| Grape pomace is the solid residue of wine pressing,mainly composed of grape skins and seeds,which accounts for about 20% of the original grape weight.Grape pomace pollutes the environment,takes up resources,and has a negative impact on the grape processing industry if not properly treated,so how to make full use of grape pomace and reduce environmental pollution has become a popular research nowadays.In this thesis,the extraction process and method of polyphenols,proteins and other functional components from the grape seeds and skins of wine grapes were optimized to make full use of the grape skins,as follows.(1)The quality by design(Qb D)concept was combined with response surface design to develop a mathematical model using grape seeds as raw material.The optimized process intervals were: 1~2 extracts,44%~50% ethanol,1:10 g/m L feed-to-liquid ratio,and 90 min.The value of proanthocyanidins in the extract was 1.48%,and the sum of catechin and epicatechin content was 0.57%.The extract content was stable(RSD < 5%)when the raw material dosage was enlarged by 10 times and extracted with optimized process parameters.(2)Grape seed extract was purified by D-101 resin,and the optimal adsorption conditions were the upper sample concentration,p H value and flow rate of 0.14 mg/m L,4and 5 BV / h,respectively,with water,15 and 40% ethanol,and 40% ethanol was collected.The OPC content measured before and after purification by the new method was 22.14%and 92.87%,respectively,and contained no catechin and epicatechin,and the OPC content was basically the same as that measured by the USP43 method(22.15%,92.88%),with low cost and less toxicity.(3)A novel method of resveratrol in bipolar acid hydrolysis from grape skin was constructed.The optimal extraction process optimized by one-way ANOVA was: grape skin enzyme solution for 24 h,1% sulfuric acid water solution and ethyl acetate volume for1:3 reflux extraction for 6 h.Preliminary purification with an aqueous solution of 0.3%Na HCO3,regulated p H = 3,and posterior ethyl acetate for multiple extraction,the purified resveratrol yield was 0.08%,8 times higher than the traditional extraction method(resveratrol yield 0.01%).(4)Using grape seed as raw material,through the response surface design experiment,the optimized grape seed protein extraction process is: p H = 9.18,35℃,the material and liquid ratio is 1:15 g/m L,60 min,and the protein extraction rate is 3.56 ± 0.01%.In addition,the Osboren method is used to extract grape seed protein by classification,in which the highest protein content is gluten,followed by globulin,albumin and alcohol-soluble protein,with the content of 0.55%,0.52%,0.46% and 0.36%,respectively. |
