Effect Of Pectinase And Maceration Treatment On Quality Characteristic Of Apple Wines

Apple is beneficial for human health, which has rich nutrition, minerals, vitamins and phenolics. China is the largest producer of apple in the world and considerable economic benefit was brought for farmers in apple-growing region with apple export. Apple is usually used for fresh eating. In apple industry, there are a lot of inferior apples with low marketable value. Apple wine-making not only can enhance additional value of the apples, but also save resources and promote sustainable development of apple production. In this study, Fuji apple wines were made with different concentration of pectinase and maceration time. Physicochemical indexes, phenolic compositions, antioxidant property and aroma profiles were obtained for investigating the effect of pectinase and maceration treatment on quality characteristic of apple wine.The main results are as following:(1) Quality of apple wine was modified in an extent and apple wine-making process was not changed with addition of pectinase and maceration treatment. Higher reducing sugar content and acidity were detected in apple wines with addition of pectinase and maceration treatment. Higher and lower acidity were obtained with higher concentration of pectinase and longer maceration time respectively. Methanol content and clarity of impregnating wines were increased significantly with addition of pectinase(P<0.05).(2) Total polyphenol content and antioxidant property of apple wines were improved with addition of pectinase and maceration treatment. Contents of gallic acid, caffeic acid, p-coumaric acid, ferulic acid, catechin, hyperin, phloridzin and phloretin were increased with addition of pectinase. Higher concentration of pectinase induced higher contents of caffeic acid, phloretin, p-coumaric acid and ferulic acid. Contents of caffeic acid, p-coumaric acid, catechin, hyperin, phloridzin and phloretin increased after maceration. Longer maceration time resulted in higher contents of caffeic acid, p-coumaric acid and phloridzin. Pectinase could decompose apple pomace to release more phenolics, promote the transformation from chlorogenic acid and phloridzin to caffeic acid and phloretin. Antioxidant ability of apple wine was markedly related to most polyphenol fractions(P<0.05).(3) Total 51 individual aroma compounds were identified in wine samples. Different families of aroma compounds were considered: alcohols, esters, fatty acids, terpenes, norisoprenoids and other compounds, alcohols, esters and acids were main aroma compositions. Different aroma profiles were found in different wine samples, and more fragrance types existed in impregnating apple wines. Apple pomace was degraded by pectinase to release aromatic substances and improve complexity of aroma, but no obvious regularity of effect of pectinase concentration and maceration time on aroma profiles was found. Content of alcohols and esters increased, acids and others decreased with maceration treatment. Negative influence on quality of apple wines could be caused by long time maceration, including dissipation of volatiles and increasing of harmful volatiles. Low concentration of pectinase could rich aroma compositions and modify alcohols and esters in apple wine.(4) High concentration of pectinase and long maceration time were not only not conducive to improve the quality of apple wine, but also showed negative influence. Aroma characteristics was modified with the presence of 50 mg/L pectinase and 4 days maceration during fermentation.