Abstract

Production and evaluation of biscuits made from wheat flour and toasted watermelon seed meal as fat substitute was studied. Extracted watermelon seeds were toasted and grounded into seed meal, which were later used to formulate composite flour blends in the ratio of 10:90 (MW1), 20:80 (MW2), 30:70 (MW3), 40:60 (MW4) and 50:50 (MW5) of water melon seed meal: wheat flour respectively, while 100% wheat flour served as control (W1). Each blend was used to produce biscuits adopting robbing process. The functional properties of flour blends, proximate composition and physical properties of the biscuit samples were determined. Sensory qualities of the biscuits were evaluated by 20 panelists. The accepted composite biscuit samples were stored on a shelf for 6 weeks and analyzed for moisture and total viable count. Data obtained were analyzed statistically (P≤0.05) for ANOVA, and means separated using Fisher’s LSD Test. The results of the functional properties showed variations in behaviour. There were no significant differences (P≤0.05) in pH, swelling index, viscosity and gelation temperature of the flour blends while significant differences ‘(P≤0.05) existed in bulk density, water absorption capacity and wetability. There were significant differences (P≤0.05) in protein, fat, crude fibre, ash and carbohydrate for both flour blends and biscuit samples respectively. The addition of toasted watermelon seed meal increased protein, fat, crude fibre and ash contents while carbohydrate content decreased with higher substitution levels of wheat flour with the toasted watermelon seed meal. Moisture content ranged from 10-11 % (flour) and 6.25 -10% (biscuit). Significant differences (P≤0.05) were recorded in thickness, spread ratio and break strength within the samples. The result of sensory evaluation showed that W1 was significantly different (P≤0.05) in taste, aroma and overall acceptance. However, MW4 and MW5 were significantly different in texture, but in terms of crispiness, MW1 and MW3 were preferred. Moisture content of the preferred samples (MW1 and MW3) stored for 6 weeks increased from 6.25-11.75 % (MW1) and 6.75 – 11.0% (MW3) while the viable microbial counts ranged from 2.0 x 102-6.8 x 105cfu/g for bacteria and 1.8 x 101-7.4 x 103cfu/g for mould respectively.

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