| The aim of this paper is to propose a structured the processing technology with ultrasound treatment of blanching and freezing fruit on edamame. The shelf-life and quality after thawing of fast frozen fruit and vegetable after ultrasound treatment had also been studied. The quality of edamame was determined by nutrition, water-holding capciaty, texture, etc.Firstly, try to find a good processing of edamame blanching by studying different blanching treatments. The influences of microwave, thermosonication, hot water on edamame quality were measured by the change of peroxidase, ascorbic acid, protein, total chlorophyll and organoleptic. The results showed that the thermosonication treatment worked 1 min at 80℃, ultrasonic frequency 25 kHz, ultrasonic power 800 W could effectively reduce POD activity and the losses of protein, ascorbic acid, and chlorophyll significantly. In addition, the organoleptic quality of edamame was improved.Secondly, the mechanism of edamame peroxidase inactivation caused by thermosonication was studied.And processing parameters was optimized.The test was performed at the temperature of 60 to 90℃, ultrasounds at the frequency of 25 kHz and powers of 800 W. Take the changes of POD activity of edamame treated at 60℃to 100℃as control sample, and the changes of POD in thermosonication treatments were studied. The results showed that the activity of peroxidase remained 1.8% after the treatment of 25 kHz, 800 W ultrasound for 1.52 min at 83℃through response surface analysis. Thermosonication can be a new process instead of traditional heat process.Thirdly, immersion freezing of edamame with the aid of power ultrasound was investigated. That is ultrasound was applied during the phase change of frozen edamame. The research mainly focused on the effect of ultrasound power; exposure time and the ultrasound pulsed on increasing freezing rate and improving quality of edamame . The freezing temperature was controlled accurately by thermocouple tracking the changes of center temperature of edamame, and the physical and chemical characteristics of frozen materials after the treatment were also studied. The analyses conducted on the microstructure of edamame tissue using light microscopy technique. The response surface analysis was used for the analyzing by the SAS software. The texture and the water-holding capacity of edamame after thawing was 6050 g, 92% when 58 W ultrasound power was applied for 0.7 min, and 50% pulsed at the coolant temperature of -20℃.Lastly, the shelf-life of frozen edamame and the quality after edamame thawing were studied. a systematic kinetic study of ascorbic acid loss and sensory of edamame was conducted in the temperature range of freezing storage. And its dynamics characteristic, has applied the vitamin C degeneration dynamics model, predicting the potential shelf-life of frozen edamame. Increasing the temperature and storage time decreased the shelf life from greater. The temperature-dependence of vitamin C loss in the -5℃to -20℃range was adequately modeled by the Arrhenius equation. Study on several kinds of defrosting methods for quick-frozen edamame, carries on the microwave to defrost, air defrosting under ambient temperature and 4℃. Through determines its defrosting after the time, defrosting which 0℃ needs edamame content of VC ,the watering-holding and texture comparison, indicated the microwave defrosting effect is obvious. |
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