The Effect Of Calcium Hydroxide On The Characteristics Of Buckwheat Dough And The Quality Of Buckwheat

Buckwheat noodle is a main buckwheat food and very popular among consumers in northwest China.However,because of the lack of gluten protein in buckwheat flour,buckwheat noodle is difficult to be processed and easy to broken and mix soup.Calcium hydroxide has been added to buckwheat flour to improve the quality of buckwheat noodle for many years.However,the use quantity of calcium hydroxide in buckwheat flour and its influence on the main components of buckwheat flour and the mechanism of the treatment were not reported.Therefore,in this study,with the pure buckwheat flour as raw material,the effects of adding different proportion(0%,0.2%,0.4%,0.6%,0.8%,1.0%)of calcium hydroxide on dough quality of buckwheat flour,quality and microstructure of buckwheat noodles were determined and analyzed by using the conventional analysis method and modern equipment such as RVA,rheometer,Mixolab and scanning microscope.The results were expected to may provide the theoretical basis and practical guidance for the buckwheat noodles.The main research findings were as follows:(1)The addition of calcium hydroxide could significantly influence the dough characteristics of buckwheat flour.It was found that the transmittance of buckwheat flour gradually decreased and the solubility increased with the increase of calcium hydroxide.The results of rheological property showed that elastic modulus and viscous modulus of buckwheat dough first decreased and then increased,and loss factor(tan8)first increased and then decreased with the increase of adding amount of calcium hydroxide,which indicated that polymerization degree of buckwheat dough was elevated by the addition of calcium hydroxide.It could be found from Mixolab measurement results that addition of calcium hydroxide reduced the formation time,stability time and cooking stability and increased the viscosity of buckwheat dough.(2)The addition of calcium hydroxide could significantly influence the color,cooking,sensory and texture quality of the buckwheat noodles.With the increase of the portion of calcium hydroxide,the L*value decreased,a*value increased,and b*value first increased and then decreased.The color of buckwheat noodles was improved by increase of calcium hydroxide.The water absorption rate,cooking loss,water content,and the broken rate of buckwheat noodles showed first increase and then decrease trend with the increase of adding amount of calcium hydroxide.However,the sensory score of buckwheat noodles increased after the first down,and structure features of buckwheat noodles also has certainly changed with the increasing calcium hydroxide.Moreover,Buckwheat noodles with 0.6%calcium hydroxide had the best comprehensive quality with lowest cooking loss and breaking rate,the highest sensory score,and bright yellow color.(3)The results of scanning microscope and SDS-page showed the addition of proper amount of calcium hydroxide in buckwheat noodles could made buckwheat noodles to form tight microstructure,promote the cross-linking of buckwheat protein,and increase the content of large molecular weight protein,which indicated that the mechanism of adding calcium hydroxide to improve the quality of buckwheat noodles is probably related to the change of protein properties.