Fresh-keeping method of macadamia nut fresh kernels

Abstract

The invention discloses a fresh-keeping method of fresh macadamia nut kernels, and belongs to the technical field of fresh-keeping storage of fresh macadamia nut products. The fresh-keeping method of the fresh macadamia nuts comprises the following steps: taking fresh macadamia nuts which are just picked, removing green peels and hard shells, and ensuring that the moisture content of the macadamia nuts is more than 15wt%; and putting the nutlet into a packaging box, adding a preservative into the packaging box, and sealing and storing to complete preservation of the fresh macadamia nut nutlet. The component of the fresh-keeping agent comprises plant polyphenol. As the content of unsaturated fatty acid and the water content are relatively high, the fresh macadamia nuts are extremely easy to oxidize and rancidify in the fresh-keeping storage process, and microorganisms such as mould are bred, the plant polyphenol is added into the fresh macadamia nuts without green peels and hard shells for sealed storage, so that the fresh macadamia nuts can be stored in the fresh-keeping storage process; the oxygen content in the macadamia nut fresh nutlet package is rapidly reduced, and meanwhile, a part of water vapor is absorbed, so that the effect of inhibiting respiration and oxidation of fresh nutlets is achieved, meanwhile, the growth of microorganisms can be inhibited, and the refreshing time of the macadamia nut fresh nutlets is prolonged.

Description

Technical Field

[0001] The invention belongs to the technical field of fresh-keeping and storage of macadamia nut fresh products, and particularly relates to a method for preserving fresh macadamia nut kernels. Background Art

[0002] Macadamia (Macadamia integrifolia Maiden & Betche), also known as macadamia nut, Queensland chestnut, etc., is a perennial evergreen fruit tree of the genus Macadamia in the family Proteaceae. Macadamia nuts have a high oil content and a strong aroma. The fat content in the kernel is about 70%-80%, of which saturated fatty acids account for about 22.39% and unsaturated fatty acids account for about 77.23%. These unsaturated fatty acids have great benefits for the human body, such as immune regulation, cell growth promotion, and prevention of cardiovascular diseases. Macadamia kernels also contain a large amount of vitamin E, phytosterols, phenols and other substances, which make them have high health biological activity, such as antioxidant and anti-aging functions. In addition, macadamia kernels also contain about 6%-9% protein, trace elements (calcium, phosphorus, iron, etc.) and bioactive substances.

[0003] At present, the macadamia nut products sold on the market are of a single type, which are basically roasted dried fruits. The products are basically roasted open shelled macadamia nuts and nut kernels and other dried fruits. The products are highly homogeneous, lack new products, and the market competition is concentrated. The situation has forced the forest farmers and primary processing plants in the nut producing areas to reduce their profits. The moisture content of the kernels in these dried fruit products is required to be less than 1.5%. However, the roasted macadamia nuts are dry and greasy, which can easily cause the human body to "get angry" after consumption, and further cause gingival swelling and pain, so the consumption is limited. In addition, studies have found that macadamia nuts undergo many heating and drying processes during the roasting process, and the unsaturated fatty acids and other nutrients in the kernels are easily oxidized and rancid, resulting in a decrease in their nutritional quality.

[0004] As people's living standards gradually improve, the diversified consumer demand for macadamia nuts is also gradually increasing. Unroasted fresh macadamia nuts have a crispy and tender taste, a unique milky flavor, and are not easy to get angry when eaten. However, fresh macadamia nuts are very easy to lose moisture, oxidize and brown, and breed mold. There are currently no fresh macadamia nut products on the market. At the same time, the harvest period of macadamia nuts is concentrated, requiring primary processing plants to complete large-scale processing in a very short time, and the production load is extremely unbalanced. Therefore, the market is in urgent need of macadamia nut preservation technology to enrich product forms and fill the gaps in the industry. However, due to the high moisture content in fresh macadamia kernels, generally about 21-25%, fresh macadamia kernels are prone to browning reactions and breed mold and other microorganisms, making the preservation technology of fresh products difficult. Patent CN202210610881.3 provides a method for fresh-eating macadamia nuts and a processing method and a storage method thereof, but this invention patent is for fresh macadamia nuts with the green skin removed, and the preservation and storage time of fresh macadamia nuts with the shell is extended by microwave treatment, soaking in a solution of an antibacterial agent natamycin, and the patent is for fresh nuts, and the moisture content of the kernel is first dried to 6-12%, which is much less than that of fresh nuts just picked, and the technical difficulty of preserving the kernel is also reduced. Patent CN202111159228.1 provides a method for preserving and storing macadamia nuts, but this invention patent is also for fresh macadamia nuts with the green skin removed. However, when eating fresh macadamia nuts with shells, the kernels are not easy to separate from the shells, and the edibility and convenience are poor. It is of great significance to directly develop fresh macadamia nuts and their preservation and storage technology. However, fresh macadamia kernels have lost the protection of their green skin and hard shell, so the moisture in the kernels is more easily lost, and unsaturated fatty acids are more easily oxidized, breeding microorganisms such as mold. Therefore, the preservation and storage technology of fresh macadamia kernels is more difficult. At present, research on the preservation technology of fresh macadamia kernels is basically blank. Summary of the invention

