| Using the ozone water and ultrasound as the main keeping fresh means to study their effects on physiology and quality of Litchi (Litchi chinensis Sonn.cv.Guiwei) in this paper. The paper involves: 1) to investigate the effects of ultrasound on the weight loss rate of litchi fruits in the preservation; 2) to study the effects of ozone water on the main enzyme activity related to browning and quality of litchi; 3) to study the responses of the physiological changes of litchi to ultrasound and ozone water combined with bio-antistaling agents during the preservation of litchi. The results are as follow:1, Effects of ultrasound on the weight loss rate of litchi fruitsLow ultrasonic intensity (1200W*300W) can cause to decreasing of the weight loss rate of litchi fruits after processed for 60s by ultrasound. However, Effects of high ultrasonic intensity (1200W*600W, 1200W*900W, 1200W1200W) are not significant on the weight loss rate of litchi fruits, these processes can not reduce the weight loss rate.High ultrasonic intensity (1200W*1200W) for 90s aggravates the weight loss rate of litchi fruits. However, other ultrasonic intensity (1200W*300W, 1200W*600W, 1200W*900W) is of benefit to holding water of litchi.2, Effects of ozone water on physiological changes of litchi during the cool preservation.The results show that ozone water can retard the decreasing of anthocyanogen and flavonoids content, holding effectively the red color of pericarp litchi (cv Geiwei). The results also suggest the process has significant effective by 0.5mg.L-1.Ozone water induce to the raising of peroxidase (POD) activity of litchi pericarp. The POD activity of litchis treated with ozone water is higher significantly than CK's, one of which processed with l.0mg.L-1 of concentration is most significant. However, ozone water restrain polyphenol (PPO) activity, which is lower significantly than CK's by l.0mg.L-1 of concentration of ozone water. These results suggest ozone effect by different mechanisms on PPO and POD activity.The study all shows that ozone water affect un-significantly on the soluble solids content (SSC) of litchi fruits, but it can retard the declining of tiratable acidity (TA)content. These suggest the nutritional quality of litchi fruits isn't badly affected by the process of ozone water.3, Effects of ultrasound and ozone water combined with bio-antistaling on the preservation of litchiProcessed by ultrasound and ozone water combined with Tl and T2 bio-antistaling, the browning index of litchi is reduced during the preservation. The results suggest the two treatmeotal means can effectively retard browning of litchi pericarp. Because of low PH value of bio-antistaling, anthocyanogen content of litchi pericarp dropped slowly in the storage.All treatments can retard the PPO activity of litchi pericarp, effect of T2 treatment on the enzyme activity is most distinct, the next is Tl treatment. The PPO activity is rising because of these treatments. The effect of T2 treatment on PPO activity is most distinct, enzyme activity of the T2 treatment is most high. The results indicate that the treatments effect by different mechanisms on PPO and POD activity. Considering the front the results relating to the effects of these treatments on browning index of litchi pericarp, the author consider that the rising of PPO activity does not accelerate the browning of litchi. Therefore, the function of PPO to the T2rowning of litchi is required to discussed further.The actions of the treatments are not observed on the reducing the relative permeability of cell membrane in pericarp and weight loss rate of fruits. The results indicate that the treatments with high-weight loss rate of fruits do not present high index of browning. Therefore, the author considers that the losing water of litchi fruits isn't main factor of browning in cool preservation.After processed by ultrasound and ozone water combined with Tl and T2 bio-antistaling, the nutritive materials are maintained significantly. The results show that th...
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