Extraction,Functional Properties And Application Of Insoluble Dietary Fiber From Spinach Root

Spinach is rich in vitamins,carotenoids,minerals and folic acid,and also has antioxidant,anti-cancer,anti-inflammatory and lipid-lowering properties.The roots of spinach are usually removed during the production and processing process,and if discarded directly it will not only cause a waste of resources,but also bring some environmental pollution problems.In recent years,people pay more and more attention to healthy diet,dietary fiber is not only not digested and absorbed by the human body,but also has the function of promoting digestion,regulating intestinal flora,preventing intestinal diseases and cardiovascular diseases,etc.The research and development of dietary fiber-based food has become a hot spot in the food field.Peach crisp is a popular traditional hot processed pastry,and it has become a new direction for the development of peach crisp industry to add nutrients beneficial to human health and develop functional peach crisp with conditioning effects.In this experiment,spinach root insoluble dietary fiber(IDF),E-IDF and EU-IDF,were prepared by two extraction methods:enzymatic method and ultrasonic-assisted enzymatic method.The IDF with better properties was selected and added to the peach crisp,and the best process and formulation of spinach root dietary fiber peach crisp was determined with the help of sensory evaluation and texture determination,aiming at rational utilization of spinach root resources,improving the utilization value of spinach,broadening the access and application prospect of dietary fiber,and developing a new peach crisp product with both nutrition and taste.The main research contents and conclusions of this thesis are as follows:(1)E-IDF was prepared by enzymatic method and EU-IDF was prepared by ultrasonic-assisted enzymatic method,and the optimal extraction process parameters of EU-IDF were determined by single-factor experiment and response surface optimization experiment as follows:material-liquid ratio 1:27 g/m L,α-amylase addition 0.1%,papain addition 0.04%,glycosylase addition 0.33%,ultrasonic power 350 W,ultrasonic temperature Under these conditions,the extraction yield of EU-IDF could reach 59.97±0.15%.(2)Comparative structural characterization studies of E-IDF,EU-IDF and spinach root raw materials were carried out.The results of Fourier infrared spectroscopy(FTIR)analysis showed that the three have similar infrared absorption characteristic peaks,and both enzyme treatment and ultrasound treatment break the glycosidic bonds inside the dietary fiber,making it have a looser structure.(3)The physicochemical and functional properties of E-IDF,EU-IDF and spinach root raw materials were measured and analyzed.Compared with the three,EU-IDF exhibited better water holding capacity(8.37±0.11 g/g),oil holding capacity(6.96±0.04 g/g),swelling capacity(6.60±0.12 m L/g),cholesterol adsorption capacity(14.03 mg/g at p H 2.0;14.72 mg/g at p H 7.0),which indicated that the dietary fiber obtained by ultrasonic-assisted enzymatic method had better functional properties and application value.(4)To determine the optimal formulation and process of spinach root dietary fiber peach crisp.The optimal recipe and process of peach crisp were optimized by single-factor and orthogonal tests with sensory evaluation and qualitative indexes as the criteria:100%low gluten flour,5%EU-IDF addition,25%sugar addition(sugar:xylitol=1:1),35%corn oil addition,1%baking soda,0.44%baking powder,1.2%ammonium bicarbonate,150°C baking temperature and 15 min baking time.The spinach root dietary fiber peach crisp made under this process was fluffy but not sweet,with a slight coarse grain feeling,uniform surface color and sweet aroma.(5)In vitro digestion simulations of spinach root dietary fiber peach crisp were conducted.The in vitro simulated digestion of starch showed that the addition of EU-IDF could significantly reduce the digestibility of starch in peach crisp.(6)The physicochemical and microbiological indices of spinach root dietary fiber peach crisp were measured.The results were as follows:moisture content was 2.92±0.39 g,protein content was 7.91±0.49 g,fat content was 23.40±1.36 g,ash content was 2.86±0.20 g per 100 g of spinach root dietary fiber peach crisp;total bacterial colony was 3.2×10~2 CFU/g,mold count was 2 CFU/g,no coliform was detected;alkalinity of peach crisp was 0.27%.All indicators are in line with the requirements of national standards.