Properties of an emulsion prepared from silk sericin and vitamin E

Abstract

An emulsion (SR-EM) was prepared from vitamin E and aqueous sericin solution obtained from cocoons of Bombyx mori. Properties such as emulsifying degree, heat stability and radical scavenging activity of SR-EM were compared with those of CS-EM and AL-EM, vitamin E emulsions prepared from casein and bovine serum albumin, respectively. The degree of emulsifying for SR-EM was three times higher than that for CS-EM. CS-EM and AL-EM were a heat-stable emulsion, whereas SR-EM was a heat-labile emulsion because absorbance spectra changed exclusively in SR-EM after treated from 115 to 127°C. These results indicated that the oil-water interface of SR-EM was unstable under the high pressure-high temperature treatments compared to those of CS-EM and AL-EM. Each emulsion showed lower radical scavenging activity than a vitamin E solution, suggesting that the interaction of vitamin E and a radical molecule may be interfered by a protective protein colloid. SR-EM and CS-EM were more stable in 60% ethanol solution at ambient temperature than AL-EM because the radical scavenging activity of SR-EM and CS-EM was some 50% lower than that of AL-EM.