Method for aging kiwi fruit wine and prolonging shelf life

Abstract

The invention discloses a method for aging kiwi fruit wine and prolonging shelf life, and belongs to the technical field of fruit wine brewing and processing. The method for aging the kiwi fruit wine and prolonging the shelf life specifically comprises the following steps: putting the kiwi fruit wine into a food-grade polyethylene bag, vacuumizing, sealing, putting into an ultrahigh-pressure reaction kettle, carrying out high-pressure treatment, setting the pressure to be 450-500MPa, the temperature to be 20-30 DEG C and the treatment time to be 15-25min, taking water as a pressure transmission medium, and increasing the pressure rate to be 80-100MPa / min; and storing at room temperature after treatment. The aroma of the kiwi fruit wine obtained by the method is obviously superior to that of new wine, the kiwi fruit wine is equivalent to the kiwi fruit wine aged for 5 months in the properties of flower fragrance, fruit fragrance, sweet fragrance and the like, the contents of ethyl hexanoate, ethyl valerate, ethyl caprylate and ethyl isobutyrate in the kiwi fruit wine are remarkably increased, the aging time of the kiwi fruit wine is remarkably shortened, and the yield of the kiwi fruit wine is increased. And the shelf life of the kiwi fruit wine obtained by the technology is more than 500 days.

Description

Technical Field

[0001] The invention relates to a method for aging kiwi fruit wine and extending its shelf life, and belongs to the technical field of fruit wine brewing and processing. Background Art

[0002] Kiwifruit wine is a key product in the kiwifruit industry, but its current production process faces two challenges. First, after fermentation, the sensory properties of kiwifruit wine, such as its fruity, floral, and sweet aromas, which are popular with consumers, are relatively low in intensity, while the alcoholic aroma is relatively strong. This typically requires aging for three months to a year to improve the flavor. However, this lengthy natural aging process significantly increases production costs and prolongs the product's time to market, placing significant pressure on companies in terms of both time and capital turnover.

[0003] On the other hand, kiwi wine is a low-alcohol wine, that is, wine with an alcohol content of less than 10% vol needs to be sterilized at high temperature to extend its shelf life to one year. The shelf life is quite different from that of wine with an alcohol content of more than 10% vol, resulting in high production costs and great sales pressure for low-alcohol kiwi wine.

[0004] To address the above problems, the existing technology usually adopts the method of artificial aging plus high-temperature sterilization or pasteurization to shorten costs and extend product launch cycle. For example, the existing technology uses ultrasonic treatment to produce blackened red date wine, and the overall sensory characteristics are significantly better than those of untreated blackened red date wine; microwave aging is used for kiwi brandy, with a microwave power of 200W for 4 minutes. It is found that artificial aging has a significant improvement effect on the various physical and chemical indicators of kiwi brandy; and combined with high-temperature sterilization or pasteurization to achieve commercial sterility requirements, the shelf life is extended.

[0005] However, although these aging and sterilization processes have shortened the aging cost and extended the shelf life to a certain extent, the aging effect is still poor, and a combination of aging and sterilization processes is still required. In addition, high-temperature sterilization is likely to destroy the flavor substances and nutrients in the fruit wine, causing adverse effects on the quality of the fruit wine. Summary of the Invention

[0006] In response to the problems of aging defects and short shelf life of kiwi wine, the purpose of the present invention is to provide a method for aging and extending the shelf life of kiwi wine. The method directly uses ultra-high pressure treatment on the fermented kiwi wine, which not only improves the flavor quality of the kiwi wine, but also effectively extends the shelf life of kiwi.

[0007] In order to achieve the above objectives, the technical solutions provided are as follows:

[0008] The present invention provides a method for aging kiwi fruit wine and extending its shelf life, the method comprising the following steps:

[0009] The fermented kiwifruit wine is placed in a food-grade polyethylene bag, vacuumed, sealed, and placed in an ultra-high pressure reactor for high-pressure treatment. The pressure is set to 450-500 MPa, the temperature is 20-30°C, the treatment time is 15-25 minutes, water is used as the pressure transmission medium, and the pressure increase rate is 80-100 MPa / min; after treatment, it can be stored at room temperature.

