Study On Apple Preservation Mechanism And Detraction Technology Based On Metabonomics

Apple is one of the four major fruits. China is the first main apple planting and output country. However, because of the mechanical damage and physiological diseases, great quality loss and economic losses would occur. Flesh browning that caused by high carbon dioxide concentration was one of the physiological disease occurred in storage. However, its mechanism was not clear. Metabonomics proceeded from the overall, systematicly and comprehensively studied all the small molecular substances in plants. Analyzing the metabolites under specific conditions, metabolite changes associated with a particular physiology, pathology and stimulation would be got. Metabonomics had a wide application on nutrition evaluation, quality detection and metabolic pathways analysis. In this study, metabolite changes of carbon dioxide injure and 1-MCP treatment were mearsured using metabonomics. The effect of 1-MCP, high carbon dioxide and ultra-low oxygen treatment on fruit quality were studied. The visible/near infrared spectroscopy application on mechanical damage were also studied.The main content and results of this research were as follows:1. Fuji and flower cattle apples were the materials to study the nondestructive testing technology of visible/near infrared spectra in judging mechanical damage. Results showed that the Fuji apple spectral datas preprocessed by multiple scattering correction (MSC) and convolution smoothing, the discriminant analysis model in 4 h and 48 h were established. The discriminant rate and validation rate were 94.56% and 90% in the 4 h model. In the 48 h model, the rates were 98% and 94%, respectively. The model of flower cattle apples were established after datas via the standard normal variables change (SNV). The discriminant rate and validation rate in the 4 h model were 89.36% and 85.71%. The rates in 48 h were 93.62% and 85.71%.2. Fuji apples were treated with 20% carbon dioxide for 28 days, the fruit quality and bowning related index were studied. The 28 day fruits were used for metabonomics analyses. The result shows that in this experiment, the activity of polyphenol oxidase (PPO) increased with time, but were not significant difference in control and treated apples. Browning fruits were detected began from 14 days. Browning degree and total phenol content were significantly different from 14 days. Vitamin C contents were lower in treatment than control from 7 days. Metabonomics analyses showed citric acid, inositol and valine, lysine, relieving glycine, serine, glutamic acid, aspartic acid, asparagine, hexadecanoic acid and octadecanoic acid were the different compounds, and their relative concentration were lower in treated apples.3. Fuji apples after treated with 1-MCP for 1 and 3 days were used for metabonomics analyses. Results showed that the treated samples could clearly separated from control. Some of the metabolites that were significantly different in 1 day did not have significant difference in 3 days. Ctric acid, glutamate and 1,4-butanediol were the metabolites that different in both 1 day and 3 days.1-MCP effect on room temperature stored fuji and delicious apples were also studied. Results showed that 1-MCP treatment had no signicicant effect on weight loss rate, firmness and soluble solids content (SSC).1-MCP treated apples had higher titratable acid (TA) and vitamin C contents, and can delay the increase of pH value.4. The effect of short time treatment of high CO2 and ultra low-oxygen on room temperature stored fuji and delicious apples were studied. Results showed that fresh harvested apples treated for 24 h, the weight loss rate were lower, titratable acid (TA) and vitamin C contents were higer, firmness were not effect. Apples that stored for 2 month in business conditions were treated with f high CO2 and ultra low-oxygen for differernt time. The optimal time for weight loss rate, firmness, soluble solids content (SSC), titratable acid (TA) content and pH value were different. TOPSIS (Technique for Order Preference by Similarity to an Ideal Solution) were used to evaluate the comprehensive effect on fruit quality. Results showed that the optimal time for high CO2 treated fuji apple were 12 h, for high CO2 treated delicious apples were 24 h, and the optimal time for ultra low-oxygen treated apples were 48 h.