Preparation method of high-stability euphausia superba oil

Abstract

The application discloses a preparation method of Euphausia Superba oil and belongs to the field of shrimp oil preparation. The preparation method of the application adopts food-grade ethanol with antioxidant added to extract Euphausia Superba powder, combines with adsorbents to reduce the content of metal ions, and then adopts the esterification of lipase to reduce the content of free fatty acids, so that the high-stability Euphausia Superba oil with low ethanol, low metal ion and low free fatty acid content is obtained. The removal rate of metal ions in the Euphausia Superba oil treated by the method of the application is above 80%, and the free fatty acid is reduced by above 30%. The application applies the physical adsorption technology to the removal of metal ions in the Euphausia Superba oil and applies the esterification of lipase to the reduction of free fatty acids in the Euphausia Superba oil, so that the prepared Euphausia Superba oil has high stability, better appearance color and good popularization and application prospect.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of shrimp oil preparation, and particularly relates to a preparation method of high-stability Antarctic krill oil. BACKGROUND

[0002] As a new type of marine functional oil, Antarctic krill oil has attracted widespread attention due to its rich nutritional ingredients such as polyunsaturated fatty acids (about 60% of total fatty acids), phospholipids and astaxanthin. It is also a product with relatively high nutritional efficacy and added value among Antarctic krill related products. The phospholipids in Antarctic krill oil belong to strong polar oil, which has strong hydrophilicity and can easily swell in water. Astaxanthin is heat sensitive and its structure can change under severe conditions. Therefore, the refining process in the production process of ordinary animal and plant oils is not suitable for the removal of impurities in Antarctic krill oil. In view of this, the extracted Antarctic krill oil has not been refined and may contain more metal ions and free fatty acids and other impurities that can promote oil oxidation, thereby affecting the oxidation stability of Antarctic krill oil and the shelf life of its related products. Therefore, there is an urgent need for a method for removing impurities and purifying Antarctic krill oil. SUMMARY

[0003] TECHNICAL PROBLEM

[0004] At present, some existing reported methods for removing impurities and purifying Antarctic krill oil cannot achieve the effects of high stability, excellent fluidity and high transparency.

[0005] TECHNICAL CONTENT

[0006] In view of the above shortcomings, the present application uses food-grade ethanol containing an antioxidant to extract Antarctic krill powder, which can effectively inhibit the oxidation loss of Antarctic krill oil during extraction. At the same time, the content of metal ions is reduced by adsorption with an adsorbent, and the content of free fatty acids is reduced by esterification with lipase, and finally the ethanol is removed by high vacuum desolventization, thereby preparing high-stability Antarctic krill oil with low ethanol, low metal ion and low free fatty acid content.

[0007] In order to achieve the above purpose, the present application provides a preparation method of high-stability Antarctic krill oil, comprising the following steps:

[0008] S1, extraction of Antarctic krill oil: mixing Antarctic krill powder and ethanol to obtain an Antarctic krill powder-ethanol solution, then adding an antioxidant, stirring, then standing, filtering, and obtaining an Antarctic krill oil-ethanol solution rich in antioxidants;

[0009] S2, removal of metal ions: taking the Antarctic krill oil-ethanol solution of step S1 and adding an adsorbent, stirring, then standing, centrifuging, and obtaining an Antarctic krill oil-ethanol solution rich in antioxidants and low in metal ion content;

[0010] S3, enzymatic esterification of free fatty acid: the Euphausia superba oil-ethanol solution rich in antioxidant and low in metal ion content obtained in step S2 is added to immobilized catalytic enzyme, then polyphenol is added, followed by stirring, standing, filtration, to obtain Euphausia superba oil-ethanol solution rich in antioxidant and low in metal ion and free fatty acid content;

[0011] S4, removal of ethanol: the Euphausia superba oil-ethanol solution rich in antioxidant and low in metal ion and free fatty acid content obtained in step S3 is subjected to ethanol removal treatment, to obtain high-stability Euphausia superba oil with low ethanol, metal ion and free fatty acid content.

[0012] Further, the antioxidant in step S1 includes one or more of food-grade vitamin C, tea polyphenol, vitamin E, ascorbic acid palmitate, bamboo leaf antioxidant, tea polyphenol palmitate, propyl gallate and rosemary extract.

[0013] Further, the ethanol in step S1 is preferably food-grade ethanol.

[0014] Further, the concentration of the antioxidant in the Euphausia superba powder-ethanol solution in step S1 is 0.0005-0.008 g / L.

[0015] Preferably, the antioxidant in step S1 is tea polyphenol palmitate.

[0016] Preferably, the mass concentration of tea polyphenol palmitate in the Euphausia superba powder-ethanol solution is 0.0016 g / L.

[0017] Further, the mass-to-volume ratio of Euphausia superba powder to ethanol in step S1 is 1 kg: 12 L.

[0018] Preferably, the mass-to-volume ratio of Euphausia superba powder to ethanol is 1 kg: 3 L.

[0019] Further, the stirring in step S1 is at 30-35°C and a rotation speed of 800-1000 rpm, and the stirring is maintained for 1-2 h.

[0020] Further, the adsorbent in step S2 includes one or more of silica gel, diatomite and attapulgite.

