| Fresh-cut vegetables, which can satisfy the demand of modern life with the advantagesof convenience,healthy and fresh,is a kind of ready-to-eat product that have been studiedand developed rapidly these years.With the change of the way people live, fresh-cutvegetables will become the trend of vegetables consumption.In this paper, carrot, potatoand spinach were used to search the optimum fresh-cut process conditions.The aim of thework was to investigate the effect of different storage temperatures(0℃,4℃,7℃and10℃) on the relevant quality of the fresh-cut vegetables. The shelf-life prediction model offresh-cut vegetables was obtained based on above properties.First, the final scheme of optimum process conditions of fresh-cut was determined byusing orthogonal test. The results were as follows:the best fresh-cut processing conditionsof carrot was:50mg/L ClO2(sterilizing for10minutes),1.5%chitosan+1.5%citric acid(coating); potato was immersed in3different kinds of solution(100mg/L ClO2,1.5%citricacid and0.1%potassium sorbate) for10minutes;spinach was immersed in two kinds ofsolution(75mg/L ClO2and0.5%NaCl) for10minutes.Then they were all packaged withPVDC cling film.Three kinds of vegetables, after fresh-cut processing,were stored in fourtemperaturegradient of0℃、4℃、7℃、10℃. The quality changing relationship betweensamples over time and temperature were mainly studied through physicochemical indexes,total plate count(TPC) and sensory evaluation. Results showed that, with the extension ofstorage time, the weight loss and TPC of three fresh-cut vegetables gradually increased,butsensory score gradually decreased;soluble sugar content of fresh-cut carrots was increasedat first, then continued to decreased after reaching a peak value; the polyphenol oxidase(PPO) activity of potato and chlorophyll contentof spinach had a gradually increasing anddecreasing trends respectively.During the storage, quality changes of three fresh-cutvegetables were significantly affected by temperature,which the change rate rise with theincrease of storage temperature.In the latestorage with a high temperature,the samplesdeteriorated faster at a higher rate, and then the storage period become shorter. During thestorage, the shelf life based on sensory evaluation and TPC is not exactly the same,it shouldconsider the actual situation.According to the change rules of each index of the three kinds of fresh cut vegetables,we has carried on the correlation analysis and regression analysis, established the first andsecond order dynamic models adapt to the indicators, and have made a prediction ofsamples shelf life. After verification and analysis, different models were obtained based on the indexs of three fresh-cut vegetables at the different shelf life end from sensoryevaluation and TPC.Model based on weight loss rate of fresh-cutcarrot:t=(y-y0)1.99×10-16e11244T,(y is the endvalue of shelf life, y0is the initial value,following the same; T is temperature,K);Model based on TPC of fresh-cut carrot:t=1.15×102/(T+4.469)2+1.67×103/(T+25.966)2,(T is temperature,℃);Model based on weight lossrate of fresh-cut potato:t=(y-y0)1.21×10-24e16280T,(T is temperature, K);Model based onPPO activity of fresh-cut potato:t=(y-y0)3.45×10-6e3690.5T,(T is temperature, K);Modelbased on TPC of fresh-cut spinach: t=1.31×102/(T+6.166)2+2.02×103/(T+40.269)2,(T istemperature,℃); Model based on chlorophyll contentof fresh-cutspinach:t=112.47-0.379T-7.5×10-4e2026.5/T,(T is temperature, K).Since the end of the shelflife from sensory evaluation and TPC is different,the application of the model need toaccording to the the specific actual conditions. |
PDF Full Text Request