Anchovy Hydrolysates: Proliferation Effect On Streptococcus Thermophiles And Evaluation Of Physiological Activity

In China,anchovy fish is an important economic fish in estuary of the Yangtze River.It is favored by the food industry because of its rich amino acids and unsaturated fatty acids.However,as a kind of low-value aquatic products,its application in Chinese food industry is relatively narrow,most of which are canned anchovies.And there will be a large number of abandoned anchovy fish every year due to the strict requirements for raw materials of anchovy.This subject focuses on the abandoned anchovy fish,optimizes the enzymatic hydrolysis process using its high protein characteristics,and aims to provide theoretical foundation for the research of low-value aquatic products anchovy fish hydrolysate as functional food.The results are as follows:1.Optimization of Enzymatic Hydrolysis Process of Anchovy Fish by Response Surface MethodologyThis work aims to optimize the enzymatic hydrolysis process of anchovy.Basing on single factor experiments,the response surface methodology?RSM?was employed to optimize the enzymatic hydrolysis condition of anchovy fish,by using proliferation effect on Streptococcus thermophilus growth as the evaluation index.The results showed that the optimum conditions were hydrolysis time 6.6 h,the ratio of raw material to water 1:2.17?v/w?and enzyme concentration 5.5%,and under these conditions,the?OD₆₀₀ of proliferated Streptococcus thermophilus was 0.556±0.017.2.Deodorization and Decolorization processing of Anchovy Fish HydrolysateThis work aims to optimize the process of deodorization and decolorization of anchovy fish hydrolysis and to evaluate the hydrolysate before and after deodorization and decolorization.By evaluating the deodorization and decolorization of four macroporous resins,DA201-C was selected as the optimum material for this process.On the basis of single factor experiment,the process of deodorization and decolorization were optimized by orthogonal experiment L₉?3⁴?with the evaluation indexes of odor,color and recovery.The results showed that the optimum conditions were pH 6,content of macroporous resin 5%,time 1.5 h,and temperature 25?C.Free amino acid content,volatile components with its content,and the effect of the proliferation of Streptococcus thermophilus were used to evaluate the hydrolysis of anchovy fish before and after deodorization and decolorization processing.The results showed that taurine,alanine,methionine,and isoleucine decreased significantly,and the relative contents of aldehydes and nitrogen compounds in volatile components also decreased significantly.There was no significant difference in the proliferation of Streptococcus thermophilus by using hydrolysis processed before and after deodorization and decolorization.3.Effect of Anchovy Fish Hydrolysate on the Proliferation of Streptococcus thermophilusThis study aims to investigate the effect of anchovy fish hydrolysate on the proliferation of Streptococcus thermophilus.The results showed that the enzymatic hydrolysate with molecular weight less than 3 kDa had the best effect on promoting the proliferation of Streptococcus thermophilus,and?OD₆₀₀ reached to 0.586.In addition,the optimal content of enzymatic hydrolysate in the medium was 1.2 g/L.Mixed anchovy fish hydrolysate and less than 3 kDa had no significant effect on the growth curve of Streptococcus thermophilus,but had significant effect on its acid production.4.Assessment of antioxidant capacity of Anchovy Fish HydrolysateThis work aims to evaluate the antioxidant capacity of anchovy fish hydrolysate.The results of scavenging reactive oxygen radical ions in vitro showed that anchovy fish hydrolysate had better scavenging effect on DPPH⁺·?IC50=3.18 mg/mL?and·OH ?IC50=43.27 mg/mL?,but weaker scavenging effect on·O^2-?no IC50?.At the same time,the results showed that the scavenging effects of hydrolysates less than 3 kDa on DPPH⁺·?IC50=2.73 mg/mL?,·OH?IC50=14.52 mg/mL?and·O^2-?no IC50?were better than those of non-segmented polypeptides.The results of enhancing the activity of free radical scavengers in rats showed that anchovy fish hydrolysate could enhance the activity of T-SOD and CAT scavengers in intestine,liver and kidney,which leads to enhance the antioxidant capacity of the body.5.Assessment of the Effect of Anchovy Fish Hydrolysate on Intestinal Flora in RatsThis study aims to evaluate the effect of anchovy fish hydrolysate on intestinal flora in rats.The results showed that there were 547 OTUs in intestinal flora of rats before and after gastric administration,while there are unique 8 OTUs on day 0 and 26OUTs on day 14.By comparing and analyzing the difference between the two samples,it was found that the content of Lactobacillus in intestinal flora of rats 14 days after gastric administration was significantly higher than that before gastric administration.The results showed that anchovy fish hydrolysate could improve the intestinal flora of rats.