Study On Promoting Polyphenol Content And Biological Activities Of Rose Residue By Probiotics Compound Fermentation

Rose can be applied to the processing of food,medicinal materials,cosmetics and other aspects,and is favored by consumers all over the world.After extracting rose essential oil in industry,a large amount of rose residue will be produced as a by-product of rose essential oil,which is rich in active ingredients and nutrients.However,it has low additional value and needs to be further processed and utilized.Compound fermentation of rose residue with Lactobacillus plantarum and Bacillus natto will take advantage of the potential benefits of complex strains,improving the nutritional composition of rose residue,increasing the utilization rate of bioactive components and improving nutritional value.In this study,mixed fermentation of rose residue with Lactobacillus plantarum B7 and Bacillus natto was optimized by response surface methodology.Under the optimal fermentation conditions,the contents of nutrients in the fermentation broth before and after probiotics fermentation were analyzed by different methods,the changes of varieties and contents of polyphenols in the fermented liquid was determined using LC-MS/MS,and the change trend of contents of four monophenols in the fermentation process was analyzed.The activities of three common functional enzymes in fermentation broth was determined,as well as the change of antioxidant activities in fermentation broth.The correlation between antioxidant activity indexes and functional active compounds was analyzed.The main research results were as follows:In rose residue,the content of protein was 14.04�0.92%,the content of fat was 1.78�0.01%,the content of polyphenol was 22.34�1.60 mg/g,the content of crude fiber was 22.14�0.08%,the content of flavonoids was 11.98�0.76 mg/g,the content of total sugar was 23,27�0.82%,the content of soluble dietary fiber was 4.45�0.81%,and the content of reducing sugar was 10.32�0.10%.The viable counts of Lactobacillus plantarum B7 and Bacillus natto reached the maximum after 14 h,which indicated the best fermentation inoculation time.Based on the single factor experiment,Box-Behnken response surface method was used to optimize the fermentation conditions of rose residue.In terms of the polyphenol content,the optimal process parameters were determined as follows:time was 40 h,temperature was 38?,inoculum size was 2%.Under these conditions,the polyphenol content reached 41.02�1.68 mg/100mL.The rose residue was fermented under the optimal conditions.After fermentation,the content of protein increased by 6.86%,the content of polyphenols increased by 24.65 mg/100mL,the content of flavonoids increased by 10.24 mg/100mL,the content of soluble dietary fiber increased by 10.75%,the content of crude fiber decreased by 4.37%,the content of fat decreased by 0.38%,the content of total sugar decreased by 7.13%,and the content of reducing sugar increased by 1.52%.15 kinds of phenolic compounds were identified by LC-MS/MS and the content of different polyphenol compounds were promoted in fermented rose residue analyzed by peak area normalization method.The contents of p-coumaric acid,gallic acid and quercetin were increased by 8,5 and 4 times,respectively.And the chlorogenic acid was a new monophenol in the fermentation broth.During the fermentation,the content of polyphenols and monophenols showed the similar upward trend.The content of polyphenols,gallic acid and quercetin reached the maximum after 40 h,while the content of chlorogenic acid and p-coumaric acid continued to rise.The enzyme activities of SOD enzyme,amylase and protease in the fermentation broth were all reached at the maximum at 40 h of fermentation,which were 52.81�1.85 U/mL,36.30�3.11 U/mL and 9.53�0.41 U/mL,respectively.The antioxidant activities of fermentation broth were gradually enhanced during the fermentation process.The scavenging ability of ABTS,hydroxyl radical scavenging ability and DPPH scavenging ability were increased by 60.93%,57.70%and 37.00%,respectively.The correlation analysis of antioxidant activity index with polyphenol content and enzyme activity in fermentation broth showed that there was extremely significant correlation among the indicators.The results have laid a solid theoretical foundation for the further development of rose residue,which is helpful to solve the problem of the of recycling of by-product of rose processing,and also provides a new way for the development and utilization of natural plant polyphenols.