than all other experimental groups after 20 days of accelerated storage, achieving a total score of 89 points. Specifically, Example 1 scored 13 points (out of 15) for aroma, 27 points (out of 30) for texture, and 27 points (out of 30) for taste, demonstrating that the preparation method provided by this invention can effectively suppress the development of rancidity and maintain the unique crisp texture and rich flavor of Trichosanthes kirilowii seeds for a long time. In contrast, the sensory scores of groups where the *Sapindus mukorossi* leaf extract was replaced with tea polyphenols (Comparative Example 1), the steam-microwave enzyme inactivation step was omitted (Comparative Example 2), or no compound antioxidant was added (Comparative Example 3) were 82, 75, and 72 points respectively. Their aroma and taste scores significantly decreased, indicating that steam-microwave enzyme inactivation, the compound antioxidant based on *Sapindus mukorossi* leaf extract, and vacuum deoxygenation packaging have irreplaceable synergistic effects in the preparation of roasted *Trichosanthes kirilowii* seeds. The absence of any one of these steps leads to a significant decline in sensory quality. The commercially available ordinary packaged product (Comparative Example 4) had the lowest total score (67 points), demonstrating its severely deteriorated quality. This indicates that the comprehensive preservation method of this invention, formed by steam-microwave synergistic enzyme inactivation, compound natural antioxidants, and vacuum deoxygenation packaging, can effectively affect the sensory attributes of the product, ultimately improving the storage quality of roasted *Trichosanthes kirilowii* seeds.

[0080] Experiment Example 4: Shelf Life Prediction I. Experimental Methods The point of view (POV) of roasted Trichosanthes kirilowii seeds under different packaging conditions was recorded. A nonlinear fitting model was constructed, and the Levenberg-Marquardt iterative algorithm was used to fit the model until convergence. The goodness-of-fit of the established model was analyzed, and the R-values ​​of each model were compared. 2 R 2 The model with a value closest to 1 is the most suitable for describing the shelf-life variation of roasted Trichosanthes kirilowii seeds under different packaging conditions. Finally, the Cubic function was selected as the shelf-life prediction model, and its equation is as follows:

[0081] In the formula, Y is the POV (potential value) after storage for X days (g / 100g); X is the number of storage days (d); and a, b, c, and d are model parameters.

[0082] II. Experimental Results Table 5. Predicted shelf life of roasted Trichosanthes kirilowii seeds under different treatments

[0083] Table 5 shows the prediction results based on the shelf-life prediction model. The roasted Trichosanthes kirilowii seeds prepared using the method provided by this invention (Example 1) have a predicted shelf life of up to 86 days at 35 °C, significantly exceeding that of other groups. This is mainly due to the synergistic effect of steam-microwave enzyme inactivation, the specific combination of rosemary extract and Sacha indica leaf extract, and vacuum deoxygenation packaging in extending the shelf life of roasted Trichosanthes kirilowii seeds. The selection of the compound antioxidant is crucial; replacing Sacha indica leaf extract with tea polyphenols (Comparative Example 1) shortens the shelf life to 51 days, a reduction of 40.7%. The absence of any core step (Comparative Examples 2 and 3) or the use of only commercially available ordinary packaging (Comparative Example 4) further shortens the shelf life to 45 days, 43 days, and 27 days, respectively. Therefore, the preparation method provided by this invention can significantly extend the shelf life of roasted Trichosanthes kirilowii seeds and effectively slow down their lipid oxidative rancidity process.

[0084] In summary, this invention employs a comprehensive preservation method combining steam pretreatment with microwave enzyme inactivation, a combination of rosemary extract and sacha inchi extract as antioxidants, and vacuum deoxygenation packaging. This successfully constructs a multi-layered synergistic inhibition system against oil rancidity during the storage of roasted Trichosanthes kirilowii seeds. This preparation method can control the POV increase of Trichosanthes kirilowii seeds at 35 ℃ for 20 days at 12.41%, the AV increase at 43.67%, and the MDA increase at 9.78%, while effectively maintaining stable fatty acid values ​​and moisture content. The sensory evaluation score reached 89 points, with key flavor and taste indicators significantly superior to other groups. Based on a predictive model, this invention can extend the shelf life of roasted Trichosanthes kirilowii seed products to 86 days at 35 ℃. Calculations using the Van't Hoff equation suggest a shelf life of up to 172 days at 25 ℃ (room temperature), more than three times longer than conventional commercially available products (54 days). The comprehensive preservation method adopted in this invention breaks through the limitations of single preservation methods, and achieves the inhibition of enzymatic oxidation and auto-oxidation. It provides reliable technical support for extending the shelf life and enhancing the commercial value of roasted Trichosanthes kirilowii seeds, and has important value for promotion and application.

[0085] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for preparing roasted Trichosanthes kirilowii seeds with improved storage quality based on Sacha indica leaf extract, characterized in that, Includes the following steps: S1. The seeds of Trichosanthes kirilowii are first steam-pretreated, then microwave-sterilized to remove enzymes, and then cooled to room temperature; S2. Dissolve rosemary extract and sacha in water to prepare a composite antioxidant solution. Apply the composite antioxidant solution evenly to the surface of the Trichosanthes kirilowii seeds obtained in step S1 and dry. S3. Stir-fry the Trichosanthes kirilowii seeds obtained in step S2 and then cool them. S4. Place the roasted Trichosanthes seeds obtained in step S3 together with the deoxidizer in a packaging bag and vacuum pack them.