[0021] Further, the volume-to-mass ratio of Euphausia superba oil-ethanol solution to adsorbent in step S2 is 30-60 L: 1 kg.

[0022] Preferably, the adsorbent in step S2 is attapulgite.

[0023] Preferably, the volume-to-mass ratio of Euphausia superba oil-ethanol solution to attapulgite is 100: 9-10.

[0024] Further, the stirring in step S2 is performed at 30-35℃ and 800-1000rpm for 1-2h.

[0025] Further, the centrifugation in step S2 is performed at 4-5℃ and 2000-5000xg for 0.25-0.5h.

[0026] Further, the immobilized catalytic enzyme in step S3 can be selected from one or more of Novozym 435, Lipozyme TL IM, Lipozyme RM IM and Amano Lipase PS lipase.

[0027] Preferably, the immobilized catalytic enzyme in step S3 is Novozym 435.

[0028] Further, the mass-volume ratio of the immobilized catalytic enzyme and the ethanol solution of Euphausia superba oil rich in antioxidants and low in metal ions in step S3 is 1kg:30-60L.

[0029] Further, the polyphenol in step S3 includes one or more of tyrosol, epigallocatechin gallate.

[0030] Further, the mass-volume ratio of the polyphenol and the ethanol solution of Euphausia superba oil rich in antioxidants and low in metal ions in step S3 is 1g:300-600L.

[0031] Preferably, the polyphenol in step S3 is epigallocatechin gallate.

[0032] Further, the stirring in step S3 is performed at 25-30℃ and 800-1000rpm for 12-24h.

[0033] Further, the ethanol removal treatment in step S4 is first performed at a vacuum degree of 10000±200pa and a temperature of 25-40℃ for 0.5-2h, and then high-vacuum low-temperature ethanol removal is performed at a vacuum degree of 12±2pa and a temperature of 50-70℃ for 1.5-2h.

[0034] The present application provides high-stability Euphausia superba oil prepared by the above method.

[0035] The high-stability Euphausia superba oil provided by the present application is applied in the field of food.

[0036] Advantages

[0037] 1. The raw material for leaching is Antarctic krill powder, and the leaching solvent is ethanol containing antioxidants, which can effectively inhibit the oxidation loss of nutrients during the extraction of Antarctic krill oil.

[0038] 2. The metal ions and free fatty acids in the Antarctic krill oil prepared by physical adsorption and lipase esterification are significantly reduced, and the appearance of the krill oil is significantly improved.

[0039] 3. The storage stability of Antarctic krill oil is significantly improved, providing a good raw material for the development of related products. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 Figure 1 shows the changes in peroxide value of Antarctic krill oil with different single antioxidants added during extraction; different lowercase letters (a-d) are marked in the column chart, indicating that there is a significant difference (P<0.05) in the peroxide value of Antarctic krill oil with different antioxidants added during extraction; Con, VC, TP, AP, VE, AOB, TPP and RE represent Antarctic krill oil samples without added antioxidants, with food-grade vitamin C, tea polyphenol, ascorbic acid palmitate, food-grade vitamin E, food-grade bamboo leaf antioxidant, food-grade tea polyphenol palmitate and rosemary extract added during extraction, respectively.

[0041] Figure 2 Figure 2 shows the changes in thiobarbituric acid value of Antarctic krill oil with different single antioxidants added during extraction; different lowercase letters (a-e) are marked in the column chart, indicating that there is a significant difference (P<0.05) in the thiobarbituric acid value of Antarctic krill oil with different antioxidants added during extraction; Con, VC, TP, AP, VE, AOB, TPP and RE represent Antarctic krill oil samples without added antioxidants, with food-grade vitamin C, tea polyphenol, ascorbic acid palmitate, food-grade vitamin E, food-grade bamboo leaf antioxidant, food-grade tea polyphenol palmitate and rosemary extract added during extraction, respectively.

[0042] Figure 3 Figure 3 shows the effects of three different concentrations of adsorbents (silica gel, diatomite and attapulgite) on the removal of Mg 2+ (figure A), Fe 2+ (figure B) and Ca 2+ (figure C) in Antarctic krill oil; different lowercase letters (a-e), uppercase letters (A-E) and numbers (1-5) are marked in the column chart, indicating that there is a significant difference (P<0.05) in the removal rate of metal ions in Antarctic krill oil with three different concentrations of adsorbents (silica gel, diatomite and attapulgite).

[0043] Figure 4Effects of different concentrations of silica gel adsorption treatment on the color (Figure A), brightness (Figure B), redness (Figure C) and yellowness (Figure D) of Antarctic krill oil; different lowercase letters (a-f) in the column chart indicate that there are significant differences in the brightness, redness and yellowness of Antarctic krill oil treated by different concentrations of silica gel adsorption (P<0.05).

[0044] Figure 5 Effects of different concentrations of diatomite adsorption treatment on the color (Figure A), brightness (Figure B), redness (Figure C) and yellowness (Figure D) of Antarctic krill oil; different lowercase letters (a-f) in the column chart indicate that there are significant differences in the brightness, redness and yellowness of Antarctic krill oil treated by different concentrations of diatomite adsorption (P<0.05).

