Kinetics of quality change associated with potatoes stored at different temperatures

Undesirable storage conditions lead to physical and chemical quality loss in stored potatoes, which affect their consumer acceptability. Studies aimed at quantifying the extent of those changes under different storage conditions are valuable for minimizing the deleterious effect on product quality. The objective of this study was to evaluate the quality change in stored potatoes and quantify the associated kinetic parameters (rate constants) and activation energy to help model the changes in potato quality as function of storage temperature and time. Potatoes were stored at five temperatures (4degreesC, 8degreesC, 12degreesC, 16degreesC and 20degreesC) and., at different storage times (at least 5 time intervals) samples were removed and evaluated for different quality parameters (physical: texture and color; chemical: ascorbic acid (AA), reducing sugars (RS), starch (S), total sugars (TS), total soluble solids, pH and titrable acidity (TA) and physiological: respiration rate). The results revealed that potatoes became softer and darker by passage of time, and higher temperature resulted in more rapid changes in the different quality parameters. Chemical changes during the storage were decreased AA, pH and S, and increased TA, RS and TS. Only small changes were observed with peroxidase and polyphenoloxidase activity. Respiration rate increased with temperature and duration of storage. In general, most changes were well described by some form of first-order rate. Temperature sensitivity of rate constants was adequately described by the Arrhenius model. (C) 2002 Swiss Society of Food Science and Technology. Published by Elsevier Science Ltd. All rights reserved.