The Protective Effects Of Egcg And Nanoencapsulation With Beta Lactoglobulin On The Stability Of Bilberry Anthocyanins

Bilberry (Vaccinium myrtillus L.) is one of the richest sources of anthocyanins. Many studies have shown that anthocyanins not only impart color to plant foods but also exhibit pharmacological properties. Numerous pharmacological studies have demonstrated its potential activities in prevention of low-density lipoprotein oxidation, and beneficial effects in cardiovascular diseases, obesity, allergy inflammation and vision. However, the instability of anthocyanins limits their application in foods and drinks. In this study, the anthocyanins in bilberry were separated by high-speed countercurrent chromatography (HSCCC) and isolated by reversed phase C18chromatography. EGCG and nanoencapsulation with P-lactoglobulin were used to improve the stability of anthocyanins.After HSCCC separation, the content of anthocyanins increased to 55.2%from23.4%. The recovery yield was calculated to be95.5%. Three anthocyanins including cyanidin-3-glucoside, delphinidin-3-glucoside and delphinidin-3-galactoside were further isolated by reversed phase C18chromatography column chromatography. The purities of all three anthocyanins were more than90%.EGCG was used as a copigment to improve the stability of total anthocyanins from bilberry. After heating at80℃for3h, EGCG showed a good protective effect on color stability of anthocyanins in various pH conditions.The thermal and light stability of solid or liquid cyanidin-3-glucoside, delphinidin-3-glucoside and delphinidin-3-galactoside were tested in present or absent EGCG. Under different treatment conditions, the anthocyanins content in present of EGCG increased13～22%higher than that in absent of EGCG.P-Lg-C3G nanoparticles were prepared,and the influences of pH (2.5,4.5,6.5) and temperature (55℃,65℃,75℃) on particle size, zeta-potential, encapsulation efficiency and protective effect on C3G antioxidant activity were investigated. P-Lg-C3G nanoparticles prepared with β-Lg preheated at75℃and pH6.5exhibited the best protection for antioxidant activity of C3G. The mean size of particles was around5.7nm and the zeta-potential of the particles were less than-30mV, indicating the system has good transparency and stability. The encapsulation rate of C3G reached to75.53%.