[0045] Figure 6 Effects of different concentrations of attapulgite adsorption treatment on the color (Figure A), brightness (Figure B), redness (Figure C) and yellowness (Figure D) of Antarctic krill oil; different lowercase letters (a-f) in the column chart indicate that there are significant differences in the brightness, redness and yellowness of Antarctic krill oil treated by different concentrations of attapulgite adsorption (P<0.05).

[0046] Figure 7 Effects of different kinds of immobilized lipase on esterification deacidification of Antarctic krill oil; different marks (a-b) in the column chart indicate that there are significant differences in the index (P<0.05).

[0047] Figure 8 Effects of the ratio of Antarctic krill oil to ethanol added with tyrosol (Figure A) and epigallocatechin gallate (Figure B) on esterification deacidification; different marks (a-c) in the column chart indicate that there are significant differences in the index (P<0.05), KO-no original Antarctic krill oil treated by any method.

[0048] Figure 9 Changes in the peroxide value of Antarctic krill oil added with different antioxidants during accelerated storage at 60℃; different lowercase letters (a-d) in the column chart indicate that there are significant differences in the peroxide value of Antarctic krill oil added with different antioxidants at the same storage time (P<0.05); Con, TP-D, TP-TPP-D, TP-A and TP-TPP-A represent Antarctic krill oil samples without added antioxidants, added with tea polyphenols during extraction, added with tea polyphenols-palmitoyl tea polyphenol ester during extraction, added with tea polyphenols after extraction and added with tea polyphenols-palmitoyl tea polyphenol ester after extraction, respectively.

[0049] Figure 10Changes in the TBA value of E. superba oil with different antioxidants during accelerated storage at 60 °C; different lowercase letters (a-d) in the column chart indicate that there are significant differences in the TBA values of E. superba oil with different antioxidants at the same storage time (P < 0.05); Con, TP-D, TP-TPP-D, TP-A and TP-TPP-A represent E. superba oil samples without antioxidants, with tea polyphenols added during extraction, with tea polyphenol-palmitate added during extraction, with tea polyphenols added after extraction and with tea polyphenol-palmitate added after extraction, respectively. DETAILED DESCRIPTION

[0050] Raw material sources

[0051] E. superba powder was purchased from Liaoyu Group Co., Ltd. (Dalian, China) and stored in a -80 °C refrigerator in the dark; food-grade vitamin C and tea polyphenols were purchased from Jianming Technology Co., Ltd. (Zhuhai, China); food-grade vitamin E, ascorbic acid palmitate and propyl gallate were purchased from Beijing Aladdin Bio-Chem Technology Co., Ltd. (Beijing, China); food-grade bamboo leaf antioxidant was purchased from Jiangsu Aikang Biological Medicine Research and Development Co., Ltd. (Nanjing, China); food-grade tea polyphenol palmitate and rosemary extract were purchased from Henan Yuzhong Biological Technology Co., Ltd. (Zhengzhou, China), and all the above antioxidants were stored in a -80 °C refrigerator; tyrosol and epigallocatechin gallate were purchased from Tianjin Alpha Esha Chemical Co., Ltd. (Tianjin, China); Novozym 435 (>10,000 U / g), Lipozyme TL IM (250 I UN / g), Lipozyme RM IM (275 I UN / g) and Amano Lipase PS (>20,000 U / g) lipases were purchased from Tianjin Novozymes Biological Technology Co., Ltd. (Tianjin, China).

[0052] Detection process

[0053] 1. Peroxide value detection:

[0054] Dissolve 0.01 g of E. superba oil in 1.5 mL of a mixture of dichloromethane and 95% ethanol (volume / volume, w / w, 3:2). Then, add 5 mM ferrous ammonium sulfate hexahydrate (100 μL), 1 M methanol-m-cresol orange tetrasodium salt (200 μL) and 0.25 M methanol-sulfuric acid (200 μL) and mix well. After 30 min at room temperature and in the dark, add pure water (1 mL) to the reaction system. Then centrifuge at 4000 x g for 5 min. Take the upper layer of the mixture (200 μL) and measure the absorbance (A 560 ) at 560 nm. After drawing the standard curve of cumene hydroperoxide, calculate the POV value (mmol / kg oil).

[0055] 2. Thiobarbituric acid value determination:

[0056] 0.10 g of Euphausia superba oil was mixed with a mixture (2.5 mL) including distilled water (196 mL), concentrated hydrochloric acid solution (4.17 mL), thiobarbituric acid (0.75 g), and trichloroacetic acid (30 g). After the mixture was heated in a boiling water bath for 10 min, it was cooled and centrifuged at 3000 x g for 10 min. The upper layer of the mixture (200 μL) was measured for absorbance (A) at 532 nm. 532 The malondialdehyde concentration was converted to TBARS value according to the following equation.

[0057] TBARS (ppm) = A 532 x 2.77 (Equation 1)

[0058] Example 1

[0059] S1 : Euphausia superba powder was mixed with ethanol added with food grade vitamin C (food grade vitamin C mass concentration was 0.006 g / L) at a ratio of 1 :8 (mass / volume, kg / L) at 30°C and 600 rpm, and stirred for 1 h, and then left to stand for 1 h, and filtered.

[0060] S2: The filtrate obtained in S1 was added to silica gel at a ratio of 1 :30 (adsorbent mass / solution volume, kg / L) at 30°C and 600 rpm, and stirred for 1 h, and then left to stand for 1 h, and centrifuged at 4°C and 3000 x g for 0.35 h.

