| Pickled mustard tuber is a famous traditional pickle in our country, known as one of the world famous three pickles. It is planting widely and has a large number of products in our country. More and more pickled mustard tuber is exported in recent years, it has became one of favourate foods of consumers at home or abroad. Technology and process have been making innovation constantly in the hundred years of development. A series of healthy and delicious new products have emerged. So far, research of pickled mustard tuber mainly focused on the raw materials planting, reform of salting process, sterilization optimization, research of flavor compounds and new product development. The researchs on the quantity of bacteria of raw materials and seasonings, packaging conditions, cooling conditions and storage conditions are still scarce.Taking three salted pickled mustard tuber as raw materials. Reference to the traditional processing technology of convenience pickled mustard tuber, optimize the desalination process by ozone water, pretreatment of seasonings, sterilization process and cooling process. Study the quality and storage characteristic of the pickled mustard tuber with different packaging and was storaged under different temperature conditions. The major results are as follows.(1) Base on the sterilization effect of different concentrations of ozone water, the best was 0.4 mg/L, which could significantly reduce the amount of bacteria of raw material of pickled mustard tuber(P=0.001). The aerobic plate count reduced from 2.1×104 CFU/g to 1.6×103 CFU/g and the sterilization rate reached 92.4%. The influence on the color and hardness of pickled mustard tuber were not significant(P=0.052, 0.068).(2) Ultra high pressure processing and microwave processing were used to reduce the amount of bacteria of seasonings. Optimization of the best pretreatment condition was treated by 300 Mpa for 15 min under the condition of UHP. The aerobic plate count reduced from 5.6×104 CFU/g to less than 30 CFU/g, and the effect on the color and fragrance of seasonings were not significant( P=0.061, 0.059). After adding pretreatment seasonings to pickled mustard tuber, the sensory score was no significant difference with the control group(P=0.064).(3) The aerobic plate count of raw materials and seasonings dropped 97.6% by the new technology before sterilization, and the sterilization time of pickled mustard tuber was reduced to two-thirds of traditional. The best sterilization condition for 60 g/bag was 95℃/8 min.(4) Compared with traditional cooling conditions(room temperature water was 25℃), the temperature below 20℃ could improve the color, hardness and sensory scores of pickled mustard tuber, and reduced the loss of nutrients. When the cooling temperature was 10℃, the color, hardness, sensory scores, total acid and amino nitrogen content of pickled mustard tuber compared to 15℃ were not significant. Compared with traditional cooling, 15℃ was used in the process of cooling could significantly improve the color, hardness and sensory scoreof pickled mustard tuber and economic burden lighter.(5) Transparent(plastic) vacuum packaging, aluminum foil(opaque) vacuum packaging, transparent nitrogen-filled packaging andaluminum foil nitrogen-filled packing were selected for the storage of picked mustard tuber, and study the changes of quality and storage characteristic of the pickled mustard tuber was stored under room temperature conditions. The pickled tuber mustard in transparent packaging had the parameters higher than aluminum foil packing such as browning, total acids and aerobic plate count, but color, hardness and sensory score were lower. The pickled mustard tuber in nitrogen-filled package had the parameters higher than vacuum package in hardness, total acids and sensory score, but browning and aerobic plate count were lower. The parameters of aluminum foil nitrogen-filled were better than the other three groups. After 180 days of storaged the hardness of aluminum foil nitrogen-filled packaging was 26.02 N and transparent vacuum packing was 18.61 N, the difference between them was significant(P=0.001). Compared with transparent vacuum packaging, the browning index of aluminum foil nitrogen-filled packaging was different with transparent vacuum packaging significantly(P=0.003). The sensory score of aluminum foil nitrogen-filled packaging was 26.5 and higher than transparent vacuum packaging(P=0.004), which sensory score was 22.6. Aluminum foil nitrogen-filled packaging can keep the quality of picked mustard tuber better.(6) The quality of pickled mustard tuber in nitrogen-filled packaging was the best when it was storaged under 5℃, but not significant different with 15 ℃ storage conditions. Some parameters of pickled mustard tuber in vacuum packaging were not significant different with 15℃ storage conditions whenit was stored under 5℃ in 120 days, such as b*, hardness, nitrite, total acid, amino nitrogen and sensory score. Combined with economic factors selected 15℃ as storage conditions. After 180 days of storaged, compared with 25℃ storage conditions, the L* of picked mustard tuber with nitrogen-filled packaging and vacuum packing in 15℃ were different significantly(P=0.025, 0.020); the hardness were 28.79 N and 30.85 N respectively, the differenence between them was significant(P=0.013, 0.015); the soft change rate were decreased 9.8% and 11.1% respectively; the sensory scores were 27.5 and 28.8 increased 10.4% and 12.1% respectively; the total acid and amino nitrogen were higher than 25℃ storage conditions, but the nitrite were lower.(7) New process of low-salt convenience pickled mustard tuber after optimized: three salted pickled mustard tuber â†' tick tendons â†' clean â†' slice â†' desalination(0.4 mg/L ozone water) â†' dehydration seasonings pretreatment(UHP by 300 Mpa/15min) â†' mix materials under sterile conditions â†' weigh and bagging â†' aluminum foil nitrogen-filled packaging â†' sterilization(95℃/8 min) â†' cooling(15℃) â†' low-salt convenience pickled mustard tuber â†' storage or transport under 15℃ conditions... |
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