Mechanism Of Frozen Storage Change Of Leavened Pancake Based On Different Cooked Methods

In recent years,with the rapid development of China's economy,people's lifestyle is constantly changing,the pace of life is also accelerating,and consumers' demand for convenient staple food is increasing.leavened pancake occupies an important position in traditional Chinese staple food,instant taste good,fermented flavor,easy to eat,loved by consumers..However,the decline of eating quality and the deterioration of taste and flavor have been the bottleneck of industrial production and circulation.Therefore,this topic takes steamed and baked leavened pancake as the research object,and deeply studies the production process,reheated methods and quality changes in the process of frozen storage of different cooked leavened pancake,so as to provide a theoretical basis for the industrial production of leavened pancake.The main results are as follows.Firstly,the effects of water addition,fermentation time,fermentation humidity,baked temperature and time,steamed time on sensory quality of leavened pancake were investigated.The results showed that when the amount of water was 48%,the fermentation time was 60 min,the baked temperature was 190 ?,the baked time was 11 min,and the fermentation humidity was 80%,the sensory quality of the baked leavened pancake was the best;when the steaming time was 15 min,the sensory quality of the steamed leavened pancake was the best.The effects of different ripening processes on the physicochemical properties and sensory quality of the steamed leavened pancake were compared.It was found that the steamed leavened pancake had higher water content,less weight loss,less hardness and larger specific volume;the baked leavened pancake had lower water content,greater weight loss,greater hardness and smaller specific volume,but it had strong aroma,uniform pores and higher sensory score than the steamed leavened pancake.The correlation analysis between texture characteristics and sensory evaluation index of baked leavened pancake showed that the taste of baked leavened pancake was significantly negatively correlated with hardness and chewiness,and the internal structure of baked leavened pancake was significantly positively correlated with resilience,which indicated that hardness and chewiness in texture index could be used to characterize the taste of baked leavened pancake,and resilience in texture index could be used to characterize it The internal structure of baked leavened pancake.Then microwave heated,baked and steamed were used to reheated the frozen precooked leavened pancake,and the effects of three reheated methods on texture characteristics and sensory quality were compared.The results showed that the reheated temperature and time of baked 7 min was 210 ? / 4 min,9 min was 200 ? / 4 min,and11 min was 190 ? / 3 min.The results showed that the reheated time of steamed bread was 15 min,and the microwave reheated time of steamed leavened pancake was 40 s;the microwave reheated time of baked leavened pancake for 7 min was 50 s;the microwave reheated time of baked leavened pancake for 9 min was 50 s;the microwave reheated time of baked leavened pancake for 11 min was 40 s.No matter steamed,baked or microwave reheated,the hardness and chewiness of leavened pancake increased with the extension of frozen storage time.The hardness of microwave reheated leavened pancake was higher than that of baked leavened pancake,and the hardness of baked leavened pancake was higher after 11 min.the recovery of microwave reheated leavened pancake decreased gradually.The changes of hardness,chewiness and resilience during frozen storage were consistent with the decreasing trend of sensory score.Microwave reheated is suitable for short prebaking time,baked reheating is suitable for long prebaked time and steamed reheating is suitable for steaming time.Finally,the moisture migration,starch crystallinity,starch thermal properties and microstructure of steamed and baked leavened pancake during frozen storage were analyzed by nuclear magnetic resonance(NMR),X-ray diffraction(XRD),differential scanning calorimetry(DSC)and scanning electron microscopy(SEM).The results showed that: the moisture content of steamed and baked leavened pancake during frozen storage decreased with the increase of frozen storage time,and the moisture content of steamed leavened pancake was higher than that of baked leavened pancake;the weak combined water content of steamed and baked leavened pancake decreased with the extension of frozen storage time,and the free water content increased;the crystallinity also increased with the increase of frozen storage time,and the moisture content of steamed leavened pancake increased with the increase of frozen storage time The results showed that the crystallinity of leavened pancake during frozen storage was higher than that of baked leavened pancake,and the crystallinity of baked leavened pancake decreased gradually with the increase of baking time;the gelatinization initial temperature,gelatinization peak temperature,gelatinization end temperature and gelatinization enthalpy of starch had no significant change;the microstructure of steamed and baked leavened pancake from continuous matrix state to thin fracture state.