Composition and functional properties of hemp seed protein isolates from various hemp cultivars

Abstract

Hemp seed protein isolates (HPI) were extracted from seven commercial hemp cultivars, a Cornell breeding line, and a commercial hemp heart product, and their composition and functional properties were investigated. HPI contained different ratios of edestin, vicilin, and albumin proteins, which affected protein solubility and functionality. Higher protein solubility was associated with cultivars that contained more vicilin and albumin, which influenced the subsequent functional properties of HPI. Significant differences in water holding capacity (0.83–1.05 g water/g protein isolate), oil holding capacity (1.28–1.81 g oil/g protein isolate), foam capacity (52.9%–84.9%), and foam stability (68.1%–89.4%) were observed across HPI. The Cornell hemp breeding line exhibited the highest protein solubility at pH 7.0 and was uniquely capable of forming an emulsion. The relationship identified between hemp seed protein composition and functionality, in conjunction with the demonstration of an on‐going hemp breeding line, suggest that continued, targeted development of hemp cultivars can improve its seed protein functional properties for ingredient utilization in plant‐based foods.

Proteomic Profiles of Whole Seeds, Hulls, and Dehulled Seeds of Two Industrial Hemp (Cannabis sativa L.) Cultivars

“…However, the protein bands in the four zones mentioned above have different intensities. The A-zone region, with the weakest staining intensity, should represent a 7S vicilin-like protein with an MW of 47–48 kDa, similarly reported by several studies [ 12 , 29 , 30 , 31 ]. The most intense protein bands are those in zones B and C, which represent acidic (MW 30–35 kDa) and basic (MW 18–20 kDa) polypeptides of the 11S protein (edestin) monomer.…”

“…Uso-31) or 1.61% (cv. Santhica 27), which is lower than the values published by other authors: Sun et al [ 4 ] reported 13%, and Liu et al [ 29 ] reported a range of 12–24% within a set of nine cultivars (here again, the values are proportions of storage proteins). The predominance of 2S albumins in the hulls or dehulled seeds is not at all clear.…”

“…The protein items A0A7J6H2R3, A0A7J6GLH5, A0A7J6HAT3, and A0A7J6G321, which could be classified as 7S proteins or vicilin-like proteins, represent about 3% of the seed protein pool in whole seeds of both cultivars, which is significantly less than that reported by other authors: Sun et al [ 4 ] reported 5% and Liu et al [ 29 ] reported a range of 9–19% (but here, as mentioned above, it is the proportion of storage proteins). In contrast to the 11S proteins, the relative abundance of 7S proteins was inconclusively higher in the hulls than in the dehulled seeds in all cases (see Table 3 ).…”

“…The D zone proteins (MW 15 kDa and less) should represent the albumin fraction of the protein. The presence of edestin and the albumin fraction in SDS-PAGE gels has also been described by Liu et al [ 29 ], Liu et al [ 30 ], and Fang et al [ 32 ].…”

“…The relative abundance of 11S globulins (summed over the three MP88 items) in whole seeds was 58.6 and 63.2% for the Santhica 27 and Uso-31 cultivars, respectively, when expressed as percentages, approximately corresponding to the literature-reported range of 60–80% [ 2 , 14 ]. Liu et al [ 29 ] reported a range of relative edestin proportions of 57–76% when studying nine protein isolates prepared from seeds of different Cannabis sativa cultivars/genotypes, but this is the relative representation of edestin among the storage proteins (11S, 7S, and 2S), not the representation of edestin in the overall protein profile of hemp seeds. All three 11S protein items (A0A7J6GWL5, A0A7J6DTA7, A0A7J6E205) of the MP88 set were found to have a conclusively (except in one case) higher relative abundance in hulled seeds than in hulls.…”