[0005] The object of the present invention is to provide a method for preserving fresh edible kernels of macadamia nuts. Freshly picked macadamia nuts are taken, the green skin and hard shell are removed, and the moisture content of the kernels is ensured to be above 15wt.%; the fresh kernels are placed in a packaging box, and plant polyphenols are added into the packaging box, and then the packaging box is sealed and stored, thereby completing the preservation of the fresh edible kernels of macadamia nuts.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A method for preserving fresh edible kernels of macadamia nuts comprises the following steps: taking freshly picked macadamia nuts and removing the green skin and hard shell; putting the kernels into a packaging box, adding a preservative into the packaging box and sealing and storing the packaging box, thereby preserving the fresh edible kernels of macadamia nuts;

[0008] The ingredients of the preservative include plant polyphenols.

[0009] The plant polyphenols used in the present invention can be selected from hydrolyzable plant polyphenols or non-hydrolyzable plant polyphenols alone, or a combination of two plant polyphenols. The plant polyphenols play a preservation role in the present invention due to their oxygen absorption characteristics.

[0010] Among them, hydrolyzable plant polyphenols include gallnut tannin, tara tannin, ellagitannin, emblica polyphenol, etc., and non-hydrolyzable plant polyphenols include bayberry tannin, larch tannin, etc.

[0011] The plant polyphenols of the present invention are preferably widely available, easy to obtain and low in cost. Other plant polyphenols besides the above plant polyphenols can also achieve the technical purpose of the present invention.

[0012] Preferably, the packaging box is made of a material with high gas barrier properties, such as polyethylene, polypropylene, etc.

[0013] Preferably, the preservative further comprises alkaline substances.

[0014] The ingredients added in the present invention may also include alkaline substances. Adding alkaline substances can provide an alkaline environment for the deoxygenation reaction of plant polyphenols, help ionize protons, further improve the oxygen and moisture absorption properties of plant polyphenols, and enhance the preservation effect.

[0015] More preferably, the alkaline substance comprises sodium carbonate or sodium hydroxide.

[0016] More preferably, the mass ratio of the plant polyphenols to the sodium carbonate is 1:0 to 1:3 and is not 1:0.

[0017] More preferably, the sodium carbonate is anhydrous sodium carbonate or sodium carbonate decahydrate.

[0018] Preferably, the sealed storage temperature is 4-25°C.

[0019] The beneficial technical effects of the present invention are as follows:

[0020] Fresh macadamia kernels are very easy to oxidize and become rancid, and breed microorganisms such as mold during the preservation and storage process due to the high content of unsaturated fatty acids and water content. The present invention adds plant polyphenols to the fresh macadamia kernels after the green skin and hard shell are removed and then sealed for storage, so that the oxygen content in the package of the fresh macadamia kernels decreases rapidly, and at the same time, it also absorbs a part of water vapor to reduce the relative humidity in the package, thereby achieving the effect of inhibiting the oxidation and rancidity of the oil of the fresh kernels, and at the same time, it can also inhibit the growth of microorganisms, thereby extending the shelf life of the fresh macadamia kernels. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1These are the appearance pictures of the preservation group and the blank control group in Example 1 on the 1st day, the 11th day and the 27th day.

[0022] Figure 2 This is a graph showing the change in oxygen content in the fresh-keeping box of the fresh-keeping group and the blank control group over time in Example 1.

[0023] Figure 3 This is a graph showing the change in acid value over time during the fresh-keeping storage process for the fresh-keeping group and the blank control group in Example 2.

[0024] Figure 4 This is a graph showing the change in peroxide value over time during the fresh-keeping storage process of the fresh-keeping group and the blank control group in Example 2.

