Foam Fractionation For The Recovery Of Proanthocyanidin From Camellia Seed Shells

Camellia oleifera Abel.,a woody perennial plant belonging to Thestarae family,is one of the four major woody oil crops in the world cultivated in most tropical and subtropical regions.Currently,Camellia seed shells have been primitively used as the base stock for manufacturing activated carbon and cultivating edible fungi.Many studies suggest that Camellia seed shells contain multiple phytochemicals,such as aldose,tannin and lignin derivatives,especially proanthocyanidin(PC).PC is a bioflavonoid with special molecular structure and it has the characteristics of low toxicity,high bioavailability and long metabolic half-life in human body.The superior capacity of PC in counteracting oxidation and scavenging free radical has been recognized by U.S.Food and Drug Administration.Moreover,PC also has medicinal importance in enhancing the integrity of blood vessel walls,improving the microcirculation of capillary endings,reducing cardiovascular inflammation and accelerating the breakdown of bad cholesterols.At present,most commercial PC standards were extracted from grape seeds.However,the industrial production of PC was severely restricted by the limited yield of grape seeds and the complex extraction technology because PC was very sensitive to environmental conditions,involving light,oxygen,heat and p H.Thus,there was a pronounced interest in developing an efficient technology to recover PC from Camellia seed shells.Water extraction has been widely used to extract active ingredients from natural substances due to its low cost,no pollution to the environment and convenient operation.However,due to the long time consumption of water extraction and the sensitivity of procyanidins to environmental conditions,ultrasonic assisted method was used to extract procyanidins from camellia oleracea shells in this work.Ultrasonic wave can produce strong vibration and cavitation effects,which are conducive to the migration of active ingredients,thus greatly reducing the extraction time.Thus,the influence of each factor on the extraction efficiency of procyanidins was studied by single factor experiment.On this basis,the optimal operating conditions for ultrasonic assisted extraction of procyanidins from camellia oleifera shell were determined by response surface methodology.Under the conditions of pH10.2,temperature 56°C and ultrasonic time 26.5 min,the maximum actual extraction rate of procyanidins was 82.02±1.17%.The ultrasonic assisted water extraction method for extraction of procyanidins from fruit shell of camellia oleracea has the advantages of fast,environmental protection,high efficiency and energy saving,which contribute to large-scale industrial production.Dodecyl dimethyl betaine(BS-12)is a kind of biological surfactant and it has been used to assist the foam fractionation for recovering procyanidins.The effects of the addition amount of BS-12,volumetric gas flow rate and liquid loading volume on the separation efficiency of procyanidins were investigated and the antioxidant properties of procyanidins before and after foam fractionation were evaluated.Under the optimal conditions of surfactant dosage 40 g/L,volumetric gas flow rate 150mL/min and liquid loading volume 500mL,the enrichment ratio and recovery percentage of procyanidins were 2.5 and 56.95%,respectively.In fact,BS-12 was difficult to selectively separate procyanidins from their similar substances through foam fractionation.In this work,chitosan nanoparticles were modified by molecular imprinting and then using to assist foam separation and efficient recovery of procyanidins from the leaching liquor of oil tea fruit shell.Molecular imprinting modified chitosan nanoparticles(CMIPs)were prepared by precipitation polymerization,and their adsorption capacity of procyanidins was evaluated.The experimental results indicated that the adsorption behavior of CMIPs was consistent with the Freundlich model and it could selectively adsorb from the complex mixture of catechin,quercetin and lignin.Under the suitable conditions of loading liquid volume 250mL,particle size of CMIPs 536.0nm,BS-12 concentration 0.15g/L and volumetric gas flow rate 100mL/min,the enrichment ratio and the recovery percentage of proanthocyanidin reached 10.34±2.11 and 85.24±3.05%,respectively.In this work,a variety of methods were developed to realize the enrichment of proanthocyanins by foam fractionation,which were significant to the selective separation of biological non-surface active and the industrialization of foam fractionation.