Characterization of coconut oil flow behavior

Blending is widely used for modification of the physicochemical properties of fats to enhance their commercial applications. This paper studied the flow behavior of coconut oil (NHCO) under variation in the temperature and proportion of fully hydrogenated coconut oil (FHCO). The oscillatory results showed that there is a change in the linear viscoelastic region, storage (G') and loss (G'') moduli with increasing proportion of FHCO in NHCO. In rotational tests, the blends showed shearthinning behavior. The viscosity of oils and their blends were investigated at different temperatures. The Herschel-Bulkley model was fitted to flow curves (shear stress in function of shear rate) of the samples. During heating, NHCO approached Newtonian behavior earlier than FHCO, because of their loosely-packed structure. Thus it indicated that the fatty acid composition affects these behaviors of the oil. The blending of fully hydrogenated coconut fat improved the elastic and textural character of the coconut oil.

Effect of high hydrostatic pressure at 400 MPa on quality attributes of liquid egg products

Samples prepared from liquid egg yolk (LEY), liquid egg white (LEW) and liquid whole egg (LWE) were processed by high hydrostatic pressure (HHP) using different holding times (60, 180, 300, 420 and 600 s). The aim of our experiment was to examine how different holding times influences technofunctional attributes of liquid egg products. The color of samples changed after 60 s HHP treatment, but visible changes were evaluated just after 180­ 300 s. The pH of samples was stable, there were no significant changes caused by HHP (one-way ANOVA, a=0,05). The apparent viscosity was measured by a rotational viscometer as a function of shear rate. The shearthinning behavior of LEY and pseudopastic behavior of LEW and LWE were fitted well into HerschelBulkley model (with a satisfying correlation of R2 > 0.96). For the selected shearing rate, viscosity was measured in relation to shearing time. Thixotropic behavior of samples was increased by longer holding time of HHP treatments.