Development Of Gluten-free Steamed Buns And Analysis Of Their Protein Structure And Flavor

Gluten-free steamed buns are suitable for people with gluten allergies,but this kind of steamed buns are not easy to form and with poor taste.In this study,rice flour and soybean flour were used as raw materials to prepare gluten-free steamed buns with better quality and flavor by adding some enzymes during the fermentation process.This product is of great significance for enriching the diversification of staple food and dietary structure of patients with celiac disease.Main conclusions are as follows:The rice flour with good silty characteristics was screened by the mixing tester and used for the preparation of gluten-free steamed buns mixed with soybean flour.These steamed buns were prepared by two step fermentations that alkaline protease was added before primary fermentation and transglutaminase(TG)was added before secondary fermentation.Using single factor and response surface method combined with sensory scoring,the optimal process conditions for the preparation of the steamed buns were 1.9% alkaline protease and 2.1% TG enzyme(with the raw powder as the dry base),the ratio of rice flour to soybean flour was 4: 6.The changes of disulfide bond and free sulfhydryl group in rice-soybean dough and steamed bread were measured.Results of scanning electron microscopyand electrophoresis showed that the small molecules and free sulfhydryl group increased under the treatment of alkaline protease.Fourier infrared spectroscopy and Raman spectroscopy results showed that,through the action of basic protease,the α-helix configuration of protein was resolved.The addition of TG significantly increased hydrogen bond content,and the protein configuration was more stable due to the increase in the β-fold configuration of disulfide bonds.Electronic nose and tongue combined with solid phase microextraction and gas phase mass spectrometry were used for analyzing flavor changes of steamed buns.It was concluded that,the content of alcohols,ketone and aromatic substances increased after the addition of alkaline protease and TG enzyme,while the aroma of fruit,oil and wood is more obvious.During the fermentation process,the addition of enzymes increased the umami and richness of gluten-free grain steamed buns,while the bitterness and acidity were reduced.