| Chayote (Sechium edule (Jacq.) Sw.) belonges to Cucurbitaceae, and the fruit is defined as pen-dulous, obovoid, or pear-shaped with a variable number of longitudinal depressions. It has low content of lipids, calories, and sodium, but rich in minerals, amino acids, and vitamins like ascorbic acid. As test materials, smooth green chayote fruit was from Ya'an in this research. Changes in postharvest quality of chayote fruit in different growing period was tested to confirm the best one to store and explore the most suitable storage temperature. Chayote fruit had serious decay and germination because of inappropriate cellar ortrench storage. In order to prolong storage life and maintain fruit quality of chayote, the current preservation methods which were widely used for melon crops storage were applied to the storage of chayote fruit. The research results were listed as follows:1. The growth curve of chayote showed single sigmoid pattern and the trends of quality indicators were different with fruit development dynamics. Respiration rate decreased rapidly with fruit development and respiration peak (11.73 mg/(kg·h)) appeared at maturity. The contents of Vc, chlorophyll and hydrolysis amino acids were high during the young fruit development, then decreased to a low level, while cellulose content and firmness showed the opposite tend. The fruit had fully grown with amino acids content of 702.964 mg/100g, with lower respiratory rate and better quality and storability on the 10th d after flowering when was the optimal harvest period.2. Symptoms including surface pitting, dark watery patches and increased decay was showed on chayote fruit which stored at the temperature of 1±1 ? and 5 ± 1?, and fruit lost storage value on 30thd and 45thd separately. The depressed and discolored peel, severe respiratory intensity and dramatic increase in cell membrane permeability and MDA led to decline in fruit quality. Compared with fruit stored at room temperature which had poor quality on 60th d with high firmness of 18.58 kg/cm2, fruit had better storage quality which stored at 9± 1? with lower respiration rate and higher content in Vc and chlorophyll.3. The four preservation methods which were controlled atmosphere, ozone, 1-MCP and salicylic acid treatments had positive effects on maintaining fruit quality in different levels. According to the result of multivariate analysis on all test data, 5%O2+5%CO2+90%N2 of controlled atmosphere,5 mg/L of ozone,900 nL/L of 1-MCP and 10 mmol/L of salicylic acid treatments turned out to be the best parameters compared with the other three treatments during storage separately. Storage quality of fruit treated with 10 mmol/L salicylic acid maintained the best with score of 0.25 on 60th d. Therefore,10 mmol/L salicylic acid was the best preservation method for chayote fruit during low temperature storage4. Amino acid variation showed that chayote fruit contained at least 17 types of amino acids. The content of total amino acids decreased during storage, while fruit treated with 10 mmol/L salicylic acid maintained the highest content of total amino acids (390.67 mg/100g) on the 90th day compared with other treatments. Moreover, correlation analysis suggested that the essential amino acids content was positively correlated with total amino acids content (r=0.91), and there were certain correlations among different amino acids. Percentages of medicinal amino acids showed different varying trends during storage period. |
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