Preparation of protein concentrate from quinoa seeds and study of its chemical composition and functional properties

Abstract

The study included preparing a protein concentrate from quinoa seeds, studying its chemical composition and comparing it with whole and defatted seeds. Chemically, there were significant differences between each of the whole seed powder, the seeds removed from the fat, and the protein concentrate in terms of the percentage of protein, and the protein center recorded the highest protein percentage, amounting to 38%. While the defatted seeds contained the highest percentage of ash, amounting to 2.6% compared to the whole seeds and the protein concentrate. The results indicated that the highest percentage of moisture, fat and carbohydrates were in the whole seeds compared to the seeds removed from the fat and the protein concentrate, while the seeds removed from the fat recorded the highest percentage of fiber 5.2% compared to the seeds removed from the fat and the protein concentrate which recorded the lowest percentage of fiber 2.0%. The results showed the functional properties, which included the ability to hold water and bind the fat for each of the whole and defatted seed powder and the protein concentrate at different pH numbers, including pH (12, 7, 4). The protein concentrator  gave the highest ability to hold water at pH 7, followed by the defatted seeds, while whole seeds recorded the least ability to hold water. As for the ability to bind fat, the protein center also recorded the highest ability to bind fat at pH 4, followed by the defatted seeds, while the powder was recorded. Whole seeds are less amenable to attachment. The results of the ability to form foam indicated the superiority of the protein concentrate, which gave the highest ability to form at pH 12 followed by the defatted seeds, while the whole seed powder recorded the least ability to form foam. As for the stability of the foam after 15, 30, 60 minutes, the results indicated the superiority of the seeds. Defatted at pH 12 by giving it the best foam stability after 60 minutes, followed by protein concentrate and then whole seed powder at the same pH. As for the results of the capacity and stability of the emulsion, it indicated the superiority of the protein concentrate by giving it the best emulsification ability and at pH 12 and the best stability of the emulsion, followed by defatted seeds, while the whole seed powder recorded less emulsifiability and less stability of the emulsion.