Induction of chilling injury in jicama (Pachyrhizus erosus) roots: changes in texture, color and phenolics

Abstract

Storage of jicama roots at 10 °C resulted in characteristic chill-induced changes in pulp color (decreased L* values and increased chroma) and texture (increased distance to rupture) after 7–14 days. Discoloration or browning of the pulp occurred first in exterior pulp tissue and then progressed to the interior tissue. Changes in texture during storage were similar in exterior and interior pulp tissues. Chill-induced color changes generally occurred before changes in texture. After 10 °C storage, transfer to 20 °C enhanced chill-induced changes in color, texture, and concentrations of phenolics. Roots stored at 13 °C for 6 weeks began to exhibit changes in pulp color but not in texture. Roots stored at 20 °C for 6 weeks had no color or textural changes although they lost about 40% of their fresh weight. Chill-induced browning was associated with increased concentrations of soluble phenolic compounds and increased phenylalanine ammonia lyase activity. Phenolic compounds in chilled jicama root had UV spectra similar to those of catechins, though ( +)-catechin and ( −)-epicatechin were not present based on HPLC. © 2002 Elsevier Science B.V. All rights reserved.