[0025] Figure 5 These are the appearance pictures of the fresh-keeping group and the blank control group in Example 3 on the 1st day and the 5th day.

[0026] Figure 6 The oxygen content in the fresh-keeping box of the fresh-keeping group and the blank control group in Example 3 on the 1st day and the 5th day.

[0027] Figure 7 The acid value of macadamia nut kernels in the fresh-keeping group and the blank control group in Example 4 on the 1st day and the 5th day.

[0028] Figure 8 The peroxide value of macadamia nut kernels in the fresh-keeping group and the blank control group in Example 4 on the 1st day and the 5th day.

[0029] Fig. 9 These are the appearance pictures of the preservation group and the blank control group in Example 5 on the 1st day and the 5th day.

[0030] Fig.10 The moisture content of macadamia nut kernels in the fresh-keeping group and the blank control group in Example 5 on the 1st day and the 5th day.

[0031] Fig.11 The oxygen content in the fresh-keeping box of the fresh-keeping group and the blank control group in Example 5 on the 1st day and the 5th day.

[0032] Fig.12 The oxygen content in the fresh-keeping box of the fresh-keeping group and the blank control group in Example 6 on the 1st day and the 5th day.

[0033] Fig.13 The moisture content of macadamia nut kernels in the fresh-keeping group and the blank control group in Example 6 on the 1st day and the 5th day.

[0034] Fig.14 The acid value of macadamia nut kernels in the fresh-keeping group and the blank control group in Example 6 on the 1st day and the 5th day.

[0035] Fig.15The peroxide value of macadamia nut kernels in the fresh-keeping group and the blank control group in Example 6 on the 1st day and the 5th day.

[0036] Fig.16 The acid value of macadamia nut kernels in the fresh-keeping group and the blank control group in Example 7 on the 1st day and the 5th day.

[0037] Fig.17 It is the peroxide value of macadamia nut kernels in the fresh-keeping group and the blank control group in Example 7 on the 1st day and the 5th day. DETAILED DESCRIPTION

[0038] Now, various exemplary embodiments of the present invention are described in detail, and this detailed description should not be considered as a limitation of the present invention, but should be understood as a more detailed description of certain aspects, characteristics and embodiments of the present invention. It should be understood that the terms described in the present invention are only for describing specific embodiments and are not used to limit the present invention.

[0039] In addition, for the numerical range in the present invention, it is understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. The intermediate value in any stated value or stated range, and each smaller range between any other stated value or intermediate value in the range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0040] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the invention pertains. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention.

[0041] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0042] Example 1

[0043] Mature and pest-free macadamia nuts were picked from the planting base, and the green skin was removed and then shelled immediately. The moisture content of the obtained kernels was about 19-21wt.%. Then 70-80g of fresh kernels were put into a polypropylene fresh-keeping box, 3g of hydrolyzed plant polyphenols (gallic tannin) were wrapped with filter paper and put into the fresh-keeping box, the box was sealed, and a filter paper bag without plant polyphenols was set as a blank control group, which was placed in a 6°C refrigerator for fresh-keeping storage for 27 days.

[0044] The appearance of the fresh-keeping group (GT) and the blank control group (Control) on the 1st, 11th and 27th days is shown in the figure. Figure 1During the fresh-keeping storage process, the HGT-01H headspace gas analyzer was used to collect the gas inside the fresh-keeping box and analyze the oxygen content in the fresh-keeping box. The change of oxygen content in the fresh-keeping box over time is shown in Figure 2 .

[0045] from Figure 1 It can be seen that the fresh nut kernels in the blank control group obviously breed a large number of microorganisms such as mold, and have grown hair visible to the naked eye, while the fresh nut kernels in the experimental group using the preservation technology of the present invention have no obvious changes on the 27th day compared with the 1st day, and the appearance is still white, tender and fresh.

[0046] from Figure 2 It can be seen that the oxygen content in the packaging boxes of the fresh-keeping group and the blank control group will gradually decrease with time. This is because the nut kernels are gradually oxidized by oxygen. However, the oxygen content in the packaging box of the fresh-keeping group decreases rapidly compared with the blank control group, and the oxygen content during the storage period is lower than that of the blank control group. This is because the plant polyphenols placed in the box absorb the oxygen in the packaging box, and the plant polyphenols also absorb some water vapor. The lower oxygen concentration and air humidity can not only inhibit the oxidation and rancidity of the nuts, but also inhibit the growth of microorganisms, thereby extending the shelf life of fresh nuts.

