| China is a big country of grain production and consumption in the world.As consumers increasingly pay more attention to the nutrition and health function of whole grain food,the development of whole grain food has formed an unstoppable trend.72%of the soil in China is deficient in selenium to varying degrees,which seriously restricts the nutritional status of selenium in food.Therefore,the development of selenium-enriched fortified whole grain food is beneficial to promote moderate grain processing,reduce the waste of resources caused by over-milling rice,and provide an effective way for people to supplement selenium-enriched nutrients.In this paper the use of ultrasonic immersion absorption coating technology,in order to leave embryo rice as the main raw material,methyl-L-selenium selenium for cysteine for selenium nutrition enhancer in ultrasonic immersion absorption,the preparation of zein film the rich selenium fortified embryo rice,as ultrasonic immersion-coating process condition,the ultrasonic immersion absorption and coating before and after processing the rich selenium content of selenium fortified leave germ meters,food quality difference and its storage stability carried on the thorough research of the system,and for developing food nutrition project has a certain theoretical and practical significance.The main research results of this paper are as follows:(1)By designing different single factor experiments,seven quality indexes of seleniumenriched enriched enriched rice were evaluated,and the single factor optimum process conditions were obtained.On this basis,the response surface experiment was designed and 7 indexes were measured.The data were analyzed by principal component analysis to form a comprehensive evaluation index and then the response surface analysis was carried out.Response surface analysis test shows that the optimal ultrasonic process parameters are as follows:ultrasonic immersion time is 8.25 min,ultrasonic immersion temperature is 40℃,ultrasonic power is 150 W,Under these conditions,Selenium content was 198.7±1.6 μg/kg,water absorption rate was 50.36±2.21%,solid loss was 2.86±0.36%,hardness was 1798±28 g,cohesion was 1.37±0.52,sensory score was 92±1,and gelatinization degree was 80.86±1.31.The comprehensive score was 97.31±0.12.(2)With zein as the coating agent,seven indexes of selenium-enriched nutrient enhancement of the left embryo rice were evaluated by designing different single factor experiments,and the optimal process conditions were obtained by single factor.On this basis,response surface experiment design and 7 quality index measurement were carried out.Principal component analysis was carried out to form a comprehensive evaluation index.Response surface analysis experiment showed that the optimal process parameters of coating technology were as follows:coating times 3 times,coating amount 8.21%,coating agent concentration 0.028 g/mL.Under these conditions,the selenium loss rate,water absorption rate,moisture content,hardness,cohesion,sensory score and total color difference of the coated embryo rice were 18.06±2.32%,36.21±2.21%,12.86±0.36%,1696±33 g,1.62±0.37,80±4 and 3.86±0.34 respectively.The comprehensive score was 99.56±0.12.(3)The cooking characteristics,texture characteristics,gelatinization characteristics and Different Scanning Calorimetry(DSC)characteristics of Se-enriched enriched enriched rice were studied and compared with blank rice.The results showed that the cooking characteristics of the rice were improved after ultrasonic immersion treatment.Compared with the blank rice,the selenium-enriched rice had lower hardness,higher cohesion and lower regenesis value,and the rice was soft and waxy,with good taste.SEM and low-field NMR analysis showed that compared with the blank rice,ultrasonic immersion changed the internal microstructure,enhanced the water absorption rate,and increased the selenium content in the rice.(4)In the process of storage,the storage characteristics of three kinds of selenium-rich preserved embryo rice obtained by soaking treatment,ultrasonic soaking treatment and ultrasonic soaking soaking-coating treatment respectively were investigated.With the remaining embryo rice as the control,the selenium-nutrient loss rate,water content,fatty acid value and absorbance difference of rice soup were taken as evaluation indexes.The results showed that the four kinds of samples in the whole storage process,each index had the same trend,but the quality of the enhanced embryo rice after coating treatment was more stable. |
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