[0010] In one embodiment, the high pressure treatment is performed at a pressure of 500 MPa, a temperature of 20 to 30° C., and a treatment time of 15 to 25 minutes.

[0011] In one embodiment, the high pressure treatment is performed at a pressure of 500 MPa, a temperature of 20° C., and a treatment time of 25 min.

[0012] In one embodiment, the high pressure treatment is performed at a pressure of 500 MPa, a temperature of 25° C., and a treatment time of 20 min.

[0013] In one embodiment, the high pressure treatment is performed at a pressure of 450 MPa, a temperature of 30° C., and a treatment time of 25 min.

[0014] In one embodiment, the high pressure treatment is performed at a pressure of 500 MPa, a temperature of 30° C., and a treatment time of 15 min.

[0015] In one embodiment, the fermented kiwi fruit wine refers to the wine formed by directly fermenting fresh kiwi fruit with microorganisms.

[0016] In one embodiment, the fermented kiwi fruit wine refers to fruit wine fermented with Pichia kudriavzevii FPW7-6.

[0017] In one embodiment, the Pichia pastoris (P. kudriavzevii) FPW7-6 was deposited in the China Center for Type Culture Collection on July 1, 2024, with a deposit number of CCTCC NO: M20241440 (a published strain).

[0018] In one embodiment, the food-grade polyethylene bag has a size of 100 to 500 mL, preferably 100 mL.

[0019] The present invention also provides kiwi fruit wine obtained by the method.

[0020] In one embodiment, the kiwi fruit wine has rich fruity, sweet and floral aromas, and has a shelf life of more than 500 days.

[0021] Beneficial effects:

[0022] Compared with traditional methods of aging and extending the shelf life of kiwi fruit wine, the method of the present invention has the following advantages:

[0023] (1) The aging efficiency is greatly improved, which not only speeds up the production cycle and improves the production efficiency of the enterprise, but also reduces storage costs and time costs;

[0024] (2) Better and more controllable flavor quality: In the traditional aging process, the formation of fruit wine flavor mainly depends on the influence of natural environmental factors, which is uncontrollable and difficult to guarantee the stability and consistency of flavor. Due to subtle differences in the aging environment, the final flavor of different batches of fruit wine may fluctuate greatly. However, ultra-high pressure aging can precisely control the generation of aroma substances and the conversion of flavor substances in fruit wine by precisely controlling parameters such as pressure, holding time, and temperature. High pressure can promote the synthesis of esters, which are an important source of fruit wine aroma, making the aroma of fruit wine more rich and complex. At the same time, high pressure can also accelerate the decomposition of macromolecular substances, making the taste of fruit wine softer and mellower.

[0025] (3) Long shelf life: the shelf life of kiwi fruit wine obtained by the method of the present invention can reach more than 500 days, while the shelf life of kiwi fruit wine obtained by the traditional high-pressure sterilization method is only more than 400 days. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is the aroma profile of kiwi fruit wine;

[0027] Figure 2 The data graph shows the content of volatile ester compounds in different kiwifruit wine samples; (A) ethyl acetate; (B) ethyl valerate; (C) ethyl octanoate; (D) ethyl isobutyrate. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present invention will be described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention. The following specific embodiments further describe the present invention.

[0029] The preparation of kiwi fruit wine involved in the present invention:

[0030] 1. Bacteria culture

[0031] To activate the strains, two strains were taken out of the -80°C freezer and thawed. After streaking on a plate, they were incubated in a 28°C constant temperature incubator for 48 hours. Single colonies of uniform morphology and size were picked for each strain and streaked again, and cultured under the same conditions. These single colonies were then transferred to 5mL test tubes to form YPD liquid culture medium, and cultured at 28°C and 180r / min for 36 hours. To expand the culture of the strains, kiwifruit juice should be sterilized in an 80°C water bath for 5 minutes in advance, and then mixed with pure YPD liquid culture medium sterilized at 115°C for 15 minutes in equal proportions in a 250mL Erlenmeyer flask. After counting the colonies in 5mL of YPD liquid culture medium, pipette and add to 250mL Erlenmeyer flasks as needed, and culture at 28°C and 180r / min for 36 hours.

