Effect of inpackage temperature and relative humidity on quality of minimally processed limau madu (Citrus reticulate) stored at 25 and 10 °C

M.N. Latifah, I. Ab. Aziz, O. Fauziah and Y. Talib

Abstract

Inpackage temperature and relative humidity of minimally processed limau madu was evaluated to relate to changes in quality during storage at 25 °C and 10 °C. Minimally processed limau madu was packed in the insulated boxes layered with thermal freeze (TF) whereas packing using the corrugated fibre board boxes (CFB) was used as control. At the initial stage, the temperature in the TF packing stored at 25 °C was maintained at 0 °C with relative humidity (RH) 100% for 24 h. The temperature later increased to 3 °C after 36 h, 15 °C after 48 h and 20 °C after 60 h. At all stages, the RH was maintained at 100%. However, temperature in the CFB packing increased from 19–26 °C with RH 55–85% from the beginning of the study until the end of the storage period (3 days). At 10 °C storage, temperature surrounding the TF packing remained at 0 °C for 60 h, then increased to 3 °C after 72 h (day 3) and later maintained at 10 °C until the end of the storage period (day 7). The RH was maintained 100% throughout the storage period. Chemical changes occurred in minimally processed limau madu during storage at 25 and 10 °C, even though no significant differences were observed in the TSS, TTA and acid ascorbic contents with different packing systems and storage temperatures. Similar trend was also observed in the pH of minimally processed limau madu in the different packing systems on day 1 and 3 for samples stored at 25 °C and day 7 for samples stored at 10 °C. Changes in the chemical components of minimally processed limau madu had contributed to the quality and acceptability of the product. Minimally processed limau madu in the TF packing was still good and well accepted even after 2 days stored at 25 °C. However, the taste of minimally processed limau madu in CFB packing was rejected at the end of day 1 even though high TSS and lower percentage of citric acid (TTA value) was determined in the product. The low RH had caused the fruitlets of limau madu to dry. Minimally processed limau madu stored at 10 °C was still accepted untill day 7 regardless of the packing systems. However, higher score was obtained for minimally processed limau madu in TF packing compared to those in CFB packing.

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