Ripening

From EncycloWine

Ripening is a process in fruit such as grapes that causes them to become more edible and more suitable to make wine. In general, fruits become sweeter, less acidic, less green, and softer as they ripen.

Stages of a plant's life are influenced by hormones. An important plant hormone involved with ripening is the chemical ethylene, a gas created by plants from the amino acid methionine. Ethylene increases the intracellular levels of certain enzymes in fruit and fresh-cut products, which include:

• Amylase, which hydrolyzes starch to produce simple sugars, and
• Pectinase, which hydrolyzes down pectin, a substance that keeps fruit hard.

Other enzymes break down the green pigment chlorophyll, which is replaced by blue, yellow, or red pigments.

Hormone levels in fruit are often connected to pollination. If too few seeds in a multiseeded fruit are formed (by fertilization of the ovules), the flesh of the fruit may not develop in some areas, and ripening will be retarded or prevented. Fruit growers increasingly monitor seed ratios in developing and/or mature fruit and adjust pollination management accordingly.