The Fruit Storage Study Of Physiological Indicators And Browning Mechanism Of A Newly Found Peach ‘Baojiajun’

Peach is a typical climacteric fruit, very prone to become aging and decay after harvest, which directly affects the quality of fresh and processed peaches, and also results in the loss of nutrients in the juice. At present, many researchers had deeply conducted a series of studies on the regulatory aspects to the fruit browning of peaches’ storage and processing methods, but these methods could only control the browning occurs to some extent, did not solve the fundamental problems about the storability and anti-browning of fruits,breeding new varieties of anti-browning and storage-tolerance is a way to solve these problems fundamentally. ‘Baojiajun’ was a less flesh browning and resistant to storage peach found by Agricultural University of Hebei, whose fruits can tolerate transport, resist browning, and possess excellent comprehensive characters. ‘Baojiajun’ as test materials,‘Okubo’ et al. as the control varieties, in order to study the storage and browning resistance properties of ‘Baojiajun’. The main findings are as follows:1. The sizes of ‘Baojiajun’ were larger than ‘Okubo’ and ‘Jing Yu’. The contents of sugar material, Vc and soluble protein were significantly higher than the control. The content of titratable acid was notably lower than‘Okubo’, but was greatly higher than ‘Jing Yu’.In the process of storage, the content of titratable acid was lower than ‘Okubo’, the fruit firmness, contents of suger, sucrose, soluble protein and Vc were higher than ‘Okubo’. It appeared 2 breath peaks of ‘Baojiajun’ during the storage, and the second breath peak was 18 d later than ‘Okubo’2. By contrasting the fruit browning trait of ‘Baojiajun’, ‘Zhonghuashoutao’, ‘Shenzhoumitao’, ‘Okubo’ and ‘Dongxuemitao’ during cold storage, the results demonstrated that ‘Baojiajun’ flesh exhibited the least browning than the other 4 varieties, and the browning of ‘Shenzhoumitao’, ‘Zhonghuashoutao’ were high. The browning degree of ‘Baojiajun’ was significantly lower than the ‘Dongxuemitao’and ‘Okubo’.In order to compare the browning resistance characteristics of “Baojiajun” more widely, ‘Baojiajun’ and 8 other peach varieties as tested fruits were studied to contrast their browning degrees. The results indicated that the browning degrees of ‘Xia Hui 6’ and ‘Yan Hong’ were the highest, then the ‘Abehakuto’, ‘Honggangshan’, ‘Okubo’ ‘Datuan Mi Lu’ and ‘Jing Yu’ were moderate degree of browning, lastly the browning degrees of ‘Baojiajun’ and ‘Baojiahong’ were the lowest. The browning degree of ‘Baojiajun’ was significantly lower than other eight varieties.3. In the late stage of fruit development, the browning degree, contents of polyphenol and flavonoid, the activity of phenylalanine ammonia lyase(PAL) and polyphenol oxidase(PPO) of ‘Baojiajun’ and ‘Okubo’ showed downward trends. Malondialdehyde(MDA) content presented the rising trend. The related browning indexes of ‘Baojiajun’ were lower than ‘Okubo’, while the activities of protection enzymes were higher than ‘Okubo’. Further studies on the correlation analysis of the browning degree and related indicators found that the activities of PAL and PPO, the contents of the total phenol and flavonoid had a high correlation with browning degree.4. During the whole storage, the browning degrees of ‘Baojiajun’ and‘Okubo’ rose rapidly in storage within 0 ~ 6 d, the browning degree of ‘Baojiajun’ was always lower than ‘Okubo’; the content of total phenol of ‘Baojiajun’ and ‘Okubo’ was on the rise during the storage, the total phenol content and PAL activity of ‘Okubo’ were significantly higher than ‘Baojiajun’; the PPO activity of ‘Baojiajun’ was always lower than ‘Okubo’, and had an extremely significant difference on 12 and 24 d after storage; the three kinds of endogenous antioxidant enzyme activities of ‘Baojiajun’ were higher than ‘Okubo’ during the whole storage.5. This experiment studied the the browning traits and related biochemical characteristics of ‘Baojiajun’, ‘Okubo’ and ‘Xia Hui 6 in the process of placing berries. The results demonstrated that the browning degree of ‘Xia Hui 6’ flesh was the highest, and ‘Baojiajun’ flesh exhibited the least browning degree among all the detected varieties. Compared with the flesh of ‘Okubo’ and ‘Xia Hui 6’, ‘Baojiajun’ contained lower levels of total phenol, flavonoids, and malondialdehyde(MDA), as well as lower activities of PPO and PAL. In contrast, the activities of POD, SOD, and CAT were higher in ‘Baojiajun’ flesh. Based on the correlation analysis between browning degrees and biochemical characteristics, we confirmed that the contents of total polyphenols, flavonoids, and MDA, as well as the activities of PAL, PPO, and POD, had a significant positive correlation with the browning degree; in particular, the content of total phenol and the activities of PPO and PAL had a very significant positive correlation with the browning degree.6. Through studying the content of amino acid of ‘Baojiajun’ ‘Okubo’ and ‘Xia Hui 6’, the findings showed that: the contents of tyrosine and phenylalanine of ‘Baojiajun’ fruits were significantly lower than that ‘Okubo’ and ‘Xia Hui 6’, and the two amino acids had the highest contents in the ‘Xia Hui 6’ fruits. The tyrosine content was positively correlated with the browning degree, total phenolic content and PPO activity; the phenylalanine content showed a significant positive correlation with the browning degree, total phenolic content and PPO activity was.