Abstract:
Based on the freezing point temperature(FPT)of celery,cauliflower and head cabbage,the effects of approaching FPT storage were studied on vegetable quality during storage and shelf life. With high precision electron temperature equipment,the freezing temperature curves were established for the bulk microstructure and the slurry body of celery,cauliflower and head cabbage,and their FPT were determined.The vegetables were stored at 5℃,approaching FPT,approaching FPT combined with ozone sterilization,respectively;and the effects of three treatments were studied on the storage and shelf qualities of the vegetables with sensory and nutrient indices.The results showed that for every vegetable variety,the FPT of bulk tissue was similar with its plasma tissue and the FPT was positively correlative to the water content of the vegetable.The FPT of celery,cauliflower and head cabbage were- 0.6℃,- 0.9℃and- 0.7℃,respectively.Sensory qualities of celery,cauliflower and head cabbage stored at approaching FPT combined with ozone sterilization were the best during storage period,and their Vc contents stored at approaching FPT were 1.77-1.84,1.42-1.45 and 1.65-1.68 times higher than those at 5℃ storage,respectively.Comparing with 5℃storage,shelf life of the three vegetables stored with approaching FPT were about 2-3,6and 4days longer,and their Vc contents were higher for 1.82-1.86,1.44-1.45and2.17-2.19 times,respectively,during shelf life period.The loss rate of weight for vegetables were lower in approaching FPT storage than those in 5℃storage.Influence of ozone sterilization on shelf life quality was not significant.Therefore approaching FPT storage combined with ozone sterilization was beneficial for improving the sensory qualities of stored celery,cauliflower and head cabbage;approaching FPT storage could extend shelf life and improve the sensory quality during shelf life,to reduce weight loss of stored vegetables and maintain their Vc contents during storage and shelf life.