[0047] Example 2

[0048] Mature, pest-free macadamia nuts were picked from the planting base, and the green skin was removed and then shelled immediately. The moisture content of the kernels was about 19-21wt.%. Then 70-80g of fresh kernels were placed in a polypropylene fresh-keeping box, and 6g of a mixture of hydrolyzed plant polyphenols (i.e., gallic tannin) / sodium carbonate decahydrate (the mass ratio of gallic tannin to sodium carbonate decahydrate was 1:1) was wrapped with filter paper and placed in the fresh-keeping box. The box was sealed, and a filter paper bag without plant polyphenols / sodium carbonate decahydrate was set as a blank control group. The boxes were placed in a refrigerator at 6°C for fresh-keeping and storage, and the acid value and peroxide value of the macadamia kernels were tested in real time.

[0049] The acid value was determined by the first method cold solvent indicator titration method in GB 5009.229-2016 "National Food Safety Standard Determination of Acid Value in Food". The peroxide value was determined by the second method potentiometric titration method in GB 5009.227-2016 "National Food Safety Standard Determination of Peroxide Value in Food".

[0050] The results of the acid value determination of the fresh-keeping group (GT) and the blank control group (Control) are shown in Figure 3 The results of peroxide value determination are shown in Figure 4 .

[0051] Acid value can reflect the content of free fatty acids in nut kernels, measure the degree of hydrolysis and rancidity of nut kernel lipids, and is also the main parameter that directly reflects the degradation of nut kernel oils. It is an important indicator for evaluating the storage quality of macadamia nuts. Figure 3 As shown, during the entire storage process, the acid value of the macadamia kernels in the fresh-keeping group was lower than that in the blank group, indicating that the fresh-keeping technology of the present invention can effectively reduce the oxygen content in the packaging box, thereby inhibiting the oxidation and rancidity of the kernels, slowing down the decomposition and oxidation rate of free fatty acids in the nut kernel oil, and ensuring the quality of fresh kernels.

[0052] Peroxide value is also an important indicator for evaluating the quality of nut oils. Nut kernels are affected by factors such as temperature and oxygen, which will accelerate the oxidation and rancidity of oils and produce hydrogen peroxides, leading to an increase in the peroxide value of the kernels. Figure 4 It can be seen that the peroxide value shows an overall upward trend with the extension of storage time. Before storage, the peroxide value of the nut kernel is 0.0030g / 100g. After storage, although the peroxide values ​​of the two groups of experiments are lower than the nut standard of 0.08g / 100g, the peroxide value of the fresh kernels in the blank group is always higher than that in the fresh-keeping group during storage, indicating that the nut oil in the blank control group is rapidly oxidized, which promotes the generation of free radicals and the decomposition and polymerization of hydroperoxides, thereby accelerating the oxidation reaction, and ultimately leading to a significant increase in the peroxide value, while the fresh-keeping group significantly inhibits the oxidation process of the nut kernel oil. It can be seen that the fresh-keeping technology of the present invention can significantly extend the shelf life of fresh macadamia nuts and improve the storage quality of the kernels.

[0053] Example 3

[0054] Mature and pest-free macadamia nuts are picked from the planting base, and the green skin is removed and then shelled immediately. The moisture content of the obtained kernels is about 19-21wt.%. Then 70-80g of fresh kernels are put into a polypropylene fresh-keeping box, 3g of hydrolyzed plant polyphenols (i.e., gallic tannin) are wrapped with filter paper and put into the fresh-keeping box, the box is sealed, and a filter paper bag without plant polyphenols is set as a blank control group, and the kernels are stored at room temperature of 25°C for 5 days.

[0055] The appearance of the fresh-keeping group (GT) and the blank control group (Control) on the first and fifth days is shown in the figure. Figure 5 , the oxygen content in the fresh-keeping box (see Example 1 for detection method) Figure 6 .

[0056] Figure 5 It was shown that the fresh nut kernels in the blank control group had grown hair visibly and had obviously bred a large number of microorganisms such as mold, while the fresh kernels in the experimental group using the preservation technology of the present invention still looked white, tender and fresh, without obvious mold growth. Figure 6It shows that the oxygen content in the packaging box of the fresh-keeping group is significantly lower than that of the blank control group. The lower oxygen concentration can not only inhibit the oxidation and rancidity of fresh nut oils, but also inhibit the growth of microorganisms, thereby extending the shelf life of nuts.

