Potato Acids, Identification and Determination of the Major Acids of the White Potato

Metabolic changes induced by sprout inhibiting dose of .gamma.-irradiation in potatoes

“…Organic Acids of Potato. According to Schwartz et al (1962) the major organc acids present in potato are citric, malic, and oxalic. In order to evaluate the functioning of Kreb cycle, incorporation 2-14C-Na acetate into these acids was studied.…”

“…Estimation of Organic Acids. The organic acids were extracted from potatoes after infiltrating 50 pd of 2-14C-Na acetate and incubating for 4 hr and 24 hr after irradiation by using boiling ethanol according to the method described by Schwartz et al (1962). For 50 g of tissue 100 ml of alcohol was used.…”

Role of citric acid in the after-cooking darkening of .gamma.-irradiated potato tubers

“…No correlation seems to exist between the distribution of pyroglutamic acid (PCA) and after-cooking darkening since darkening is more pronounced in the cortical regions while maximum PCA levels were detected in the central pith region. The presence of PCA in uncooked potatoes has been reported as probably or wholly due to the method of sample preparation (Schwartz et al, 1962) and its formation by nonenzymatic cyclization of glutamine is known to be rapid above 65 °C (Shallenberger et al, 1959). However, in the present studies the observed accumulation of PCA in irradiated tubers during storage does not appear to be an artifact of sample preparation since tissues extracted by hot or cold alcohol did not show appreciable differences in the PCA content.…”

Starch swelling pressure of cooked potatoes

“…The net effect is a weakened middle lamella and an increased tendency to develop cell separation during cooking. This concept is supported by the observation that mealy potatoes tend to contain relatively high concentrations of these acids (Schwartz et al, 1961).…”

“…A number of these factors have been recognized in numerous publications. A theory of any validity will have to consider the effect of calcium (Personius and Sharp, 1939;Whittenberger and Nutting, 1950), the generally recognized highly significant correlations between mealiness and starch content, specific gravity, and total solids (Barrios et al, 1961;Bettelheim and Sterling, 1955;Le Tourneau and Zaehringer, 1965), the effects of cell size, (Barrios et al, 1963), the influence of organic acids (Schwartz et al, 1961;Wager, 1963), age and storage time of the tuber (Barrios et al, 1961a), the effect of different amylose-amylopectin ratios, rate and extent of starch retrogradation (Barrios et al, 1961b;Reeve, 1954; Unrau and Nylund, 1957), and the rate of diffusion of amylose into the cell wall (Linchan and Hughes, 1969).…”