Spray-drying of tomato (Lycopersicon lycopersicum (L.) Karsten)

The study was conducted in order to produce powders from the pulp of ripe tomato using spray-drying technology. Optimum combinations of spray-drying parameters and standard formulations for the production of tomato powder and instant tomato juice were established. Physico-chemical properties of the powder produced were determined to know the effects of various spray-drying conditions and feed mixture formulations on the sensory qualities of the product. Preliminary spray-drying runs showed that high levels of carrier increased total recovery but significantly affected the physical and chemical properties of tomato powder and instant juice. Increasing amounts of maltodextrin resulted in poor rehydration characteristics of the rproducts. Addition of higher amount of sucrose improved sinkability, dispersibility and solubility of instant tomato juice but increased its hygroscopicity, especially if the level is above 20%. Liquid feed mixture formulation consisting of 60% tomato puree and 40% maltodextrin was chosen for the production of tomato powder. For instant tomato juice, 60% tomato puree, 20% maltodextrin and 20% sucrose was found to be the most satisfactory formulation. Reduction in proximate composition was noted after spray-drying tomato puree into powder and instant juice. The levels of carotenoids, ascorbic acid and tocopherol in the spray-dried powders also decreased. Effects of different antioxidants and anti-caking agents on the physical, chemical and sensory properties of the products were evaluated. Addition of 0.02% Vitamin E significantly minimized destruction of vitamins, pigments and flavor. Instant tomato juice with Vitamin E was the most acceptable in terms of color, aroma and taste. Aside from minimizing oxidation, BHA and BHT helped reduce microbial load of tomato powder and instant tomato juice. Two percent anti-caking agent added to the liquid formulation improved flowability but had minimal effect on caking behavior and sorption isotherm of the powders. Addition of anti-caking agents had no significant effect on the microbial count of the products. Comparative cost analysis showed that spray-drying is a more advisable process of producing powder than convection-oven drying because of higher volume of production, shorter drying time and consequently, higher sales and profit.