Water sorption isotherms of fried yam chips were determined using a static gravimetric method with saturated salt solutions in the range of water activity between 0.22 and 0.85 at 293, 303 and 313K. Four sorption models namely GAB, Peleg, modified Mizrahi, and BET were fitted with the sorption data generated. The GAB model followed by Peleg and modified Mizrahi models were found to best represent the experimental data in the a w range of 0.22-0.85. However, the BET model was more applicable between a w range of 0.22-0.55. The adsorption isotherm of fried yam chips clearly showed the influence of temperature, decreasing the moisture content at a fixed water activity value with higher temperature. The net isosteric heats of sorption of water were estimated by applying the Clausius-clapeyron equation to the adsorption isotherms at different temperatures. The net isosteric heat of sorption was observed to be decreasing as moisture content increases. Samples stored in desiccators of 0.44 and 0.55 a w at 303 and 313K, respectively, were rated higher in terms of textural properties investigated.

A simplex centroid mixture design (SCMD) was used to optimize ingredient combination comprising cassava starch (CS), high quality cassava flour (HQCF) and fish flour (FF) in the production of cassava-fish crackers. The standard slurry method was used and the effect of ingredient combination on some quality attributes of the crackers fried at 180 8C 6 5 8C for 15 s was investigated.Ingredient combination has a significant positive effect on oil and moisture contents, texture but expanded less. Increase in CS and FF resulted in decrease oil uptake while it increases with HQCF.Lightness decreased with increase in FF while redness and yellowness increases. Regression analyses indicated that the quadratic, cubic as well as special cubic nonlinear terms were significant (p < 0.05) in many of the models derived. Optimum ingredient mixture resulting in lower oil content and breaking force with maximum expansion and desirable physico-chemical properties was 85% CS, 10%HQCF and 5% FF. Practical applicationsThis work provides valuable information on deep fat frying of cassava-fish crackers using different levels of CS, HQCF and FF which are appreciated in many countries due to its pleasant sensory characteristics. The technique used is cost effective and produces fried cassava-fish crackers of relatively good quality. This study could be used by small and medium scale food processors that are interested in producing cassava-fish crackers of good quality due to availability of relatively cheap ingredients. The understanding of the influence of ingredient combinations on quality parameters is useful for deciding the appropriate level of each for an acceptable product. Predictive models generated can also be a viable tool for predicting product attributes as a function of the independent variables as well as designing of the frying process.

Plant-based proteins have shown great potential as an alternative substitute for animal proteins to meet the increasing global demand. Nevertheless, several limitations mitigate plant-based protein application and utilization. As a panacea to meeting the market demand, it is imperative to modify plant-based proteins to produce improved quality and technofunctionalities compared to conventional animal protein ingredients. Enzymatic, chemical, and physical modi cations have been used for plant-based proteins, which has shown exciting results in improving their techno-functional properties, digestibility, and inherent allergenicity. Among these modi cation methods, the low cost, limited time, high sensitivity, and high reproducibility give enzymatic modi cation leverage over chemical and physical methods. This review gave a concise summary of the advantages and disadvantages of enzymatic modi cations. The e cacy of enzymatic modi cation in producing protein ingredients from plant sources with improved techno-functional properties, digestibility, and alleviated allergenicity was discussed. Furthermore, the application of enzymatic modi cation in the production of bioactive compounds with health-bene cial properties adds in no small measure to the novelty of this review.

Complementary food produced from fermented maize and sprouted velvet bean flour in ratios 90:10, 80:20, 70:30, 60:40, 50:50 and 100% maize (control) was studied in this research work. Proximate composition, anti-nutritional and sensory properties of the blends was evaluated using standard analytical methods. Results showed that moisture (5.49% - 8.35%), ash (0.55% - 1.25%), crude fiber (3.50% - 4.98%), protein (8.05 -13.05%) increased with increased velvet bean flour while carbohydrate content decreased (77.37% - 63.48%). Phytate (2.11 - 2.34 mg/100 g) and oxalate (0.40–10.1 mg/100 g) are within lethal doses. The colour, taste, and mouth-feel of the sample with 10% velvet bean flours were significantly (p<0.05) being the most acceptable by the assessors. This study showed that protein-energy malnutrition in developing nations could be alleviated with complementary foods.

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