Preparation Of Sea Buckthorn And Highland Barley Complex Jiaosu And Its Functional Activity

Jiaosu are functional foods made from vegetables,fruits,herbs and other raw materials,using beneficial microorganisms such as yeast,lactobacillus and acetic acid bacteria as fermenting agents to convert large molecules into small molecules and produce nutrients such as primary metabolites and secondary metabolites.Sea buckthorn,as a "medicinal food" plant,contains a large number of flavonoids and vitamins,which have the ability to improve immunity,antioxidant capacity and anti-tumour properties.Highland barley contains a large amount of dietary fibre,which has the function of lowering blood lipids,lowering blood sugar and improving antioxidant capacity.In order to develop the application of sea buckthorn and highland barley in the field of functional food,this study uses sea buckthorn and highland barley as raw materials to optimize the process of sea buckthorn and highland barley complex Jiaosu and conduct preliminary analysis and research on the functional activity of the Jiaosu products.The main research contents include:(1)screening of sea buckthorn and highland barley complex Jiaosu strains;(2)process optimization of sea buckthorn and highland barley complex Jiaosu;(3)determination of the activity of sea buckthorn and highland barley complex Jiaosu;(4)storage study of sea buckthorn and highland barley complex Jiaosu.The main research results are as follows.(1)Using super-oxide dismutase(SOD)activity and total flavonoid content as evaluation indexes,three strains of yeast,lactic acid bacteria and highland barley Monascus were differently compounded,and finally it was concluded that highland barley Monascus + yeast + lactic acid bacteria produced the highest SOD activity and total flavonoid content,which were significantly higher than the control group and other groups(p<0.05).The SOD activity and total flavonoid content using highland barley Monascus + lactic acid bacteria + yeast were 381.45 U/m L and1.46 mg/m L respectively.(2)A three-step fermentation method was used to prepare sea buckthorn and highland barley complex Jiaosu.The best fermentation process can be obtained by single-factor and response surface optimization: inoculum amount of 8.3 %,fermentation time of 8.5 d,initial water addition of 1:1.05,fermentation temperature of 30 ℃;the best fermentation process can be obtained by single-factor and response surface optimization in the second fermentation step with SOD vitality as the evaluation index The best fermentation process can be obtained through single-factor and response surface optimization: the amount of sugar added is 8.1 %,the raw material(sea buckthorn: highland barley)is3.3:1,the fermentation time is 19 h,the amount of strain added is 0.2 %,the material-liquid ratio is 1:1,and the fermentation temperature is 26 ℃;in the third step,using the number of live lactic acid bacteria as the evaluation index,the best fermentation process can be obtained through single-factor and response surface optimization: the fermentation time is38 h,the fermentation temperature is 33.4 ℃,the p H is 3.49 and 2 %inoculum.(3)The bioactive substances of the optimised sea buckthorn and highland barley Jiaosu were measured,and it was found that the bioactive substances,potent enzymes,antioxidant capacity and lactic acid bacteria live count were much higher than those before fermentation.The contents of total flavonoids,total phenols,ascorbic acid and protein increased by22.36 %,22.60 %,266.67 % and 384.86 % respectively compared to those before fermentation.In the determination of the enzyme activity,the contents of SOD,lipase and protease increased by 253.41 %,221.42 % and 373.4 %,respectively,compared to the pre-fermentation levels.In the determination of the antioxidant capacity,the reducing power increased by 46.74 % and the hydroxyl radical scavenging rate increased by 14.9 %.1,1-Diphenyl-2-picrylhydrazyl radical(DPPH)and superoxide anion radical scavenging rate increased by 6.01 %respectively compared to the pre-fermentation period.The scavenging rates of DPPH and superoxide anion radicals increased by 6.01% and10.34%,respectively,compared with those before fermentation.In addition,the lovastatin(Monacolin K,MK)content,the number of viable yeast and the number of viable lactic acid bacteria in the sea buckthorn and highland barley complex Jiaosu reached 1.99 μg/m L and 108CFU/m L,respectively(p<0.05).(4)From the storage properties of the Jiaosu solution at different temperatures,it can be known that 4 ℃ has better storage properties compared to 25 ℃.From the sensory evaluation,it can be seen that sea buckthorn and highland barley complex Jaiosu has a higher sensory evaluation score at 4 ℃,with a better aroma and a more sweet and sour taste.In the determination of total phenols and total flavonoids,the Jiaosu content was found to be higher at 25°C,but the difference in content was not significant.In the determination of antioxidant capacity,the antioxidant capacity at 4 ℃ was more stable,while the antioxidant capacity at 25 ℃ was more variable and therefore could not be stored for a long time.