[0057] Example 4

[0058] Mature macadamia nuts without diseases and insect pests were picked from the planting base, and the green skin was removed and then shelled immediately. The moisture content of the obtained kernels was about 19-21wt.%, and then 70-80g of fresh kernels were put into a polypropylene fresh-keeping box, 6g of a hydrolyzed plant polyphenol (i.e., gallic tannin) / anhydrous sodium carbonate mixture (the mass ratio of gallic tannin to anhydrous sodium carbonate was 1:1) was wrapped with filter paper and put into the fresh-keeping box, the box was sealed, and a filter paper bag without plant polyphenol / anhydrous sodium carbonate was set as a blank control group, and the kernels were stored at room temperature of 25°C for 5 days to detect the acid value and peroxide value of the macadamia kernels (the detection method was referred to Example 2).

[0059] The results of the acid value determination of the fresh-keeping group (GT) and the blank control group (Control) are shown in Figure 7 The results of peroxide value determination are shown in Figure 8 .

[0060] Depend on Figure 7 and Figure 8 It can be seen that after 5 days of storage at room temperature, the acid value and peroxide value of the nut kernels in the fresh-keeping group and the blank control group were higher than those on the first day, but the acid value and peroxide value of the nut kernels in the fresh-keeping group were significantly lower than those in the blank control group. The acid value and peroxide value are two important indicators of nut kernels. The lower the value, the fresher the nut kernels. It can be seen that the fresh-keeping technology of the present invention significantly inhibits lipid oxidation and rancidity during the storage of fresh-eating macadamia kernels, and improves the quality of the nut kernels during the fresh-keeping storage period.

[0061] Example 5

[0062] Mature, pest-free macadamia nuts from the planting base were picked, and after the green skin was removed, the shells were immediately peeled, and the moisture content of the obtained kernels was about 19-21wt.%, and then 70-80g of fresh kernels were placed in a polypropylene fresh-keeping box, 3g of non-hydrolyzable plant polyphenols (i.e., bayberry tannin, with bayberry tannin accounting for 100% by mass) were wrapped with a special packaging paper for a deoxidizer and placed in the fresh-keeping box, the box was sealed, and packaging paper without plant polyphenols was set as a blank control group. After being stored at room temperature of 25°C for 5 days, the appearance of the two groups of nuts was observed, and the oxygen content in the package (the detection method is shown in Example 1) and the moisture content of the macadamia kernels were measured.

[0063] The appearance of the fresh-keeping group (GT) and the blank control group (Control) on the first and fifth days is shown in the figure. Fig. 9, the moisture content of macadamia kernels is Fig.10 , the oxygen content in the fresh-keeping box is shown in Fig.11 .

[0064] Fig. 9 The results show that after 5 days of storage at room temperature, the fresh nut kernels in the blank control group obviously breed a large number of microorganisms such as mold, have grown hair visibly, and are inedible; while the kernels in the experimental group using the preservation technology of the present invention are still white, tender and fresh in appearance, without any hair growth.

[0065] Moisture content is an important indicator that affects the taste of nuts. When the moisture content of macadamia kernels is higher than 5%, they can be called fresh edible kernels. Fig.10 As shown, after 5 days of storage at room temperature, the moisture content of the nuts in the preservation technology group was still maintained at about 17%, indicating that the nuts in the preservation technology group still maintained a fresh, crisp and tender taste.

[0066] like Fig.11 As shown in the figure, after 5 days of storage at room temperature, the oxygen content in the packaging boxes of the fresh-keeping group and the blank control group decreased to a certain extent, and the oxygen content in the packaging boxes of the fresh-keeping group was significantly lower than that of the blank control group. The lower oxygen concentration can inhibit the oxidation and rancidity of the oil of fresh nuts, and also inhibit the growth of microorganisms, thereby extending the storage period of the nut kernels.

[0067] Example 6

[0068] Mature macadamia nuts without diseases and insect pests are picked from a planting base, and after the green skin is removed, the nuts are immediately shelled, and the moisture content of the obtained nuts is about 19-21wt.%, then 70-80g of fresh nuts are put into a polypropylene fresh-keeping box, 6g of a non-hydrolyzable plant polyphenol (i.e., bayberry tannin) / sodium carbonate decahydrate mixture (the mass ratio of bayberry tannin to sodium carbonate decahydrate is 1:1) is wrapped with a special packaging paper for a deoxidizer and put into the fresh-keeping box, the box is sealed, and packaging paper without plant polyphenol / sodium carbonate is set as a blank control group. After being stored at room temperature of 25°C for 5 days, the oxygen content in the package (the detection method is shown in Example 1) and the moisture content, acid value and peroxide value of the nuts (the detection method is shown in Example 2) are measured.

