The Effect of Pre- Treatment and Oven Drying Temperatures on the Nutritional, Anti-Nutritional Values and Colour Properties of the Fruits of Solanum Torvum
Abstract
Fruits of Solanum torvum are generally consumed by lactating and nursing mothers, pregnant women and anemic patients when cooked for medicinal and nutritional purposes. Lack of preservation method has led to its high postharvest losses. However processing methods such as drying can affect differently the nutrient, colour and anti-nutrient content of food samples at different temperatures. This work therefore sought to determine the effects of treatment and different temperatures on the nutritional and anti-nutritional composition of the dried fruits. Proximate composition, some minerals (iron, magnesium, and calcium), anti-nutrients (Alkaloid, Oxalate and Tannin) and colour of the fresh and pre-treated dried samples were determined. AOAC (1995) methods were used for the determination of moisture, fiber, fat and ash content. AOAC (1990) method was used for the determination of protein. Minerals were determined using the Atomic Absorption Spectroscopy methods. Oxalate was determined by titrimetric method, Tannins by the spectrophotometric method and Alkaloids by the Gravimetric method. The results indicate that the fresh fruits possess high moisture content of 78.3% and 82 on wet basis. Fat, fiber, ash and protein contents increased with the exception of carbohydrate which decreased for the dried samples irrespective of the drying pretreatment. Minerals determined increased after drying for all temperatures with the effect of the treatments not well established. Vitamin C decreased after drying with the exception of the berries pretreated with ascorbic acid. Alkaloids and Tannins reduced after drying but oxalate was not affected by heat. Boiling reduced the browning effect with the 5% ascorbic acid treated samples recording the highest range of browning values. The high iron content of the fruits proves the fact that the fruits truly have hematinic property. These present research indicate that Solanum torvum fruits boiled and dried at 70oC has the best nutritional qualities, reduced anti-nutritional properties and a better desirable colour properties.
Description
A thesis Submitted to the Department of Food Science and Technology, College of Science, in partial fulfilment of the requirements for the degree of Master of Science in Food Quality Management,