Effects of Process Parameters on Rheological Properties of Pepper and Tomatoes Purees

Abstract

Abstract This study investigated the effects of temperature, time, and moisture content on the rheological properties (apparent viscosity, flow behavior index, and consistency coefficient) of stored purees of pepper and tomato. The purees were prepared using the hot-break method to have moisture contents of 85%, 90%, and 95% (w/v) respectively. The rheological properties were determined at an interval of 2 days for 6 days of storage durations and at 5°C, 10°C, and 15°C temperatures. Results showed that the values of the apparent viscosity, consistency coefficient, and flow behavior index of tomato puree were in the range of 2519.9-4324.6 mPa S, 258.0-550.6 mPa Sn, and 1.80 − 0.48 respectively. Also, the values obtained from the pepper puree range as 2105.6–4562.0 mPa S, 268.4-580.4 mPa Sn, and 0.22–0.48 respectively. The values of the apparent viscosity, flow behavior index, and consistency coefficient of the purees vary significantly (p ≤ 0.05) with temperature and storage time. However, the moisture content has no significant (p < 0.05) effects on the rheological properties of the purees. In addition, the flow behavior and consistency coefficient of the purees were observed to vary relatively with the apparent viscosity. The purees exhibited pseudoplastic behavior as the flow behavior indices of both purees were between 0 and 1. The optimum conditions for the processing and storage of the purees were in the range 13.21–14.42°C, for 2 days, 92.22–94.23% (w/v) moisture content for pepper, and 8.42–11.77°C for 2–6 days, 85% (w/v) moisture for tomato.