[0032] 2. Kiwi wine fermentation

[0033] The kiwifruit was washed, peeled, and pulped with water. 20 mg / L pectinase (37 ± 2°C, 30 min) and 65 mg / L potassium metabisulfite were added, stirred, and then enzymatically hydrolyzed in a 40°C waterbath for 4 h. Sucrose was added to increase the sugar content to a total soluble solids content of 25° Brix. The juice was then pasteurized (65°C, 30 min) and cooled to room temperature. The kiwifruit juice, mixed with the pomace, was transferred to a glass fermenter. On the third day, Pichia kudriavzevii FPW7-6 was inoculated at a 2:1 inoculation ratio, fermented at 25°C, and fermented for 16 days. Pichia kudriavzevii FPW7-6 was deposited with the China Center for Type Culture Collection on July 1, 2024, with the deposit number CCTCC NO: M20241440 (a publicly available strain).

[0034] The test method involved in the present invention is:

[0035] 1. Sensory evaluation

[0036] A total of 20 evaluators (7 women, 5 men, average age 24) participated in the sensory tasting. These evaluators were all from the School of Brewing and Food Engineering at Guizhou University and were trained using the aroma standard "Le Nez du Vin" (Jean Lenoir, Provence, France). The study selected seven main aroma attributes: fruity, floral, sour, mellow, sweet, medicinal, and woody. Evaluators were asked to rate the intensity of these attributes using a six-point scale ranging from 0 to 5. The results of the 20 evaluators were then plotted into an aroma profile. All sensory evaluations were conducted in a sensory room at a temperature of 22-24°C.

[0037] 2. Quantitative analysis of volatile compounds

[0038] HS-SPME extraction of volatile compounds

[0039] 5 ml of kiwifruit wine and 1.5 g of sodium chloride were added to a 20 ml headspace vial. 20 μL of a 25 mg / L toluene-d8 solution was added as an internal standard, and the vial was sealed with a headspace seal. The headspace vial was placed in an automatic sampling device and equilibrated at 50°C for 15 minutes before extraction for 35 minutes. Subsequently, the analytes were analyzed in a GC injection port at 250°C in a non-fragmented mode for 5 minutes. GC-MS analysis was performed. Each sample was repeated three times.

[0040] GC-MS identification and quantification of volatile compounds

[0041] Volatile compounds in kiwi wine were analyzed using gas chromatography-mass spectrometry. Chemical components were separated using a DB-Wax column (60 m × 0.25 mm × 0.25 μm). The temperature program was as follows: an initial column temperature of 40°C for 1 minute, then increased at a rate of 4°C / min to 150°C, and finally increased at a rate of 8°C / min to 230°C, where it was held for 10 minutes. High-purity helium was used as the carrier gas at a flow rate of 1.0 mL / min. The ion source temperature was set at 230°C, and the quadrupole temperature was maintained at 150°C. An electron impact ionization (EI) source was used with an ionization energy of 70 eV and a source temperature of 230°C, over a scan range of m / z 35 to 500. Volatile compounds were identified by comparison of mass spectra, retention times, and retention indices (RIs) with those of pure standards. The RI of volatile compounds was calculated based on the linear retention time of n-alkanes (C7-C40) on the DB-WAX column. The content was calculated by calculating the peak area ratio to the internal standard and multiplying it by the internal standard concentration.

[0042] 3. Shelf life calculation

[0043] The shelf life of kiwifruit wine was studied using an accelerated shelf life test (ASLT). The accelerated test temperatures were 45°C and 55°C, with room temperature at 25°C serving as the control temperature (predicted temperature) for the study. Currently, sensory and microbiological indicators are generally used to determine if kiwifruit wine has exceeded its shelf life. The sensory indicator combines the color, aroma, and taste of the kiwifruit wine, with a score of 10. A score below 6 is considered exceeded. Microbiological indicators refer to the agricultural industry standard "Green Food Fruit Wine" (NY / T 15080-2017), which stipulates that the total colony count in the wine must be ≤50 CFU / mL. The total colony count in kiwifruit wine was tested according to the method described in "Determination of Total Colony Count" (GB 4789.2-2016).