2. The method for preparing roasted Trichosanthes kirilowii seeds based on Sacha indica leaf extract to improve storage quality according to claim 1, characterized in that, Step S1 satisfies at least one of the following conditions: 1) The Trichosanthes seeds are screened before steam pretreatment to remove bad seeds; 2) Steam pretreatment conditions: Steam temperature 70~95 ℃, time 3~8 min; 3) Microwave enzyme inactivation conditions: power 600~1000 W, frequency 2200~2600 MHz, time 10~40 s.

3. The method for preparing roasted Trichosanthes kirilowii seeds based on Sacha indica leaf extract to improve storage quality according to claim 1, characterized in that, Step S2 satisfies at least one of the following conditions: 1) The mass ratio of rosemary extract to sacha inca leaf extract is 1~2:1; 2) Based on the weight of Trichosanthes kirilowii seeds, the amount of rosemary extract is 0.2~0.5 g / kg, and the amount of Sacha indica leaf extract is 0.1~0.4 g / kg; 3) The amount of water added should be 5% to 6% of the weight of the Trichosanthes kirilowii seeds; 4) The drying temperature is 25~35℃; 5) The Sacha indica leaf extract is a water extract of Sacha indica leaves.

4. The method for preparing roasted Trichosanthes kirilowii seeds based on Sacha indica leaf extract to improve storage quality according to claim 1, characterized in that, Step S3 satisfies at least one of the following conditions: 1) Mix Trichosanthes seeds and roasted sand at a mass ratio of 1~2:1 and then roast them; 2) The frying temperature is 140~180 ℃, and the frying time is 30~50 min; 3) Immediately after roasting, separate the Trichosanthes seeds from the roasted sand; 4) After frying, spread the Trichosanthes seeds out to cool.

5. The method for preparing roasted Trichosanthes kirilowii seeds based on Saxifraga stolonifera leaf extract to improve storage quality according to claim 1, characterized in that, Step S4 satisfies at least one of the following conditions: 1) The deoxidizer is an iron-based deoxidizer; 2) The mass ratio of deoxidizer to roasted Trichosanthes kirilowii seeds is 1:70~150; 3) Vacuum packaging conditions: pressure 0.05~0.25 MPa, evacuation time 10~15 s, cooling time after heat sealing 1~5 s.

6. The method for preparing roasted Trichosanthes kirilowii seeds based on Sacha indica leaf extract to improve storage quality according to claim 1, characterized in that, Step S1 satisfies at least one of the following conditions: 1) Steam pretreatment conditions: Steam temperature is 90~95 ℃, and time is 5~7 min; 2) Microwave enzyme inactivation conditions: power 800~900 W, frequency 2450~2600 MHz, time 20~30 s; And / or, step S2 satisfies at least one of the following conditions: 1) The mass ratio of rosemary extract to sacha inca leaf extract is 1~1.5:1; 2) Based on the weight of Trichosanthes kirilowii seeds, the amount of rosemary extract is 0.3~0.4 g / kg, and the amount of Sacha indica leaf extract is 0.2~0.3 g / kg; 3) The amount of water added should be 5.5% to 6% of the weight of the Trichosanthes kirilowii seeds; 4) The drying temperature is 30~35℃; And / or, step S3 satisfies at least one of the following conditions: 1) Mix Trichosanthes seeds and roasted sand at a mass ratio of 1.5~2:1 and then roast them; 2) The frying temperature is 160~170 ℃, and the frying time is 30~40 min; And / or, step S4 satisfies at least one of the following conditions: 1) The mass ratio of deoxidizer to roasted Trichosanthes kirilowii seeds is 1:100~120; 2) Vacuum packaging conditions: pressure 0.10~0.20 MPa, evacuation time 10~13 s, cooling time after heat sealing 3~4 s.

7. The method for preparing roasted Trichosanthes kirilowii seeds based on Sacha indica leaf extract to improve storage quality according to claim 1, characterized in that, The preparation method of the Sacha indica leaf extract includes the following steps: Sacha indica leaves are washed and then water is added. The mixture is extracted by stirring in a boiling water bath, and the solid and liquid are separated. The separated extract is filtered, and the filtrate is freeze-dried to obtain the Sacha indica leaf extract.

8. The method for preparing roasted Trichosanthes kirilowii seeds based on Sacha indica leaf extract to improve storage quality according to claim 7, characterized in that, In the preparation steps of Sacha inchi leaf extract, The ratio of Sacha in marigold leaves to water is 1:10~30, expressed in g / mL. The boiling water bath extraction time is 2–4 hours; Solid-liquid separation conditions: centrifuge at 3000–5000 rpm for 10–20 min; Filtration was performed using microporous membranes with pore sizes of 0.20–0.45 μm; Freeze-drying conditions: temperature -60 to -30 ℃, time 24 to 72 h; The freeze-dried Sacha indica leaf extract was stored at 2–8 °C.

9. The method for preparing roasted Trichosanthes kirilowii seeds based on Saxifraga stolonifera leaf extract to improve storage quality according to claim 7, characterized in that, In the preparation steps of Sacha inchi leaf extract, The ratio of Sacha in marigold leaves to water is 1:20~22, expressed in g / mL. The boiling water bath extraction time is 3–4 hours; Solid-liquid separation conditions: centrifuge at 4000–4500 rpm for 15–18 min; Filtration was performed using a microporous membrane with a pore size of 0.30–0.45 μm; Freeze-drying conditions: temperature -48 to -40 ℃, time 48 to 52 h; The freeze-dried Sacha indica leaf extract was stored at 4–6 °C.

10. The roasted Trichosanthes kirilowii seeds obtained by the preparation method according to any one of claims 1 to 9.

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