Changes During The Cooling And Storing Process Of The Quality Of Steamed Bread

The influence of different cooling conditions, including cooling temperature, coolingwind speed, and cooling relative humidity, on the quality of steamed bread during the coolingand storing process were studied. The reasons and mechanisms of the changes in the qualityof steamed bread were analyzed. At the same time, the new fresh technology of the steamedbread had carried on the preliminary research.The influence of cooling conditions on the quality of steamed bread during the coolingprocess was studied, and with the relevant of the quality, such as the atrophy, smoothness andtoughness, of the skin of steamed bread. The skin of steamed bread was composed of a layerof irregular bubbles. The moisture content of the skin of steamed bread was graduallydecreased, and it had certain relevance with the skin color. The different cooling conditionshad large effects on the moisture gradient and temperature gradient of steamed bread duringthe cooling process, and had a great influence on the cooling rate of steamed bread. Themoisture content, the weight of steamed bread and the high ratio were gradually reduced. Thewhiteness of the steamed bread to decline then raise declining trend. The water activity andgelatinization of steamed bread had decreased, but not significantly. The hardness of steamedbread increases gradually, but the softness was on the decline. After the cooling process, theprotein digestibility characteristic of steamed bread had decreased and the starch digestioncharacteristic had increased. After cooling, the microstructure of steamed bread was changedlittle, and the pore structure was dense, changed smaller.The influence of cooling conditions on the quality of steamed bread during the storingprocess was studied. During the storing process, the microbial quantity had increasedgradually, the water activity and gelatinization of steamed bread had decreased, and thehardness was on the rise trend. The different cooling conditions had an effect on moisturecontent and epidermis tenacity of steamed bread during the cooling process, thus influencedof the quality of steamed bread during the storing process. At low cooling temperature, thegrowth of microorganisms were inhibited during the cooling process, and the possibility ofmicrobial contamination was increased when the cooling wind speed increased, the increase of the cooling relative humidity was conducive to the microbial breeding. The combination ofstarch and gluten protein of steamed bread was loose and become clear gradually during thestoring process, and the surface of the starch granule grain structure.The new fresh technology of the steamed bread during the storing process was studied.The technology of "Film" Fresh-keeping and High Temperature Storage of steamed bread hadcarried on a preliminary study. It was kept a good quality of steamed bread when the storagetemperature was greater than or equal to60℃, the relative humidity storage was greater thanor equal to80%during the high temperature storing process. The shelf life of steamed breadwas prolonged about three times by used3c pof heat shrinkable film of food-grade during thesealing film processing after cooled completely of steamed bread. But the quality of steamedbread changed a little.