[0044] In the experiment, Q10 is used to indicate the sensitivity of the reaction to temperature. The calculation formula is as follows:

[0045] Q10=T1 / T2 (1)

[0046] Where: Q10: the ratio of the shelf life of the same samples at a temperature difference of 10°C in the shelf life prediction test;

[0047] T1: shelf life of the sample under T1 temperature conditions;

[0048] T2: shelf life of the sample at temperature T2 (T1+10);

[0049] The calculation of shelf life at actual storage temperature is as follows:

[0050] T=T3×Q10 ΔT / 10 (2)

[0051] Where: T: actual storage temperature of the sample, i.e. predicted shelf life temperature;

[0052] T3: Shelf life at a specific temperature.

[0053] Example 1

[0054] A method for aging kiwi fruit wine and extending its shelf life, comprising the following steps:

[0055] The kiwi fruit wine obtained after fermentation was placed in a food-grade polyethylene bag, vacuumed, and sealed. Each bag contained 100 mL and was placed in an ultra-high pressure reactor for high-pressure treatment. The pressure was set to 500 MPa, the temperature was 20°C, the treatment time was 25 min, water was used as the pressure transmission medium, and the pressure increase rate was 100 MPa / min. After treatment, the wine was stored at room temperature.

[0056] Example 2

[0057] A method for aging kiwi fruit wine and extending its shelf life, comprising the following steps:

[0058] The kiwi fruit wine obtained after fermentation was placed in a food-grade polyethylene bag, vacuumed, and sealed. Each bag contained 100 mL and was placed in an ultra-high pressure reactor for high-pressure treatment. The pressure was set to 500 MPa, the temperature was 25°C, the treatment time was 20 min, water was used as the pressure transmission medium, and the pressure increase rate was 100 MPa / min. After treatment, the wine was stored at room temperature.

[0059] Example 3

[0060] A method for aging kiwi fruit wine and extending its shelf life, comprising the following steps:

[0061] The kiwi fruit wine obtained after fermentation was placed in a food-grade polyethylene bag, vacuumed, and sealed. Each bag contained 100 mL and was placed in an ultra-high pressure reactor for high-pressure treatment. The pressure was set to 450 MPa, the temperature was 30°C, the treatment time was 25 min, water was used as the pressure transmission medium, and the pressure increase rate was 100 MPa / min. After treatment, the wine was stored at room temperature.

[0062] Example 4

[0063] A method for aging kiwi fruit wine and extending its shelf life, comprising the following steps:

[0064] The kiwi fruit wine obtained after fermentation was placed in a food-grade polyethylene bag, vacuumed, and sealed. Each bag contained 100 mL and was placed in an ultra-high pressure reactor for high-pressure treatment. The pressure was set to 500 MPa, the temperature was 30°C, the treatment time was 15 min, water was used as the pressure transmission medium, and the pressure increase rate was 100 MPa / min. After treatment, the wine was stored at room temperature.

[0065] Comparative Example 1

[0066] A method for aging kiwi fruit wine and extending its shelf life, comprising the following steps:

[0067] The kiwi fruit wine obtained after fermentation was placed in a food-grade polyethylene bag, vacuumed, and sealed. Each bag contained 100 mL and was placed in an ultra-high pressure reactor for high-pressure treatment. The pressure was set to 400 MPa, the temperature was 30°C, the treatment time was 20 min, water was used as the pressure transmission medium, and the pressure increase rate was 100 MPa / min. After treatment, the wine was stored at room temperature.

[0068] Comparative Example 2

[0069] A method for aging kiwi fruit wine and extending its shelf life, comprising the following steps:

[0070] The kiwi fruit wine obtained after fermentation was placed in a food-grade polyethylene bag, vacuumed, and sealed. Each bag contained 100 mL and was placed in an ultra-high pressure reactor for high-pressure treatment. The pressure was set to 400 MPa, the temperature was 20°C, the treatment time was 15 min, water was used as the pressure transmission medium, and the pressure increase rate was 100 MPa / min. After treatment, the wine was stored at room temperature.

