Study On The Preparation And Characterization Of Blueberry Anthocyanin-loaded Nanoparticles

Blueberry belongs to the genus Vaccinium and family Ericaceae and originates from North America.Blueberries contain abundant nutrients and bioactive components,such as sugers,acids,vitamin,flavonoids,tannin,phenolic acids and anthocyanins.Anthocyanins are important water-soluble pigments,widely existed in nature and non-toxic,safety.According to modern pharmacological research showed that anthocyanins had many pharmacological activities,such as anti-oxidant,anti-inflammator,anti-cancer and providing protection against cardiovascular diseases,and it had wide application and development prospects.However,anthocyanins were highly sensitive to factors,such as temperature,oxygen,antioxidants,nucleophilic reagent,enzyme,metal ion and light,leading to its stability was relatively poor,thus limiting to its used in the food industry.The method of microencapsulation to improve the stability of anthocyanins in the present work,the preparation procedure of anthocyanins-loaded chitosan nanoparticles was optimized,the physicochemical characterization and storage stability of anthocyanins-loaded chitosan nanoparticles were studied.The main research contents and results are as follows:1.The composition of the anthocyanins were identified by HPLC-DAD-MS/MS and the pH-differential method.The result demonstrated that the fifth anthocyanins,namely delphinidin-3-O-glucoside,cyanidin-3-O-arabinoside,cyanidin-3-O-glucoside,malvidin-3-O-glucoside and malvidin-3-O-arabinoside,total anthocyanins was 320.41mg/g,cyanidin-3-O-glucoside accounted for 89.52% of the total anthocyanins.2.Design the single factor experiment of encapsulation efficiency influenced by carboxymethyl chitosan concentration,chitosan hydrochloride concentration and amount of anthocyanis,on the basis of the result of the single factor experiment,anthocyanins-loaded chitosan nanoparticles preparation parameters were optimized using response surface methodology.The result suggested that the optimized conditions were carboxymethyl chitosan(CMC)concentration of 2.86 mg/mL,chitosan hydrochloride(CHC)concentration of 0.98 mg/mL and amount of anthocyanis of 5.97 mg.Using the modeled optimized conditions,the predicted encapsulation efficiency was 61.80%.3.Physicochemical characterization of anthocyanins-loaded chitosan nanoparticles presented:(1)SEM analysis showed that after encapsulation,the coarse and loose surfaceswith anomalous shapes of anthocyanins-loaded chitosan nanoparticles.The synthesis results indicated that the anthocyanins-loaded chitosan nanoparticles became the new phases after encapsulating with carboxymethyl chitosan and chitosan hydrochloride,and the anthocyanins-loaded chitosan nanoparticles were indeed formed.(2)FT-IR analysis showed that for the anthocyanins-loaded chitosan nanoparticles,many absorption peak of anthocyanins were covered by the chitosan expert characteristic absorption peak of O-H,amide group,and C-H,the anthocyanins-loaded chitosan nanoparticles were indeed formed.(3)DSC analysis showed that after encapsulating with carboxymethyl chitosan and chitosan hydrochloride,it proved that the anthocyanins-loaded chitosan nanoparticles were the new phase the phrase,because transition temperature and the enthalpy of the anthocyanins-loaded chitosan nanoparticles changed.The enthalpy value could judging the thermal stability,the results showed that the stability of anthocyanins-loaded chitosan nanoparticles higher than free anthocyanins.4.The release properties of anthocyanins-loaded chitosan nanoparticle was studied in simulated gastrointestinal fluid.The results showed that the nanoparticles with carboxymethyl chitosan and chitosan hydrochloride was a superior carrier.Compared to free anthocyanins,the release rate of was decreased obviously,the release time of blueberry anthocyanins was prolonged and anthocyanins-loaded chitosan nanoparticles could control the release rate of blueberry anthocyanins.5.The stability of anthocyanins from anthocyanins-loaded nanoparticles or anthocyanins alone was studied in a model beverage system under different storage conditions.The results showed that The stability of the encapsulated anthocyanins was84.5%,68.4% and 30.8% after either 35 days at 4 °C,12 days 25 °C or 9 days 40 °C,respectively,while that of the free anthocyanins was 71.2%,49.7% and 6.3% for the same time periods at 4°C,25°C or 40°C,respectively,thus microcapsule technology can improve the stability of blueberry anthocyanins.