Journal of Experimental Agriculture International

There is a growing need for sustainable plant-based protein sources; therefore, research has been conducted to investigate nutritionally rich pseudocereals such as buckwheat as alternative protein sources. The effects of pH and time during the extraction process on the recovery and functional properties of buckwheat protein concentrate (BPC) were evaluated. Alkaline extraction followed by isoelectric precipitation was used for the preparation of BPC. Protein from buckwheat flour was extracted at pH levels of 8, 10, and 12 for extraction periods of 1, 2, and 3 h. The protein concentrates obtained were analysed for protein content, extraction yield, and protein recovery. Functional characteristics were then evaluated in terms of nitrogen solubility, water-holding capacity (WHC), and fat absorption capacity (FAC). Protein content ranged from 67.17 to 71.89%, while extraction yield and protein recovery increased significantly with increasing extraction pH and time. At pH 8 for 3 h, the highest protein content was recorded (71.89%), whereas the highest extraction yield (10.33%) and protein recovery (57.47%) were obtained at pH 12 for 3 h. However, extraction at pH 10 for 3 h resulted in a protein content of 71.14%, an extraction yield of 8.45%, and protein recovery of 48.30%, indicating suitable conditions for protein extraction. Nitrogen solubility was highly pH-dependent; BPC obtained at pH 10 for 3 h showed the maximum solubility at pH 7 (69%) and pH 9 (90%). WHC ranged from approximately 3.3 to 3.5 g/g, with the highest value recorded for the concentrate prepared at pH 10 for 3 h, whereas FAC showed relatively little variation (2.87-2.91 g/g) among the samples. Considering protein concentration, extraction yield, protein recovery, and functional properties, pH 10 for 3 h was selected as a suitable extraction condition, providing 71.14% protein content, 8.45% yield, and 48.30% protein recovery. Although pH 12 for 3 h produced the maximum protein recovery, pH 10 for 3 h offered an acceptable balance among protein concentration, yield, recovery, and functional properties. Therefore, alkaline extraction of buckwheat protein at pH 10 for 3 h was identified as a suitable condition for preparing a protein-rich buckwheat protein concentrate with favourable functional properties.