[0061] S3: The supernatant obtained in S2 was added to Novozym 435 immobilized catalytic enzyme at a ratio of 1 :30 (enzyme mass / solution volume, kg / L), and tyrosol was added at a ratio of 1 :300 (polyphenol mass / solution volume, g / L) at 30°C and 600 rpm, and stirred for 12 h, and then left to stand for 1 h, and filtered.

[0062] S4: The filtrate obtained in S3 was subjected to ethanol removal at a vacuum degree of 10000 Pa and 30°C for 1 h, and then subjected to high-vacuum low-temperature ethanol removal at a vacuum degree of 12 Pa and 50°C for 1 h, to obtain Euphausia superba oil with high stability, low ethanol content, low metal ion content, and low free fatty acid content.

[0063] Example 2

[0064] S1 : Euphausia superba powder was mixed with ethanol added with tea polyphenol (tea polyphenol mass concentration was 0.0014 g / L) at a ratio of 1 :9 (mass / volume, kg / L) at 35°C and 700 rpm, and stirred for 1 h, and then left to stand for 1 h, and filtered.

[0065] S2: The filtrate obtained in S1 was added to diatomite at a ratio of 1:40 (adsorbent mass / solution volume, kg / L) and stirred at 35°C and 700 rpm for 1 h. Then it was allowed to stand for 1 h and centrifuged at 4°C and 4000 x g for 0.4 h.

[0066] S3: The supernatant obtained in S2 was added to Lipozyme TL IM immobilized catalytic enzyme at a ratio of 1:40 (enzyme mass / solution volume, kg / L) and epigallocatechin gallate at a ratio of 1:400 (polyphenol mass / solution volume, g / L), and stirred at 35°C and 700 rpm for 12 h, allowed to stand for 1 h, and filtered.

[0067] S4: The filtrate obtained in S3 was subjected to ethanol removal at a vacuum of 10000 Pa and 35°C for 1 h, and then subjected to high-vacuum low-temperature ethanol removal at a vacuum of 12 Pa and 50°C for 1 h, to obtain high-stability Antarctic krill oil with low ethanol, low metal ion, and low free fatty acid content.

[0068] Example 3

[0069] S1: Antarctic krill powder was mixed with vitamin E-added ethanol (vitamin E mass concentration 0.0016 g / L) at a ratio of 1:10 (mass / volume, kg / L), stirred at 40°C and 800 rpm for 1 h, allowed to stand for 1 h, and filtered.

[0070] S2: The filtrate obtained in S1 was added to attapulgite at a ratio of 1:50 (adsorbent mass / solution volume, kg / L) and stirred at 40°C and 800 rpm for 1 h. Then it was allowed to stand for 1 h and centrifuged at 4°C and 5000 x g for 0.45 h.

[0071] S3: The supernatant obtained in S2 was added to Lipozyme RM IM immobilized catalytic enzyme at a ratio of 1:50 (enzyme mass / solution volume, kg / L) and tyrosol at a ratio of 1:500 (polyphenol mass / solution volume, g / L), and stirred at 40°C and 800 rpm for 12 h, allowed to stand for 1 h, and filtered.

[0072] S4: The filtrate obtained in S3 was subjected to ethanol removal at a vacuum of 10000 Pa and 40°C for 1 h, and then subjected to high-vacuum low-temperature ethanol removal at a vacuum of 12 Pa and 60°C for 1 h, to obtain high-stability Antarctic krill oil with low ethanol, low metal ion, and low free fatty acid content.

[0073] Example 4

[0074] S1: Take the Euphausia Superba powder in a ratio of 1:11 (mass / volume, kg / L) and mix with ethanol added with ascorbyl palmitate (0.0006 g / L of ascorbyl palmitate mass concentration), keep stirring at 40°C and 900 rpm for 1.5 h, stand for 1.5 h, and filter.

[0075] S2: Take the filtrate obtained in S1 in a ratio of 1:60 (adsorbent mass / solution volume, kg / L) and add to silica gel, keep stirring at 30°C and 900 rpm for 1.5 h. Then stand for 1.5 h, and centrifuge at 4°C and 5000 x g for 0.4 h.

[0076] S3: Take the supernatant after centrifugation obtained in S2 in a ratio of 1:50 (enzyme mass / solution volume, kg / L) and add to Amano Lipase PS immobilized catalytic enzyme, and then take in a ratio of 1:500 (polyphenol mass / solution volume, g / L) and add to epigallocatechin gallate, keep stirring at 30°C and 1000 rpm for 24 h, stand for 1.5 h, and filter.

[0077] S4: Take the filtrate obtained in S3 and perform ethanol removal under a vacuum degree of 10000 pa and at a temperature of 30°C for 1.5 h, and then perform high-vacuum low-temperature ethanol removal under a vacuum degree of 12 pa and at a temperature of 70°C for 1.5 h, to obtain high-stability Euphausia Superba oil with low ethanol, low metal ion, and low free fatty acid content.

