Extraction,Functional Properties And Application Of Dietary Fiber In Adzuki Bean Cooking Liquid

Adzuki bean is rich in carbohydrates,lipids,proteins and minerals,and has various pharmacological effects such as anti-inflammatory,anti-diabetes and anti-cancer.It frequently produced large amounts of cooking liquor during its processing into food products.The cooking liquid is generally dumped into the natural environment as waste,which not only causes waste of resources,but also brings environmental pollution problems.Therefore,the rational use of Adzuki bean cooking liquid resource is conducive to improving the sustainable value of the Adzuki bean industry.Dietary fiber is known as the "seventh nutrient" necessary for the human body and plays an indispensable role in a balanced diet.Biscuits are widely popular due to their diverse flavors,long shelf life and low cost,and have long occupied a major position in snack foods.In recent years,due to market competition and increased demand for healthy,natural and functional products,there are attempts to add dietary fiber and other healthful substances to cookies to improve their nutritional value and functionality.In this study,dietary fiber（BP-P）was obtained directly from the original Adzuki bean cooking liquid,and then modified dietary fiber was obtained by ultrasonication（PBU-P）and high-pressure homogenization（PBH-P）.Subsequently,E-P,EU-P and EH-P were obtained using enzymatic,enzymatic-sonication and enzymatic-high-pressure homogenization.The composition analysis,structural characterization and functional properties determination of the six kinds of dietary fibers obtained from Adzuki bean cooking liquid were carried out to provide a theoretical basis for their application in food.EU-P was identified as the most functional dietary fiber,and then it was added to the dough to prepare dietary fiber biscuits.The composition analysis,texture testing and sensory evaluation were carried out to determine the optimal formula of the Adzuki bean cooking liquid dietary fiber biscuit.Finally,the in vitro digestion properties,physicochemical properties and microbial indicators of the Adzuki bean cooking liquid dietary fiber biscuits were determined.The main research contents and conclusions of this paper are as follows:（1）The composition determination showed that both EU-P and EH-P had lower ratio of insoluble dietary fiber to soluble dietary fiber,2.21 and 2.10,respectively,which belonged to high-quality dietary fiber.Structural characterization showed that the use of separate enzyme extraction,ultrasonic wave and high-pressure homogenization modification could destroy the molecular structure and polymeric network of dietary fiber,and even destroy its crystal structure and convert it into irregular and amorphous structures.Enzymatic extraction combined with ultrasonication or high-pressure homogenization modification could re-crosslink the fragments cleaved by enzymatic extraction to form some new network/polymer structures to varying degrees,which would significantly affect the functional properties of dietary fibers.（2）The measurement of functional properties showed that EU-P and EH-P exhibited good emulsifying performance,water holding capacity,oil holding capacity,cholesterol adsorption capacity and nitrite adsorption.These unique functional properties make it promising as a natural emulsifier,adsorbent or antioxidant for application in the food industry.（3）The best technological formula of the Adzuki bean cooking liquid dietary fiber biscuit was: based on flour as 100%,EU-P 5%,butter 20%,complex sweeteners 20%,egg liquid 30%,baking soda 2%,edible salt 1.5%,0.3% glycerol monostearate;the upper tube of the oven is 160°C,the lower tube is 140°C,preheated for 10 minutes,put it into the oven for15 minutes,and then cool to room temperature.The biscuits made under this process can take into account both taste and health,which provides a new idea for the research and development of dietary fiber biscuits.（4）The addition of EU-P significantly changed the texture quality of biscuits and reduced the digestibility of starch in biscuits.The determination of the physicochemical and microbial indicators of the Adzuki bean cooking liquid dietary fiber biscuit conformed to the national standards such as GB 7100-2015.The results were as follows: per 100 grams of Adzuki bean cooking liquid dietary fiber biscuit was fat 17.23 g,protein 8.11 g,moisture 2.59 g,ash 1.82 g.The total number of colonies was 420 CFU/m L,and the mold was 2 CFU/m L.Escherichia coli and pathogenic bacteria were not detected.