Variations in nutrient composition and oil stability of oyster nuts (telfairia pedata) across different agro- climatic conditions in Northern Tanzania

Abstract

In sub-Saharan Africa, nutrient deficiency remains a challenge. The challenge is partly due to the underutilization of available nutrient sources and failure to optimize nutrients based on agroclimatic conditions. Oyster nuts (Telfairia pedata) are the under-utilized oilseeds with promising

food and non-food applications. This

study investigated oyster nut's nutrient composition and variations across different sites and elevation levels encompassing different agro-climatic conditions. Additionally, the stability of crude oyster nuts oil, flaxseed oil, and sunflower oil were compared. Fats were the most abundant contents of the nuts with 68%, followed by 25% protein, 5% carbohydrates, and 2% ash. Fatty acid contents were dominated by linoleic acid (47%), while magnesium was the most abundant mineral (150 mg/100 g). Protein and fat contents increased significantly with declining elevations, while sites did not show any significant effects. In contrast, linoleic acids and minerals such as magnesium (Mg) and phosphorus (P) of the nuts decreased significantly in low elevations. Other nutrients such as carbohydrates, potassium (K), palmitic acid, iron (Fe), and stearic acid in the nuts were not significantly affected by neither site nor elevations. Finally, oyster nut oil produced high peroxide value (PV) and free fatty acids (FFA) compared to flaxseed and sunflower oil at room temperature. Our results highlight that oyster nuts oil stability should be improved before storage. Likewise, in lower elevations associated with high temperature and low precipitation, oyster nuts' quality is optimized. Hence, oyster nuts can improve nutritional status and income generation to farmers and communities in Tanzania.