[0078] Example 5

[0079] S1: Take the Euphausia Superba powder in a ratio of 1:12 (mass / volume, kg / L) and mix with ethanol added with tea polyphenol palmitate (0.0016 g / L of tea polyphenol palmitate mass concentration), keep stirring at 35°C and 1000 rpm for 2 h, stand for 1.5 h, and filter.

[0080] S2: Take the filtrate obtained in S1 in a ratio of 1:60 (adsorbent mass / solution volume, kg / L) and add to diatomite, keep stirring at 30°C and 1000 rpm for 2 h. Then stand for 1.5 h, and centrifuge at 4°C and 5000 x g for 0.5 h.

[0081] S3: Take the supernatant after centrifugation obtained in S2 in a ratio of 1:50 (enzyme mass / solution volume, kg / L) and add to Novozym 435 immobilized catalytic enzyme, and then take in a ratio of 1:500 (polyphenol mass / solution volume, g / L) and add to tyrosol, keep stirring at 30°C and 1000 rpm for 24 h, stand for 1.5 h, and filter.

[0082] S4: The filtrate obtained in S3 is subjected to ethanol removal under the conditions of a vacuum degree of 10000 Pa and a temperature of 40℃ for 2h, and then subjected to high-vacuum low-temperature ethanol removal under the conditions of a vacuum degree of 12 Pa and a temperature of 70℃ for 2h, to obtain high-stability Euphausia superba oil with low ethanol, metal ion and free fatty acid contents.

[0083] Example 6

[0084] This example is an exploration of preferred antioxidants:

[0085] S1: Take Euphausia superba powder and mix with ethanol at a ratio of 1:8 (mass / volume, kg / L) without adding or adding food-grade vitamin C (mass concentration of 0.006 g / L), tea polyphenol (mass concentration of 0.0016 g / L), ascorbic acid palmitate (mass concentration of 0.0008 g / L), food-grade vitamin E (mass concentration of 0.0008 g / L), food-grade bamboo leaf antioxidant (mass concentration of 0.002 g / L), food-grade tea polyphenol palmitate (mass concentration of 0.0025 g / L), rosemary extract (mass concentration of 0.0012 g / L) (a total of 8 groups), under the conditions of 25℃ and a rotation speed of 1000 rpm, keep stirring for 0.5h, stand for 0.5h, and filter.

[0086] S2: The filtrate obtained in S1 is subjected to ethanol removal under the conditions of a vacuum degree of 10000 Pa and a temperature of 40℃ for 2h, and then subjected to high-vacuum low-temperature ethanol removal under the conditions of a vacuum degree of 12 Pa and a temperature of 70℃ for 2h, to obtain Euphausia superba oil with different single antioxidants added during extraction.

[0087] The Euphausia superba oil prepared in Example 6 is detected, and the results are shown in Figure 1 and 2 It can be found that the Euphausia superba oil in the tea polyphenol group and the tea polyphenol palmitate group has better oxidation stability.

[0088] Example 7

[0089] This example is an exploration of preferred adsorbents:

[0090] S1: Take Euphausia superba powder and mix with ethanol at a ratio of 1:8 (mass / volume, kg / L) under the conditions of 25℃ and a rotation speed of 1000 rpm, keep stirring for 0.5h, stand for 0.5h, and filter to obtain a filtrate.

[0091] S2: The filtrate obtained in S1 was added with 1%, 3%, 5%, 7%, 9% of silica gel, diatomite or attapulgite (a total of 15 groups) in proportion of adsorbent mass / solution volume, kg / L, at 30°C and 1000 rpm, and stirred for 2 h. Then it was left to stand for 1.5 h, and centrifuged at 4°C and 5000 x g for 0.5 h.

[0092] S3: The supernatant obtained in S2 after centrifugation was de-ethanized at a vacuum of 10000 pa and a temperature of 40°C for 2 h, and then high-vacuum low-temperature de-ethanized at a vacuum of 12 pa and a temperature of 70°C for 2 h, to obtain Euphausia superba oil with low ethanol and metal ions.

[0093] The 15 kinds of Euphausia superba oil prepared in Example 7 were detected, and the results are shown in Table 2. Figures 3-6 As can be seen from Table 2, diatomite is not very ideal for removing Mg 2+ , Fe 2+ and Ca 2+ , attapulgite is better in removing Fe 2+ and Ca 2+ , and silica gel is very good in removing Mg 2+ , and the maximum removal rate can be approached at an addition amount of 5-7%. Therefore, 9% of attapulgite is selected in consideration of all factors.

[0094] Example 8

[0095] This example is to explore the preference for enzymes:

[0096] S1: Euphausia superba powder was mixed with ethanol at a ratio of 1:8 (mass / volume, kg / L) at 25°C and 1000 rpm, and stirred for 0.5 h, left to stand for 0.5 h, and filtered.

[0097] S2: The supernatant obtained in S1 after centrifugation was added with Novozym 435, Lipozyme TL IM, Lipozyme RM IM or Amano Lipase PS immobilized catalyst enzymes at a ratio of 1:30 (enzyme mass / solution volume, kg / L), and stirred at 30°C and 1000 rpm for 24 h, left to stand for 1.5 h, and filtered.

[0098] S3: The filtrate obtained in S2 was de-ethanized at a vacuum of 10000 pa and a temperature of 40°C for 2 h, and then high-vacuum low-temperature de-ethanized at a vacuum of 12 pa and a temperature of 70°C for 2 h, to obtain Euphausia superba oil with low ethanol, low metal ions and low free fatty acid content and high stability.

