Effect Of Physical Processing On Antioxidant Activity Of Coix Seed Polyphenols And Quality Analysis

The nutrition of food was concerned in the theoretical system of health advocate and promotion environment.Coix Seed,by virtue of its important value in health and pharmaceutical,was vital in the national health industry.Coix Seed is rich in nutrients and active components such as polyphenols,which can reduce the burden of gastrointestinal,promote human metabolism and easy to be absorbed.The physical processing before consumption can affect the bio-active ingredients and the content of basic nutrients.In this paper,steamed,frozen and microwave were applied to evaluate the impact of physical processing on Coix Seed quality and antioxidant properties.In addition,the correlation between the content of polyphenols and in vitro antioxidant was explored.And the conclusion was as followed:1.Extraction of polyphenols from Coix Seed.Single factor experiment,the ethanol concentration,liquid ratio,temperature and time,was conduct to investigate the effect on polyphenol content.Response surface methodology was applied to optimize the extraction condition and the desired polyphenol content was 0.47mg/g under the condition:ethanol concentration 80%,extraction temperature 70?,ratio of liquid to material 15mL/g and extraction time80min.The analysis of variance showed that the ratio of liquid to material had the most significant effect on the extraction of polyphenols.2.The impact of dehulling on Coix Seed qualityCoix Seed was divided into 4 grades after dehulling,and all of them contained certain nutrients.The nutrition of polished milled rice was as following:?1?Nutritional ingredient:The results displayed that crude fat was 8.04%,protein was 20.17%and reducing sugar was 86.52%in polished milled rice.The total content of Vitamin B₁,B₂ and E was 1.192mg/100g and the total amount of Ca and Fe was 376.75mg/kg.It can be seen from the data that it remained most of the nutrient after dehulled.?2?Amino acid evaluation:There were sixteen kinds of amino acids in Coix Seed.And seven of which were essential amino acids.The total amino acids and essential amino acids in polished milled rice were 15.25%and 5.18%,respectively.The amounts of glutamate?3.77%?,leucine?2.11%?,alanine?1.50%?and proline?1.40%?were relatively high.It showed that the dehulled rice also contained abundant amino acids,as well as complete in categories.?3?Texture characteristics:The viscosity of polished milled rice was 39.80mPa·s.Compared with other grades of barley rice,the color varied and tended to be white.In addition,its 1000-grain weight increased with the rise of diameter.3.Analysis the effect of Steamed,frozen and microwaved on the quality of Coix Seed.?1?Nutritional ingredient:The results displayed that crude fat was 5.99%,protein was 19.42%and reducing sugar was 84.91%after steaming for 40min.When Coix Seed was frozen for 24 hours,the total contents of vitamin B₁,B₂ and E and Ca,Fe were 1.061mg/100g and 503.64mg/kg,respectively.The loss of nutrient after 5min microwaving was comparatively high.Although the loss of nutrient was diverse among different pre-ripened processing,there were still certain nutrients retained in the rice.The method of steamed and forzen was more favorable for the retention of nutrients in Coix Seed.?2?Amino acid evaluation of polished milled rice:The content of total amino acid for steaming?40min?,frozen?24h?and microwaved?5min?were 16.48%,14.47%and 16.74%,respectively.The analysis showed that steamed was the best processing method,which was able to increase the content of total amino acid.?3?Texture characteristics:The maximum viscosity was 47mPa·s when steamed for 40min,and followed by methods of frozen and microwave.The color became white with steamed processing,remain unchanged with frozen,and displayed scorched with microwaved.The thousand grain weight increased with the rise of diameter,the results of frozen and microwaved were opposite.4.Polyphenol content and antioxidant activity in Coix Seed by fractionated dehulled process.There were certain polyphenol active components in different dehulled grade of Coix Seed.The content of polyphenol in polished milled rice was 0.49mg/g,and the scavenging rate of DPPH radical,ABTS radical and FRAP reduction ability were92.71%,97.44%and 1.14mmol/g,respectively.The data showed that the anti-oxidation activity of polyphenols in the polished milled rice was strong.According to the correlation analysis,the content of polyphenols increased with the antioxidant activity increased.5.Study on the effects of steamed,forzen and microwaved on the content of polyphenols and Antioxidant activity of Coix Seed.The content of polyphenols by processing of frozen?24h?,microwaved?5min?and steamed?40min?were 0.31mg/g,0.28mg/g and 0.18mg/g,respectively.The highest scavenging rate of DPPH free radical was 85.98%by steamed treating,the highest scavenging rate of ABTS free radical was 72.31%and the reduction power of FRAP iron ion was 1.07 mmol/g by frozen processing.According to the correlation analysis,the antioxidant activity increased with content of polyphenols increased,and steamed treating can significantly improve the antioxidant activity of Coix Seed.This shows that the steamed processing technology could maximize the retention rate of the antioxidant properties.On conclusion,even though the contents of nutrients and active components in the Coix Seed were reduced by step dehulled,steamed,forzen and microwaved treating methods,it was still rich in nutrients and had significantly antioxidant effect after processing,which was great importance for human health.