Physicochemical and functional properties of 11S globulin from chan (Hyptis suaveolens L. poit) seeds

The 11S globulin is one of the most abundant and important storage proteins of the chan seed (Hs11S). Therefore, we investigated its physicochemical and functional properties. Studying parameters related to emulsifying properties, a critical micelle concentration (CMC) at 0.6 mg/mL and a surface activity until 55.5 mN/m were determined using a DuNouy tensiometer. Zeta potential revealed isoelectric points (pI) with a clear NaCl influence (without NaCl pI = 3.5, at 0.05 M NaCl pI = 3, at 0.5 M NaCl pI = 2.5) and electrostatic potential dependent upon the pH. The Hs11S was highly soluble at pH 7.6 (≥94.5%) with salt variations (0-0.4 M). The thermostability of Hs11S by dynamic light scattering showed that it organizes in oligomeric forms: trimer, tetramer, hexamer, octamer, dodecamer and aggregates. Oscillatory rheology studies indicate the onset for the heat-induced gelation of Hs11S which occurred around 74-76 °C, developing strong gels with an elasticity of ∼103 Pa, while a denaturation temperature of 94.1 °C and an enthalpy of 44.49 kJ/mol were found by differential scanning calorimetry. According to ΔHexpTm/ΔHvHTm and ΔT1/2 data, the Hs11S denaturation is not a cooperative process. Our results indicate that Hs11S might be used as potential thermostable ingredient in food systems.