[0099] The Euphausia superba oil prepared in Example 8 was detected, and the results are shown in Table 9. Figure 7 As shown in Table 9, it can be found that the acid value of the shrimp oil prepared by using Lipozyme TL IM, Lipozyme RM IM and Amano Lipase PS is higher than that of the shrimp oil prepared by using Novozym 435 at the same dosage, which indicates that the use of Novozym 435 is preferred in the preparation of Euphausia superba oil.

[0100] Example 9

[0101] This example is a preferred exploration of the ratio of polyphenols and Euphausia superba powder and ethanol:

[0102] S1: The Euphausia superba powder was mixed with ethanol at a ratio of 1:1, 1:2, 1:3, 1:4, 1:5, 1:7, 1:9 (mass / volume, kg / L) at 25℃ and 1000 rpm, and stirred for 0.5h, and then filtered.

[0103] S2: The supernatant obtained by centrifugation in S1 was added to Novozym 435 at a ratio of 1:30 (enzyme mass / solution volume, kg / L), and tyrosol and epigallocatechin gallate were added at a ratio of 1:500 (polyphenol mass / solution volume, g / L), respectively, and stirred at 30℃ and 1000 rpm for 24h, and then filtered.

[0104] S3: The filtrate obtained in S2 was subjected to ethanol removal at a vacuum degree of 10000pa and a temperature of 40℃ for 2h, and then subjected to high-vacuum low-temperature ethanol removal at a vacuum degree of 12pa and a temperature of 70℃ for 2h, to obtain high-stability Euphausia superba oil with low ethanol, metal ion and free fatty acid content.

[0105] The Euphausia superba oil prepared in Example 9 was detected, and the results are shown in Table 9. Figure 8 As shown in Table 9, it can be found that the acid value of the shrimp oil prepared by using Lipozyme TL IM, Lipozyme RM IM and Amano Lipase PS is higher than that of the shrimp oil prepared by using Novozym 435 at the same dosage, which indicates that the use of Novozym 435 is preferred in the preparation of Euphausia superba oil.

[0106] Example 10

[0107] This example is a preferred exploration of the ratio of polyphenols and Euphausia superba powder and ethanol:

[0108] S1: Antarctic krill powder was mixed with ethanol at a ratio of 1:8 (mass / volume, kg / L) at 25°C and 1000 rpm, and stirred for 0.5 h, and then allowed to stand for 0.5 h, and then filtered.

[0109] S2: The filtrate obtained in S1 was subjected to ethanol removal under a vacuum of 10000 Pa and at a temperature of 40°C for 2 h, and then subjected to high-vacuum low-temperature ethanol removal under a vacuum of 12 Pa and at a temperature of 70°C for 2 h, to obtain Antarctic krill oil.

[0110] S3: 0.4 g / kg of tea polyphenol or tea polyphenol-tea polyphenol palmitate was added to the Antarctic krill oil obtained in S2, to obtain Antarctic krill oil with tea polyphenol or tea polyphenol-tea polyphenol palmitate added after extraction.

[0111] The Antarctic krill oil prepared in Example 10 was detected, and the results are shown in Tables 1 and 2. Figure 9 and 10 It can be found that the oxidation stability of the krill oil prepared by adding tea polyphenol and tea polyphenol-tea polyphenol palmitate during extraction is higher than that of the krill oil prepared by adding tea polyphenol and tea polyphenol-tea polyphenol palmitate after extraction at the same dosage, which indicates that the effect of adding an antioxidant during the extraction of Antarctic krill oil is better. And by comparing the antioxidant effects of tea polyphenol and tea polyphenol-tea polyphenol palmitate, it can be found that TP-TPP-D, i.e., adding tea polyphenol-tea polyphenol palmitate during extraction, has the lowest thiobarbituric acid value and peroxide value, which indicates that the best antioxidant to use is tea polyphenol-tea polyphenol palmitate added during extraction.

[0112] Example 11

[0113] S1: Antarctic krill powder was mixed with tea polyphenol palmitate-added ethanol (tea polyphenol palmitate mass concentration of 0.0016 g / L) at a ratio of 1:3 (mass / volume, kg / L) at 35°C and 1000 rpm, and stirred for 2 h, and then allowed to stand for 1.5 h, and then filtered.

[0114] S2: The filtrate obtained in S1 was added to attapulgite at a ratio of 9:100 (adsorbent mass / solution volume, kg / L) at 30°C and 1000 rpm, and stirred for 2 h, and then allowed to stand for 1.5 h, and then centrifuged at 4°C and 5000 x g for 0.5 h.

[0115] S3: The supernatant after centrifugation obtained from S2 was added with Novozym 435 immobilized catalytic enzyme at a ratio of 1:30 (enzyme mass / solution volume, kg / L) and then epigallocatechin gallate was added at a ratio of 1:500 (polyphenol mass / solution volume, g / L), and then stirring was maintained at 30°C and a rotation speed of 1000 rpm for 24 h, and then standing for 1.5 h, and then filtration.

