Isolation and Characterization of Soluble Proteins from Moringa (Moringa Oleifera Lam) Seeds for Possible Use in Food Industries

Background: Proteins are crucial for the functional properties and sensory characteristics of foods. This study aims to isolate and characterize soluble proteins from Moringa oleifera seeds. Methods: The seeds were defatted using chloroform, methanol, and water (1:2:0.8). Protein isolates were prepared by aqueous extraction, 0.1M NaOH precipitation, and 60% (NH4)2SO4 precipitation. Moreover, proximate composition of the dry seeds, and the protein yield, physicochemical properties, functional properties, and amino acid composition of the isolates were determined using standard methods. Results: 100 g of dry seed contained 29.09±0.40 g proteins. The aqueous extract had the greatest protein content (73.0±0.5 g/100g), followed by NaOH (54.0±0.2 g/100g) and (NH4)2SO4 (45.0±0.3 g/100g). As a result, the aqueous extract showed a significantly (P<0.05) maximum in vitro digestibility (82.63±0.27g) after 6 hours. Strong UV absorption at 280 nm was recorded for all the protein isolates. All essential amino acids were present, and phenylalanine was the chief amino acid (8.93±0.67 mg/100g in (NH4)2SO4 fraction) which was significant at P<0.05. NaOH and (NH4)2SO4 fractions were most soluble at pH 10 which were significant at P<0.05. The NaOH fraction had the peak foaming capacity (28.0±0.4%) at pH 10, and the most stable foam was observed in the NaOH fraction after 10 minutes. Significantly (P<0.05) elevated in the (NH4)2SO4 fraction (32.0±0.6%), followed by aqueous extract (28.0±0.5%) at pH 10 was the emulsifying capacity. The (NH4)2SO4 fraction had significantly (P<0.05) more water-holding capacity (2.80±0.04 g/g); the prime oil-holding capacity was also observed in the aqueous extract (3.20±0.02 g/g). Conclusion: Moringa oleifera seeds possess essential amino acids and functional properties beneficial for food systems, potentially enhancing value or developing new products.