DEVELOPMENT AND PRODUCTION OF NUTRITIOUS HIGH CALORIE FOOD BARS FROM INDIGENOUS OIL SEEDS
Nigeria is one of the largest importers of processed food products. This is evident in the varieties of calorie food bars in the market. These products are priced beyond the reach of an average Nigerian. The main objectives of this study were to develop, produce and evaluate calorie food bars targeted at people that require quick energy but do not have time for a meal.
Some economical and underutilised indigenous food sources with good nutritional value were explored to develop novel nutritious calorie food bars. The oil seeds investigated in the study were peanut, soybean and sesame seeds. Other materials were sugar, honey, sweeteners and sorghum flour, and some fruit sources.
Market survey was carried out to establish the brand name, basic ingredients, nutrient composition, cost and manufacturer of calorie food bars sold in superstores and local markets in Lagos State. Suitable processing technology for production of nutritious local calorie food bars from indigenous oil seeds was studied and developed.
The proximate chemical compositions of the ingredients and formulated food products as well as their physical and functional properties were determined. Evaluation of the sensory qualities of the produced food bars was carried out. Correlation between textural sensory scores (mouth bite, chews ability and mouth feel) and mechanical flexural values (hardness and deflection) of calorie bars were also determined. Microbiological analysis of the food products were also carried out using the total plate count method.
The survey revealed 18 different products of which 95 percent was imported and only 5 percent was produced locally. Major suppliers for the Nigerian market were Europe, Asia, and South Africa. The imported brands contain (per 100g) 37-61% sugar, 2-8% protein and 45-70% carbohydrate. The fat content ranged between 20-40%, of 50- 80% was saturated fat while the fibre content of bars was less than 2%. The energy level ranged from 400 – 490kcal and average component energies from fat and carbohydrate contents, and added sugar were 54%, 46% and 40% respectively. The market price for these bars ranged from N2.50–N4.00 per gram.
In comparison with RDDA in g/d for life group stage 19-50 years, the average chemical composition of bars (g/100g) showed that 33.80 and 41.15% of protein, 35.99% of carbohydrate, 12.47 and 18.96% of fibre and, 20.89% of energy (based on 2200kcal of Energy/day) were achieved for men and women respectively. The average component energies from protein, fat, carbohydrate contents and added sugar were 16.48%, 42.80%, 46% and 17.41% respectively. The result of the flexural property of food bars showed that the handling property of the food bar increases directly with increase in sugar level. Thus, food bar produced at 22% sugar level was the hardest (90.50±10.560N) while that which was produced at 18% sugar level was the softest (17.25±1.097N). The pattern with deflection at peak was however different. The highest deflection (2.38±0.724mm) was recorded for the bar produced at 20% sugar level while the least (1.21±0.184mm) was recorded for the bar produced at 18%. Salmonella spp., staphylococcus spp. and fungi were not detected in all the calorie bar samples analyzed. Coliform spp. was not also detected in the samples except in bar sample produced at 18% caramel level.
The bars were not significantly different (P<0.05) in terms of colour, taste and aroma. The mouth bite of the food bar produced at 20% caramel was significantly different from others produced at 18% and 22% respectively and it was the most preferred and food bar produced at 22% caramel was the least. Calorie food bar produced at 22% caramel was the hardest at 90.50±10.560N while that which was produced at 18% caramel was the softest at 17.25±1.097N. The pattern with deflection was different; being highest (2.38±0.724mm) for the bar produced at 20% caramel and least (1.21±0.184mm) for the bar produced at 18%. Correlation between textural sensory scores and mechanical flexural values of calorie bars showed that acceptance testing using the nine-point hedonic scale provides direction to the formulation efforts and gives a reliable estimate of the degree of liking while mechanical testing depicts the handling property of the bar.