The in vitro protein digestibility, microbiological quality and gelatinization behaviour of macaroni as affected by cowpea flour addition

Cowpeas were germinated, fermented, cooked, ground to flour and added to standard durum wheat semolina at 20% (w/w) level for macaroni production. Macaroni samples were analysed for in vitro protein digestibility, microbial count (total bacteria, mould and yeast) and gelatinization behaviour over a 6-month storage period at room temperature (<25 °C). Starch gelatinization behaviour of the samples was analysed using differential scanning calorimetry. Supplementing semolina with cowpea flour did not have a significant affect on in vitro protein digestibilities or aerobic plate counts of macaroni samples (p < 0.05). There was a small but significant increase in mold and yeast counts after 6 months of storage in cowpea treated samples. Two endothermic peaks were observed with significant differences in ΔH values of control and cowpea treated macaroni samples. The transition peak (Tp) temperatures were in the range of 66.9–67.9 and 86.9–100.4 °C for the first and second peaks, respectively. The transition enthalpies (ΔH) were in the range 2.41–4.21 and 1.71–3.86 J/g for the first and second peaks, respectively.