The Quality Properties Of Tomatoes (Lycopersicon esculentum) As Influenced By Processing With A Chemical Preservative And Storage

Abstract

Blanched sulphited and unblanched unsulphited tomato slices (control) were subjected to different storage temperatures (6-8^oC) and (-12^oC) respectively for 15 weeks. Solar dried (blanched sulphited and unblanched unsulphited) tomato slices were stored at ambient temperature (28-30^oC). Within the 15 weeks of storage, ascorbic acid,pH, titratable acidity, microbial population and sensory attributes were determined Blanched sulphited frozen (BLSF), unblanched unsulphited frozen (UNUF), blanched sulphited solar dried (BLSSD) and unblanched unsulphited solar dried (UNUSD) samples showed a decrease in pH with an increase in titratable acidity during storage. On the other hand blanched sulphited refrigerated (BLSR) and unblanched unsulphited refrigerated (UNUR) samples had an increase in pH and a decrease in titratable acidity. The moisture content of both frozen and solar dried samples reduced but that of refrigerated samples increased. The frozen samples retained more ascorbic acid (69.26% for BLSF and 55.41% for UNUF) than other samples but the blanched sulphited frozen sample retained the highest ascorbic acid (69.26%). The solar dried samples were better (45% for BLSSD and 48.15% for UNUSD) than the refrigerated samples which retained lesser ascorbic acid (30.57% for BLSR and 26.55% for UNUR). The frozen and solar dried samples showed an appreciable decrease of microbial population while there was an increase in the refrigerated samples at the end 15 weeks. Sensory evaluation indicated no significant differences in colour, flavour, texture and general acceptability between the blanched sulphited frozen and the fresh tomatoes at P< 0.05. Blanched sulphited solar dried and unblanched unsulphited solar dried samples were inferior in color, texture and general acceptability but not in flavour.

Key words: Blanching, sulphiting, Solar drying, Tomatoes.

Nigerian Food Journal Vol.22 2004: 195-202