Rheological Properties of Green and Gold Kiwifruit Purees at Different Temperatures

Abstract

A study was conducted to determine the rheological properties of green and gold kiwifruit purees with total soluble solids of 16 to 17 °Brix at different temperatures (25, 35 and 45 °C). The rheological properties of the samples were determined using a rotational rheometer at a shear range of 32 to 4835 s -1. The green and gold kiwifruit purees were found to be Non-Newtonian fluids following the Herschel-Bulkley model. The yield stress and consistency coefficient of the green kiwifruit puree at different temperatures were higher than those of the gold kiwifruit purees but the opposite was observed for the flow behavior index. Moreover, all rheological properties of the green and gold kiwifruit purees decreased with increasing temperature. The consistency coefficient was related to temperature using an Arrhenius-type relationship. The gold kiwifruit puree (8.96 kJ/mol) has higher activation energy than the green kiwifruit puree (5.82 kJ/mol). The yield stress values of the green and gold kiwifruit purees can be related to temperature by linear regression equations and the flow behavior index values by exponential regression equations.

Rheological properties of thermally or non‐thermally treated juice/nectar/puree: A review

“…Some mathematical models (Newtonian, Power‐Law, Herschel‐Bulkey, and Bingham) describe the flow behavior of liquids by using shear stress and sheat rate as parameters. Between them, Herschel‐Bulkey was considered the best fit model to describe the flow behavior of juice, followed by Power‐Law and Bingham (Diamante et al, 2016). It was indicated that the flow behavior of concentrated mandarin juice within the temperatures −12 and 6°C was described by power‐law model, and the juice behaves like viscoelastic material (Falguera et al, 2010).…”