Heat-induced hollow microcapsule formation using fava bean legumin

This study evaluated the effects of extrinsic factors on the formation of hollow microcapsules (HMs) using fava bean legumin. It was found that the ability of HM formation was highly dependent on NaCl concentration, heating temperature and pH value, where the optimum conditions were 0.05 M NaCl, temperature close to 80 °C and pH 7.17. The protein concentration in the range of 2–10 g/L had minimal influence on the ability of HM formation, while higher protein concentration contributed to form more HMs. The size of the majority of particles allocated within a fine micrometer size range of 1–10 μm and the hollow internal structure exhibited either one vacuole or multi-vacuoles. Formation of NaCl-induced relatively stable, small protein micro-domains could be regard as a precursor of the subsequent HM formation via heating, and the hollow structure could be induced by a balance of partial dispersion of proteins from the clusters to the aqueous phase and formation of permanent linking between the remaining proteins.