Neutrons and Food 8 at MLZ

In recent decades, the utilization of sustainable protein sources has become a major focus of food research. Within the field of plant-based proteins, green biomass proteins are attracting increasing interest. Alfalfa (Medicago sativa L.) represents a promising regional biomass source, yielding large amounts of protein-rich material [1].

However, the isolation of pure and functional protein fractions from green biomass remains challenging due to rigid cell walls and secondary metabolites [2]. To access the white protein fraction, rich in ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCo), different isolation protocols were evaluated [3,4]. Two promising approaches, developed at Aarhus University were selected. One protocol is based on acid precipitation followed by washing and microfiltration, whereas the second protocol relies on ultrafiltration.

The resulting protein concentrates were analyzed with respect to their techno-functional properties using neutron-based techniques. Small angle neutron scattering (SANS) revealed pronounced differences in structural properties between the two concentrates. The ultrafiltrated protein concentrate showed higher solubility and higher RuBisCo purity than the acid-precipitated and microfiltered concentrate.
These structural differences directly influenced techno-functional characteristics, particularly protein behavior at oil/water interface.
Protein samples were kindly provided by Trine Dalsgaard and colleagues (Aarhus University).