Optimization Of Anthocyanin Microcapsule In Purple Sweet Potato

Sweet potato is a kind of convolvulaceae,originated from Latin America.It is various in colors,such as white,yellow,orange,pink and purple.Anthocyanins,a flavonoid group of polyphenolic compounds,leads to different colors of horticultural products,such as fruits and vegetables.It has been widely regarded as natural non-toxic food additives.The content of anthocyanins and other phenolic compounds?PSPAs?in purple potato is high,and PSPAs exhibit diverse biological activities,ranging from antioxidant activities,treatment of liver injury to protection of vision.In this paper,an improved ultrasonic-assisted enzyme extraction method of anthocyanins from purple sweet potato was proposed,and its various properties were tested.Finally,purple sweet potato anthocyanins microencapsulation were carried out to improve the storage stability.The results are as follows.By utilizing ultrasonic extraction method,the extraction effeciency was continuously optimized.The optimum extraction condition is as follows,50 ^oC of ultrasonic temperature,40 min of ultrasonic treatment time,120 U/mL of the concentration of enzyme and 1:30 of ratio,resulted in better extraction of anthocyanins?1194?g/g?.The results showed that it contains no protein,35.9%total sugar,10.40%total phenol and 8.9%total flavonoids content.It had been found that anthocyanins is more stable at normal temperature and low pH.In order to maintain the relative stability of anthocyanins and prevent their reduction reaction as reducing agents,the simultaneous use of reducing agents should be avoided.The study showed that the highest DPPH scavenging activity value was 94.05%at a concentration of 300?g/mL,similar to the positive control value of 96.13%.The OH^-scavenging activity values was 96.39%at a concentration of 3 mg/mL,and was slightly lower than Vc at the same concentration was 99.72%.The O₂^-scavenging activity value was 78.67%at a concentration of 300?g/mL,and was significantly lower than Vc at the same concentration was 98.74%.The ABTS scavenging activity value was 71.92%at a concentration of 300?g/mL,Vc was 83.45%.The optimum conditions for preparation of anthocyanin microcapsules are as follows,6 mg of anthocyanins,1.2 mg/mL of chitosan hydrochloride and 3 mg/mL of carboxymethyl chitosan were added simultaneously.The volume density of microcapsules was 25 mg/mL,which can be effectively released in gastrointestinal fluid and show a high rate of DPPH scavenging activity.The extraction time was shortened by utilizing ultrasonic enzyme method,the extraction efficiency was obviously improved,the extraction cost was reduced,and the safety of the product was improved.Embedding can prolong its storage time,avoiding environmental factors interference,and enhance its application in food field and human health.