Optimisation of Composite Cassava–Yam Gari, Packaging Material, Storage Stability, and Techno-Economic Analysis of Optimised Product

Abstract

Incorporating D.praehensilis into cassava gari could improve the nutritional profile of cassava-yam composite gari. This study investigated the effects of yam quantity (X1), fermentation duration (X2), and roasting temperature (X3) on the physico-nutritional qualities of the cassava-yam composite gari and then evaluated the effects of packaging materials and storage conditions on the quality attributes. A three-factor three-level response surface methodology (RSM) was used for the optimisation study while the storage study was done using 32×3 factorial. Interestingly, an increase in yam quantity, fermentation duration, and roasting temperature resulted in a significant increase in the beta-carotene content. The iron and zinc contents of the cassava-yam composite gari increased significantly when the yam quantity was increased. Swelling capacity was reduced by yam quantity however, the roasting temperature increased the swelling capacity significantly to 3.40. Yam quantity reduced the flavour, taste, texture, and overall acceptability but was positively influenced by fermentation. Roasting temperature affected the brownness more than the other processing variables. All sensory attributes, L*, beta carotene, and swelling capacity were reduced under all packaging materials and storage conditions. However, the reduction was significantly higher under polyethylene (PE) packaging material at 32.22 ± 3.34⁰C. The brownness (a*) increased in PE, polyethylene/ polyethylene terephthalate (PE/PET), and polyethylene/polyethylene terephthalate/aluminium (PE/PET/ AL) packaging materials but the increase was significantly higher in PE under open market (OM) condition at 32.22 ± 3.34⁰C. PE/PET and PE/PET/AL provided a strong barrier property against temperature (32.22 ± 3.34⁰C). Considering fixed and variable costs, producing a tonne of the optimised gari yielded profit.