CN110150368B - A kind of preservation method for prolonging the shelf life of banana - Google Patents

Abstract

The invention discloses a preservation method for prolonging the shelf life of bananas, which specifically comprises the steps of taking a banana color card as a standard, selecting bananas with an initial state of 4 and no mechanical damage or black star points, placing the bananas below a UV-C lamp tube, carrying out UV-C irradiation, spraying a citric acid solution on the surfaces of the bananas in the irradiation process, completely immersing the bananas subjected to UV-C treatment and storing the bananas in rice hulls, and preferably drying the rice hulls obtained after the banana leaf extract aqueous solution is subjected to spray treatment; the invention solves the problems of toxic residue, drug resistance and environmental protection caused by the chemical bactericide serving as the preservative of the picked bananas in the prior art, has low browning and decay speed and good quality, greatly prolongs the shelf life of the bananas, and improves the economic value of the bananas.

Description

A kind of preservation method for prolonging the shelf life of banana

technical field

The invention relates to the technical field of fruit preservation, in particular to a fresh-keeping method for prolonging the shelf life of bananas.

Background technique

After harvesting, bananas need to be ripened before they can be eaten. Before ripening, the banana peel is green, and the pulp is astringent and hard, which is inedible, but has strong disease resistance and is not easy to rot. After ripening, banana peels turn yellow and pulp becomes soft, so they have edible value, but ripe bananas are very perishable, and the general shelf life is only 2-3 days. If they cannot be sold or eaten within 2-3 days, bananas will be very The commodity value and edible value are quickly lost, causing economic losses to both sellers and consumers.

The substance that causes bananas to ripen is an endogenous hormone called ethylene. After the bananas are harvested, they will automatically ripen through the ethylene produced by themselves. Therefore, taking certain measures to reduce the ethylene content in the storage environment can delay the ripening of bananas and prolong the preservation period. However, this does not reduce the rot of bananas after ripening. The rot of bananas after ripening is mainly caused by fungal pathogens. The current method of fruit preservation mainly uses chemical fungicides to control the disease and reduce the occurrence of rot. Bringing toxic residues, drug resistance and environmental protection problems, so the search for efficient, fast and pollution-free banana preservatives has received widespread attention.

Zhang Shanshan et al. treated banana fruit with chlorine dioxide. The results show that chlorine dioxide can inhibit the production of endogenous ethylene in bananas, delay the appearance of the climacteric peak, and significantly reduce the respiration intensity. However, chlorine dioxide treatment increases the production of polyphenol oxidase. Activity; 1-Methylcyclopropene (1-MCP) is a non-toxic ethylene antagonist that can irreversibly bind to ethylene receptor proteins in fruit and vegetable tissues to inhibit ethylene, but 1-MCP must Respiration and ethylene release can be inhibited by application before the fruit has undergone climacteric change and autocatalytic ethylene is produced; South China Agricultural University has disclosed a patent for banana preservation, which can control ripening by soaking bananas in hot water at 48-60°C. Bananas rot and prolong shelf life, but hot water treatment is only suitable for green bananas that are stored at room temperature for no more than 48 hours.

Although domestic and foreign scholars have carried out a lot of research on the postharvest physiology and fresh-keeping technology of bananas, so far, no satisfactory results have been obtained. .

SUMMARY OF THE INVENTION

The object of the present invention is to provide a safe and environmentally friendly method for extending the shelf life of bananas, slow down the ripening and decay of bananas, prolong the shelf life of bananas, and improve the commodity value and edible value of bananas.

A fresh-keeping method for extending the shelf life of bananas provided by the invention comprises the following steps:

Step 1: Use the banana color card as the standard, select the bananas with the initial state of 4, and require the same size, no mechanical damage and black stars, wipe them with a clean cloth, and place them in a perforated container;

Step 2: Put the banana under the UV-C lamp tube, and irradiate it with UV-C. During the irradiation process, spray citric acid solution on the surface of the banana, turn off the UV-C light source, and dry it;

Step 3: Fully immerse the UV-C treated banana in the rice husk for preservation.

