EFFECT OF ROASTING TEMPERATURE ON THE NUTRITIONAL AND SENSORY PROPERITIES OF GROUNDNUT PASTE
Abstract
ABSTRACT
This study investigated the effect of roasting temperature on the nutritional, antioxidant, and sensory properties of groundnut paste, aiming to identify conditions that optimize quality and consumer acceptability. The objectives were to determine the impact of roasting temperatures (120°C, 150°C, 180°C and 200°C) on proximate composition (protein, fat, moisture, and ash), assess the influence of roasting on vitamin E (tocopherol) content and fatty acid profile, evaluate sensory attributes (colour, taste, aroma, and texture), and identify the optimal roasting temperature for maximizing nutritional retention and overall acceptability. Groundnut samples were roasted for 15 minutes at the specified temperatures and analyzed for proximate composition, antioxidant activity, and sensory characteristics. Results showed significant differences (p < 0.05) in moisture, ash, fat, fibre, carbohydrate, and sensory attributes with roasting temperature. Moisture decreased significantly with increasing temperature, reaching the lowest value at 180°C (0.11%), while ash and fibre increased steadily, peaking at 1.54% and 3.74%, respectively, at 200°C. Fat content was highest at 180°C (49.52%) and declined significantly at 200°C (41.75%), whereas protein remained relatively stable (38.55–39.20%). Antioxidant activity showed no significant difference (p > 0.05), ranging from 0.93 to 0.94, indicating stable tocopherol and fatty acid content across temperatures. Sensory evaluation revealed significant differences (p < 0.05) in appearance, colour, mouthfeel, and overall acceptability, with the sample roasted at 180°C receiving the highest ratings for most attributes, including appearance and colour (7.65 ± 0.93) and overall acceptability (7.15 ± 1.04). It was therefore revealed that 180°C for 15 minutes is the optimal condition that provides the best combination of nutrient retention, antioxidant stability, and consumer-preferred sensory qualities.
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