Effect Of Fermented Buckwheat Rice On Rheological Properties Of Mixed Dough And The Quality Of Mantou

In this study,buckwheat was used as raw material,and referred to the production process of fermented glutinous rice with some modification to prepare fermented buckwheat rice.The effects of different fermentation time on the composition and dynamic rheological properties of fermented buckwheat rice,and the determination of the rheological properties,microstructure and quality of buckwheat mantou were performed.The results are shown as follows:(1)The composition of fermented buckwheat rice were significantly affected by different fermentation time.With the prolongation of fermentation time,the reducing sugar content of fermented buckwheat rice increased from 0.31 g/100 g on 0 d to 10.52 g/100 g on the 5th day.After the fourth day,the content of reducing sugar did not increase significantly;the alcohol content increased from 0.00 %vol on 0 d to 2.48 %vol on the 5th day,and during the first three days,the increasement was significant;the acidity increased from 0.99 mL/10 g on 0 d to 4.01 mL/10 g on the 5th day,and there was no significant difference in acidity increase from the third day.(2)The results of frequency sweep and temperature sweep showed that the fermented and unfermented buckwheat rice exhibited the characteristics of elastomer.Fermented buckwheat rice had greater viscosity and better fluidity.The suitable fermentation time could improve the viscoelasticity of fermented buckwheat rice and enhance the viscosity of fermented buckwheat rice.Scanning electron microscopy showed that the viscous material of the fermented buckwheat rice was more connective than that of the unfermented buckwheat rice.(3)The fermented buckwheat rice which was fermented for 3 days was added to the wheat flour at a ratio of 15%,25%,35%,45% to prepare a mixed dough,and then the texture characteristics,tensile properties,stress relaxation characteristics and microstructure of the dough were determined.The results showed that fermented buckwheat rice could significantly affect the hardness,adhesiveness,springiness and cohesiveness of dough compared with the mixed dough with unfermented buckwheat rice,making the dough more softer,more cohesive,and easier to form a dough.The extensibility of the fermented and unfermented buckwheat mixed dough was lower than that of the wheat dough,but the fermentation group was higher than the unfermented group,indicating that the fermented buckwheat rice mixed dough had less elasticity and better ductility.In addition,the mixed dough with fermented buckwheat rice had significantly lower residual stress and a significantly smaller damping coefficient than the mixed dough of unfermented buckwheatrice.The gluten network structure of the mixed dough of which with fermented and unfermented buckwheat rice addition was more connective than that of the wheat dough,but the gluten network structure of the fermented buckwheat rice mixed dough was more connective than that of the unfermented group.(4)The specific volume of mantou with fermented and unfermented buckwheat rice decreased,and the specific volume of buckwheat mantou in the fermented group was slightly larger than that in the unfermented group.The L* value of crust and crumb decreased with the increasement of fermented and unfermented buckwheat rice,and the brightness decreased,while the a* value and b* value increased gradually with the increasement of addition.Compared with the unfermented group buckwheat mantou,the brightness was higher and the color was yellowish and greenish of the fermented group buckwheat mantou.The hardness of the fermented buckwheat rice mantou were significantly lower than those of the unfermented buckwheat mantou,which was easier to chew.It could be seen from the results of the sensory evaluation that the fermented buckwheat rice mantou had sweeter taste and more unique flavor,which was more popular among people.The score of 15% fermented buckwheat rice mantou was closer to that of wheat mantou,and it was more easily accepted by people,as well as the flavor was better.Although the 25% and 35% addition of buckwheat mantou sensory score decreased,it was slightly higher or equal to the unfermented buckwheat mantou.Considering the promotion of mantou flavor and nutrition and increasing the use of buckwheat main food,the maximum addition of fermented buckwheat rice could be 35%.It could be seen from the above analysis that the fermentation time had a significant effect on the composition of fermented buckwheat rice.Compared to unfermented buckwheat rice,the fermented buckwheat rice had stronger viscosity and fluidity.The mixed dough with the fermented buckwheat rice addition had smaller hardness,stronger cohesiveness and easier to form a dough,as well as better ductility,lower residual stress and relatively better gluten network structure than the control group.Compared with unfermented buckwheat rice mantou,the fermented buckwheat rice mantou had larger specific volume,higher brightness,more yellowish and greenish color;and the hardness and chewiness of the mantou were smaller.The taste of the fermented buckwheat rice mantou was sweeter.The value of the mantou with 15% fermented buckwheat rice addition was close to that of the wheat mantou.While the maximum amount of fermented buckwheat rice could be 35%.