| Blueberry,also known as bilberry,blueberry,etc.,is the fruit of the genus Vaccinium spp.of the Ericaceae family.Blueberry is rich in anthocyanins and other functional substances,has anti-arteriosclerosis,anti-aging,anti-cancer and improve light-induced retinopathy.As an important participant in human metabolism,intestinal microbes can improve diseases such as obesity and diabetes by biotransforming functional components.In this paper,ultrasonic-assisted macroporous resin XAD-7HP was used to purify anthocyanins from blueberries,and the purified anthocyanins were microencapsulated in different wall materials to investigate the metabolism of anthocyanins in in vitro gastrointestinal digestion and colon fermentation.And the influence on the microbial structure of the intestine,and then further study the utilization of anthocyanins by a single intestinal probiotic in different systems,and finally developed a berry beverage rich in probiotics.The research results are as follows:1.In this study,the impact of ultrasound on the adsorption and desorption features of blueberry anthocyanins on macroporous resins were studied.Sonication was performed at 106-279 W/L and 20-30? in a pulsed mode,respectively.Generally,ultrasound treatments within the selected experimental range enhanced the adsorption/desorption process of anthocyanins on macroporous resins.The recovery of blueberry anthocyanins after ultrasound-assisted adsorption/desorption process at 279 W/L and 20? was 82.12%,which was 52.84%higher than that obtained after adsorption/desorption with shaking at 100 rpm.Meanwhile,higher acoustic energy density(AED)levels and lower temperatures benefited the adsorption process through enhancing the adsorption capacity and shortening the equilibrium time,whereas higher temperatures promoted the desorption process.Furthermore,malvidin-3-galactoside had the highest adsorption and desorption capacities among all the studied monomeric anthocyanins.No organic acids and sugars were detected after adsorption/desorption processes,indicating the successful improvement of anthocyanin purification.Sonication mainly enhanced the adsorption process by means of strengthening the formation of hydrogen bond on resins surface and increasing their surface roughness.Overall,ultrasound can be an effective tool to improve the purification of anthocyanins using macroporous resins.2.In this study,the effects of four wall materials(gelatin,soy isolate protein,maltodextrin and arabic gum)used for blueberry anthocyanin encapsulation on anthocyanin release,degradation and the regulation of gut microbes in vitro simulated gastrointestinal digestion and fermentation were investigated.Generally,encapsulation using the selected wall materials enhanced the intestinal bioaccessibility of anthocyanins(p<0.05).Soy isolated protein and gelatin delayed the release of anthocyanins(p<0.05),whereas the other two wall materials had no significant effect on release time of anthocyanins(p>0.05).Two new compounds,namely cinnamaldehyde and syringic acid,were detected after in vitro faecal fermentation of anthocyainins and soy isolated protein encapsulated anthocyanins had the highest concentration among all phenolic acids(p<0.05).Meanwhile,different anthocyanin microcapsules could significantly decrease the composition and abundance of Fimicutes and increase that of Bacteroidetes.Furthermore,the presence of anthocyanin microcapsules,especially soy isolated protein encapsulated anthocyanin,promoted the biosynthesis of short-chain fatty acids by intestinal microbiota(p<0.05).Overall,among all the selected wall materials,soy isolated protein is a functional and suitable wall material to improve anthocyanin bioaccessibility and prevent disease through promoting the gut health.3.To further explore the metabolism of anthocyanins in gut microbes,three commercial enteric probiotics(Lactobacillus plantarum,Streptococcus thermophilus and Bifidobacterium bifidum)were studied in different systems(blueberry juice,blackberry juice and medium supplemented with anthocyanin extract).The results showed that there were significant differences in the total number of colonies in different systems during fermentation(p<0.05).Lactobacillus plantarum and Bifidobacterium bifidum had the highest viable counts in blackberry juice(p<0.05),while Streptococcus thermophilus had the highest vitality in anthocyanin-medium(p<0.05).And during fermentation,compared with Streptococcus thermophilus,both Lactobacillus plantarum and Bifidobacterium had higher ?-glucosidase activity(p<0.05).In addition,the changes of color in different fermented liquids were significant(p<0.05),the red color ratio of blackberry juice was the largest(p<0.05),and the blueberry juice was mainly red and blue(p<0.05),while yellow accounted for the largest proportion in anthocyanin-medium(p<0.05).Principal component analysis of anthocyanins,phenolic acids and organic acids in the fermentation process,the distribution of the samples was mainly based on its systems,and the loading mapswere divided into three categories according to the ease of degradation of anthocyanins and the change of phenolic acid content.Organic acids were divided into two categories based on their rise and fall.In the sensory evaluation,blueberry juice contained Lactobacillus plantarum and blackberry juice contained Bifidobacterium bifidum had the highest acceptability and purchase intention value(p<0.05).4.The changes of viable cell count and physical and chemical indicators of Lactobacillus plantarum blueberry juice and Bifidobacterium bifidum blackberry juice during storage for 21 days were studied.The results showed that storage at low temperature was helpful for preservation of live bacteria(p<0.05),and the number of viable cells of Lactobacillus plantarum began to decrease significantly to less than 107 CFU/mL(p<0.05)after 14 days of storage,while the number of Bifidobacterium bifidum was less than 107 CFU/mL after 7 days of storage.The number of bacteria in storage at 4? and-4? was significantly higher than that 20? at(p<0.05),but there was no significant difference between 4? and-4?(p>0.05).The total anthocyanin content and total phenol content stored at 4 ? and-4? were higher than those stored at 20 ?(p<0.05).At 21 days of storage,the total phenolic content of probiotic blueberry juice at 20,4 and-4? decreased by 2.46%,1.06%and 1.07%,respectively,and the probiotic blackberry juice decreased by 5.45%,1.46%and 1.05%,respectively.Probiotic blueberry juice and blackberry juice stored at 4 and-4? had higher a value(p<0.05)and smaller total color difference(p<0.05)and higher soluble solids content(p<0.05)than higher storage at 20?(p<0.05),thus finally having a higher sensory overall score(p<0.05).Considering the viable cell count,functional properties and energy consumption,the recommended optimal storage temperature and optimal storage time for Lactobacillus plantarum blueberry juice and Bifidobacterium bifidum blackberry juice were 4? and 14 days and 4? and 7 days,respectively. |
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