| Proanthocyanidins have various physiological and pharmacological activities and are widely present in various plants,such as grapes,hawthorn,etc.They are mainly distributed in the skin,seeds,bark,and leaves of plants,with grape seeds being the most abundant in content.This study used 16 common wine grapes from Yangling,Shaanxi,including Cabernet Sauvignon,Merlot,Melite,Beimei,Matherian,Cabernet Gernischt,Carignan,Yan73,Shiraz,Pinot Noir,Malbec,Petit Verdot,Chardonnay,Agri,Weddell,and Riesling,as raw materials.The distribution of anthocyanin content in grape fruits,skin residue,and wine was measured and analyzed,providing a basis for the development of food and health products rich in anthocyanins.At the same time,using Cabernet Sauvignon grape seeds after brewing as raw materials,the procyanidins in defatted grape seed meal were purified using macroporous adsorption resin to explore suitable methods for industrial production of procyanidins extraction and purification,in order to increase the added value of wine by-products.The main results are as follows:(1)The distribution of proanthocyanidin content in fruit,skin residue and wine of 16 wine grape varieties was analyzed.Compared with other wine grape varieties,the content of proanthocyanidin in stem(41.81 mg/g),skin(7.43 mg/g),grape juice(756.31 mg/L),skin residue(10.05 mg/g)and wine(696.52 mg/L)of Yan73 dyed grape varieties was significantly higher than that of other wine grape varieties(P<0.05);The content of procyanidins in the peel,grape juice and grape skin residue of red wine grape was significantly higher than that of white wine grape;The content of anthocyanins in seeds and grape skin residue(seeds)of Cabernet Sauvignon and Chardonnay is significantly higher than that of other varieties;The content of anthocyanins in 12 red wines was higher than that in 4 dry white wines;The content of proanthocyanidins in grape seeds is higher than that in grape skins of the same variety;Through Pearson correlation analysis,the content of anthocyanins in grape fruits,pomace,and wine is closely related to the physical and chemical indicators of the fruit.(2)Cold pressing extraction refined grape seed oil from fermented grape skin residue,and extracted and determined the proanthocyanidins in defatted grape seed cake.Grape seed oil was extracted from grape seeds after Cabernet Sauvignon wine brewing using cold pressing method,and refined using four physical methods: centrifugal separation,activated carbon adsorption,diatomaceous earth adsorption,and mixed adsorption of activated carbon and diatomaceous earth,Determine the content of proanthocyanidins in grape seed oil under the optimal process.The results are as follows: Centrifugal separation is a good physical refining method for grape seed oil,and the transparency and clarity of the refined oil are the best.Under this refining process,the content of proanthocyanidins in grape seed oil is 3.02mg/g.The content of proanthocyanidins in defatted grape seed meal is 38.36 mg/g.(3)The purification process of defatted grape seed procyanidins using macroporous adsorption resin method has been determined.The AB-8 resin has the best purification effect on defatted grape seed procyanidins.The optimal purification process is as follows: the concentration of the sample solution is 5.0 mg/m L,the flow rate of the sample solution is 1.0m L/min,and 70% ethanol solution is used as the elution solvent,with an elution flow rate of1.0 m L/min.Under this optimal process,the recovery rate of proanthocyanidins is 88.4%,and the purity of purified proanthocyanidins can reach 89.32%. |
