A pilot-scale process for the extraction of raffinose-oligosaccharides from pulse protein concentrates

Pulse protein concentrates have gained popularity in recent years as part of a shift towards more sustainable food production. Their production via dry fractionation is well-established and leads to a protein ingredient that is, however, rich in raffinose family oligosaccharides (RFOs). These can cause gut discomfort (especially in sensitive individuals) yet might also serve as a potential valuable substrate to promote growth of beneficial gut bacteria and alternatively as feedstock for biotechnological applications. By using a process including mildly acidic extraction, separation and sequential filtration, a carbohydrate fraction containing 48 % dm and 26 % dm RFOs was isolated from peas and faba beans, respectively. Simultaneously, a fraction with elevated protein concentration (5–6 % increase compared to the starting material) and only minor changes in amino acid composition was produced that could be texturized by extrusion, like the starting material. This process could serve ingredient manufacturers that seek to reduce RFOs in protein concentrates or to produce RFOs for biotechnological or chemical conversion towards new products. It also has the potential to reduce the amount of acid and base compared to protein isolate production through wet fractionation. Furthermore, the whole process was performed with industrially relevant and scalable equipment. • Raffinose Family Oligosaccharides (RFOs) were extracted from pulses with pilot-scale equipment. • Carbohydrate extracts contained up to 50 % RFOs, representing 10 % of starting material. • RFO content of the protein was reduced by >75 % in faba bean and > 90 % in pea. • Protein content was increased by 5 % in the protein fractions. • Proteins remained functional in low-moisture extrusion.