Study On Extraction, Seperation, Antioxidation And Bacteriostasis Activity Of Anthocyanins In Red Bayberry Juice

Red bayberry (Myrica rubra Sieb.et Zucc.) is one of the specific fruit species in China, and it’s favored by consumers of all ages for its uniqe flavor. As one of the major processed products of red bayberry, red bayberry juice has a good development value and prospect. Amount of anthocyanins is present in red bayberry juice. In this paper, three extraction methods were used, which included conventional solvent extraction, ultrasonic assisted extraction and pulsed electric field (PEF) assisted extraction, and the extraction technical parameters were optimized. In addition, in study of the separation of anthocyanins, macroporous resins were used, and we got the optimum process of the separation and had a preliminary identification of anthocyanins being separation by the method of UV-Vis spectroscopy. Then we had a research on vitro antioxidant activity and bacterio static activity. The main research results were as follows:(1)With the anthocyanins content in extracting solution as the evaluation index, we used single factor experiment and the orthogonal experiment design, concluded that the optimum process parameters of conventional solvent extraction were:70% ethanol, the ratio of material and solvent 1:12, extracting time 80min, extracting temperature 30℃, and the anthocyanins content in extracting solution was 13.876mg/g; the optimum process parameters of ultrasonic assisted extraction were: 90% ethanol, the ratio of material and solvent 1:10, ultrasound power 350W, extracting time 30min, and the anthocyanins content in extracting solution was 16.251mg/g; the optimum process parameters of PEF assisted extraction were:85% ethanol, the ratio of material and solvent 1:8, electric field strength 21KV/cm, cycle times 2, and the anthocyanins content in extracting solution was 22.043mg/g. Through comparison of the three extraction methods, PEF assisted extraction not only needed less extraction time, but also can improve the extraction yield, so we chose PEF assisted extraction.(2)Through comparisons among six kinds of resins’adsorption, desorption property, AB-8 resin was selected as the preferable resin, as its adsorption rate was 76.34%, desorption rate was 69.23%. The single factor tests showed that the optimum parameters of AB-8 static adsorption were:pH 3.0, adsorption 5h, desorption 2.5h, desorption solution 80% ethanol. After separated, the anthocyanins became atropurpureus powder, with the color value 68.8; the recovery rate 72.41%.(3)Through the preliminary identification to the anthycyanins by UV-Vis spectrum analysis method, we concluded that the pigment we extracted were anthocyanins. The anthocyanins were not acylated; it mainly consisted of Cyanidin-3-O-glu-chloride.(4)The antioxidant activity of the anthocyanins in red bayberry juice was researched, through three kinds of in vitro antioxidant model:total antioxidant capacity, superoxide anion radical scavenging capacity and hydroxyl radicals scavenging capacity. The results showed that compared with VC, total antioxidant capacity and superoxide anion radical scavenging capacity of anthocyanins were lightly lower, and hydroxyl radicals scavenging capacity was higher.(5)The circular filter paper method was used to research the inhibition of anthocyanins in red bayberry juice on 6 kinds of pathogens. The results showed that anthocyanins had no apparent inhibition on Penicillium and Saccharomyces cerevisiae, while it played an obviously suppressive role on Escherichia coli, Bacillus subtilis, Staphylococcus aureus and Salmonella typhimurium. With the increase of the concentration of anthocyanins, the bacteriostatic activity increased. The degree of bacteriostatic activity was:Salmonella typhimurium> Escherichia coli> Bacillus subtilis> Staphylococcus aureus, and the minimal inhibitory concentration of them were 0.625mg/mL,1.25mg/mL,1.25mg/mL and 2.5mg/mL.