EFFECT OF INCORPORATION OF DATE PULP ON SENSORY EVALUATION AND STORAGE STABILITY OF TOMATO KETCHUP

Abstract

The main aim of this study was to prepare date incorporated tomato ketchup and to evaluate its sensory properties, physicochemical properties and shelf life. Date pulp was mixed with sugar in the different ratios: 0:100, 25:75, 50:50, 75:25 and 100:0 to prepare five formulations. The prepared samples were subjected to sensory evaluation using a 9-point hedonic rating to evaluate the best product in terms of color, smell, taste, texture, mouthfeel and overall acceptance. The formulation with 25% sugar and 75% date pulp was selected as the best product. Proximate analysis of tomato, date pulp, control and best product were done. The storage stability of the best product was studied under room and refrigerated conditions in different packaging i.e. PET bottle and glass bottle. During the storage period, changes in TSS, pH, acidity, vitamin C and TPC of the product were evaluated. The moisture content, TSS, pH, protein, crude fiber, ash, carbohydrate and lycopene of date pulp was found to be 16.01%, 72.31%, 4.02%, 9.41%, 4.36%, 1.98%, 72.28% and 0 respectively and that for tomato was 94.37%, 3.12%, 4.15%, 11.21%, 1.1%, 8.22%, 58.73% and 9.01% respectively. The values obtained for TSS, pH, acidity, moisture content, vitamin C, crude fiber, crude ash, total sugar, reducing sugar, non-reducing sugar and lycopene of the best formulation ketchup were 28.33%, 4.13%, 1.5%, 68.23%, 11.99%, 1.12%, 3.48%, 20.33%, 17.85%, 2.48% and 10.18% respectively. Whereas for control sample, it was found to be 28.17%, 4.37%, 1.36%, 68.16%, 9.84%, 0.3%, 2.92%, 21.7%, 6.97%, 14.73% and 10.17% respectively. During storage, TSS and acidity of the ketchup increased whereas pH and Vitamin C content decreased. The product kept at refrigeration and packaged in glass had the highest TSS, lowest change in acidity and pH and highest vitamin C retention. The TPC count showed that it was within the acceptable range of ketchup in both plastic and glass bottles and at both room and refrigerated temperature without any artificial preservatives used.