Nutritional Quality, Chemical, and Functional Characteristics of Hemp (Cannabis sativa ssp. sativa) Protein Isolate

(1) Background: Hemp seeds are a source of plant-based protein, making them an appropriate supplement to a plant-based diet. The current work was focused on the preparation of the protein isolate from the hemp seeds with eco-friendly and cheap technology. Moreover, it evaluated the physicochemical and functional properties of hemp protein isolate for its potential application in food manufacturing. (2) Methods: The protein content of hemp seeds has been isolated through two main steps: (1) extraction of the protein content of an alkaline pH (10-12); (2) precipitation of the extracted protein on an acidic pH as an isoelectric point (pH = 4.5). (3) Results: The edastin protein is the most predominant protein in the protein profile with a molecular weight of 58.1 KDa beside albumin with a molecular weight of 31.5 KDa. The FTIR spectrum detected the absorption peaks of the amide I at 1750 and 1600 cm(-1), which pointed to C=O stretching while N-H stretching at 1650-1580 cm(-1). The peak at 3250 is found to be related to N-H stretching of the aliphatic primary amine (3400-3300 cm(-1)) and the N-H stretching for the secondary (II) amine appeared at 3350-3310 cm(-1). The Hemp protein isolate (HPI) showed a high content of arginine (15.52 g/100 g), phenylalanine + tyrosine (9.63 g/100 g), methionine + cysteine (5.49 g/100 g), leucine + isoleucine (5.21 g/100 g), and valine (4.53 g/100 g). It contains a moderate level of threonine (3.29 g/100 g) and lysine (2.50 g/100 g) with tryptophan as the limiting amino acid (0.22 g/100 g). The HPI showed an appropriate water-and-oil holding capacity (4.5 +/- 2.95 and 2.33 +/- 1.88 mL/g, respectively). The foaming capacity of the HPI was increased with increasing the pH values to reach the maximum value at pH 11 (67.23 +/- 3.20%). The highest emulsion ability index of the HPI was noted at pH 9 (91.3 +/- 2.57 m(2)/g) with low stability (19.15 +/- 2.03). (4) Conclusions: A strong positive correlation (r = 0.623) was shown between protein concentration and solubility. The current easy-to-use, cheap, and eco-friendly technology provides the industrial sector with a cheap protein isolate for manufacturing protein-rich diet and beverages. The HPI showed a good nutritional quality and functional properties that might be helpful in utilizing it in different food products such as beverages and bakery products.

Automated summary

The study focuses on the preparation of hemp protein isolate using eco-friendly and cheap technology and evaluates its physicochemical and functional properties for potential applications in food manufacturing. The results show that the hemp protein isolate has good nutritional quality and functional properties, making it suitable for protein-rich diet and beverage production.