Evaluation of methods to increase free procyanidin content in the cider fermentation process of Jonathan Apples.

摘要

Procyanidins impart the desired astringent mouthfeel and bitterness flavor in fermented cider. Methods were investigated to enhance free procyanidin levels in fermented cider made from Jonathan dessert apples during and prior to fermentation. Colorimetric assays (i.e. BuOH/HCl and Vanillin in methanol) were found to be more effective in analyzing procyanidins than HPLC acid---phloroglucinol method.; Cider samples were fermented using DV-10 yeast for 20 days at temperatures 13--14°C at 0, 10, and 30% apple solids (crushed apples with no peel and core). No significant effect of alcohol production was observed on the procyanidin content, chain length and consequently, mean degree of polymerization (mDP). mDP of procyanidins increased in samples containing 30% apple solids between Day 0 and 5. Procyanidin content was higher in samples containing 0% apple solids on Day 14 vs Day 5. Overall, alcohol production, apple solids and time did not impact procyanidin content in hard cider during yeast fermentation.; Unfermented cider samples heated at treatments of 30, 40, and 50°C had no significant differences in free procyanidin content. Unfermented cider samples treated with tenfold pectolytic enzyme concentrations of industrial dosages (∼1000 ppm) significantly increased procyanidin concentrations without affecting mDP. Procyanidin levels in cider were enhanced using high concentration pectolytic enzyme treatments.