[0069] The oxygen content in the fresh-keeping box of the fresh-keeping group (GT / SD) and the blank control group (Control) on the first and fifth days is shown in Fig.12 , the moisture content of macadamia kernels is Fig.13 , the acid value of macadamia kernels can be found in Fig.14 , the peroxide value of macadamia kernels is Fig.15 .

[0070] Fig.12The results showed that after 5 days of storage at room temperature, the oxygen content in the packaging boxes of the fresh-keeping group and the blank control group decreased to a certain extent, and the oxygen content in the packaging boxes of the fresh-keeping group decreased more significantly. The lower oxygen concentration can inhibit the oxidation and rancidity of fresh nuts. After 5 days of storage at room temperature, the moisture content of the nuts in the fresh-keeping group decreased significantly, but still remained above 9%, and the fresh and crisp taste of the nuts was still retained ( Fig.13 ).like Fig.14 and Fig.15 As shown, after 5 days of storage at room temperature, the acid value and peroxide value of the nut kernels in the fresh-keeping group were lower than those in the blank control group, indicating that the fresh-keeping technology of the present invention significantly inhibited the lipid oxidation and rancidity of fresh macadamia kernels during storage, and improved the quality of macadamia kernels during the fresh-keeping storage period.

[0071] Example 7

[0072] Mature macadamia nuts without diseases and insect pests are picked from a planting base, and after the green skin is removed, the nuts are immediately shelled, and the moisture content of the obtained kernels is about 19-21wt.%, then 70-80g of fresh kernels are put into a polypropylene fresh-keeping box, 6g of a hydrolyzed plant polyphenol (emblica polyphenol) / sodium carbonate mixture (the mass ratio of emblica polyphenol to sodium carbonate is 1:1) is wrapped with a special packaging paper for a deoxidizer and put into the fresh-keeping box, the box is sealed, and packaging paper without plant polyphenol / sodium carbonate is set as a blank control group. After being stored at room temperature of 25°C for 5 days, the acid value and peroxide value of the nuts are measured (see Example 2 for the detection method).

[0073] The acid value of macadamia kernels in the fresh-keeping box on the 1st and 5th day in the fresh-keeping group (YG / SD) and the blank control group (Control) is shown in Figure 2. Fig.16 , the peroxide value of macadamia kernels is Fig.17 .

[0074] like Figure 16-17 As shown, after 5 days of storage at room temperature, the acid value and peroxide value of the kernels of the blank control group (Control) were 0.554 mg / g and 0.021 g / 100 g, respectively, and the acid value and peroxide value of the kernels of the preservation group (YG / SD) were 0.302 mg / g and 0.010 g / 100, respectively. It can be seen that the acid value and peroxide value of the kernels of the preservation group were significantly lower than those of the blank control group, indicating that the preservative of the present invention inhibits lipid oxidation and rancidity in the storage process of fresh macadamia kernels, and improves the quality of macadamia kernels during the preservation storage period.

[0075] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for preserving fresh-edible macadamia kernels, characterized in that: The following steps are involved: Take freshly picked macadamia nuts, remove the green skin and hard shell, and ensure that the moisture content of the kernel is above 15wt.%; put the kernel into a packaging box, add a preservative into the packaging box, and seal and store it, so as to preserve the fresh kernel of the macadamia nuts; The ingredients of the preservative include plant polyphenols.

2. The method for preserving fresh-edible macadamia kernels according to claim 1, characterized in that: The packaging box is made of a material with high gas barrier properties.

3. The method for preserving fresh-edible macadamia kernels according to claim 1, characterized in that: The preservative further comprises alkaline substances.

4. The method for preserving fresh-edible macadamia kernels according to claim 1, characterized in that: The alkaline substance includes sodium carbonate or sodium hydroxide.

5. The method for deoxygenating and preserving fresh-edible macadamia kernels according to claim 4, characterized in that: The mass ratio of the plant polyphenols to the sodium carbonate is 1:0 to 1:3 and is not 1:

0.

6. The method for preserving fresh-edible macadamia kernels according to claim 5, characterized in that: The sodium carbonate is anhydrous sodium carbonate or sodium carbonate decahydrate.

7. The method for deoxygenating and preserving fresh-edible macadamia kernels according to claim 1, characterized in that: The sealed storage temperature is 4-25°C.

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