Effects of Added Slow-Release Pelletized Edible Essential Oils on the Chemical Composition and Sensory Evaluation of Stored Cowpea Grains

Abstract

The study evaluated the effect of pelletized clove, West African black pepper (WABP) and ginger oils on chemical composition and sensory attributes of cowpea grains stored in jerry can and galvanized tins for duration a duration of 4 months. Each 100g of cowpea grains were treated with pelletized WABP, clove and ginger at four concentrations: 0.0 g (control), 0.50 g, 0.75 g, and 1.00 g. Chemical composition (proximate, minerals and anti-nutrient) of the treated cowpea with pelletized WABP and clove was analysed, Sensory attributes of boiled treated cowpea grains with WABP, clove and ginger were also assessed using a 9–point hedonic scale using a standard methods, Data were collected at the end of every 28 days. Sensory attributes of WABP oil treatments produced superior aroma (6.77%), taste (7.08%), and overall acceptability (7.30%) compared to clove oil and ginger treatment, cowpea grains treated with clove and WABP oils had significant (P<0.05) effect on moisture (14.52-15.25%), fiber (0.97– 2.18 %), carbohydrate content (61.65-65.04%) at end of 4 months of storage. Both oils improved zinc (4.04-4.79%), magnesium (4.03-4.79%) and phosphorus (4.24-4.57%) and reduced anti-nutritional factors: oxalate (0.15-0.20%), tannins (0.17-2.10%), trypsin (0.43-0.62%), saponnins (0.01-0.39%), phytate (0.01-0.11%) although phytate levels remained unchanged. Jerry cans were more effective than galvanized tins in maintaining lower moisture levels (14.61%) and higher carbohydrate content (63.73%). These findings showed that pelletized WABP at 0.25 enhance sensory appeal, clove at 1.00g, and WABP at 0.05g, 0.75g gave the best performance in terms of its effects on the proximate composition, enhanced minerals content, and played an important role in reducing anti-nutritional factors of the stored cowpea grains.