阅读说明：本技术 一种用解淀粉芽孢杆菌m73发酵产物保鲜血橙的方法 (Method for preserving blood orange by using bacillus amyloliquefaciens M73 fermentation product ) 是由 孙群 郭晓梅 刘卓翀 乔孟婷 罗可 杨轶凡 刘健 于 2021-04-28 设计创作，主要内容包括：本发明涉及一种用解淀粉芽孢杆菌M73发酵产物保鲜血橙的方法,属于果蔬保鲜领域。以血橙为试材,用解淀粉芽孢杆菌M73发酵产物涂抹果皮,以不作处理作为对照,通过测定果实品质及采后生理生化指标考察其对冷藏条件下(4℃)血橙的保鲜效果。结果表明,解淀粉芽孢杆菌M73发酵产物可降血橙腐烂率,减缓贮藏期间血橙可溶性固形物、可滴定酸、VC含量的损失,促进花色苷的积累,有效改善血橙的贮藏品质,是一种高效、低廉、具有实际应用前景的新方法。(The invention relates to a method for preserving blood orange by using a fermentation product of bacillus amyloliquefaciens M73, belonging to the field of fruit and vegetable preservation. The fresh-keeping effect of the blood orange under the refrigeration condition (4 ℃) is examined by measuring the fruit quality and post-harvest physiological and biochemical indexes by taking the blood orange as a test material, coating the fruit peel with a fermentation product of bacillus amyloliquefaciens M73 and taking no treatment as a control. The result shows that the fermentation product of bacillus amyloliquefaciens M73 can reduce the rotting rate of the blood oranges, slow down the loss of soluble solid matters, titratable acid and VC content of the blood oranges in the storage period, promote the accumulation of anthocyanin, effectively improve the storage quality of the blood oranges, and is a novel method which is efficient and low in cost and has practical application prospect.)

1. A method for preserving blood orange by using a fermentation product of Bacillus amyloliquefaciens M73 is characterized by comprising the following steps:

selecting blood orange fruits which are harvested in sunny days, have consistent appearance coloring and uniform size, and have no plant diseases, insect pests and mechanical damage.

2. Soaking the blood orange fruits in a fresh-keeping solution for 5 s, taking out, airing the fresh-keeping solution on the surfaces of the fruits, and storing the fruits after packaging; the fresh-keeping liquid is a fermentation product of bacillus amyloliquefaciens M73 fermented for 48 hours.

3. The method of claim 1, wherein the soaking time is 5 seconds.

4. The method as claimed in claim 1, wherein the preservation solution is a fermentation product of Bacillus amyloliquefaciens M73 after 48 hours of fermentation.

5. The method of claim 1, 2 or 3, wherein the preservative solution comprises lipopeptide, a major bacteriostatic substance of Bacillus amyloliquefaciens M73.

6. The method as claimed in claim 1, wherein the packaging is carried out by bagging the air-dried fruits in a polyethylene film bag of 0.01-0.03 mm.

Technical Field

The invention relates to the field of fruit and vegetable preservation, and in particular relates to a method for preserving blood orange by using a bacillus amyloliquefaciens M73 fermentation product.

Background

The blood orange is rich in polyphenol, flavonoid, ascorbic acid and other antioxidant active substances, has rich nutritional value and is popular with consumers. The blood orange is a typical variety colored by anthocyanin, and the content of the anthocyanin determines the pulp color of the blood orange, so that the blood orange is an important evaluation index of the commercial value of the blood orange. Anthocyanins are a broad class of pigments found in plants and belong to the class of flavonoids. The anthocyanin not only endows plants with bright colors to facilitate pollination and seed propagation, resist plant insect damage and prevent ultraviolet irradiation damage of the plants, but also has a plurality of physiological health care functions for human beings, such as clearing free radicals in vivo, resisting tumors, resisting cancers, resisting inflammation, inhibiting lipid peroxidation and platelet aggregation, protecting livers, preventing diabetes, losing weight, protecting eyesight and the like. The blood orange coloring needs larger day and night temperature difference, the blood orange growing in tropical and subtropical climatic regions is generally not dark in color and uneven in color distribution, and the commercial value of the blood orange is seriously influenced. It is very important to adopt effective treatment measures to keep good quality of the picked fruits.