[0116] S4: The filtrate obtained from S3 was subjected to ethanol removal at a vacuum degree of 10000 pa and a temperature of 40°C for 2 h, and then high-vacuum low-temperature ethanol removal was performed at a vacuum degree of 12 pa and a temperature of 70°C for 2 h, to obtain high-stability Euphausia superba oil with low ethanol content, low metal ion content, and low free fatty acid content.

[0117] Comparative Example 1

[0118] Euphausia superba powder was mixed with ethanol at a ratio of 1:12 (mass / volume, kg / L), and then stirring was maintained at 35°C and a rotation speed of 1000 rpm for 2 h, and then standing for 1.5 h, and then filtration. The filtrate was subjected to ethanol removal at a vacuum degree of 10000 pa and a temperature of 40°C for 2 h, and then the concentrated solution obtained was Euphausia superba oil.

[0119] The peroxide value of the Euphausia superba oil prepared in Comparative Example 1 was 0.42 mmol / kg, the thiobarbituric acid value was 0.82 mg MDA / kg, and the acid value was 10.38 mg KOH / g (as in Figure 1 , 2 and 7). Sensory evaluation showed that the Euphausia superba oil had a strong fishy smell, and the fishy smell was particularly strong after storage for a period of time. The Euphausia superba oil had poor flowability under low-temperature conditions, was in a semi-solid state, and became turbid in appearance and had poor transparency after standing for a period of time.

[0120] Comparative Example 2

[0121] Euphausia superba powder was mixed with ethanol at a ratio of 1:12 (mass / volume, kg / L), and then stirring was maintained at 35°C and a rotation speed of 1000 rpm for 2 h, and then standing for 1.5 h, and then filtration. The filtrate was subjected to ethanol removal at a vacuum degree of 10000 pa and a temperature of 40°C for 2 h, and then the concentrated solution obtained was Euphausia superba oil. According to the national standard GB 2760-2014, the antioxidant tea polyphenol was added to the oil at 0.4 g / kg.

[0122] The peroxide value of the Euphausia superba oil prepared in Comparative Example 2 was 0.42 mmol / kg, the thiobarbituric acid value was 0.82 mg MDA / kg, and the acid value was 10.38 mg KOH / g (as in Figure 1 , 2and 7). The sensory evaluation showed that the phosphorus shrimp oil had heavy shrimp smell, poor fluidity at low temperature, semi-solid state, and poor transparency after being placed for a period of time. The Antarctic krill oil prepared in Comparative Example 2 was subjected to the storage period oxidation stability test, and the results showed that after being stored for 8 days, the peroxide value was 0.54 mmol / kg and the thiobarbituric acid value was 2.5 mg MDA / kg, and the specific change curves of the peroxide value and the thiobarbituric acid value with the storage time are shown in Figure 8 and 9 .

[0123] The high-stability Antarctic krill oil prepared in Examples 1-5 and Comparative Examples 1-2 was subjected to detection of peroxide value, thiobarbituric acid value, Fe 2+ removal rate, Mg 2+ removal rate, Ca 2+ removal rate, and acid value, and the results are shown in Table 1 below.

[0124] Table 1: Detection data of Examples 1-5 and Comparative Examples 1-2

[0125]

[0126] The Antarctic krill oil prepared in Example 1 was subjected to the storage period oxidation stability test, and the results showed that after being stored for 8 days, the peroxide value was 0.39 mmol / kg and the thiobarbituric acid value was 0.78 mg MDA / kg, while the peroxide value of the Antarctic krill oil prepared in Comparative Example 1 was 0.42 mmol / kg, the thiobarbituric acid value was 0.83 mg MDA / kg, and the acid value was 10.38 mgKOH / g (as shown in Figure 1 , 2 , 3 and 7). The sensory evaluation showed that the phosphorus shrimp oil prepared in Example 1 had lighter shrimp smell, good fluidity and transparency, and compared with the comparative examples, the Antarctic krill oil prepared by the method had significant advantages in various evaluation indexes (as shown in Figure 4 , 5 and 6).

[0127] The Antarctic krill oil prepared in Example 2 was subjected to the storage period oxidation stability test, and the results showed that after being stored for 8 days, the peroxide value was 0.35 mmol / kg and the thiobarbituric acid value was 0.72 mg MDA / kg, while the peroxide value of Comparative Example 1 was 0.42 mmol / kg and the thiobarbituric acid value was 0.83 mg MDA / kg, indicating that the oxidation stability of the Antarctic krill oil prepared in the example was obviously better than that of the comparative example, and had good storage stability, and the specific change curves of the peroxide value and the thiobarbituric acid value with the storage time are shown in Figure 8 and 9 .

[0128] Example 3 prepared Antarctic krill oil with a peroxide value of 0.38 mmol / kg, a thiobarbituric acid value of 0.78 mg MDA / kg, and an Fe content of [missing information]. 2+ The removal rate was 81.76%, Mg 2+ The removal rate was 72.84%, Ca 2+ The removal rate was 64.28%, and the acid value was 8.03 mg KOH / g. In contrast, the Antarctic krill oil prepared in Comparative Example 1 had a peroxide value of 0.42 mmol / kg, a thiobarbituric acid value of 0.83 mg MDA / kg, and an acid value of 10.38 mg KOH / g (e.g., ...). Figure 1 , 2 Sensory evaluation showed that the krill oil had a milder fishy smell. It also exhibited good flowability and transparency. Compared to the comparative sample, the Antarctic krill oil prepared by this method showed significant advantages in all evaluation indicators (e.g., ...). Figure 4 , 5 and 6).

