Study On The Application Of Defatted Flaxseed Meal In Flour Products

Flaxseed is an important source of unsaturated fatty acids,and its demand is increasing in recent years.However,more flaxseed meal is produced as a by-product of oil extraction.Although flaxseed meal contains a large amount of protein,dietary fiber and phenols,which can reduce the risk of diabetes and cardiovascular disease,it has not been paid attention to and is only used as animal feed or waste disposal,resulting in great waste.World Health Organization(WHO)predicts that the prevalence rate of adult diabetes worldwide will increase to 7.7% by 2030.The application of flaxseed meal to flour products to produce low-GI flaxseed foods can meet the dietary needs of such consumers.In this paper,flaxseed meal was added to wheat flour to produce and prepare flaxseed biscuits and flaxseed noodles,and the quality was improved to obtain flaxseed food with low-GI that could inhibit the increase of blood glucose.The main research contents were as follows:Flaxseed meal was added to wheat flour to make flaxseed biscuits.With the addition of flaxseed meal from 0% to 70%,the hardness of the biscuits increased by 67.6%,the crushing distance increased by 129.4%,the ductility increased by 52.6%,the color decreased by 49.8%,and and the sensory score decreased by 23.6%.The amount of flaxseed meal should not exceed 50%,otherwise the quality of the biscuits will be adversely affected.In vitro starch digestion results showed that flaxseed meal could reduce the starch hydrolysis rate and e GI value of biscuits from 89.45% and 79.78 to 60.13% and 68.86,respectively.The starch digestibility of biscuits was significantly decreased when oat β-glucan supplemental level was above 10%.Mulberry leaf extract had no significant effect on in vitro starch digestion(P > 0.05).The simulated small intestinal absorption results showed that flaxseed meal had a significant effect on glucose adsorption and diffusion,and the glucose dialysis retardation index reached the highest at 60 min,which was 15.46%.The results of postprandial blood glucose response in humans showed that 50% and 70% of flaxseed biscuits belonged to medium GI foods(59.29)and low GI foods(47.23),respectively.According to the above analysis of biscuit quality and starch digestibility,the mulberry leaf extract was added to 50%flaxseed biscuit and the quality was improved.It was found that the texture and sensory quality of the biscuit were significantly improved,and the biscuit could be reduced to the category of low GI food.The rheology of dough has an important effect on the quality of noodles.The effect of the addition amount of flaxseed meal on the rheological properties of wheat dough was studied.The results showed that flaxseed meal could improve the farinograph properties of wheat flour,the water absorption,formation time and stability time of dough were significantly increased,and the farinograph quality index increased from 36 to 188.The peak viscosity during gelatinization was increased,and more than 30% flaxseed meal had a certain inhibitory starch retrogradation.Increased the viscoelasticity and hardness of the dough,but reduced the extensibility of the dough,resulting in sticky roll problems.Then,according to the effect of flaxseed meal on starch digestion in vitro and dough rheology,the addition amount of 0% ～ 50% flaxseed meal was selected to prepare flaxseed noodles.The results of cooking and texture showed that when the addition amount of flaxseed meal reached 50%,the cooking loss rate increased by 23%,hardness and chewiness decreased by 20.2% and 42.5%,respectively.The transverse relaxation time showed that the free water content of the noodles increased significantly.Therefore,the effects of wheat gluten,glutamine transaminase and whole egg liquid on the quality of 50% flaxseed noodle were studied.The results showed that both wheat gluten and whole egg liquid could reduce the cooking loss rate of flaxseed noodles,and all of them could improve the hardness,elasticity and chewiness of flaxseed noodles.The cooking loss rate of flaxseed noodles was decreased by 21%,the chewiness was increased by83.5%,and the sensory score was increased by 8% when the mixture of 15% wheat gluten,0.1% glutamine transaminase and 4% whole egg liquid was added.Scanning electron microscope(SEM)observation showed that the starch granules in the compound flaxseed noodles were wrapped in a dense network structure,which had a certain effect on starch digestion.The in vitro starch hydrolysis rate and GI value of the compound flaxseed noodles were 35.26% and 53.2,respectively,indicating that it was the low-GI flaxseed noodle.