Influence of roasting parameters on quality of 'Tonda Gentile delle Langhe' hazelnut for the processing industry.

摘要

The Piemonte Region (North-West Italy) has a long tradition of handicraft and industrial processing of sweets and cakes prepared with roasted hazelnuts and Venchi Ltd. is one of the main local companies. The aim of this study was the evaluation of the influence of roasting parameters on the final quality of roasted hazelnut kernels "Nocciole Piemonte IGP". The effects of the different temperatures on paste and chopped kernel colour was evaluated with two different instruments (colorimeter and scanner) to define the best technique for evaluation and the possible correlations between roasting temperatures and colorimetric results. Sensory analysis was conducted on roasted kernels. Comparing the characteristics of the nuts roasted at different temperatures, the samples roasted at lower temperatures have lower saturation values and consequently lighter colour. Comparing the results between scanner and colorimeter methods, a higher sensitivity in evaluating the color appears using the scanner. Indeed, for both paste and chopped kernels a larger range of values were found in comparison with the results calculated using the colorimeter. The evaluation of the sensory parameters was obtained with a trained panel. It was found that using "hazelnut odor" it was possible to significantly distinguish between samples. Furthermore, this parameter is positively correlated with appreciation, with aroma of hazelnut, softness, odor and aroma of caramel and intensity of sweet taste. The aroma of rank, as expected, is negatively correlated with the general judgment.