ABSTRACT

The purpose of this research was to extend the shelf life and fortification of wheat using walnut (Tetracapium conophorum) and sour-sop (Annona muricata) flour for granola, chin-chin and stiff porridge in Nigeria. Twelve specific objectives were formulated. The study adopted research and development design. Four hypotheses guided the study. Walnut and sour-sop were processed into flour for the production of granola, chin-chin and stiff porridge at different ratios of 90:10%, 80:20%, 70:30%, 60:40% and 50:50% using wheat flour as a control. Functional and pasting properties of the flour blends were determined. Proximate composition, energy content, storage periods and acceptability index of the food products were determined. A 9 point hedonic scale was used. Results were analysed statistically by the analysis of variance and differences between the means were separated. Results for functional properties of wheat/walnut flour blends revealed that WGA 1.35g/g absorbed more moisture, WGF 0.77g/g absorbed more oil, WGF was high in bulk density 0.86g/g and least in solubility 11.36%. Results for pasting properties showed that WGA was high in all parameter except pasting temperature WWF 81.45RVU. There was significant differences (p>0.05) in all samples, WWE and WWF 5.87RVU were not significantly different (p>0.05). Results for proximate composition of wheat/walnut granola revealed that values increased in ash 1.70% for control, fat 15.63% WGF and protein 14.29% WGF. Results for proximate composition of chin-chin showed that moisture and carbohydrates reduced as level of substitution increased. This was due to the fat content of walnut flour. There were no significant differences (p>0.05) in WGA, WGB, WGC 35.08%. Results for stiff porridge revealed that at 50% level of substitution ash, fat, protein and fibre increased while carbohydrate reduced. Results for energy content of granola showed that WGE had 436.07Kcal/100g, chin-chin had WGE 420.33Kcal/100g and stiff porridge WGB 162.06Kcal/100g. Results for storage periods (mould and fungi counts) revealed that granola and chin-chin products had more counts in week four, stiff porridge had more counts for 12 hours of storage. At 50:50%, granola was most preferred for colour and texture, crispness, flavour and overall acceptability was recorded 70:30% in chin-chin, WSPD was preferred in overall acceptability. Results for functional properties of wheat/sour-sop flour showed SWF 1.23% absorbed more water, SWA 9.80% was high in swelling power. This was due the functional properties in sour-sop flour. Pasting properties results revealed that 100% had high values and least in 50:50% in parameters of peak, breakdown, final and peak time. Proximate composition of granola showed that ash had 1.43 in SWF; fibre had 1.53%, carbohydrate increased at 50:50% level of substitution. Results for proximate composition for chin-chin and stiff porridge revealed that at 50:50% levels of substitution moisture, ash, fat increased while crude fibre and carbohydrates reduced. There were significant differences (p<0.05). Energy contents results revealed that granola had 430.90Kcal/100g, chin-chin had 403.06Kcal/100g and stiff porridge 149Kcal/100g. Results for (moulds) storage periods had least count in week 2 and more in week 4, fungi had more counts in 12 hours. At 50:50%, granola was more preferred in SGF in aroma, chin-chin preferred in crispness and taste, stiff porridge had general acceptability in SSPF. Based on the findings, the study recommended that 50% of walnut and sour-sop can be substituted to fortify wheat flour based foods