Study On Optimization Of Extraction Process,biological Activity Of Polyphenols From Castanopsis Sclerophylla And Product Development Of Castanopsis Sclerophylla Chips

Castanopsis Sclerophylla is a kind of fagaceae plant.But there are few researches on Castanopsis Sclerophylla kernels,mainly focusing on starch,polysaccharide and rough processing.Preliminary research by our group found that the Castanopsis Sclerophylla is rich in phenolic compounds.The constitute of polyphenols form Castanopsis Sclerophylla kernels and their physiological activities are rarely reported.Therefore,in this paper,using the Castanopsis Sclerophylla kernels as raw materials,the ultrasonic-assisted extraction method was used to optimize the extraction process of the polyphenols,and UHPLC-MS/MS technology was used to identify the composition of polyphenols and study their antibacterial and antioxidant activities.Finally developed a ready-to-eat crisps.The main results of this paper are as follows:1.Taking the yield of Castanopsis Sclerophylla polyphenol as an index,the optimal extraction process of Castanopsis Sclerophylla kernels polyphenols was optimized by single factor experiment and orthogonal experiment:extraction time20min,temperature 60℃,ethanol concentration 50,solid-liquid ratio 1:30,and extraction times 2 times.Under this condition,the yield of polyphenols was35.53±0.02 mg/g.A total of 20 polyphenolic compounds were identified from the kernels of Castanopsis Sclerophylla,including 11 phenolic acids and their derivatives,6 flavonoids and their derivatives,1 coumarin and 2 tannin.A total of 18kinds of polyphenolic compounds were identified in the de-astringent Castanopsis Sclerophylla starch,including 8 kinds of phenolic acids and their derivatives,7 kinds of flavonoids and their derivatives,1 kind of coumarin and 2 kinds of tannins.2.The polyphenols in Castanopsis Sclerophylla kernel and de-astringent Castanopsis Sclerophylla starch have strong scavenging ability to DPPH_·and ABTS_·~+,and both have strong antioxidant properties.The polyphenols of Castanopsis Sclerophylla kernel had the strongest inhibitory effect on Escherichia coli,followed by Staphylococcus aureus and Salmonella typhimurium;and the MIC values were 1.25 mg/m L,1.25 mg/m L,0.625 mg/m L,respectively,the MBC values were 1.25 mg/m L,2.5 mg/m L and 2.5 mg/m L,respectively.The antibacterial activity of de-astringent Castanopsis Sclerophylla starch polyphenols against Staphylococcus aureus was stronger than that of Escherichia coli and Salmonella typhimurium,and the MIC were 1.25 mg/m L,0.625 mg/m L and 0.625 mg/m L,respectively,the MBC values were 1.25 mg/m L,1.25 mg/m L and 2.5 mg/m L,respectively.At the concentration of 0.15625-10 mg/m L,the polyphenol of Castanopsis Sclerophylla kernels and de-astringent starch had no antibacterial activity against Candida albicans.3.Using de-astringent Castanopsis Sclerophylla starch as raw material,Castanopsis Sclerophylla crisps were prepared by microwave puffing.The product formula is:20%sucrose,20%edible oil,3 min microwave time,and microwave power 400 W.The volatile flavor compounds of the Castanopsis Sclerophylla crisps were studied by GC-MS technology,and the results showed that the characteristic aromas were fruity,fatty and caramel aromas,and the content of polyphenols in the product was 3.37±0.14 mg/g.This product is the first ready-to-eat snack food developed with Castanopsis Sclerophylla as the raw material,which is of great significance in promoting the development and utilization of Castanopsis Sclerophylla resources.