Application of feather microbial degradation liquid in litchi preservation

Abstract

The invention discloses an application of a feather microbial degradation liquid in litchi preservation. The method comprises the following steps: degrading waste feathers by adopting bacillus, filtering a feather microbial degradation solution by gauze to obtain a filtrate, and then directly spraying the filtrate to the surfaces of picked litchi fruits; litchi peels sprayed with the filtrate in a natural state in midsummer only have a small number of browning spots on the second day, obvious partial browning occurs on the third day, the browning time is obviously prolonged, and the litchi peels of a control group (sprayed with water) are completely browned on the first day, so that the filtrate has certain anti-browning and anti-corrosion effects on the picked litchis, and the effect of preventing browning and corrosion of the litchis is obviously improved. As a result, oligopeptides and functional metabolites with antibacterial and antioxidant activity are generated when the feathers are degraded by the bacillus, the activity of microorganisms and oxidase which cause browning is inhibited, and the water loss of the litchi pericarp is slowed down. Therefore, the filtrate of the feather microbial degradation liquid remarkably prolongs the shelf life of the picked litchis, and economic benefits are increased.

Description

Technical field:

[0001] The invention belongs to the technical field of fruit preservation, and particularly relates to application of feather microbial degradation liquid in litchi preservation. Background technology:

[0002] Lychee (Litchi chinensis Sonn.) is a subtropical fruit that is loved by people for its rich nutritional value and sweet flavor and taste. It is called the "king of fruits" and the "queen of fruits". my country has a long history of cultivating lychees and is the country with the largest planting area in the world; at the same time, the annual output is about 2 million tons, accounting for about 77% of the world's total lychee production. Because lychee fruits mature in the hot and humid summer, they have vigorous metabolic activities after picking, and lose a lot of water. They are susceptible to infection by pathogens and browning and corruption. Usually, the lychee peel is prone to browning within 24 hours at room temperature. This seriously limits the storage and transportation and commercial value of lychee fruits in my country. At present, in the market circulation of lychee fruits in my country, 18-30% of the total annual output of lychees rotted due to browning, with an annual loss of about 4 billion yuan.

[0003] With the continuous research on litchi preservation technology, the preservation effect of litchi after harvest has made certain progress. Litchi preservation technology includes physical preservation technology (rapid precooling, atmosphere preservation, refrigerated preservation, etc.), chemical preservation technology (pharmaceutical preservation, color preservatives and quick freezing preservation, etc.), biological antibacterial preservation technology (such as antagonistic microorganisms, functional metabolites) and packaging preservation technology (such as spontaneous atmosphere, nano-bioantibacterial materials and edible coatings). In particular, the ultra-low temperature freezing and locking technology in recent years has extended the shelf life of litchi to 1 year, and the litchi after thawing still maintains a high quality. Among them, these physical and chemical preservation technologies still face some specific problems, including high cost, reduced fruit quality or food safety and environmental risks. Therefore, a new type of anti-browning and anti-corrosion preservation technology is urgently needed for litchi fruits after harvest. In contrast, biological preservation technology has a higher potential for litchi preservation because it is green, economical and safe.

[0004] Currently, it is still unknown whether the degradation liquid produced by microbial degradation of discarded feathers can have a preservation effect on post-harvest lychees. Summary of the invention:

[0005] In order to overcome the above problems, the present invention provides an application of feather microbial degradation liquid in litchi preservation. The present invention obtains feather microbial degradation liquid containing amino acids and functional metabolites by microbial degradation of discarded feathers, and uses the feather microbial degradation liquid or its filtrate as a litchi preservative; spraying it on the surface of litchi fruit has the effect of preventing browning, rotting and preserving at room temperature.

[0006] The purpose of the present invention is achieved through the following technical solutions:

[0007] The invention provides application of feather microbial degradation liquid of Bacillus cereus in litchi preservation.

[0008] Preferably, the Bacillus cereus is Bacillus cereus C3752, which was published in NCBI on January 30, 2022, and its accession number is OM368754.