[0071] Comparative Example 3

[0072] A method for aging kiwi fruit wine and extending its shelf life, comprising the following steps:

[0073] The kiwi fruit wine obtained after fermentation was placed in a food-grade polyethylene bag, vacuumed, and sealed. Each bag contained 100 mL and was placed in an ultra-high pressure reactor for high-pressure treatment. The pressure was set to 450 MPa, the temperature was 15°C, the treatment time was 20 min, water was used as the pressure transmission medium, and the pressure increase rate was 100 MPa / min. After treatment, the wine was stored at room temperature.

[0074] Comparative Example 4

[0075] A method for aging kiwi fruit wine and extending its shelf life, comprising the following steps:

[0076] The kiwi fruit wine obtained after fermentation was placed in a food-grade polyethylene bag, vacuumed, and sealed. Each bag contained 100 mL and was placed in an ultra-high pressure reactor for high-pressure treatment. The pressure was set to 450 MPa, the temperature was 25°C, the treatment time was 15 min, water was used as the pressure transmission medium, and the pressure increase rate was 100 MPa / min. After treatment, the wine was stored at room temperature.

[0077] Comparative Example 5

[0078] A method for aging kiwi fruit wine and extending its shelf life, comprising the following steps:

[0079] The kiwi fruit wine obtained after fermentation was placed in a food-grade polyethylene bag, vacuumed, and sealed. Each bag contained 100 mL and was placed in an ultra-high pressure reactor for high-pressure treatment. The pressure was set to 400 MPa, the temperature was 25°C, the treatment time was 25 min, water was used as the pressure transmission medium, and the pressure increase rate was 100 MPa / min. After treatment, the wine was stored at room temperature.

[0080] Comparative Example 6

[0081] A method for aging kiwi fruit wine and extending its shelf life, comprising the following steps:

[0082] The fermented kiwifruit wine was placed in an ultra-high temperature sterilizer. After the sterilization equipment was preheated and stabilized, it was sterilized at 110°C for 10 seconds. After treatment, it was stored at room temperature.

[0083] Result Analysis

[0084] 1. The effects of different high pressure conditions on the total bacterial count in kiwi fruit wine are shown in Table 1:

[0085] Table 1. Total bacterial counts in kiwifruit wine under different treatment conditions

[0086]

[0087]

[0088] 2. Sensory analysis of the kiwi fruit wine obtained in Example 1

[0089] The sensory evaluation team conducted a sensory evaluation on kiwi wine and finally determined that the seven attributes of mellow, fruity, sweet, sour, floral, woody and medicinal aromas were the main aroma attributes that contributed to the overall aroma of kiwi wine. Figure 1As shown, three samples were selected for sensory analysis of kiwi wine, namely, kiwi wine after fermentation (a), kiwi wine after fermentation that was aged for 5 months (b), and kiwi wine after fermentation that was directly subjected to ultrahigh pressure treatment without aging (c, i.e., Example 1).

[0090] As shown in the figure, the kiwi wine (a) immediately after fermentation, due to lack of storage, smells quite pungent, with a high aroma intensity of 3.7. However, the kiwi wine has relatively pleasant aroma attributes, with weaker fruity, sweet, and floral aromas. The aroma of the kiwi wine stored for five months shows significant improvement (b), with the wine's irritation significantly reduced, the aroma dropping from 3.7 to 3.2, and a significant increase in the intensity of the fruity, sweet, and floral aromas. Although the newly brewed kiwi wine only underwent 25 minutes of high-pressure treatment, its main aroma attributes are similar to those of the wine aged for five months. In fact, some aroma attributes, such as fruity, sweet, and floral aromas, are superior to those of the wine aged naturally for five months (c).

