Study On Modification And Application Of Diterary Fiber From Hulless Barely

Green barley,a kind of cereal crop of the genus barley in gramineae.It is mainly planted in highland areas such as Tibet and Qinghai.It has the nutritional characteristics of "three highs and two lows(high dietary fiber,high protein,high vitamin,low sugar,low fat).Dietary fiber(DF)is an indispensable part of people's dietary balance,and it has physiological effects such as preventing obesity and diabetes.As a good dietary fiber source,barley has great potential as a basic processing material.In this paper,the green fiber was used as raw material to study the micro-chemical pulverization,ultrasonic,enzymatic hydrolysis and enzymatic hydrolysis-ultrasonic treatment.The main functional properties and microstructure characteristics of different dietary methods for Qinglan dietary fiber were analyzed and explore the effects of four modification methods on the quality of green noodles.The comparison results of the four modified methods showed that the yield of the soluble dietary fiber(SDF)modified by enzymatic hydrolysis-ultrasonic modification was the highest,being 12.59%.In the combined modified single factor experiment,pH,temperature,Enzyme and substrate concentrations and ultrasonic power have a significant effect on the yield of S.Based on the single factor,the above four factors were selected for the response surface optimization test.The results showed that the optimum process of combined modification was:pH 4.8,temperature 43.7 ?,enzyme and substrate concentration 250 U/g,ultrasonic power 300 W.At this time,the SDF yield was 11.69%.The results of physicochemical properties showed that the four modification methods can improve the water retention,oil holding capacity and swelling of the DF of green barley.Among them,the most significant combination of modified group DF,water holding capacity,oil holding capacity and expansion capacity increased by 54%,79.3%and 86.3%,respectively.Followed by the ultrasonic modification group,the swelling property after enzymatic modification was the lowest among the four modification methods,only increased by 25.8%.The results of functional properties showed that the four modified methods could improve the glucose adsorption capacity and amylase inhibition ability of the DF of green barley.Among them,the combined modified barley DF had the best effect on amylase inhibition,the inhibition rate was 40.57%,followed by the ultrasonic modification group,the inhibition rate was 32.47%;for the glucose adsorption capacity,the enzymatic modification group had the most effect,about 9.7095 mmol/g,followed by the combined modification group,9.4899 mmol/g.The structure of dietary fiber of barley meal showed that SEM showed that the surface structure of DF was dense and formed into a complete block.After modification,the surface of the DF the green barley became more porous and increased in specific surface area.Water and swelling are closely related.It was found by infrared spectroscopy and XRD spectroscopy that several modification methods destroyed the structure of dietary fiber to varying degrees.The results of DSC showed that the stability of dietary fiber was better.The results show that the ultrasonic assisted enzymatic hydrolysis method is the best method for the main functional modification of green barley dietary fiber.The application results of the modified barley noodles showed that the four modification methods changed the water absorption rate,cooking loss rate,organoleptic properties and texture characteristics of the barley noodles.Among them,the most obvious change is the combined modification group.In the in vitro digestion experiment,the digestibility of the noodles after the combined modification is significantly lower than that of the unmodified one,so the modification has an important influence on the quality of the green noodles.