The citrus in China is mainly sold fresh and needs to be stored in a large amount in a busy season, and the picked citrus fruits are easy to rot and deteriorate in the storage process, so that huge economic loss is caused. The citrus postharvest diseases are divided into invasive diseases and non-invasive diseases, wherein the non-invasive diseases refer to plant diseases directly or indirectly caused by severe physical, chemical and other non-biological environmental factors, and are also called physiological diseases and comprise edema diseases, brown spot diseases, water blight diseases, oil spot diseases and the like. Infectious diseases are diseases caused by infection of microorganisms (mostly pathogenic fungi), mainly including greenish mold caused by penicillium italicum and penicillium digitatum; acid rot caused by geotrichum candidum, black stalk rot caused by geotrichum candidum, brown stalk rot caused by sphacelotheca citricola, black spot caused by sphacelotheca citricola, brown rot caused by phytophthora parasitica, black rot caused by alternaria citrina, anthracnose caused by colletotrichum gloeosporioides and the like. Among various diseases of citrus after harvest, the disease is particularly serious as green-green mildew, and the loss caused by the disease during storage is generally about 10 percent, and is more than 30 percent, so that great loss is brought to production and operators.

The commercial blood orange is usually refrigerated for preservation, but penicillium can still grow under the low-temperature condition, so that the method for preserving the blood orange under the low-temperature condition is extremely important to find. The bacillus amyloliquefaciens can be used as a biological preservation method for postharvest preservation of fruits, and researches show that the bacillus amyloliquefaciens can effectively delay the ripening and the deterioration of bananas; prolonging the shelf life of litchi and longan and enhancing the disease resistance of litchi and longan. The high-efficiency biocontrol bacillus amyloliquefaciens M73 is obtained through mutation breeding in the laboratory, the bacteriostatic effect on various plant pathogenic fungi (such as gibberella and botrytis cinerea) is stronger, and the strain can inhibit botrytis cinerea in the laboratory and basically reaches the level of chemical pesticide procymidone. Its main bacteriostatic substances have been identified as lipopeptides.

Previous researches find that the bacillus amyloliquefaciens M73 can prevent and control mildew of the penicillium longan. Therefore, the bacillus amyloliquefaciens M73 serving as a microbial preservative for the penicillium can be used for preserving blood oranges under refrigeration conditions.

Disclosure of Invention

The invention aims to provide a method for keeping blood orange fresh by using a bacillus amyloliquefaciens M73 fermentation product, which can reduce the rotting rate of the blood orange under the refrigeration condition, maintain the appearance quality of fruits and prolong the fresh-keeping period of the blood orange, is simple to operate, green, safe and low in cost.

The invention discloses a method for preserving blood orange by using a bacillus amyloliquefaciens M73 fermentation product, which is characterized by comprising the following steps of:

(a) selecting blood orange fruits which are harvested in sunny days, have consistent appearance coloring and uniform size, and have no plant diseases, insect pests and mechanical damage.

(b) Soaking the blood orange fruits in a fresh-keeping solution for 5 s, taking out, airing the fresh-keeping solution on the surfaces of the fruits, and storing the fruits after packaging; the fresh-keeping liquid is a fermentation product of bacillus amyloliquefaciens M73 fermented for 48 hours.

The packaging is to use polyethylene film bags with the thickness of 0.01-0.03 mm to package the aired fruits (mainly to prevent water loss).

The storage is refrigeration storage (4 ℃).

According to the method, the blood orange is preserved under the refrigeration condition, the preserved blood orange is not easy to rot in the storage process, the rotting rate of the preserved blood orange can be reduced, the loss of VC, titratable acid and soluble solid matters in the storage process is reduced, the accumulation of anthocyanin of the blood orange is promoted, and the preservation period of the blood orange is prolonged. Therefore, the invention can greatly improve the economic value of blood orange. The method can also be used for keeping longan fresh.

Drawings

FIG. 1 is a graph showing the effect of fermentation product of Bacillus amyloliquefaciens M73 of example 1 on the decay rate of blood orange fruits;

FIG. 2 is a graph showing the effect of fermentation product of Bacillus amyloliquefaciens M73 of example 1 on VC content in blood orange fruits;

FIG. 3 is a graph showing the effect of fermentation product of Bacillus amyloliquefaciens M73 of example 1 on soluble solids content of blood orange fruits;

FIG. 4 is a graph showing the effect of fermentation product of Bacillus amyloliquefaciens M73 of example 1 on titratable acid content of a blood orange fruit;

FIG. 5 is a graph showing the effect of fermentation product of Bacillus amyloliquefaciens M73 of example 1 on the total anthocyanin content of blood orange juice.

Detailed Description

The following examples are further illustrative of the present invention and are not intended to be limiting thereof.

Example 1:

1. material

Blood orange (Citrus sinensis L. Osbeck) was collected from the capital county of Sichuan province, and the breed is "No. 2".

