Peck Substances of Sweet Cherries and Their Alteration during SO2 Brining

SUMMARY— During ripening the proportion of protopectin in the cherries decreased as did the average intrinsic viscosity of the pectic material. Brining of the cherries resulted in a further decrease in the intrinsic viscosity and a conversion of protopectin and pectinic acid to the pectic acid form. The texture of the brined cherries softened with increasing maturity of the starting material. On prolonged storage in SO² brine the texture of the cherries softened, and the intrinsic viscosity of the pectic materials decreased. The use of brines with pH levels above and below pH 3.1-3.5 caused a decrease in the intrinsic viscosity. A slight increase in pectic breakdown was seen when the SO² was raised to the 2% level. The overall effect of brining on the pectic materials of the cherries was to cause extensive de-esterification and a decrease in the viscosity average molecular weight.