Study On The Quality Improvement And Function Mechanism Of Xylanaxe On Frozen Dough

As a commen additive in baking industry, xylanase could improve speciifcvolume and hardness of bread obviously, and could resist retrogradation. Frozendough technology has become a new trend, and was favored by more and more peoplein recent years. Steamed bread is the staple food in China. This paper studied theinfluence of xylanase on the quality of frozen dough and steamed bread. Based on theresearch of the ice crystals、 gluten and araboxylan, it explained the functionmechanism of xylanase on improving the frozen dough quality. The main results wasas follows:By measuring the bleeding rate, wet gluten content, water holding capacity ofwet gluten, color and tensile properties of frozen dough, the influence of xylanase onfrozen dough quality was discussed. The experimental results showed: Comparedwith control test, there were signiifcant difference among the bleeding ratio, wetgluten content, L*value and tensile area, and no signiifcant difference among the drygluten content, water holding capacity of wet gluten, a*value and b*value with theaddition of xylanase.The correlational analyses revealed that the wet gluten contentwere in signiifcant correlation with L*value and the xylanase, and the L*value wasin signiifcant correlation with the tensile area of frozen dough which wasunfermented. In the path analysis, the total effects of wet gluten content on the tensilearea were positive, while the total effects of water holding capacity of wet gluten anddry gluten content on the tensile area were negative.The study of frozen dough after frozen storage showed that xylanase couldimprove fermenti’ng power and yeasts survival rate, had signiifcant effect on thewhiteness of steamed bread skin，water content and speciifc volume, while nosigniifcant effect on the whiteness of steamed bread core. The TPA test showed thatxylanase had signiifcant effect on hardness and adhesiveness while no signiifcanteffect on springiness, cohesiveness and resilience. The analysis of the hardening rateand resilience change of steamed bread kept in room temperature showed thatxylanase had a good effect on retrogradation resistance. After a14d freezing storage,the dose of xylanase showed strong correlation with retrogradation resistance. DSC was used to study the thermodynamic properties of frozen dough, theresults showed that the initial melting point of ice crystal, melting scope of ice crystaland melting peak of ice crystal all reduced remarkable, and the content of freezablewater were less compared with controlled test. SEM observation results indicate thatthe microstructure of frozen dough were more integrity than it in controlled test.Orcinol-hydrochloric acid method was used to analyze the change of water-solublearaboxylan content during the preparation of frozen dough. Results showed thatwater-soluble araboxylan levels increased obviously after dough mixing，reached thepeak value after thawing and decreased after steaming. Fourier Transform InfraredSpectroscopy results demonstrated that the alpha helical content increased, while thebeta folder decreased compared with control group。...