Post harvest Management of Horticultural Crops (2+1)

ASTRINGENCY

Astringency is the dry, puckering (to gather something around the lips) mouth feel caused by tannins found in many fruits such as red grapes, blackthorn, quince, persimmon fruits, and banana skin.
Why we feel astringent?

The tannins denature the salivary proteins, causing a rough sand papery sensation in the mouth. It coagulates the viscous protein on the surface of our tongues, we feel its astringency. Astringency tastes unpleasant to many which tend to avoid eating astringent fruits.

Astringent is Latin word meaning ‘to bind fast’.



Astringency occurs in many fruits due to the presence of tannins. These can impart an unpleasant flavor and are associated with immature fruit. In banana, tannins polymerise as the fruit ripen and lose their astringency.



Varieties of fruits high in phenolics (phenols have no particular taste charterstics, except astringency of condensed flavor and bitterness in some of the citrus falvonoids) are more astringent than varieties with low in phenolics.

For eg. Red grapes (var. Cabernet Sauvignon) have high astringency than white grape.



During maturation, the condensation of phenolics continuously increases and at the same time the astringency decreases, perhaps because highly condensed flavans are less soluble and tightly bound to other cell components.