Color of Processed Sweet Potatoes: Effect of Additives

Abstract

The additives, ethylenediaminetetraacetic acid (EDTA), stannous chloride, citric acid, ascorbic acid and sodium bisulphite were added to syrup and vacuum packs of sweet potatoes. Addition of EDTA, SnCl2, citric acid and sodium bisulphite was effective in decreasing darkening of the processed product. SnCl2, EDTA and citric acid were also effective in preventing discoloration after exposure of the product to air. The action of the additives is attributed to a disruption of the reaction leading from oxidation of polyphenols to the production of dark‐colored compounds.

PREVENTION OF BROWNING OF BANANA SLICES USING NATURAL PRODUCTS AND THEIR DERIVATIVES1

“…2) as observed by changes in color values. Metal chelating agents, such as EDTA, have also been reported to inhibit PPO activity by chelating the copper in the prosthetic group of the enzyme (Twigg et al 1974). We tested EDTA and its femc salt at concentrations from 0.001 M to 0.005 M, the upper limits of its solubility, but found that they appeared to accelerate the browning reaction.…”

Chemistry and Safety of Acidified Vegetables

“…Addition of 1% or 3% ascorbic or citric acid to processed sweet potatoes did not improve the color (36). With a pH change from 8.0 to 3.0 elicited by a citrate buffer, sweet potatoes' color and attractiveness improved (37).…”

Effect of substrate levels and polyphenol oxidase activity on darkening in sweet potato cultivars

“…Efforts to avoid processing-induced darkening have centered on producing cultivars with low discoloration potential. However, some research has been conducted on using pre-peel heating, longer lye-peeling time, and/or additives (Scott and Kattan, 1957;Twigg et al, 1974) to prevent darkening. In order to produce sweet potato cultivars of low discoloration potential, it has been suggested that plant breeding programs screen selections for PPO activity (Jones, 1972) and reject those selections which are high in the enzyme.…”