This study evaluated the effects of storage on the quality characteristics of extruded snacks produced from yellow yam (Dioscorea cayenensis) and jackbean (Canavalia ensiformis) composite flour. Composite flour blends consisting of 94.11% yellow yam and 5.89% jackbean were extruded under the processing conditions of screw speeds of 100-110 rpm, barrel temperatures of 90-100?C, and feed moisture of 60-65%. The most acceptable extruded snack was filled in high-density polyethylene films and kept at ambient temperature (28 ? 2?C) for sixteen weeks. The storage effects were measured after two weeks intervals by establishing the change in the moisture content, the free fatty acid, colour properties, sensory and microbial quality. Results showed a gradual increase in moisture content (2.91-6.28%) and FFA (0.004-0.029 mg KOH/g) during storage, indicating limited lipid oxidation and hydrolytic activity. Lightness (L*) and redness (a*) decreased, while yellowness (b*) increased throughout storage, reflecting minor non-enzymatic browning and carotenoid stability. Sensory scores of appearance, texture, crispness, flavour and overall acceptability decreased during the storage period, although these scores remained acceptable during 6 weeks of storage period. Microbial counts remained within permissible limits, with minimal bacterial and fungal growth detected after 14 weeks. The study concludes that yellow yam-jackbean extruded snacks stored in HDPE packaging are microbiologically safe and retain acceptable quality for up to six weeks under ambient conditions.
Oke et al. (Thu,) studied this question.