[0009] Preferably, the feather microbial degradation liquid is a feather microbial degradation liquid obtained by inoculating Bacillus cereus into a culture medium containing discarded feathers.

[0010] Preferably, the feathers are chicken feathers, duck feathers or goose feathers.

[0011] Preferably, the culture medium containing discarded feathers comprises, by mass fraction, 0.01-0.07% NaCl, 0.02-0.08% KH2PO4, 0.01-0.07% K2HPO4, 0.003-0.007% MgSO4, 1% chicken feathers or 1% duck feathers or 1% goose feathers, and the remainder is water, with a pH of 9.0.

[0012] Preferably, the feather microbial degradation liquid is obtained by inoculating the seed liquid of Bacillus cereus C3752 into a culture medium containing discarded feathers at a volume ratio of 2-10%, and culturing at 30-40°C and 150-200rpm for 20-30h.

[0013] Furthermore, the seed solution is obtained by streaking Bacillus cereus C3752 on solid LB medium, culturing at 30-40°C for 16-28h, picking a single colony to liquid LB medium, and culturing at 30-40°C and 150-200rpm for 10-20h as the seed solution.

[0014] Preferably, the application is to spray the feather microbial degradation liquid directly on the surface of the lychee fruit after being picked and placed in a natural state in midsummer.

[0015] Preferably, the feather microbial degradation liquid is filtered through gauze to obtain a filtrate of the feather microbial degradation liquid, and the filtrate is directly sprayed on the surface of the post-harvest litchi fruit and placed in a natural state in midsummer.

[0016] Compared with the prior art, the present invention has the following advantages:

[0017] 1. The present invention utilizes feather microbial degradation liquid or its filtrate to preserve lychees, which can turn waste into treasure, realize value-added utilization, and is environmentally friendly and safe.

[0018] 2. The preservation process of the present invention is simple and easy to operate. The feather microbial degradation liquid or its filtrate is directly sprayed on the surface of the litchi fruit without water soaking, which can effectively prevent browning and rot in the natural state in midsummer.

[0019] The Bacillus cereus is Bacillus cereus C3752, which was published in NCBI on January 30, 2022: https: / / www.ncbi.nlm.nih.gov / nuccore / OM368754, and its accession number is OM368754. The applicant also holds this strain and guarantees that it will be available to the public within 20 years from the date of application. Description of the drawings:

[0020] Figure 1 The feather microbial degradation liquid obtained by degrading waste feathers with Bacillus cereus C3752 in Example 1 and its scanning electron microscope image.

[0021] Figure 2 The effect of the filtrate of the feather microbial degradation liquid in Example 2 on the browning of post-harvest litchi fruit. Specific implementation method:

[0022] The present invention is further explained below in conjunction with the accompanying drawings and specific embodiments, but does not constitute any limitation to the present invention.

[0023] Bacillus cereus is Bacillus cereus C3752, which was published in NCBI on January 30, 2022, and its accession number is OM368754.

[0024] Example 1 Degradation of waste feathers by Bacillus cereus

[0025] Streak Bacillus cereus C3752 on solid LB medium and culture at 37°C for 20 hours. Pick a single colony to liquid LB medium and culture at 37°C and 160rpm for 10 hours as seed liquid; inoculate the seed liquid into a medium containing discarded chicken feathers at a volume ratio of 6%, and culture at 37°C and 180rpm for 24 hours to obtain feather microbial degradation liquid. Figure 1 As shown in the figure, Bacillus cereus C3752 degraded most of the discarded chicken feathers in 24 hours, and there was no obvious chicken feather in the culture medium, and the feather microbial degradation liquid was obtained. Scanning electron microscopy showed that the bacteria gathered on the feather fibers, and many holes of different sizes were formed in the feather fibers. It is speculated that bacterial colonization and the formation and expansion of holes may play an important role in the feather degradation process.

