Research On Applaction Of Microwave Technology On Canned Apple

Microwave heating has the advantages of short heating time, fast heating, energysaving, less lose of nutritional and flavor. Now there is no wide application ofmicrowave heating in the solid liquid coexist system. Apple is a common fruit with alot of nutrients has the function of dietotherapy and adjuvant treatment. Canned appleproduced by traditional process have the disadvantage of flesh too soft and lowerquality. In order to study the application of microwave heating in canned fruit, choosethe canned apple as the sample. Analyze the temperature distribute, temperatureincrease, sterilizing effect during the microwave heating. Research on the effect ofmicrowave heating on quality of canned apple and campared with the traditionalproduct. Through the response surface analysis experiments come out the optimalmicrowave sterilization processing and certain the new microwave processing ofcanned apple. Study some preservation experiment.1. The tempreture distribution of samples heated by microwave: the tempretureincreased from the glass wall to the center in the same level of sugar solution. thetempreture increased from bottom to top in the veritical direction and the tempreturewas highest in the tank deck. The tempreture of fruit pieces was higher than sugarsolution, and the tempreture within the fruit was higher than on the surface. The resultshowed that:the tempreture of sugar solution presented linear growth, the tempretureof fruit pieces increased rapidly in the short time,the increase was slow when thetempreture reached95℃and remained stable. The lowest tempreture testing point ofmicrowave sterilization was1cm from the bottom and neared the tank wall.2the study on the effect of microwave sterilization: the tempreture increasedrapidlier and the effect of microwave sterilization was better, as the microwavepowder got greater. the effect of fruit size on the tempreture was not obvious, thebigger fruit size was,the better effect of sterilization was, but it had some residualbacteria count.the effect of sugar solution on the sterilization was obvious, hightempreture of sugar solution can improve the sterilization effect. the change ofsterilization effect was not obvious when the tempreture reached80℃.themicrowave sterilization time was1/3of the conventional sterilization.3. Effects of microwave heating on the quality of canned apple: microwaveheating could raise temperature of samples quickly, when to reach the sametemperature the time microwave heating need is1/5of that of traditional heating. Thetime of sample in high temperature is shorter. Microwave heating could increase thehardness, Vc Preservation rate and sensory evaluation of samples. Higher microwavepower and longer heating time were unfavourable for the hardness, Vc Preservationrate and sensory evaluation of samples. When the samples were too big may causeuneven heating which lead to decrease of quality, come out partly soft.4. Optional sterilization process: Response surface methodology(RSM) wasemployed to improve the quality of samples under the insure of safety. The optionalsterilization processing is microwave power500W, heating time3min, sample’sweight16g. The verification testing result is consistent with predictive value. Theeffect of total bacteria and quality of canned apple of each factor are: heating time>microwave power> samples weight.5. Microwave processing and preservation experiment: preservation experimentof two different processings, the quality of samples produced by new processing isbetter than traditional processing. But after180d storage, total bacterial count ofmicrowave processing samples raise, so the traditional processing sterilizingcompletely. The shelf life of microwave processing is not as long as traditionalprocessing. The lower preservation temperature leads to better inhibition of bacterial,longer the shelf life and better quality of samples.