Preferably, in step 2, the power of the UV-C lamp tube is 36W, the irradiation distance is 50cm, and the irradiation time is 1min;

Preferably, the concentration of the citric acid solution in step 2 is 0.2%;

Preferably, the rice husks described in step 3 are obtained by spraying an aqueous solution containing banana leaf extract through a spray device for 6-12 hours and then drying;

Preferably, the preparation method of the banana leaf extract comprises the following steps:

(1) Pretreatment: select banana leaves with good growth conditions and no defects, cut into small pieces after cleaning, air-dry, and then use a pulverizer to make a powder with a particle size of less than 50 meshes;

(2) Pre-extraction: take the above powder and place it in deionized water to soak for 24-30h;

(3) leaching: the above-mentioned pre-extraction solution is leached in a water bath for 60-90min;

(4) Filtration: filter the extract with four layers of gauze;

(5) Concentrated filtrate: the obtained filtrate is put into a rotary evaporator, and the water is distilled off by rotary evaporation at a temperature of 70 to 75° C.

The extract is obtained in the form of extract;

(6) Drying: dry in an oven at 30-40 °C, and store in a drying bottle.

Preferably, in above-mentioned step (2), banana leaf powder and deionized water are added according to the ratio of material to liquid 1:10-12, using

Soak in ultrasonic conditions;

Preferably, the leaching temperature in the above step (3) is 45-50°C;

Preferably, the residue after the filtration of the above step (4) is subjected to repeated leaching and filtration, and the filtrate after repeated filtration is combined

Carry out step (5) and concentrate the filtrate;

The present invention has the active ingredient activity of prolonging the fresh-keeping period of bananas in the banana leaves without destroying the activity of the active ingredients through the above-mentioned operations.

Extract it sufficiently.

Preferably, the mass fraction of the banana leaf extract in the aqueous solution of the banana leaf extract is 10-35%;

Preferably, the banana container submerged in rice husks is stored in an environment of 0-4°C.

The present invention includes at least the following beneficial effects:

The banana with an initial state of 4 is slightly yellow, indicating that the starch is gradually being converted into sugar. Banana treatment during this period can slow down the browning and decay rate of the banana to the greatest extent, and improve the fresh-keeping period of the banana;

UV-C irradiation can destroy the microbial cell membrane and nucleic acid structure, make the genetic material inactive, cause the microbial cells to die or lose their ability to reproduce, control the reproduction of pathogenic microorganisms, prevent rot and delay the post-harvest aging of fruits and vegetables;

Citric acid is a naturally occurring organic acid in living organisms and is a type of phenolic copper chelator. The main reason for enzymatic browning of bananas is a polyphenol oxidase containing copper ion oxidase. The synergistic effect inhibits the activity of polyphenol oxidase so as to slow down the browning and rotten speed of bananas;

Simultaneous treatment of bananas with UV-C irradiation and citric acid accelerated the chelation of citric acid with polyphenol oxidase, and the acidic environment provided by citric acid also accelerated the destruction of microbial cell membranes by UV-C irradiation. It can greatly slow down the browning and rotten speed of bananas;

Rice husks have good toughness and porosity. Putting the bananas after UV-C irradiation and citric acid treatment in rice husks can reduce the mechanical damage during banana storage on the one hand, and on the other hand, rice husks also It can play the role of breathability, moisture absorption, anti-oxidation, and anti-mildew. More importantly, the porous structure in the rice husk can absorb the ethylene produced by bananas, thereby reducing the content of exogenous ethylene in the environment and further slowing down the exogenous ethylene produced during storage. Source ethylene for further ripening of bananas.

After the rice husk is sprayed with an aqueous solution containing banana leaf extract through a spray device for 6-12 hours, the banana leaf extract is adsorbed in the pore structure in the rice husk, and the banana leaf extract is effective in maintaining the capacity of catalase in banana. The internal environment plays a very important role. By immersing the bananas treated with UV-C radiation combined with citric acid and storing them in rice husks containing banana leaf extracts, it helps to restore the activity of catalase and greatly improves the efficiency of the treatment. The fresh-keeping effect of bananas can slow down the browning and rotten speed of bananas, and greatly prolong the fresh-keeping period of bananas.

Other advantages, objects, and features of the present invention will appear in part from the description that follows, and in part will be appreciated by those skilled in the art from the study and practice of the invention.

Detailed ways

The present invention will be further described in detail below, so that those skilled in the art can implement it with reference to the description.

In order to illustrate the technical solutions of the present invention more clearly, specific embodiments will be further described.

