Effect Of PVP On The Quality And Storage Of "Xiahui 5" And "Baihua" Honey Peach Fruits

The honey peach fruits of "Xiahui 5" and "Baihua" treated with water, 0.05%, 0.1%, 0.2%, 0.3%, 0.4% Polyvinylpyrrolidone, 1.0% Chitosan, 1.0% Chitosan +0.1% Polyvinylpyrrolidone and 1.0% Chitosan +0.2% Polyvinylpyrrolidone coating respectively were packaged into polyethylene bags and then stored at 1 0.5 C to investigate the effect of PVP on the changes of physiological, biochemical and qualitative induces such as respiratory rate, nutritous composition and enzyme activities during storage period. These studies were to intend to understand the storage mechanism and keeping freshness of honey peaches. The main results were showed as follows:1. For honey peach fruits of "Xiahui 5", 0.1 %PVP and 1.0%CTS coating among all treatments could inhibit respiratory rate and climacteric, delay the increase of MDA content, slow down the convertion of insoluble pectic substances into soluble pectin, retain better firmness and higher vitamin C. The treatments of 0.1%PVP and 1.0%CTS coating could also inhibit weight loss and the increases of reducing sugar and soluble solids. Overall, the effect of 0.1 %PVP coating was better than 1.0%CTS.2. Compared to CK, all PVP and PVP+CTS coating could inhibit the PPO, POD and PG activities in "Xiahui 5" peach fruits for a certain extent, and also the PAL activity excluding 0.3%PVP coating, during storage period. The effect of inhibition was more obvious for 0.1%PVP and 1.0%CTS. However, PME activity didnot show significantly different in the fruits of all treatments including CK and smoothly, decreased during storage. Comparing with other treatments, the effect of 0.1%PVP coating was again the best.3. The respiration of "Baihua 5" peach fruits coated with higher concentration of PVP or with PVP+CTS during storage was relatively high, even hiher than that of CK. Only 0.1%PVP coating could inhibit respiration rate and lower respiratory peak. The treatment Baihua honey peaches could also slow down the increase of MDA and soluble pectin, retain flesh firmness and vitamin C content and freshness, reduce weight loss, narrow the change of reducing sugar and soluble solid contents, delay the loss of titratable acidity and weight, and alleviated the development of rot.4. Only 0.1%PVP and 0.2%PVP coating among all treatments had lower PPO and POD activities in "Baihua" peach fhuts than that in CK, and 0.1%PVP was better than 0.2%PVP. All PVP and PVP+CTS treatments had positive effect on inhibiting the increase of PAL; however the one of 0.1%PVP coating was the best.5. The results of thin layer chromatography of silica gel G, HPLC chromatogram analysis showed that the main enzymatic browning substrates in honey peach fruits of Xiahui'Sth'and Baihua were also chlorgenic acid and catechol.6. The change differences of PPO, POD, PG, PAL, PME enzymes between "Xiahui 5"and "Baihua"two peach cultivars during cold storage existed. In opposition to Xiahui 5 peach, Baihua manifested with stable PG activity and wide change of PME activity in Baihua peach.7. 0.1% was the optimal concentration of PVP for coating both"Xiahui 5"and "Baihua" peach cultivars.