Determination of the surface waxy substances of grapes

Abstract

19 2 0 2 1 2 2 23 2 4 19%-34, 229 ex$. Two quantitative methods for the determination of waxy substances on the surfaces of grapes are compared. These methods applied t o the varieties of grapes used for drying in Australia gave the following results for total extractable waxy substances (pg./sq. cm.) : sultanas 125-140, currants 111, gordos 178, Waltham Cross 107.

Polyphenolic Composition of Raisins

“…The phenolic compositions of grapes (Lea et al, 1979;Cheynier and Rigaud, 1986;Jaworski and Lee, 1987;Merida et al, 1991;Souquet et al, 1996), grape juices (Spanos and Wrolstad, 1990), and wines (Baranowski and Nagel, 1981;Salagoity-Auguste and Bertrand, 1984;Oszmianski et al, 1986) have been investigated by many researchers. Raisins are an important processed product in many parts of the world where grapes are grown (Dudman and Grncarevic, 1962). The USA is the third largest grape producer after Italy and France, and the world's largest raisin producer (Pollack and Perez, 1997).…”

The Surface Wax of Several Grapes in Japan

“…Since this type of surface structure is a strong barrier to the transpiration from berries, the chemical nature and fine structure of the wax have been investigated by many workers in `Thompson Seedless (Sultana)' , the most extensively grown raisin grape in the world (1,2,5,6,7,8,9,10,11). On the table grape cultivars, however, there have been hardly any detailed reports on them.…”

Loss of fatty acid esters from grape surfaces during drying

“…Fatty acid esters are used in Australia to provide as much as a three-fold increase in the drying rate of grapes (1). Possingham (2) reports that the fatty acid esters interact with the waxy cuticle of the grape skin, which acts as a water barrier, allowing an increased rate of water loss during drying.…”