Preliminary report on the preservation of Litchi a

2022-08-23
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Preliminary report on litchi preservation at room temperature

Abstract after being treated with preservative 94623-2 and stored at 28-34 ℃ for 6-8 days, the good fruit rate of March Red, fragrant litchi and Heli is more than 85%. After storage, compared with before storage, the soluble solids of Heli pulp increased, titratable acids decreased, vitamin C lost, and cell permeability increased, but the plasma membrane and vacuolar membrane were intact. Description preservative. Here is a simple comparative analysis of the performance characteristics of the common universal experimental machine on the market, which really plays a role in keeping fresh. After being treated with preservative, the good fruit rate of Heli stored at room temperature for 8 days and then transferred to 10-25 ℃ for 20 days is still more than 80%

key words litchi fresh-keeping agent at room temperature

the planting area of famous Southern litchi in our region has reached more than 2.7 million mu, but due to the lag of fresh-keeping, storage and transportation technology, the radiation range and market share of fresh fruit sales are limited. Low temperature preservation of litchi has been recognized as a feasible method of preservation, but it should be supported by sufficient storage equipment, and the fresh fruits will soon browning and qualitative change after delivery, so it is difficult to promote at present. In the normal temperature preservation method, it is better to use polyethylene film packaging after the treatment of drug warm soup, but it needs constant temperature water bath and other related equipment, and there are still some difficulties in practical application. The non-toxic and efficient preservative developed by the author from Guangxi raw materials is simple and effective for litchi preservation at room temperature

1materials and methods preservative

94623-2 is a liquid mixed with wax esters, fungicides, preservatives, color protectants and physiologically active substances. The mixing process is as follows:

fungicide preservative

wax ester dissolution → emulsification → stability → mixing → draining → packaging

color fixative physiologically active substances

litchi tested has early maturing variety March Red, medium maturing variety Hexi, late maturing variety Xiangli. Fresh fruits are treated with preservative and then packaged with 0 04—0. 06mm polyethylene film bag, carton and bamboo basket for outer packaging

the preservation process is all carried out indoors, with the temperature of 28 ℃ - 34 ℃, with an average of 30 4 ℃, relative humidity 62% - 80%, average 72 5%。 Fresh keeping treatment: pruning and cutting leaves, removing diseased and bad fruits → sterilization → preservative → draining → polyethylene film bag packaging → normal temperature storage. The whole process is carried out at room temperature

the grading of Peel Browning is divided into five grades according to Luo Baokang's grading standard, and grades 1-2 are good fruits. Soluble solids, titratable acids, vitamin C, cell permeability and polyphenol oxidase were measured by routine physiological and biochemical methods. The plasma membrane and vacuolar membrane of pulp cells were observed by electron microscope

2 results and analysis

the trial began in 1992 and was repeated for 5 years. Now the test results in 1995 are compiled into a table. The results showed that after treatment with preservative 94623-2, the average weight loss of March Red and fragrant litchi stored for 6 days and Heli stored for 8 days was about 7%, and the good fruit rate was more than 85%. The soluble solids in the flesh of litchi after storage increased by 1. 5% compared with that before storage 5 percentage points, titratable acid reduced by 0 09 percentage points, vitamin C loss 10 5% of the wind on the fruit And nutrition. The permeability of pulp cells increased by 3 9 percentage points. The observation of transmission electron microscope showed that the plasma membrane and vacuolar membrane were still intact, and the separation of plasma wall was also observed, indicating that the cells of pulp were still living cells, and 94623-2 preservative played a role in keeping fresh. However, the polyphenol oxidase activity of peel increased and browning began to occur

attached table 1995 litchi fresh-keeping results at room temperature

variety

treatment

fruit weight

(kg)

fresh-keeping period

(days)

weight loss rate

(% researchers through careful design of the molecular structure of hydrophilic polyurethane resin)

good fruit rate

(%)

soluble

solids

(%)

titratable acid (g/100 · GFW)

vitamin C (mg/100g · FW)

relative cell permeability

can be divided into wedge-shaped clamps (referring to the clamps with inclined locking principle structure), pair clamp clamps (referring to the clamps with single-sided or double-sided rib top tightening principle structure), winding clamps (referring to the clamps with samples locked by winding), eccentric clamps (referring to the clamps with eccentric locking principle structure), lever clamps (referring to the clamps with lever force amplification principle structure) Shoulder fixture (refers to the fixture suitable for shoulder samples), bolt fixture (refers to the fixture suitable for testing rib strength of bolts, screws, studs, etc.), 90 ° peel fixture (refers to the fixture suitable for hanging two samples

peel polyphenol

oxidase activity (aod/gfw · min)

March Red

fresh keeping

58 industry is gradually mature 5

6

6.9

85.6

ck

10.0

6

12.7

Heli

fresh keeping

307.0

0

100.0

16.5

0.41

34.3

46.8

42.9

16.8

ck

14.5

8

7.2

88.6

18.0

0.32

23.8

50.2

46.8

27.2

fragrant litchi.

preservation

7.5

6

12.0

18.0

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