Effects Of Phytase Treatment On Structure,function And In Vitro Digestion Of Cinnamomum Camphora Seed Kernel Protein

Cinnamomum camphora,a new oil and protein resource,is a natural medium carbon chain oil with oil content of 55-65% and medium chain triglyceride content of over 90%,and protein content of over 18%.Phytate(inositol-1,2,3,4,5,6-hexaphosphate,IP6)is the main storage form of phosphorus in most cereals and bean seeds.However,as an anti-nutritional factor,phytate will inhibit the activity of digestive enzymes and affect the absorption of trace elements,minerals and proteins.Phytate was also found in Cinnamomum camphora seed kernel,which may limit the application of Cinnamomum camphora seed kernel protein isolate.In this study,exogenous phytase was added to reduce phytate content in Cinnamomum camphora seed kernel protein isolate.Through the optimization of enzyme treatment conditions(time,temperature,addition amount and pH),Cinnamomum camphora seed kernel protein isolate samples with different phytate content were prepared.The effects of phytate content on structure,physical and chemical properties,functional properties and in vitro digestion of Cinnamomum camphora seed kernel protein isolate were further investigated,which provided a theoretical basis for promoting the application of Cinnamomum camphora seed kernel protein isolate.The main research contents are as follows:In the first part,Cinnamomum camphora seed kernel protein was isolated by the traditional method of alkali extraction and acid precipitation,and phytase was added in the process of acid precipitation.By adjusting the temperature,time and addition amount,Cinnamomum camphora seed kernel protein isolated samples with different phytate content were prepared.The results showed that the phytase still had good activity at room temperature(25 ℃),and the optimal pH coincided with the pH of the extraction process(acid precipitation).After controlling the treatment time of phytase at 20 U/g,pH 5.0 and 25 ℃ for 0,5,10,20,40 and 60 min respectively,the isolated protein samples from Cinnamomum camphora seed kernel with different phytate content could be prepared simply and efficiently.In the second part,the effects of phytate content on the structure and physicochemical properties of Cinnamomum camphora seed kernel protein isolate were studied.The results showed that phytase treatment did not significantly change the secondary structure of Cinnamomum camphora seed kernel protein isolate,the content of free sulfhydryl group increased,and the particle size was smaller and the thermal stability was better;In terms of potential,the decrease of phytate content had a significant effect on potential,and the potential of the system shifted to the positive direction.After phytase treatment,the isoelectric point of Cinnamomum camphora seed kernel protein isolate shifts from pH 4.7 to pH 5.1.In the third part,the effects of phytate content on the functional properties and in vitro digestion of Cinnamomum camphora seed kernel protein isolate were studied.The results showed that phytase treatment could improve the functional characteristics and in vitro digestion of Cinnamomum camphora seed kernel protein isolate.In terms of functional properties,phytase treatment improved the solubility of Cinnamomum camphora seed kernel protein isolate at pH 4,and enhanced the emulsifying activity,emulsion stability and foaming capacity.Phytase treatment increased the protein release rate of Cinnamomum camphora seed kernel protein isolate during the gastric digestion stage,and the content of free amino acids was higher,which was more easily hydrolyzed into small peptides or amino acids by digestive enzymes.In conclusion,phytase was added to reduce phytate content in Cinnamomum camphora seed kernel protein isolate,and the enzyme treatment conditions were optimized to prepare Cinnamomum camphora seed kernel protein isolated samples with different phytate content.Phytase treatment can improve the thermal stability,emulsifying activity,emulsion stability and foaming capacity of Cinnamomum camphora seed kernel protein isolate on the basis of retaining most of the secondary structure.In addition,phytase treatment had a positive effect on the in vitro digestion of Cinnamomum camphora seed kernel protein isolate and significantly improved the biological accessibility of protein.This provides a theoretical basis for the high value utilization of Cinnamomum camphora seed resources.