| Begonia fruit can not only be used for ornamental purposes,but also for consumption,and is widely distributed in China.Begonia fruit is rich in nutrients,but its utilization rate is low.Therefore,exploring the health function of Begonia fruit provides a theoretical basis for further development of Begonia fruit products.Based on the analysis of the antioxidant activity of different polar parts of Begonia fruit and the screening of lactic acid bacteria strains,this experiment analyzed the effects of using lactic acid bacteria to ferment the juice produced from Begonia fruit,and optimized the processing technology of the fermented juice.Furthermore,Begonia fruit juice was further used in the preparation of yogurt,and the quality and processing technology of fruit flavored yogurt were optimized.To provide method guidance for using Begonia fruit and its primary processed products as food raw materials and developing fermented foods,as well as provide reference for reducing losses and value-added utilization of Begonia fruit.The specific research contents are as follows:(1)Five different organic solvents,water,70% ethanol,petroleum ether,ethyl acetate,and n-butanol,were used to extract the active components from Begonia fruit and observe their antioxidant activity.The results showed that there was a positive correlation between the content of total phenols and flavonoids in different polar parts of Begonia fruit and its antioxidant activity.The content of total phenols and flavonoids in the 70 % ethanol fraction was the highest,2.89 mg GAE/g DW and 4.28 mg RE/g DW,respectively.The corresponding DPPH free radical and ABTS free radical scavenging abilities were the strongest,reaching 10.35 μg Trolox/g DW and 23.04 μg Trolox/g DW,respectively,confirming the bioactive components contained in Begonia fruit and their antioxidant activity.(2)Screening of Lactic Acid Bacteria for Fermentation of Begonia Fruit Juice and Optimization of Its Processing Technology.Six different lactic acid bacteria(Lactobacillus plantarum,Lactobacillus acidophilus,Streptococcus thermophilus,Lactobacillus casei,Lactobacillus fermentans,Lactobacillus rhamnosus)were used to ferment begonia fruit juice to analyze the changes in physicochemical indicators,active ingredients,and antioxidant properties before and after fermentation.Principal component analysis was used to screen suitable strains for the fermentation of begonia fruit juice.Optimize the fermentation process of begonia fruit juice using the selected strains through fuzzy mathematics.The results indicate that Lactobacillus plantarum is more suitable for the fermentation of begonia fruit juice.The optimal conditions for Lactobacillus plantarum to ferment begonia fruit juice are: fermentation temperature of35 ℃,juice concentration of 50 %,and inoculation amount of 2 %,fermentation time72 hours,addition of 8% sugar.(3)The processing technology of begonia fruit yoghurt was optimized by comprehensive score of multiple indicators.Begonia fruit yoghurt was developed with fresh milk and begonia fruit juice as raw materials.The processing conditions of begonia yoghurt were optimized by single factor test and response surface methodology,and the quality of begonia yoghurt was determined.The results showed that the optimum technological conditions of begonia fruit yoghurt were: fermentation time 10 h,inoculum 0.05%,sugar 8%,juice 9%.Under the optimum conditions,the comprehensive score was 0.85,the protein content was 2.67g/100 g,the acidity was75.04 ° T,and the number of lactic acid bacteria colonies was 1.215 × 107 CFU/m L,Escherichia coli,Staphylococcus aureus and mold were not detected.The water holding capacity was 72.31%,the DPPH clearance rate was 43.76%,and the ABTS clearance rate was 50.83%.The use of crabapple fruit juice in yogurt products can yield high-quality yogurt products with health benefits. |
