Acrylamide content and color formation of hazelnuts roasted at different processing temperatures and times

Abstract

The acrylamide content and color formation (CIE L*, a* and b*) of hazelnuts which processed at different roasting temperatures of 130 °C, 150 °C, 160 °C and 170 °C with roasting time for 15 and 30 min were evaluated. Acrylamide contents of roasted hazelnuts were measured by means of Ultra Performance Liquid Chromatography (UPLC). Acrylamide formation of roasted hazelnuts was undetectable and stayed under the instrument detection level in all treatments with an exception. The only acrylamide formation was detected in treatment of the highest heat (170 °C) and longest time (30 min) with the value of 19 ± 2.5 μg/kg which was just below the instrument’s detection limit of 20 μg/kg. Color analyses were performed using computer-aided image processing technology (CIE L*a*b*). The Euclidean distance (ΔE) and Browning index (BI) were calculated. Color L* values which show brightness and the degree of roasting ranged from 55.14 to 76.16. The lowest color L* values were calculated from the treatment that detected acrylamide. The color L* values, therefore, may be useable as a quick quality control parameter to estimate the sufficient roasting time and temperature in roasting process of hazelnuts. The roasting temperature at 170 °C and time for 30 min may be accepted as threshold values to avoid acrylamide formation in roasting process of hazelnut according to findings of the present study.