Exploring operational parameters and key characteristics in extraction and purification of rubber tree (Hevea brasiliensis) seed protein using the hierarchical Osborne method and ultrafiltration technology

The present study investigated the fractionation and purification of protein fractions in rubber trees ( Hevea brasiliensis ) seed meal using a combination of the Osborne hierarchical extraction method and ultrafiltration membrane purification technology. The protein content of the meal was measured at 21.5 ± 1.3 g/100g. Analysis revealed the presence of 17 amino acids, including 7 essential amino acids. The predominant protein fractions identified were albumin (8.1 g/100g) and glutelin (16.2 g/100g). Following ultrafiltration purification, the protein fractions exhibited purity levels exceeding 90 g/100g. Molecular weight analysis indicated variability among the four protein fractions, with weights falling within the range of 10–55 kDa. Notably, the rubber seed albumin and globulin displayed higher molecular weights and compact structures compared to gliadin and glutelin, which exhibited larger and looser structures. These findings offer valuable insights into the extraction, purification, and potential utilization of rubber tree seed meal as a potential protein source in food or animal feed applications. Highlights • The main protein factions in rubber seed meal are albumin and glutelin. • Key rubber seed amino acids are glutamic acid, aspartic acid, and arginine. • The molecular weights of rubber seed protein fractions are 10–55 kDa. • Ultrafiltration treatment yielded protein fractions with over 90 g/100g purity. • Albumin and globulin are continuous, while gliadin and glutelin are cluster-like.