Effects Of Storage Conditions On Nitrate Content And Quality Of Vegetable Noodles

Noodles can be seen everywhere on Chinese dining table,and they are a very popular food.However,the fine processing of wheat by modern industry will destroy the nutrition of flour,resulting in the lack of dietary fiber and vitamins in the produced noodles.As vegetables contain a lot of dietary fiber and vitamins,they can be added into noodles to improve their nutritional value.However,leaf vegetables have more nitrate content.The nitrate content may change during the storage of vegetable noodles,which brings certain threat to people's health.Therefore,in this study,the vegetable noodles were stored under different conditions,and the variation rules were explored by detecting the quality of dissolved nitrate and nitrite,as well as acidity,fatty acid,total colony,cooking characteristics,starch gelatinization characteristics and microstructure.The experimental results are as follows:1.The addition of vegetable powder significantly improved the amount of nitrate dissolved in noodles.The room temperature storage had less nitrate content than the low temperature storage of vegetable noodles,the second day of low temperature storage was the highest at 1110.24 mg/kg,and the third day of normal temperature storage was the lowest at 45.95 mg/kg.The low-temperature storage of vegetable noodles delayed the deterioration of the protein network structure and prolongs the shelf life of the noodles.During low temperature storage,the cooking loss of vegetable noodles increased slightly to 6.80%,the acidity increased rapidly and then stabilized to 2.09 m L,the fatty acid content decreased to 31.08 mg/100 g,the total number of colonies gradually increased to 145 CFU/g,the starch gelatinization rate first decreased and then stabilized to 26.12%,the flour swelling potential increased to 7.35,the starch gelatinization temperature and gelatinization enthalpy decreased,the PPO activity was small,and the fluctuation was large.The maximum value was 1.84 u/g on the 3rd.The storage of vegetable noodles at room temperature accelerates the deterioration of the protein network structure and shortens the shelf life of the noodles.During normal temperature storage,the cooking loss of vegetable noodles increased to 9.92%,the acidity increased to 18.05 mL,the fatty acid content increased to 278.28 mg/100 g,the total number of colonies increased rapidly to 7500CFU/g,and the starch gelatinization rate did not change significantly(49.40% on day 4),flour swelling potential increased to 9.50,starch gelatinization temperature and gelatinization enthalpy increased,PPO activity quickly increased to 2.66u/g.2.Vacuum storage of vegetable noodles reduced nitrate content,from the initial 1209.06 mg/kg to 208.32 mg/kg on the 7th day.During vacuum storage of vegetable noodles,the protein network structure changes little,and the quality of noodles will still deteriorate due to storage at room temperature.During vacuum storage,the cooking loss of vegetable noodles was relatively stable(initial 7.62%),the acidity fluctuated greatly(initial 1.87mL),the fatty acid content was stable for the first 4 days,and then increased to 216.49 mg/100 g,and the total number of colonies gradually increased to 5900CFU/g,starch gelatinization rate rose to 67.29%,flour swelling potential decreased to 7.08,starch gelatinization temperature and gelatinization enthalpy showed fluctuating changes,PPO activity first decreased and then stabilized to 1.1.3 u/g.3.The dehydrated storage of vegetable noodles,the nitrate content was generally stable,the second day was 128.69mg/kg,while delaying the deterioration of the protein network structure,so that the quality of noodles was more stable.In the process of dehydration storage,the water absorption rate and cooking loss of dried vegetables were relatively stable,the acidity increased to 4.39 mL,the fatty acid content fluctuated greatly in the first 3 days,and then gradually increased,the total number of colonies increased slowly,810 CFU/g on the 10 th day,starch gelatinization decreased to 29.31%,the flour swelling potential decreased from 7.77 on the first day to 6.72 on the second day,and gradually increased again on the third day,and the PPO activity increased to 1.78u/g.