The effect of ultra-high pressure homogenization (UHPH) and conventional heat treatments (HT) on physicochemical properties of almond beverage was studied. Almond beverage base product (BP) was produced by soaking and grinding Marcona almonds. The milky liquid obtained was pre-homogenized by using a vacuum rotor-stator system and afterwards homogenized with a high pressure homogenizer by applying 62, 103 and 172 MPa. In samples submitted to HT, 85 °C/30 min or 121 °C/15 min conditions were used prior to the homogenization step. Physicochemical characterization was carried out in BP and in samples submitted to HT and UHPH throughout the determination of the rheological behavior, color parameters, particle size distribution, ζ-potential and thermal analysis. Results showed that physicochemical properties of the product were severely modified by HT and also by UHPH in lesser extent. PB samples and those processed with the lowest homogenization pressure showed a bimodal and polydisperse distribution. Samples treated with the higher homogenization pressures (103 and 172 MPa) evidenced a significant reduction of particle size and clusters’ deflocculation, leading to a monodisperse distributions. The HT caused an increment of particle size due to coagulation phenomena, this effect being more intense when using higher temperatures. ζ-potential was especially lowered in samples submitted to both thermal and UHPH treatments, leading to lower electrically charged particles. Color differences between BP, UHPH and HT samples were found. Thermal treatments led to a notable decrease (p<0.05) in the luminosity of samples. Nevertheless, this negative effect was diminished when these samples were ultra-homogenized. BP showed a Newtonian behavior and UHPH and HT decreased the flow index parameter, thus showing a shear thinning behavior (n<1). The viscosity of the treated samples (HT or UHPH) increased, although the differences between BP and UHPH were low. The analysis of DSC thermograms from different samples revealed that the homogenization pressures used were not high enough to affect the denaturalization pattern of proteins.
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