The fresh-keeping liquid is a fermentation product of bacillus amyloliquefaciens M73, and the preparation method comprises the following steps:

the method comprises the following steps: inoculating the cultured seed solution into a fermentation culture medium according to the proportion of 1 percent of the volume ratio, shaking the culture medium at 200 r/min, and culturing for 48 hours at 30 ℃.

Step two: and (4) centrifuging the fermentation liquor obtained in the first step for 5 min at 5000 r/min.

Wherein: in the first step, the seed solution is obtained by the following method: firstly, streaking and transferring a bacillus amyloliquefaciens strain M73 into a PDA (personal digital assistant) plate, and placing the PDA plate in an incubator for constant temperature culture at 28-37 ℃ for 24-48 hours; inoculating the lawn of the obtained bacillus amyloliquefaciens strain M73 into a PDA liquid culture medium, and performing shaking culture at 28-37 ℃ for 24-48 hours to obtain a seed solution;

in the first step, the fermentation medium comprises the following components: 5 g of L-sodium glutamate, MgSO₄.7H₂0.5 g of O, 20 g of glucose and FeSO₄0.15 mg, potassium chloride 0.5 g, K₂HPO₄ 1.0 g，MnSO₄•H₂O 5.0 mg，CuSO₄•5H₂00.16 mg, distilled water 1000 ml, pH 7.2, autoclaving at 115 ℃ for 15 min.

2. Treatment method

Collecting fresh blood oranges in sunny days, and selecting blood oranges with consistent appearance coloring, uniform size, no plant diseases and insect pests and no mechanical damage as experimental materials. Cleaning the surface of the fruit with clear water, taking out and airing, then respectively soaking the fruit in a fresh-keeping solution (a fermentation product of bacillus amyloliquefaciens M73) and a control solution (clear water) for 5 s, then taking out, airing, then respectively packaging the fruit in polyethylene film bags with the thickness of 0.015 mm, and storing the fruit in 4 bags at 4 ℃.

3. Rate of decay

Fruit rotting rate: the diseased fruits or rotten fruits with the diameter of more than or equal to 0.50 cm appearing on the surfaces of the fruits are marked as rotten fruits. After the fruits are stored, the number of rotten fruits is counted regularly according to the number of the alternate days, the rotten rate is the percentage of the number of the rotten fruits in the total number of the fruits, and the calculation formula is as follows: fruit rot rate (%) = number of rotten fruits/number of total stored fruits × 100%.

4. Soluble solid

Randomly extracting 4 fruits from each treatment, squeezing the fruits, filtering and weighing the fruit juice through gauze, and measuring the soluble solid matter, titratable acid, Vc content and total anthocyanin content.

Measured by Abbe refractometer.

5. Titratable acid, VC

And (3) measuring by using a radicle biological kit.

6. Total anthocyanins

Juicing blood orange, centrifuging at 10000 r/min for 10 min, collecting 2 mL supernatant, and adding into pH1.0

Diluting with potassium chloride/hydrochloric acid buffer solution and pH 4.5 sodium acetate/hydrochloric acid buffer solution, mixing well, and measuring absorbance at 510 nm. The calculation formula is as follows.

C(mg·L^-1)=(A_{pH 1.0}- A_{pH 4.5}) × 484.82 × DF × 1000/24 825

Wherein 484.82 is the molecular weight of cyanidin-3-glucoside, 24825 is the molar absorptivity,

DF is the dilution.

7. Results and analysis of the experiments

The experimental results are shown in FIG. 1, FIG. 2, FIG. 3, FIG. 4 and FIG. 5, and FIG. 1 shows that the starch bud is removed

The fermentation product of the bacillus M73 has a remarkable effect on reducing the rotting rate of blood oranges under the refrigeration condition, the rotting rate of a treatment group is half of that of a control group at 90 days after storage, and the preservation period is prolonged by about 30%. As shown in fig. 2, fig. 3 and fig. 4, the fermentation product of bacillus amyloliquefaciens M73 can reduce the loss of soluble solid, titratable acid and VC contents of blood orange in the storage period, and the content of the soluble solid, titratable acid and VC is not significantly different from that of the soluble solid, titratable acid and VC in 30 days after storage, so that the fresh-keeping effect is good. As shown in figure 5, the fermentation product of the bacillus amyloliquefaciens M73 can promote the accumulation of blood orange anthocyanin in the storage period, the content of the anthocyanin is 2.49 times of that of a control group on the same day at the 30 d after storage, the content of the blood orange anthocyanin is increased in a short time, and the storage quality of the blood orange is effectively improved.