[0026] The above-mentioned culture medium containing discarded chicken feathers includes, by mass fraction, 0.03% NaCl, 0.02% KH2PO4, 0.07% K2HPO4, 0.005% MgSO4, the remainder is water, 1% chicken feathers, pH 9.0; the culture medium is prepared by mixing the components evenly, adjusting the pH value, and then sterilizing at 121°C for 15 minutes.

[0027] Example 2 Effect of feather microbial degradation liquid on the preservation of post-harvest litchi

[0028] The feather microbial degradation liquid in Example 1 was filtered through 6 layers of gauze to obtain the filtrate of the feather microbial degradation liquid. The feather microbial degradation liquid and the filtrate of the feather microbial degradation liquid were sprayed on the surface of the harvested litchi fruit to form droplets. At the same time, the spraying water was used as a control group to observe the changes in the litchi fruit in the natural state in midsummer. Figure 2 As shown in the figure, the peel of litchi in the control group underwent obvious and complete browning on the first day, while the peel of litchi in the experimental group sprayed with feather microbial degradation liquid had a small amount of browning spots on the first day, obvious browning occurred on the second day, and most of the peel of litchi had browned on the third day. The peel of litchi in the experimental group sprayed with the filtrate of feather microbial degradation liquid began to form a small amount of visible browning spots on the second day, and obvious partial browning occurred on the third day. Compared with the control group sprayed with water, spraying the filtrate of feather microbial degradation liquid at room temperature can significantly prolong the time for browning of litchi after harvesting, from less than 1 day to nearly 2 days. Moreover, the preservation effect of the filtrate of feather microbial degradation liquid sprayed is stronger than that of feather microbial degradation liquid sprayed, which indicates that the filtrate of feather microbial degradation liquid has a certain preservation effect on litchi after harvesting. This may be because Bacillus cereus produces active oligopeptides and antibacterial and antioxidant functional metabolites in the process of degrading chicken feathers, slowing down the water loss of litchi peel and inhibiting the activity of microorganisms and oxidases that cause browning. Therefore, the filtrate of the feather microbial degradation liquid significantly prolonged the shelf life of litchi after harvest.

Claims

1. Application of feather microbial degradation liquid of Bacillus cereus in litchi preservation.

2. The use according to claim 1, characterized in that: The Bacillus cereus is Bacillus cereus C3752, and its accession number in NCBI is OM368754.

3. The use according to claim 1 or 2, characterized in that: The feather microbial degradation liquid is obtained by inoculating Bacillus cereus into a culture medium containing discarded feathers.

4. The use according to claim 3, characterized in that: The feathers are chicken feathers, duck feathers or goose feathers.

5. The use according to claim 3, characterized in that: The culture medium containing discarded feathers comprises, by mass fraction, 0.01-0.07% sodium chloride, 0.02-0.08% potassium dihydrogen phosphate, 0.01-0.07% dipotassium hydrogen phosphate, 0.003-0.007% magnesium sulfate, 1% chicken feathers or 1% duck feathers or 1% goose feathers, and the balance is water, with a pH of 9.

0.

6. The use according to claim 1 or 5, characterized in that: The feather microbial degradation liquid is obtained by inoculating the seed liquid of Bacillus cereus C3752 into a culture medium containing discarded feathers at a volume ratio of 2-10%, and culturing at 30-40°C and 150-200rpm for 20-30h.

7. The use according to claim 6, characterized in that: The seed liquid is obtained by streaking Bacillus cereus C3752 on solid LB medium, culturing at 30-40°C for 16-28h, picking a single colony to liquid LB medium, and culturing at 30-40°C and 150-200rpm for 10-20h as the seed liquid.

8. The use according to claim 1 or 5, characterized in that: The application is to spray the feather microbial degradation liquid directly on the surface of the lychee fruit after being picked.

9. The use according to claim 1 or 5, characterized in that: The feather microbial degradation liquid is filtered through gauze to obtain a filtrate, which is directly sprayed on the surface of the litchi fruit after harvest.

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