[0129] Example 4 prepared Antarctic krill oil with a peroxide value of 0.39 mmol / kg, a thiobarbituric acid value of 0.79 mg MDA / kg, and an Fe content of [missing information]. 2+ The removal rate was 92.75%, Mg 2+ The removal rate was 70.39%, Ca 2+ The removal rate was 58.09%, and the acid value was 7.59 mg KOH / g. In contrast, the Antarctic krill oil prepared in Comparative Example 1 had a peroxide value of 0.42 mmol / kg, a thiobarbituric acid value of 0.82 mg MDA / kg, and an acid value of 10.38 mg KOH / g (e.g., ...). Figure 1 , 2 Sensory evaluation showed that the krill oil had a milder fishy smell. It also exhibited good flowability and transparency. Compared to the comparative sample, the Antarctic krill oil prepared by this method showed significant advantages in all evaluation indicators (e.g., ...). Figure 4 , 5 and 6).

[0130] Example 5 prepared Antarctic krill oil with a peroxide value of 0.36 mmol / kg, a thiobarbituric acid value of 0.70 mg MDA / kg, and an Fe content of [missing information]. 2+ The removal rate was 91.25%, Mg 2+ The removal rate was 58.47%, Ca 2+ The removal rate was 62.84%, and the acid value was 7.37 mg KOH / g. In contrast, the Antarctic krill oil prepared in Comparative Example 2 had a peroxide value of 0.42 mmol / kg, a thiobarbituric acid value of 0.82 mg MDA / kg, and an acid value of 10.38 mg KOH / g (e.g., ...). Figure 1 , 2, 3 and 7). The sensory evaluation showed that the phosphorus shrimp oil had a weak fishy smell. Meanwhile, the phosphorus shrimp oil had good fluidity and transparency, and each evaluation index of the phosphorus shrimp oil prepared by the method showed a significant advantage compared with the comparative examples (for example Figure 4 、 5 and 6).

[0131] The above merely describes preferred specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can make equivalent replacements or changes within the technical scope disclosed by the present application and according to the technical solutions and inventive concept of the present application, which should be covered within the protection scope of the present application.

Claims

1. A method for preparing high-stability Euphausia superba oil, characterized by, The method comprises the following steps: S1, extraction of Antarctic krill oil: mixing Antarctic krill powder with ethanol to obtain an Antarctic krill powder ethanol solution, then adding an antioxidant, stirring, then standing, filtering, and obtaining an Antarctic krill oil-ethanol solution rich in antioxidants; the mass-volume ratio of the Antarctic krill powder to ethanol is 1 kg: 3 L; the antioxidant is food-grade tea polyphenols and / or tea polyphenol palmitate; S2, removal of metal ions: taking the Antarctic krill oil-ethanol solution of step S1, adding an adsorbent, stirring, then standing, centrifuging, and obtaining an Antarctic krill oil-ethanol solution rich in antioxidants and low in metal ion content; the adsorbent is attapulgite; the volume-mass ratio of the Antarctic krill oil-ethanol solution to the adsorbent is 100 L: 9 kg; S3, enzymatic esterification of free fatty acids: taking the Antarctic krill oil-ethanol solution rich in antioxidants and low in metal ion and free fatty acid content of step S2, adding immobilized catalytic enzyme, then adding polyphenols, then stirring, standing, filtering, and obtaining an Antarctic krill oil-ethanol solution rich in antioxidants and low in metal ion and free fatty acid content; the immobilized catalytic enzyme is Novozym 435; the polyphenol is epigallocatechin gallate; S4, removal of ethanol: taking the Antarctic krill oil-ethanol solution rich in antioxidants and low in metal ion and free fatty acid content of step S3, performing ethanol removal treatment, and obtaining high-stability Antarctic krill oil; The ethanol removal treatment is first ethanol removal treatment under the conditions of a vacuum degree of 10,000±200 pa and a temperature of 25-40 ℃ for 0.5-2 h, and then vacuum ethanol removal treatment under the conditions of a vacuum degree of 12±2 pa and a temperature of 50-70 ℃ for 1.5-2 h.

2. The method of claim 1, wherein The concentration of the antioxidant in the Antarctic krill powder ethanol solution in step S1 is 0.0005-0.008 g / L.

3. The method of claim 1, wherein The mass-volume ratio of the immobilized catalytic enzyme to the Antarctic krill oil-ethanol solution rich in antioxidants and low in metal ion content in step S3 is 1 kg: 30-60 L.

4. The method of claim 1, wherein The mass-volume ratio of the polyphenol to the Antarctic krill oil-ethanol solution rich in antioxidants and low in metal ion content in step S3 is 1 g: 300-600 L.

5. The method of claim 1 wherein, The stirring in step S3 is stirring at a temperature of 25-30 ℃ and a rotation speed of 800-1,000 rpm for 12-24 h.

6. The high-stability Antarctic krill oil obtained by the method of any one of claims 1-5.

7. The high-stability Antarctic krill oil of claim 6 for use in the field of food.

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