Research On Process And Antioxidant Properties Of Barley Ferment Powder And Its Meal Replacement Powder

There are abundant nutrients in barley leaves,which can be easily absorbed by human body and help improve the quality and immunity of human body.There has been some barley functional foods in the market already,but most of them taste poor and usually with a low additional value.In this paper,a barley ferment product is developed by yeast and lactic acid bacteria(LAB)fermentation with barley leaves as main raw materials,and made into powder by spray drying,added into meal replacement powder,improving the additional value of the product effectively,providing technical basis not only for the industrial production of barley ferment powder and its meal replacement powder,but also for the comprehensive utilization of barley to benefit farmers.The main contents are as follows:Firstly,the optimum conditions for the fermentation of barley ferment by Lactobacillus plantarum and Saccharomyces cerevisiae were determined by the research on the influencing factors of fermentation.The optimum conditions are as follows: the frozen barley leaves get squeezed and pre-treatmented,adding 6.0% of sucrose and other nutrients,adjusting pH to 4.0,and then get sterilized,inoculating 0.40% of S.cerevisiae at a temperature of 32°C and ferment for 18 h.Then,adjust the pH of the ferment broth to 6.3,inoculating 1.5% of L.plantarum at 37°C,and ferment for 24 h.Under these conditions,the SOD activity of the barley ferment product reaches 277.2 U/mL,the concentration of S.cerevisiae reaches 8.79×108 CFU/mL,the concentration of L.plantarum reaches 8.31×108 CFU/mL,and the titratable acidity reaches 0.47%.The results of antioxidant test show that the CAT activity,total polyphenol content,hydroxyl and DPPH radical scavenging rate of barley ferment are 1.3826 U/(m L·min),137.1 ?g/mL and 52.85%,and 90.17% respectively.The reducing force is also strong,showing a strong antioxidant function.Secondly,the optimum conditions for the spray drying of barley ferment was studied.The effects of three drying aids,namely maltodextrin,soluble starch and ?-cyclodextrin,on the spray drying of barley ferment were studied based on drying effects,sensory analysis,storage indicators and nutrients content.All the drying effects of the three drying aids were good.The sensory quality of the barley ferment powder with maltodextrin was best,and the storage quality of powder with ?-cyclodextrin was best,while the nutrients content did not appear much difference.The maltodextrin is used as the drying aid considering the cost,and according to the single factor test its addition ratio is set at 1:1.According to the single factor test and orthogonal test of spray drying,the optimal drying parameters are: inlet temperature at 140°C,outlet temperature at 80°C,solid content of feeding liquid at 7%,atomizer speed at 18000 r/min.Thirdly,in order to make full use of barley ferment powder and give it a higher additional value,barley ferment powder,konjac flour,soybean fiber powder,and apple fiber powder are used as the main raw materials to develop a barley ferment meal replacement powder.The effect of konjac flour on the quality of the meal replacement powder was especially significant.It is found that the addition of superfine konjac flour powder is superior to that added with common konjac flour on the solubility,sensory quality,and rheological properties.Although its antioxidant activity lost slightly,it is still within the acceptable range.According to the orthogonal test of meal replacement powder formulation,the optimum formula is as follow: 33% of barley ferment powder,30% of superfine konjac flour,23% of soybean fiber powder,5% of apple fiber powder,7% of fish collagen,0.5% of sodium hexametaphosphate,0.6% of citric acid,and 0.6% of xylitol.Finally,in order to understand the storage conditions,shelf life,storage stability and antioxidant activity of barley ferment powder and its meal replacement powder in the storage process and human body,the two products were studied by storage test and in vitro digestion test.The results showed that the total polyphenol content and SOD activity loss rate of the two products stored at 4°C with light avoiding and vacuum packaging were 18.34% and 20.43% respectively,which were significantly better than other storage conditions.A shelf area model of A = 2.432-21.26e-2373.6/Tt and A? = 1.924-1.249e-1534.3/T? t? was established with the total polyphenol content as the indicator.The model predicts the shelf life of the two products stored at 4°C and are 300 days and 195 days.It agrees with the results of storage test.The results of the sensory evaluation showed that the sensory quality of the two products during the storage period could meet the demand.The results of the antioxidant test showed that the maintenance of the antioxidant substances such as polyphenol in the low temperature condition was beneficial to the anti-oxidation ability of the product.The total polyphenol content in the stimulated gastric fluid was 2.74 times and 2.75 times higher than that in the control group respectively,and the SOD activity decreased by 45.54% and 38.99% respectively,and the antioxidant ability was significantly increased.Indicators changed little in simulated intestinal digestion.The increase in total polyphenol release during in vitro digestion not only compensated for the inactivation of SOD,but also improved the antioxidant ability of the digestive juice,indicating that the administration of the two products is beneficial to human anti-oxidant function.