Effect of homogenizing pressure and sterilizing condition on quality of canned high fat coconut milk

Abstract

The effect of homogenizing pressure (15–27 MPa) and commercial sterilizing condition (109.3–121.1 °C under pressure of 5–15 psi) on the quality of canned high fat (30%) coconut milk was investigated. All heat-treated homogenized samples exhibited pseudoplastic behavior with flow behavior index ( n) between 0.719 and 0.971. At similar sterilizing condition, a decrease in n value and an increase in consistency index ( K) were observed for samples passing higher homogenizing pressures. A reduction in apparent viscosity was found for the homogenized samples undergoing higher sterilizing temperatures. For color determination, Hunter L/b values of homogenized coconut milk were greater than that for fresh sample and the values increased with increasing pressures. The reduction in L/b values was observed when the homogenized samples were subjected to heat treatment. Sterilizing at 121.1 °C for 60 min could provide an acceptable color comparing to fresh coconut milk while heating at lower temperature but for longer time permitted more browning reaction and resulted in an increase of b value. Overall, the results suggested that quality of canned high fat coconut milk in terms of rheological and optical properties was influenced by both homogenizing pressure and sterilizing condition.