Lye Peeling of Citron (Citrus medica L.)

Abstract

Peeling of citron (Citrus medica L.) by means of boiling lye-solutions was investigated. Good peeling resulted without need for hand-trimming when mature green citrons were subjected to any of the following: 6 minutes in a 10-percent, 5 minutes in a 15-percent, 3 minutes in a 20-percent, and 2 minutes in a 25-percent boiling lye solution. The average weight loss as peel under each of the above treatments was 19.4-, 19.0-, 19.6-, and 17.5- percent, respectively. For an acceptable operation tolerating some peel tissue remaining in the final product, the exposure/concentration ratio can be 5 minutes in 10-percent, 4 minutes in 15-percent, 2 minutes in 20-percent, and 1 minute in 25-percent boiling lye solution, with a corresponding increase in pulp yield which varied from 2.7 to 6.7 percent in these experiments. An increase in the time of exposure to lye-solutions increased the pH and decreased titrable acidity and color. No relationship was found between weight of fruit and volume of lye-solution necessary for good peeling. Citrons are peeled adequately when the solution or its foam makes contact with the fruit during treatment.