Development And Quality Improvement Of Special Wheat Flour For Brown Sugar Steamed Bread

Brown sugar steamed bread(BSSB)is popular among consumers because of its unique flavor and nutritional characteristics.However,the existing general steamed bread flour can’t meet the processing requirements of BSSB with high sugar content,which affects the edible quality of BBSB.Therefore,it is necessary to develop special wheat flour for BSSB.In this paper,the effects of wheat flour characteristics,particle size and quality improvers on the special wheat flour of BSSB were studied.The formula of special wheat flour for BSSB was optimized through three aspects of raw materials,production and processing and quality improvement,which providing theoretical basis and reference for the industrial production of special wheat flour of BSSB.First of all,nine kinds of wheat raw materials were selected to systematically measure the physicochemical indexes,gelatinization properties,farinograph and extensograph properties and fermentation rheological properties of wheat flour,and BSSB was made.The influence of wheat flour characteristics on the quality of BSSB was explored through correlation analysis and principal component analysis.The results showed that the dough prepared by wheat flour with protein content of 10.20%～11.74%,the wet gluten content of 28.69%～35.38%,the average particle size of 82.44μm～94.66μm and the water absorption of 59.30%～61.80%had better gas production and holding capacity.The BSSB made by it had specific volume of more than 2.90m L/g,lower hardness and chewiness,higher cohesiveness and resilience.The results of correlation analysis and principal component analysis showed that protein content,wet gluten content,water absorption,swelling power,average particle size,xylanase activity and solvent retention capacity were the main indicators affecting the quality of BSSB.Yangmai 16,Yannong 19,American soft red spring wheat(SRW)and Australian standard white wheat(ASW)were suitable wheat varieties for making BSSB.Secondly,in order to explore the influence of wheat flour blending on the special wheat flour for BSSB,Yangmai 16 was used as the main flour,and Yannong 19,ASW and SRW were matched with them in the proportions of 30:70,50:50 and 70:30.The results showed that with the increase of the proportion of Yangmai 16,the water absorption,dough formation time and stabilization time of blending flour were significantly increased(p<0.05)and the retrogradation value was decreased significantly(p<0.05).The fermentation rheological experiments showed that the total volume of released gas(V_t),the retained volume(V_r)and the maximum expansion height(H_m)of the fermentation curve were increased significantly(p<0.05)with the increase of the proportion of Yangmai 16,and the dough fermentation characteristics of Yannong 19 and ASW groups were better.Dynamic rheological experiments showed that the elastic modulus(G’)and viscous modulus(G")of the SRW group were obviously larger,which corresponded to the results of texture hardness of BSSB.When the proportion of Yangmai 16 and Yannong19 was 70:30,the BSSB had a specific volume of 3.08 m L/g,better texture quality and sensory score,higher surface fraction of internal pores,bigger pores and the moderate density.Then,the effects of particle size on physicochemical properties of wheat flour,quality of dough and BSSB were studied.The results showed that with the decrease of particle size of wheat flour,the content of damaged starch increased by 4.58%,and the content of moisture and wet gluten decreased by 1.38%and 1.60%respectively,and the content of glutenin macromers increased first and then decreased.As a result,the gelatinization temperature,peak time,peak viscosity,minimum viscosity and final viscosity of wheat flour decreased significantly(p<0.05),and the swelling power increased significantly(p<0.05).X-ray results showed that the crystalline form of starch didn’t change,but the relative crystallinity decreased by 2.95%.According to the results of Mixolab,the water absorption of dough increased by 9%with the decrease of particle size,and the dough formation time and stabilization time were increased significantly(p<0.05).Dynamic rheological experiments showed that the decrease in particle size both increased the G’and G"of dough.When the average particle size of wheat flour ranged from 33.32μm to 52.17μm and the content of damaged starch ranged from 5.68%to 6.41%,the BSSB had a larger specific volume and a better sensory score.SEM also observed that starch granules were well covered by gluten protein,and the protein network has good continuity.Finally,the improvement effects of emulsifiers and enzyme on the comprehensive qualities of BSSB were studied.The results showed that sodium stearyl lactate(SSL)could improve the cooking qualities of BSSB significantly(p<0.05).Adding 5 g/kg sucrose fatty acid ester(SFAE-15)increased the specific volume of BSSB by 8.56%,and decreased the hardness and chewiness by 23.22%and 20.08%respectively.Compared with maltogenic amylase(MA),adding 60 mg/kg lipase(LPS)improved the specific volume,hardness and chewiness of BSSB,and increased the internal pore size from 1.29 mm~2 to 1.65 mm~2.In addition,all four quality improvers could reduce the hardening rate of BSSB during storage,among which 20 mg/kg MA has the most obvious improvement effect on the water holding capacity of steamed bread.When 1.0 g/kg SSL,5.0 g/kg SFAE-15,20 mg/kg MA and 60 mg/kg LPS were used in combination,the specific volume of BSSB increased by 11.99%,and the initial hardness of steamed bread and the final hardness of steamed bread storage for 72 h decreased by 39.25%and 60.57%respectively,and the sensory score was increased by 13.6 points.There was a certain synergistic effect between the compound improvers.