[0091] Further analysis found that after the kiwifruit wine was treated with ultra-high pressure treatment technology, the fruity, sweet and floral properties were significantly higher than those of the newly brewed kiwifruit wine, and slightly higher than those of the kiwifruit wine stored for 5 months. Volatile ester compounds have aroma properties such as fruity, sweet and floral. By quantitatively analyzing the contents of ethyl hexanoate (A), ethyl valerate (B), ethyl octanoate (C) and ethyl isobutyrate (D) in the three kiwifruit wines, it was found that (such as Figure 2 ), the contents of these four ester compounds in kiwifruit wine increased significantly after high-pressure treatment technology, the content of ethyl hexanoate in new wine was 439.4μg / L, which was 627.8μg / L after aging for 5 months and 725.1μg / L after ultra-high pressure treatment for 20 minutes; the content of ethyl valerate in new wine was 324.4μg / L, which was 390.7μg / L after aging for 5 months and 449.7μg / L after ultra-high pressure treatment for 20 minutes; the content of ethyl octanoate in new wine was 20.3μg / L, which was 33.0μg / L after aging for 5 months and 47.3μg / L after ultra-high pressure treatment for 20 minutes; the content of ethyl isobutyrate in new wine was 36.3μg / L, which was 40.1μg / L after aging for 5 months and 64.7μg / L after ultra-high pressure treatment for 20 minutes. Ultrahigh pressure treatment can significantly increase the content of volatile ester compounds in a short time and improve the aroma quality of kiwi wine.

[0092] 3. Research on the shelf life of kiwi fruit wine

[0093] The sensory score and total colony count were used as the end point of the shelf life. However, after 110 days of storage, the total colony count exceeded the standard at both 35 and 45°C, and the sensory score was already below 6 points. Therefore, the sensory score below 6 points was used as the end point of the shelf life.

[0094] The kiwi fruit wine obtained in Example 1 was stored at 45 and 55° C. for 110 days and 50 days, respectively.

[0095] The high temperature sterilization adopted in Comparative Example 6 is a common sterilization method for kiwi fruit wine. Taking this method as a comparison, it can be seen that the high temperature sterilization can store kiwi fruit wine for 80 days and 35 days at 45 and 55°C, respectively.

[0096] According to formula (1), under ultrahigh pressure sterilization conditions, Q10 = 110 / 50 = 2.2, and under high temperature sterilization conditions, Q10 = 80 / 35 = 2.29.

[0097] According to formula (2),

[0098] The shelf life of kiwi wine under ultra-high pressure sterilization conditions is:

[0099] T3×Q10 ΔT / 10 =110×2.2 2 =532d

[0100] The shelf life of kiwi wine under high temperature sterilization conditions is:

[0101] T3×Q10 ΔT / 10 =80×2.29 2 =419d.

[0102] The embodiments provided above are not intended to limit the scope of the present invention, nor are the steps described to limit their execution order. Any obvious improvements to the present invention made by those skilled in the art in combination with existing common knowledge shall fall within the scope of protection defined by the claims of the present invention.

Claims

1. A method for aging kiwi fruit wine and extending its shelf life, characterized in that: The method comprises the following: The fermented kiwifruit wine is placed in a food-grade polyethylene bag, vacuumed, sealed, and placed in an ultra-high pressure reactor for high-pressure treatment. The pressure is set to 450-500 MPa, the temperature is 20-30°C, the treatment time is 15-25 minutes, water is used as the pressure transmission medium, and the pressure increase rate is 80-100 MPa / min; after treatment, it can be stored at room temperature.

2. The method according to claim 1, characterized in that The pressure of the high-pressure treatment is 500 MPa, the temperature is 20-30° C., and the treatment time is 15-25 minutes.

3. The method according to claim 1, characterized in that The high pressure treatment was performed at a pressure of 500 MPa, a temperature of 20° C., and a treatment time of 25 min.

4. The method according to claim 1, wherein The high pressure treatment was performed at a pressure of 500 MPa, a temperature of 25° C., and a treatment time of 20 min.

5. The method according to claim 1, wherein The high pressure treatment was performed at a pressure of 450 MPa, a temperature of 30° C., and a treatment time of 25 min.

6. The method according to claim 1, characterized in that The high pressure treatment was performed at a pressure of 500 MPa, a temperature of 30° C., and a treatment time of 15 min.

7. The method according to claim 1, characterized in that The fermented kiwi fruit wine refers to the fruit wine directly formed by fermenting fresh kiwi fruit with microorganisms.

8. The method according to claim 1, characterized in that The fermented kiwi fruit wine refers to fruit wine fermented by using Pichia kudriavzevii P. kudriavzevii FPW7-6.

9. The method according to claim 1, characterized in that The specification of the food-grade polyethylene bag is 100-500 mL.

10. Kiwi fruit wine obtained by the method according to any one of claims 1 to 9.

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