Sensory and Shelf-life evaluation of a Food Multi-Mix formulated for rural children in South Africa

Abstract

Food multi-mix (FMM) assists in providing ingredients balance from each food group within the formulation and to ensure maximum nutritional value.The objective of the study is to evaluate the sensory and shelf life of a food multi-mix formulated for rural children in South Africa.. The food multi-mix was formulated in conformity with the nutritional requirements of children .The multi-mix ingredients consisted of maize ,which is a common staple in South Africa , spinach, sugar beans, carrots, pilchards in tomato sauce ,as an inexpensive source of protein and oil. The ingredients were dried , pasteurized and cooled at room temperature, 25oC . The FMM was ground into powder and immediately vacuum –sealed. The final recipes were standardized with 100g of multi-mix . They included peanut-butter biscuit , sweet muffin and savoury muffin.The inclusion of these ingredients improved the nutritional value and boosted energy density. The sensory evaluation of the FMM by the rural children was carried out using three attributes ; appearance , taste and smell , and a four –face hedonic scale representing very good , good , bad and very bad. The shelf-life of the FMM at room temperature , 25oC , for a period of 28 days was determined . 10g of FMM was aseptically used and homogenized with 90ml of diluent ( buffered peptone water ) . Total aerobic plate counts on tryptone soy agar incubated at 25oC for 3h, were analyzed .Coliform and E.coli counts on a violet red bile 4-methyl umberlifery –beta-D-glucuronide agar and incubated at 37oC for 2h , were determined. The presence of B.cereus and B. aureus were determined on the 1st day of the shelf life test. Results of the sensory evaluation by the rural children showed that 83.9 % of them preferred peanut butter and muffin , rated 73.1% for savoury muffin , and 94.5 % for the sweet muffin.The children had preference for sweet snack items.The total aerobic plate count in the FMM tested over a period of 28 days were below log 4/ g .Coliform and E .coli counts remained below 10 cfu / g throughout the shelf –life evaluation , while B.cereus and S . aureus were not detected. The presence of microbes detected in the FMM were less than 10 ,which indicated that the FMM is safe for human consumption when stored at room temperature for 28 days Data of the sensory and shelf evaluation of the formulated and prepared food multi-mix indicate that it is acceptable ,safe , suitable and may improve the nutritional intake of children.. Keywords: Food multi-mix, sensory evaluation, , shelflife ,maize, peanut-butter , muffin Nigerian Food Journal Vol. 25 (1) 2007: pp. 56-66