Example 1

Using the banana color card as the standard, select bananas with an initial state of 4, the same size, without mechanical damage and black star points, wipe them with a clean cloth, and place them in a perforated container; put the bananas in a 36W UV light 50cm below the -C lamp tube, UV-C irradiation is carried out, the irradiation time is 1min, and it is stored at room temperature. Observe and record the banana storage situation, see Table 1;

Example 2

Using the banana color card as the standard, select bananas with an initial state of 4, the same size, without mechanical damage and black stars, wipe them with a clean cloth, and place them in a perforated container; spray 0.2% citric acid solution, Dry and store at room temperature. Observe and record the banana storage situation, see Table 1;

Example 3

Using the banana color card as the standard, select bananas with an initial state of 4, the same size, without mechanical damage and black star points, wipe them with a clean cloth, and place them in a perforated container; put the bananas in a 36W UV light 50cm below the -C lamp tube, carry out UV-C irradiation, the irradiation time is 1min; spray 0.2% citric acid solution, air dry, and store at room temperature. Observe and record the banana storage situation, see Table 1;

Example 4

Using the banana color card as the standard, select bananas with an initial state of 4, the same size, without mechanical damage and black star points, wipe them with a clean cloth, and place them in a perforated container; put the bananas in a 36W UV light 50cm below the -C lamp tube, irradiate with UV-C, the irradiation time is 1min, spray citric acid solution with a concentration of 0.2% on the surface of the banana during the irradiation process, turn off the UV-C light source, dry it, store it at room temperature, and observe Record the banana storage situation, see Table 1;

Example 5

Using the banana color card as the standard, select bananas with an initial state of 4, the same size, without mechanical damage and black star points, wipe them with a clean cloth, and place them in a perforated container; put the bananas in a 36W UV light 50cm below the -C lamp tube, irradiate with UV-C, the irradiation time is 1min, spray citric acid solution with a concentration of 0.2% on the surface of the banana during the irradiation process, turn off the UV-C light source, and dry; The processed bananas are completely immersed in rice husks and stored at room temperature. Observe and record the banana storage situation, see Table 1;

Example 6

Using the banana color card as the standard, select bananas with an initial state of 4, the same size, without mechanical damage and black star points, wipe them with a clean cloth, and place them in a perforated container; put the bananas in a 36W UV light 50cm below the -C lamp tube, irradiate with UV-C, the irradiation time is 1min, spray citric acid solution with a concentration of 0.2% on the surface of the banana during the irradiation process, turn off the UV-C light source, and dry; The treated bananas were completely immersed in rice husks and stored at 0-4°C. Observe and record the banana storage situation, see Table 1;

Example 7

Step 1. Preparation of banana leaf extract: select banana leaves with good growth conditions and no defects, cut into small pieces after cleaning, air-dry, and then use a pulverizer to make powder with a particle size of less than 50 meshes; take banana leaf powder and deionized water according to the feed liquid Immerse in deionized water at a ratio of 1:10 for 24-30h; extract the pre-extraction solution in a water bath at 45-50°C for 60-90min; filter the extraction solution with four layers of gauze; Repeat the leaching at 50°C for 60-90min, combine the two obtained filtrates, put them into a rotary evaporator, and rotate to evaporate the water at a temperature of 70-75°C to obtain an extract-like extract, which is dried in an oven at 30-40°C. , stored in a dry bottle for later use.

Step 2. Add deionized water to the prepared banana leaf extract to make a 15% banana leaf extract aqueous solution, spray the rice husks with the banana leaf extract aqueous solution for 6h by a spray device, and take it out to dry for use;

Step 3. Using the banana color card as the standard, select bananas with an initial state of 4, the same size, without mechanical damage and black star points, wipe them with a clean cloth, and place them in a perforated container; put the bananas in a 50cm below the 36W UV-C lamp tube, carry out UV-C irradiation, the irradiation time is 1min, spray the citric acid solution with a concentration of 0.2% on the surface of the banana during the irradiation process, turn off the UV-C light source, and dry it; The bananas treated with UV-C were completely immersed in rice husks treated with an aqueous solution of banana leaf extract and stored at room temperature. Observe and record the banana storage situation, see Table 1;

Example 8

The treatment method is the same as in Example 7, except that the difference is that 0-4 ° C is placed, and the storage situation of the bananas is observed and recorded, as shown in Table 1;

Example 9

Step 1. Preparation of banana leaf extract: select banana leaves with good growth conditions and no defects, cut into small pieces after cleaning, air-dry, and then use a pulverizer to make powder with a particle size of less than 50 meshes; take banana leaf powder and deionized water according to the feed liquid The ratio of 1:10 is placed in deionized water for 24-30h; the pre-extract is extracted by heating and refluxing for 60-90min; the extract is filtered with four layers of gauze; the filtration residue is repeated in a water bath at 45-50°C Leaching for 60-90min, the filtrate obtained by combining twice is put into a rotary evaporator, and the water is evaporated by rotary evaporation at a temperature of 70-75 ℃ to obtain an extract-like extract, dried in a 30-40 ℃ oven, put into Store in a dry bottle for later use.

