Nutritional Quality of <i>Nyam ngub, </i>Traditionally Textured Product Derived from Wild Orchid Tubers Eaten as Meat in the North West and Western Region of Cameroon

Abstract

The knowledge gaps in the nutritional composition and quality of traditionally textured plant-based products eaten as meat is affecting the global acceptance despite the acclaimed health, environmental, ethical, religious, and social benefits. This paper aimed to prepare and evaluate the nutritional quality of Nyam ngub for potential valorization and vulgarization. Standard methods were used to determine the chemical composition and to evaluate the quality of protein. Protein fractions were used to estimate the solubility and individual amino acids were analysed with rapid amino acid analyser. Nutrient bio accessibility was determined firstly by calculation through the phytate: mineral ratio for iron and while the simulated in-vitro gastrointestinal test evaluated the protein digestibility and mineral accessibility. Results indicated that nyam ngub had an ash content of 13.02±1.14g/g at a moisture content of 89.56±2.43% and dry matter of 12.86±0.30%. The reducing and total sugar content were 0.8±0.02 g/1000mL and 51.42±4.26 g/1000mL respectively yielding a moderate energy supply (67.26±0.72 Kcal/mol) compared to other tubers. The crude fibre, fat and protein were respectively 6.7±0.3 (g/100g), 3.07±0.42 (g/100g) and 6.03±0.15 (g/100g). The Calcium, iron, Zinc and Copper contents were 0.01±0.00 mg/100g, 1.60 g/100g, 0.25±0.04 mg/100g and 2.87±0.00 µg/g respectively while vitamin A after conversion from β- carotene was 1.65±0.77µgRE/g and vitamin C was 5.043±0.54 mg/100g. The albumin, globulin, prolamin, and glutelin fractions were 70.51±2.48, 65.93±1.44, 16.41±3.21 and 18.46±1.35 mgBSA/100g respectively. Iron and zinc were 57.32±0.58% and 51.73±0.23% accessible while protein had the greatest digestibility in the gastric phase (74.63%) compared to 70.15% in the intestines. The essential amino acids quantified in mg/ 100g were Arg (1.39), His (0.61), Leu (2.04), Lys (1.52) Met (0.59), Phe (1.40), and Thr (1.11). Despite the limited protein content and lack of some essential amino acids, the protein of nyam ngub was relatively soluble and available and the micronutrients are accessible.