a. chlorophyll
In general, most of the fruits, the disappearance of the color green is a sign of maturity. During the chlorophyll content in fruit ripening slowly declining. The loss of the green color of the fruit, perhaps due to the oxidation of the double bond or saturation of the chlorophyll molecule.
b. Carotenoids and Flavonoids
The synthesis of carotenoids can be inhibited by treatment with gibberellate or accelerated by the use of ascorbic acid or abscisic acid. Carotene synthesis is not dependent on the temperature, but the synthesis and degradation of the lycopene is affected by temperature. Generally, temperatures between 60-70 ° F is optimum for the synthesis of lycopene, but the temperature is above 85% o F can inhibit the formation of lycopene in tomatoes.
c. volatile products
The main chemical compounds in the fruit aromas are esters of aliphatic alcohols and acids are short-chain fatty. Volatile compounds produced and secreted by the fruit only when the fruit begins to mature.
d. Phenol derivatives
Phenol based kekomplekkannya can be divided into two groups: simple phenolic compounds and phenol compounds complex. Simple phenolic compounds consisting of the amino acid tyrosine, dehidroksifelalanin (DOPA), katecol of kafeat acid. Complex phenolic compounds consisting of anthocyanins, lignin and tannin. Tannins are generally found in every plant that the location and the amount differs depending on the type of crop, age of the plant, and the organs of the plant itself.
Generally fruits contain more tannin than other plant parts, which give astringency astringent flavor to the fruit. Tannin generally unchanged after the fruit is harvested. The contents of the fruit depends on the level of development, as shown in Figure III.9. In the figure III.9, tannins contained in apples reach the highest content at the time the fruit is still young, and decreased after dark fruit. Things like this also occurs in fruits other than apples.
The decrease in tannins during the ripening of fruits might be due to the degradation of tannins, the polymerization / depolymerization of tannin, or oxidation of the tannins.
Figure 23. Schema changes tannin content in apples