All the other steps are with embodiment 7, observe and record banana storage situation, see Table 1;

Table 1 embodiment 1-9 banana storage situation record table

Can draw from Table 1, carry out UV-C radiation, citric acid treatment to banana and all can prolong the fresh-keeping period of banana to a certain extent, but the effect of UV-C radiation, citric acid treatment simultaneously is better than separate treatment, will UV-C radiation, citric acid treat simultaneously. The bananas treated with C radiation and citric acid at the same time can significantly prolong the fresh-keeping period of bananas when placed in rice husks. However, the combined use of UV-C radiation combined with citric acid inhibits the respiration intensity of bananas and the production of endogenous ethylene, and also leads to banana resistance. The oxidase system is destroyed, and the activities of superoxide dismutase and catalase in bananas are reduced. Therefore, UV-C radiation combined with citric acid compound treatment has a good preservation effect. Once it begins to brown and rot, the speed will increase. Compared with no UV-C radiation, banana leaf extract has a very important role in maintaining the internal environment of catalase in bananas. By combining UV-C radiation combined with citric acid, the immersion of bananas treated with citric acid is combined with banana leaves. Preserving the extract in the rice husk helps to restore catalase activity, greatly improves the fresh-keeping effect of bananas, slows down the browning and rotten speed of bananas, and greatly prolongs the fresh-keeping period of bananas.

Although the embodiment of the present invention has been disclosed as above, it is not limited to the application listed in the description and the embodiment, and it can be applied to various fields suitable for the present invention. For those skilled in the art, it can be easily Therefore, the invention is not limited to the specific details and illustrations herein without departing from the general concept defined by the appended claims and the scope of equivalents.

Claims (7)

1. a fresh-keeping method extending banana shelf life, is characterized in that, comprises the following steps: Step 1: Use the banana color card as the standard, select the bananas with the initial state of 4, and require the same size, no mechanical damage and black stars, wipe them with a clean cloth, and place them in a perforated container; Step 2: Put the banana under the UV-C lamp tube, and irradiate it with UV-C. During the irradiation process, spray citric acid solution on the surface of the banana, turn off the UV-C light source, and dry it; Step 3: Fully immerse the UV-C treated banana in the rice husk for preservation; In step 2, the power of the UV-C lamp is 36W, the irradiation distance is 50cm, and the irradiation time is 1min; The concentration of the citric acid solution in step 2 is 0.2%; The rice husks described in step 3 are obtained by spraying the aqueous solution containing the banana leaf extract through a spray device for 6-12 hours and then drying. 2. the preservation method of extending banana shelf life as claimed in claim 1 is characterized in that, the preparation method of described banana leaf extract comprises the following steps: (1) Pretreatment: select banana leaves with good growth conditions and no defects, cut into small pieces after cleaning, air-dry, and then use a pulverizer to make a powder with a particle size of less than 50 meshes; (2) Pre-extraction: take the above powder and place it in deionized water to soak for 24-30h; (3) leaching: the above-mentioned pre-extraction solution is leached in a water bath for 60-90min; (4) Filtration: filter the extract with four layers of gauze; (5) concentrated filtrate: the gained filtrate is put into the rotary evaporator, and the water is evaporated by rotary evaporation under the condition that the temperature is 70～75 ℃ to obtain the extractive extract; (6) Drying: dry in an oven at 30-40 °C, and store in a drying bottle. 3. the fresh-keeping method of extending banana shelf life as claimed in claim 2, is characterized in that, in step (2), banana leaf powder and deionized water are added according to solid-liquid ratio 1:10-12, adopt ultrasonic condition to soak. 4. the fresh-keeping method of extending banana shelf life as claimed in claim 2, is characterized in that, step (3) leaching temperature is 45～50 ℃. 5. the preservation method of extending banana shelf life as claimed in claim 2, is characterized in that, the residue after step (4) filtration carries out repeated extraction and filtration, and the filtrate after repeated filtration merges and carries out step (5) concentrated filtrate. 6 . The fresh-keeping method for prolonging the shelf life of bananas as claimed in claim 1 , wherein the mass fraction of the banana leaf extract in the aqueous solution of the banana leaf extract is 10-35%. 7 . 7. The fresh-keeping method for prolonging the shelf life of bananas as claimed in claim 1, wherein the banana container immersed in rice husks is placed in a 0-4°C environment for preservation.