| Juice peach(Prunus persica) fruits are famous for their rich nutrition and suitable ratio of sugar to acid as well as their strong flavor. However, they are hard to be preserved which is an internationally technical problem due to their high sugar, causing economic losses. Fenghuang region (Zhangjiagang, Jiangsu) is one of the most famous growing areas for juice peaches, where the planting range is expanding and the production is growing yearly. Therefore, it’s very significant for the social and economic benefits to study postharvest physiology and technology for storage of juice peaches at ambient temperature.The’BaiHua’juicy peaches (P.persica.cv’BaiHua’) picked from Zhangjiagang City, Jiangsu Province, were selected as the experiment material in this paper. Eight physiological and biochemical indexes,water loss rate, rot rate, fruit firmness, soluble solids, respiratory intensity, relative electric conductivity, malondialdehyde (MDA) content and polyphenol oxidases (PPO) activity, of these fruits were measured after picking without treatments for researching changing patterns. Preservation effect was compared and analyzed using ginger juice (Zingiber officincde Roscoe), suspensions of Cryptococcus laurentii, cold shock and calcium chloride (CaCl2),sodium chloride (NaC1) and sodium bicarbonate (NaHCO3) solution. Comprehensive assessment for fruit growers and factory production application was based on effectiveness, economy, feasibility and food safety of different methods. Through the experiment, it is draw the following conclusions:(1) During preservation, the weight loss of juice peaches happened firstly, and then flesh browning happened. Finally, fruits got rotten accelerated by mold contamination. The significant physiological index is respiratory intensity. The results showed that BaiHua juice peaches had an apparent process of respiratory climacteric, which arrived on the fourth day in storage, and dropped to initial level one day later. At the beginning of storage, physiological indexes of fruits changed seldom, and with respiratory intensity increasing significantly over time, weight loss declined quickly and the number of browning spot in shin of fruits went up obviously. Then, the respiratory rate reached its peak.(2) After picking, the respiratory rate of fruits always kept in the high level, and other physiological indexes showed apparent change when respiratory climacteric happened. It might be the main cause of peaches decayed in a very short time.In addition, hot and humid storage environment and fungus invasion could accelerate rotting of fruits. Therefore, inhibiting respiratory, controlling storage condition and preventing fungus invasion were the key of prolonging storage period.(3) The indexes of treated groups by ginger juice, on matter combinations of concentrations and treatment time, are significantly better than that of control group, and increasing soak time was more effective than increasing concentrations of ginger juice. Comprehensive consideration suggests that the best combination was1:30g/ml concentration of ginger juice and1h treatment time, which was better in keeping the weight and firmness and slowing down the respiratory rate.(4) There was no significant difference of suspensions of Cryptococcus laurentii with four preparation methods, fermentation liquor, sterile fermentation, bacterium suspension and supernatant fluid. Given feasibility, fermentation liquor was better for popularization. The treated groups by higher concentration of C. laurentii and longer treatment time were more effective than others. Comprehensive consideration suggests that the best combination was30times diluted fermentation liquor for lh, which could alleviate the decay of peach fruits, slow down the respiratory rate to a great extent.(5) The cold shock treatment with10min was better in slowing down rod index and the respiration rate, maintaining the firmness and reducing MDA content, while, treatment with30min was more effective in controlling the membrane permeability and refraining the PPO activity. The lh treatment had no effect in inhibiting the respiration rate and restraining the increase of MDA content, perhaps causing chilling injury. Therefore, treatment with10min and30min were more effective than lh and10min was the best treatment time for saving treatment time. (6) The treatment by CaCl2was better in reducing the weight loss, inhibiting the leakage and MDA content increase, however, which could not alleviate the decay and restrained PPO activity of peach fruits. The physiological and biochemical indexes of fruits treated by NaHCO3and NaC1were higher than control group, driving the spread of decay and process of spoilage. So CaCl2, NaHCO3and NaCl were not fit for The ’BaiHua’juicy peaches.In all, based on analysis of postharvest physiology and decay mechanism of juice peaches, ginger juice, cold shock and C. laurentii were all effective and fitted the food safety policy, among which ginger juice and cold shock methods had low cost and simple operation, just RMB100-200per mu, suitable for popularization in fruit growers, and C.laurentii method, operating with large-scale equipments and professionals, was fit for factory production application. CaCl2、NaHCO3and NaCl took no effect on preservation of juice peaches, and NaHCO3and NaCl even promoted rotten, so these chemical methods were not suitable to be extended and applicated.In this paper, through the innovative and deep analysis of postharvest physiology and decay mechanism of juice peaches and different combinations of concentrations, treatment time and preparation methods of different treatment methods, ginger juice, C. laurentii and cold shock, best combinations chosen were compared along four aspects, food safety, effectiveness, economy, and feasibility. Preservation methods suitable for fruit growers and factory production popularization were studied out, which made this subject had high application value. |
PDF Full Text Request