Thermal Degradation of Pigments and Relative Biochemical Changes in Cherries and Apricots

The extent and nature of biochemical changes that take place in canned fruits during storage temperatures above freezing have been reviewed and discussed by Pederson, et al. (1947). These changes include loss in nutritive value, e.g. ascorbic acid, thiamine (Brenner, et al., 1948) and deterioration of color (Tressler, et al., 1955). Bauernfeind (1953) reported that canned peaches, apricots, and sweet cherries, after a few months of storage at 70°F, frequently undergo changes such as destruction of anthocyanin and carotenoid pigments with the subsequent formation of brown colored compounds. Darkening of fruit-color eventually results in their unacceptability at consumer level. Preference for fruit is mainly based upon the attractive appearance of the products. Thus, color is an important factor governing the quality of fruits and fruit products. In earlier studies, conducted elsewhere, emphasis was placed on effects of low storage temperatures on the quality of canned apricots and cherries. Paucity of scientific literature on the stability of processed apricots and cherries gave impetus to a study of the comparative influence of high storage temperatures and their duration, as such tests will have considerable economic bearing upon storing and shipping processed products to tropical countries. This thesis presents the effects of storage temperatures (40, 70, 100, and 120° F) and their duration (16 weeks) on colors (anthocyanins and carotenoids), total titratable acidity, pH, viscosity, carbohydrates (total 2 and free reducing sugars, pectins), volatile reducing substances, hydroxymethyl furfural, and organoleptic quality of canned apricots and cherries