Effect Of Different Fermentation Methods On The Quality Of Refrigerated Steamed Bread

With the continuous development of the industrialization of staple foods,steamed bread have become an indispensable commodity and greatly facilitated people's lives.Because of the high water content and high water activity,fresh steamed bread are susceptible to microbial infections and have a short shelf life,which does not meet the requirements of industrial development.Therefore,nowadays,manufacturers will package steamed bread in advance and use refrigerated or frozen delivery and storage.Consumers will also re-steam them after purchase and consume them.Therefore,for consumers,the packaging,storage,and re-cooking of steamed bread are the key factors that affect the final quality of steamed bread.This paper selects three packaging forms to package the steamed bread,and studies and analyzes the deterioration of the steamed bread during refrigerated storage,determines the suitable packaging forms for refrigerated steamed bread,uses three fermentation methods to make the steamed bread,and analyzes the fermentation process of different steamed steamed bread during the refrigeration process.The quality changes in the fermentation process and the quality of steamed bread before and after re-steaming are compared.The main results are as follows:Three types of packaging,sealed packaging(SP),deaeration packaging(DP),and breathable packaging(BP),were used to pack and freeze the bread.BP bread showed a large disadvantage in terms of whiteness,specific volume,and hardness.BP bread in the water distribution,the adsorbed water decreases rapidly,and the indicators of the steamed bread are deteriorating.There is no obvious difference in the whiteness and moisture of SP and DP steamed bread,but the specific volume and hardness of DP steamed bread have a tendency to deteriorate.In terms of the growth rate of the total number of colonies,BP> SP> DP.In terms of molds,the growth rate of SP bread molds is faster than that of the other two packaging forms' steamed bread.The early mold of BP bread shows a rapid growth rate followed by a slow growth rate.The combination of the total number of buns colonies and the number of molds was used to evaluate the three packaging forms of SP,DP and BP.The shelf life is 10 d,18 d,and 14 d.The first-time fermentation steamed bread(OF),the fast second-time fermentation steamed bread(SF),and the overnight old dough dough fermentation steamed bread(SD)were used for refrigerated storage.During the cold storage period,various texture indicators of the steamed bread have deteriorated,including increased whiteness,increased hardness,decreased cohesion,reduced restoring force,decreased elasticity,and increased chewability.All the indicators are better than SF bread and OF bread.The specific volume of the three types of steamed bread did not change significantly.The protein digestion of SD steamed bread in vitro was significantly larger than the other two fermentation methods.The moisture content of steamed bread in the three fermentation methods decreased in a fluctuating manner.The various water loss ratios in the steamed bread are increasing,and the combined water and adsorbed water are decreasing during the continuous migration process.Fitting the crystallinity data through the Avrami model,It can be concluded that the aging rate of OF steamed bread is greater than the other two fermentation methods' steamed bread.The aging rate of SF steamed bread is slightly higher than that of SD steamed bread.The thermal enthalpy value in the thermal characteristics of buns in cold storage also appears as OF>SF>SD,and the data are consistent.SD steamed bread has obvious advantages in microorganisms.According to the different requirements of the total number of colonies and the number of molds,the edible period of OF steamed bread,SF steamed bread,and SD steamed bread were 10 d,10 d,and 12 d,respectively.By re-steaming the steamed bread of different fermentation methods during the refrigeration process,the hardness of the steamed bread can be greatly reduced after re-steaming,and it is close to that of freshly steamed steamed bread.The specific volume of steamed bread before and after re-steaming did not change much.The whiteness recovery rates of the three steamed bun cores showed a consistent trend,with a much smaller change than that of the steamed scalp.The size of the whiteness recovery rate of the three kinds of steamed bread cores during the refrigerating process was SD> SF> OF.After steaming the steamed bread,the content of resistant starch decreased,and the content of rapidly digested starch increased.Prolonged and gradually decreased,the resistance starch content of SD steamed bread was significantly higher than the other two steamed bread in the three fermentation methods.Comparing the total sensory evaluation scores of three steamed bread at 0 d and 10 d,SD steamed bread were more stable,and the sensory scores of OF steamed bread fell the most.The flavor substances detected in the three types of steamed bread were all quite different,which made the flavors in different samples different.At the same time,there were some common ingredients that simultaneously formed the flavors of steamed bread.After analyzing the samples by the OAV method,11 substances that have a significant effect on the flavor of steamed bread were selected.Nonanal,Decanal,and Geranyl acetone of OF steamed buns contribute significantly to the flavor of steamed buns during refrigeration and before and after re-steaming.The key flavors of SF steamed bread are Nonanal,Decanal and Ethyl Hexanoate.The key flavors of SD steamed bread are Nonanal,Decanal,Ethyl Hexanoate and Ethyl caprate.