Preliminary report on the storage test of the hott

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Preliminary report on storage test of August red pear (Part 1)

August red pear is a new crisp red pear variety jointly bred and introduced by fruit tree Research Institute of Shaanxi Academy of Agricultural Sciences and Fruit Tree Research Institute of Chinese Academy of Agricultural Sciences. This variety was hybridized in 1973 and named in 1995. Its fruit color is bright, its flesh is thin, crisp, juicy, sweet and sour, and pleasant aroma. It matures from late August to early September in western Liaoning. Since its publication, it has been popular with domestic consumers. Due to the high temperature during harvest, postharvest storage is a problem that needs to be studied and solved in the development of production. At present, there is no literature report on the storage of August red pear. We carried out storage experiments from 1999 to 2000. The results are reported as follows

1 materials and methods

1.1 source and treatment of materials

August red pears were collected from the new pear variety test demonstration base - the 4-year-old mountain Yangpo pear garden in Longcheng District, Chaoyang City, Liaoning Province. It was collected on September 1st, 1999 and transported to the experimental cold storage of the Institute on the same day. It was pre cooled for 24 hours and then treated accordingly

the test temperature is controlled by wmnk-406 digital temperature controller (± 0.5 ℃), 20L wide mouth glass bottle (sealed with rubber plug) is used as the controlled atmosphere storage bottle, and the steel cylinder is filled with N2, O2 and CO2 as the gas source. The gas ratio and flow are controlled by the CA system. The prepared gas is delivered to the controlled atmosphere storage bottle through a pipe, and then the anchor nut is tightened. The tail gas in the bottle is directly discharged into the atmosphere. The gas flow is 100ml/min. The gas composition shall be monitored by cyes- type O2 and CO2 tester (± 0.5%), and the gas composition of each ratio shall be corrected regularly

(1) controlled atmosphere storage temperature 0 ℃, o23 levels: 3%, 5%, 7%; Co24 levels: 1.5%, 3%, 5%, 7%. In addition, cold storage treatment (the bottle mouth is open to the atmosphere) is set, and 60 fruits are processed each time

(2) four levels are set for small package test temperature at different temperatures: 0 ℃, 3 ℃, variable temperature 10 ℃ (12 days) → 6 ℃ (20 days) → 4 ℃ (40 days) → 0 ℃, room temperature (24 ± 1 ℃). The small package adopts 0.05mm thick PVC bag to tie the mouth and pull the mouth, and 0.03mm thick PVC bag to tie the Pingmei Guoneng 10gwh high specific energy lithium-ion battery project is an advanced lithium-ion battery and system integration production project jointly implemented by Xinxiang Municipal government, Pingmei Shenma Group, Xinxiang battery research institute and Guoneng battery, with a processing capacity of 7.5kg

1.2 determination of physical and chemical indexes

hardness was determined by hg-12 fruit hardness tester, soluble solid content was determined by handheld refractometer, and single fruit was repeated for 10 times. Titratable acids were determined by acid-base neutralization titration and ethanol by oxidation-reduction method

1.3 grading standard for pear black skin disease and flesh browning

pear black skin disease is divided into five grades: grade 0: the peel does not change color; Grade 1: the fruit surface is light brown, accounting for less than 1/3 of the peel area; Grade 2: the fruit surface is light brown, accounting for 1/3 ~ 1/2 of the peel area; Grade 3: the fruit surface is light brown, accounting for more than 1/2 of the peel area, or 1/3 ~ 1/2 of the peel area is dark brown or black; Grade 4: the fruit surface is dark brown or black, accounting for more than 1/2 of the peel area. The number of inspection results is 40

grading of flesh browning (CO2 damage), cut the fruit along the maximum transverse diameter, and divide it into five grades according to the browning area of the transverse section: grade 0: no damage; Grade 1: slight browning on the cross section (can be clearly identified); Grade 2: slight browning on cross section ~ 1/4 area browning on cross section; Grade 3: the browning area accounts for 1/4 ~ 1/2 of the cross section area; Level 4: 4. Experimental principle and method the browning area of the cross section is greater than 1/2 of the cross section area. The number of results per inspection is 10

pulp Browning (pear black skin disease) index (%) = ∑ (grade × Number of results at this level)/(highest level × Total number of inspection results) × 100

2 results and analysis

2.1 effects of different gas components on flesh browning index during controlled atmosphere storage

August red pears were stored at 0 ℃ to the 33rd day. As a necessary equipment for product quality control, the 3%o2 experimental machine +1.5%co2, 5%o2+1.5%co2, 7%o2+1.5%co2, 7%o2+3%co2 and 21%o2+0%co25 treatments did not browning, while the other 8 treatments did not Browning to varying degrees, The pulp browning of 22 treatments (3%o2+7%co2 and 3%o2+3%co2) was the most serious. On the 64th day after storage, 22 treatments (7%o2+1.5%co2, 21%o2+0%co2) did not undergo flesh browning, and the other 7 treatments experienced flesh browning. The flesh browning indexes of 22 treatments (7%o2+5%co2, 3%o2+5%co2) reached 70.0 and 62.5 respectively. After storage for 104 days, 7%o2+1.5%co2 treatment began to cause flesh browning. After 165 days of storage, 21%o2+0%co2 treatment just began to cause Flesh Browning (Table 1). After 165 days of cold storage, the ventricular wall of some August red pears appeared browning, but it did not affect the flesh or commodity properties. In addition, it can be seen from table 1 that the effects of different concentrations of O2 and CO2 on pulp browning are as follows: when the O2 concentration is constant, the higher the CO2 concentration, the more serious the pulp Browning (the greater the browning index), and the earlier the damage occurs; When the CO2 concentration was constant, the lower the O2 concentration was, the more serious the flesh browning was, and the earlier the damage occurred

Table 1 Effects of different gas components on flesh browning index

o2+co2 concentration (%). Storage period (days) +1.500.150*5+1.500.150*7+1.5000.300*3+30.250*5+30.150*7+300.425*3+50.1000.625*5+50.0500.275*7+50.0250.700*3+70.275*5+70.175*7+7

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