PECTIN METHYL ESTERASE ACTIVITY CHANGE IN INTERMEDIATE MOISTURE SUN-DRIED FIGS AFTER STORAGE

Abstract

Intermediate moisture fruits can be obtained by rehydrating dried fruits. Intermediate moisture fruits are suitable for direct consumption compared to dry fruits and can be directly used in the production of various products such as bakery products, dairy products and candies. Aim of this study is to compare the pectin methyl esterase (PME) activity of intermediate moisture figs which causes softening of the texture and to compare their microbial stability after 3 months storage period. For this purpose, dried figs were rehydrated in 30 and 80 degrees C water until they reach 30% moisture content. Rehydrated samples were stored for 3 months at +4 degrees C. Results showed that there was no statistically significant difference between the control samples and the samples rehydrated at 80 degrees C according to the total viable counts. At the end of the storage period, results of residual PME activity in control samples was 24.1 mu mol COOH min(-1)g(-1), while it was found 17.4 mu mol COOH min(-1)g(-1) in samples rehydrated at 80 degrees C. As a result rehydration conducted at 80 degrees C provided 28% reduction in PME activity compared to the control samples rehydrated at 30 degrees C, although it did not affect the microbial load significantly after storage.