The use of 3D-nonlinear regression analysis in mathematics modeling of colour change in roasted hazelnuts

Simsek A.

JOURNAL OF FOOD ENGINEERING, vol.78, no.4, pp.1361-1370, 2007 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 78 Issue: 4
  • Publication Date: 2007
  • Doi Number: 10.1016/j.jfoodeng.2006.01.008
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.1361-1370
  • Karadeniz Technical University Affiliated: No


In this research, round hazelnut cultivars (Fosa, Palaz and Tombul) harvested from the Ordu, Giresun and Trabzon regions in 2001 and 2002 were supplied by the Fiskobirlik Company. Changes in L, a and b values of hazelnut varieties during different roasting applications (125-165 degrees C 10-55 min) were used to determine the optimum conditions of the roasting process and develop mathematical equations. As a result of variance analysis, the effects of the roasting process, cultivars and measurement types on colour values (L, a and b) of hazelnuts were found to be statistically significant (p < 0.01). Values of a and b for hazelnut samples showed an increase while L decreased. The regression coefficients (R-2) which described the prediction models for the dependent variables ranged from 0.73 to 0.97. In addition, changes in colour values, particularly a and L values, gave high R-2 and the obtained three-dimensional (3D) nonlinear equations may be utilized to determine the optimum roasting degree based on time and temperature. (c) 2006 Elsevier Ltd. All rights reserved.