Influence of high pressure homogenisation on stability of emulsions containing skipjack roe protein hydrolysate

Abstract

Background/Objectives: Skipjack Roe Protein Hydrolysate (SRPH) can serve as the natural emulsifier. Nevertheless, homogenising conditions have also shown to determine the stability of emulsion. Thus, the aim of this study was to elucidate the impact of different homogenisation pressures on stability of emulsion containing SRPH. Methods/Statistical Analysis: Emulsions containing SRPH or sodium caseinate were prepared using varying homogenisation pressures (13.8, 20.7 and 27.6 MPa). During the 14 days of extended storage, emulsion samples were tested for particle size, flocculation factor, coalescence index, ζ-potential, creaming index, interfacial protein, confocal laser scanning microscopy and SDSPAGE of interfacial and unabsorbed proteins respectively. Findings: Higher homogenisation pressure resulted in the higher decrease in particle sizes as evidenced by the decreased volume frequency distribution (d43) (P < 0.05). The protein concentration at interface was increased with increasing homogenisation pressures (P < 0.05). Dominant interfacial proteins of SRPH stabilised emulsions had the molecular weight in the range of 7.0-16.4 kDa. During the extended storage, particle size, creaming index, flocculation factor (Ff) and coalescence index (Ci) of SRPH stabilised emulsions sharply increased, especially in emulsions prepared at 20.7 and 27.6 MPa (P < 0.05). Nevertheless, emulsions containing SRPH showed the lower stability, compared with those stabilised by sodium caseinate (P < 0.05). Applications/Improvements: The stability of emulsion stabilised by SRPH could be improved by homogenisation at an appropriate pressure (13.8 MPa).