Document Type : Research Paper
Abstract
In this article, the influence of temperature and roasting time on the oxidation and Color of pistachio oil was investigated. Roasting is one of the most important steps in pistachio processing, so optimization and modification of this process and also improvement of product quality are of high priority. In this study the process of pistachio roasting by hot air was investigated. The effects of different temperatures (120, 140, and 160°C) and times (20, 30, and 50 minutes) on the color and oxidation variation of roasted pistachio were evaluated. Qualitative tests relating to changes of color indexes include measurement of L, a, b, the general changes in color, the angle of the hue, the browning index and the peroxide index. The outcome of analysis of variance (ANOVA) showed that for all responses, there was a significant statistical difference between experiments. With increasing temperature and roasting time, all color indices changed; significant changes in the color of the final product is not desirable from the consumer's point of view. As temperature increased, the process of changing the color, including browning, became faster which indicated browning during roasting. Increasing time and temperature also increased the pistachio peroxide index which indicated fat oxidation in higher temperatures.
Keywords
Main Subjects
The Effect of Different Temperatures of Roasting in the Color and Oxidation of Pistachio Oil and Their Kinetics
E. dehdashti, M. Hojjatoleslamy*, A. Shaker Ardakan, N. Jahanbakhshian
* Corresponding Author: Associate Professor, Department of food science and technology, Islamic Azad University, Shahrekord Branch, Shahrekord, Iran. Email: mohojjat@gmail.com.
Received: 5 May 2018, Accepted: 7 February 2020
Abstract
In this article, the influence of temperature and roasting time on the oxidation and Color of pistachio oil was investigated. Roasting is one of the most important steps in pistachio processing, so optimization and modification of this process and also improvement of product quality are of high priority. In this study the process of pistachio roasting by hot air was investigated. The effects of different temperatures (120, 140, and 160°C) and times (20, 30, and 50 minutes) on the color and oxidation variation of roasted pistachio were evaluated. Qualitative tests relating to changes of color indexes include measurement of L, a, b, the general changes in color, the angle of the hue, the browning index and the peroxide index. The outcome of analysis of variance (ANOVA) showed that for all responses, there was a significant statistical difference between experiments. With increasing temperature and roasting time, all color indices changed; significant changes in the color of the final product is not desirable from the consumer's point of view. As temperature increased, the process of changing the color, including browning, became faster which indicated browning during roasting. Increasing time and temperature also increased the pistachio peroxide index which indicated fat oxidation in higher temperatures.
Keyword: Color index; Oxidation; Peroxide; Pistachio; Roasting
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