Study On The Processing Technology Of A Compound Coarse Cereal Beverage And Its In Vitro Antioxidant Activity

Coarse cereal is rich in nutrition,as well as famous for its high health function and economical value.In recent years,with the rapid development and in-depth research of the coarse cereals industry,the green,natural,nutrition,health care,and other excellent characteristics of coarse cereals are well known to large number of consumers.As a convenient and edible food,the coarse cereal beverage could satisfy the demand of consumers under the modern fast rhythm,and its development prospect is very broad.In this study,quinoa,oat and tartary buckwheat were selected as the main raw materials.Through baking,powder,gelatinization,enzymatic hydrolysis,compound and other technology,a kind of novel compound coarse cereal beverage was developed.The optimum production technology and formula of compound coarse cereal beverage were determined by single factor experiment,orthogonal experiment,and combined with fuzzy mathematics methods.Moreover,the quality analysis and in vitro antioxidant activity evaluation of the beverage were carried out.The main results are as follows:1.Study on key preparation technology of a compound coarse cereal beverage.Optimization of the raw material baking process,and determination of the ratio of compound coarse cereal powder.Choosing sensory evaluation and total flavonoids as the evaluation indexes,the baking parameters of quinoa were 140?,30 min,and that for tartary buckwheat were 150? and 30 min.Among them,the quality ratio of compound coarse cereal powder was determined as: quinoa 40%,oat 40%,buckwheat 20%.The effects of water ratio,?-amylase addition,enzymatic temperature and time on the enzymatic hydrolysis effect of compound coarse cereal beverage were investigated by using raw material utilization rate,dextrose equivalent(DE)value and soluble solids as the testing factors.Through the single factor and orthogonal tests,the optimum enzymatic hydrolysis process was determined as follows,the water ratio was 1:20(g/mL),the amount of ?-amylase added was 16 U/g,the temperature was 70?,the time was 60 min,and the DE value was as much as85.9%.2.Optimization on the production formula and stability of the compound coarse cereal beverage.The prepared enzymatic hydrolysis solution of coarse cereal was used as the major material.And through the AHP-fuzzy mathematics comprehensive evaluation method,the suitable addition amount of excipients was as follows,non-dairy powder 0.8%(w/v),citric acid 0.01%(w/v),fructose syrup 3.0%(v/v).In addition,the stability of compound coarse cereal beverage was studied.The sucrose ester,glycerin monostearate,sodium carboxymethyl cellulose(CMC-Na)and carrageenan were selected as the stabilizers,and the centrifugal precipitation rate and zeta potential were selected as the evaluation indexes.The optimal addition amountwas determined as sucrose ester 0.04%,glycerin monostearate 0.03%,CMC-Na0.05%,and carrageenan 0.04%.Under this condition,the beverage has good stability.3.Quality analysis of the compound coarse cereal beverage.The beverage quality was evaluated in detail on the basis of its typical characteristics such as the sensory evaluation,nutritional and functional components,volatile flavor substance,as well as its microbial index.Sensory evaluation: color,milky white;odor,with rich coarse cereal baking aroma;palate,delicate lubrication,moderate sour and sweet;tissue status,uniform texture of the product,no precipitation.The results of nutritional and functional components analysis showed that the total amount of amino acids in the compound beverage was 0.168 g/100 g,including 8 kinds of essential amino acids for human body.And its protein content was 0.27 g/100 g,fat content was0.1 g/100 g,pH value was 6.05.The total flavonoids content of the beverage was about 139.4 ?g/mL,and the total polyphenol content was 90.0 ?g/mL.In addition,the gas chromatography-mass spectrometer(GC-MS)method was used to analyze and determine the volatile flavor substances of this coarse cereal beverage.The results indicated that a total of 39 major flavor substances were identified,and the aldehydes,alcohols and pyrazines heterocyclic compounds were the major flavor substances of this compound coarse cereal beverage.Finally,through the microbial testing,the microbial indicators in the beverage have not exceeded the standard,in line with the requirements of the national standard.4.Study on the simulated digestion in vitro and antioxidant ability of the compound coarse cereal beverage.The dynamic changes of flavonoids,polyphenols,and antioxidant activity of the compound coarse cereal beverage were investigated by in vitro simulating oral digestion and gastrointestinal digestion tests.The results showed that the total flavonoids and polyphenols content of the beverage was determined as 50.1 ?g/mL and 59.0 ?g/mL,respectively after gastrointestinal digestion,indicating that the digestion treatment has an influence on the dissolution of antioxidant active ingredients in the beverage.In addition,the experimental results of the simulated digestion in vitro suggested that there was a closely correlation between the antioxidant activity and the total flavonoids and polyphenols of the compound coarse cereal beverage.In this study,a kind of novel coarse cereal beverage with delicate taste,suitable flavor,nutritional and healthy value was successfully developed.It is beneficial for enriching the varieties of coarse cereals-based products,and improving the processing technology level,as well as more helpful for promoting the healthy and rapid development of coarse cereals industry of China.