OPTIMIZING PROCESSING CONDITIONS FOR CHEMICAL PEELING OF POTATOES USING RESPONSE-SURFACE METHODOLOGY

Using Response Surface Methodology the effects of NaOH concentration ( 4-20%), process temperature (55-95-degrees-C) and time (1-7 min) was d etermined on the yield, peeling quality, unpeeled skin and total usage of NaOH. Also evaluated were titratable NaOH in the potato tissue, Na OH penetration and ''heat ring'' depths during one stage chemical peel ing of potatoes (Huincul variety). The best peeling quality, maximum y ield and minimum total usage of NaOH was obtained for the following ra nges: concentration, 11-13%, time 5-5.70 min and temperature, 90-95-de grees-C. The maximum temperature for which the ''heat ring'' and NaOH penetration depths were equal was 72-degrees-C where, at 20% NaOH and 7 min, peeling quality was very good and ''heat ring'' was absent.