| Bilberry is a kind of dual-use health food,which is often used as an important raw material for extraction of active substances.The fresh bilberry will produce a large amount of pomace after anthocyanin extraction,which is usually treated as waste.However,in fact,the pomace still contains up to 61.8% of the total dietary fiber and a small amount of anthocyanin,vitamins and other available substances.Stichopus japonicas is rich in protein,polysaccharide and fatty acids.In Stichopus japonicas’ organs,Stichopus japonicas intestines are discarded because they contain large amounts of sediment,but in the same quality of stichopus japonicas’ organs,stichopus japonicas intestines have the highest protein content,higher fat and sea cucumber saponins content.It even have taurine which is not found in their body.In terms of the utilization of sea cucumber,enzymatic hydrolysis is often used in market processing to prepare sea cucumber oligopeptides.The products have large molecular weight,deep color,heavy odor,and insignificant antioxidant function,which limits their application and low market acceptance.In order to reduce the environmental pressure further,avoid the waste of resources,improve the comprehensive application of nutrients in bilberry pomace and stichopus japonicas intestine,and solve the problem of fishy smell of stichopus japonicas peptides prepared by enzymatic hydrolysis,we uses bilberry pomace and stichopus japonicas intestine as the main raw materials to prepare dietary fiber and stichopus japonicas intestine oligopeptide,which use bacterial enzyme interaction technology.The prepared dietary fiber is used as the functional biological wall material,and stichopus japonicas intestine oligopeptide is used as the functional core material of microcapsules.Microcapsules are prepared by the piercing embedding technology.Therefore,in order to achieve the above objectives,this paper optimized the extraction process of soluble dietary fiber from bilberry pomace and oligopeptide from stichopus japonicas intestine,and explored the swelling and adsorption capacity of soluble dietary fiber from bilberry pomace and the antioxidant capacity of oligopeptide from stichopus japonicas intestine.Subsequently,in order to prepare efficient microcapsules,stichopus japonicas intestinal oligopeptides were used as functional core material,bilberry pomace soluble dietary fiber was used as bioactive wall material,and the embedding rate was selected as the evaluation index to prepare microcapsules.At the same time,the optimal embedding process of microcapsules was obtained by response surface optimization.Finally,the microcapsules prepared by each optimization process were applied to the development of functional products.The main elements and results of the work are listed below :（1）As a mixture,bilberry pomace soluble dietary fiber is rich in pectin and other components,which has a certain viscosity and adsorption.It can be used to improve the embedding rate of sea cucumber intestinal oligopeptides in the preparation of microcapsules.First,we find the most method by comparing the soluble dietary fiber,which prepared by acid-base method,enzymatic method and fermentation method.In the extraction process of soluble dietary fiber,the optimum conditions of different strain ratios,temperature,p H,and inoculation amount were explored through single factor experiments.Then,we choose orthogonal optimization to conduct the comprehensive analysis of the data.Finally,the optimum extraction process of dietary fiber from bilberry pomace was determined as follows : Bacillus subtilis screened from the intestines of stichopus japonicas,Lactobacillus plantarum screened from bilberry pomace,and the mixed bacterial liquid of commercial yeast at p H=7,solid-liquid ratio of 1:10,inoculation amount of 14%,and fermentation at 33.5℃ for24 h.Under these conditions,the extraction rate of dietary fiber was the highest,reaching 10.92%.The properties of dietary fiber extracts were tested,and it was found that the water holding capacity of water-soluble dietary fiber was 11.39±0.13（g/g）,the swelling capacity was 12.45±0.07（g/g）,the adsorption capacity for glucose was1.34±0.03（g/g）,and the adsorption capacity for nitrite was 43.47±0.17（μmol/g）.In the oil holding capacity,the unsaturated fat was 3.24±0.03（g/g）,and the saturated fat was 2.17±0.60（g/g）.（2）After enzymatic treatment,the polypeptide concentration increased,but the overall polypeptide chain was still relatively long and the bioavailability was low.The odor of enzymatic hydrolysate was still obvious due to the presence of flavor amino acid combination.Besides,the antioxidant capacity needed to be further improved.The use of bacterial enzyme interaction technology could improve the antioxidant capacity of polypeptide,the polypeptide yield,and shorten the polypeptide chain.At the same time,some flavor amino acid combinations were effectively destroyed,the odor was reduced.It was determined through experiments that the intestinal oligopeptide of stichopus japonicas could promote the growth of fermentation bacteria.Secondly,the optimal fermentation strain ratio,temperature,p H and inoculation amount were determined.Then we choose orthogonal optimization to determine the optimal preparation process of intestinal oligopeptides of stichopus japonicas.The results showed that the highest yield of intestinal oligopeptides of stichopus japonicas was 16.58% when the mixed bacteria liquid of Bacillus subtilis,Lactobacillus plantarum and yeast was fermented at 37℃ for 7 days at p H=8 and inoculation amount 7.5%.（3）The prepared stichopus japonicas intestinal peptide was used as the core material,the bilberry pomace dietary fiber and sodium alginate were mixed as the wall material,the calcium chloride solution was used as the coagulation solution,and the microcapsules were prepared by the acute hole method.After sensory evaluation and embedding rate comprehensive evaluation,the optimal preparation process of sstichopus japonicas intestinal oligopeptide dietary fiber microcapsules was finally determined.When sodium alginate and dietary fiber were mixed according to 2:1 as the wall material,0.3% sucrose fatty acid ester was added,and the core-wall ratio was controlled to 0.21.After 3.51% coagulation solution treatment,the theoretical embedding rate was 79.32%.Under the same experimental conditions,the embedding rate was 79.25%.On this basis,by modifying the formula,a stable and sensory sea cucumber peptide functional soft sugar was obtained. |
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