Study On Quality And Safety Changes And Their Control Of Normal Temperature Snowy Mooncake During Processing And Storage

The snowy moon cake is mainly made by the cold processing technology,and it is widely favored by consumers because it maintains the appearance color and softness of the original raw material.However,due to the nutrient-rich raw materials and the lack of sterilization or antibacterial process in the processing process,the snowy moon cake,especially the products stored at room temperature,have great safety risks and the quality is also unstable.In view of the above problems,this paper selected water-sand moon cake(filling material is water-based bean paste)and oil sand moon cake(filling material is oily bean paste)as a typical representative,using high-throughput sequencing technology and low-field nuclear magnetic resonance technology to study different processing and storage stages.The quality and safety of the snowy moon cakes were analyzed by the traditional culture method.The effects of short-time heat combined with ultraviolet treatment on the quality and safety of the normal-temperature snowy moon cake were discussed.Guaranteed guidance.The main research contents and results are as follows:(1)For the microbiological safety problem of snowy moon cake storage at room temperature,the microbes in the product of the snowy moon cake were measured and traced by high-throughput sequencing technology combined with traditional culture techniques.High-throughput sequencing showed that there are mainly 14 species of genus Cyanobacteria,Bacillus and Staphylococcus.On this basis,the traditional culture methods were used to separate and purify the microorganisms in the raw materials,processing samples and products.The results showed that the two techniques had certain similarities in the results.Active microorganisms present in the whole process included Bacillus,Stenotrophomonas,Paenibacillus,Bacillus(different from ? sequence),Staphylococcus and Mucor,Penicillium and Aspergillus.After analysis,it was found that the original excipients were the main source of spoilage,among which ?,? and Mucor were mainly derived from snowy moon cake premix,?,?,? and Penicillium and Aspergillus were from fillings.(2)According to the relationship between the quality change of snowy moon cake and water migration,the texture characteristics,thermodynamic properties method and low field nuclear magnetic resonance technique were used to determine the skin of the snowy moon cake with the extension of storage time.The hardness was significantly increased,the water dispersion loss was increased,and the water loss rate of the water-sand moon cake skin layer was higher than that of the oil sand moon cake;and the moisture migration rate of the untreated moon cake sample filling material to the leather material,and the water dispersion rate of the leather material were consistently;the hardness of both moon cakes was significantly correlated with water migration(the amount of moisture exchange with the external environment)(P<0.01),and the water-sand moon cake was also significantly correlated with the water activity of the leather(P<0.01);The resonance spectrum showed that there were only two peaks in the snowy mooncake spectrum,and the area of the semi-bonded water peak accounted for 99%.With the extension of the storage time,the time points corresponding to the two peaks are shifted to the left,indicating the degree of water binding.(3)In view of the safety and quality improvement of snowy moon cake,the effects of short-time heat drying and UV treatment on water migration and quality were investigated without affecting the sensory quality of snowy moon cake.The results showed that short-term heat combined with UV treatment could ensure the microbiological safety of the snowy moon cake;the hort-term heat treatment could increase the hardness of the snowy moon cake leather.MRI imaging pseudo-color map and grayscale image showed that the boundary between the oil sand moon cake leather and the filling material becomes more and more blurred,with the short-time hot-bake time and storage time prolonged,the overall water distribution was even,and the water sand moon cake was not obvious;short-time hot baking combined with UV treatment helps the water balance between the oil sand moon cake and the filling,and reduces the degree of internal moisture migration,but the effect on the water sand moon cake was not obvious.