THERMAL ANALYSIS OF ISOTHERMAL CRYSTALLIZATION KINETICS OF MILK FAT ENRICHED WITH GAMMA-LINOLENIC ACID | ||||
| Journal of Food and Dairy Sciences | ||||
| Article 10, Volume 34, Issue 7, July 2009, Page 7809-7816 PDF (698.2 K) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/jfds.2009.115381 | ||||
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| Author | ||||
| A. E. Fatouh* | ||||
| Food Science Department, College of Agriculture, Ain Shams University, Shoubra El-Khamia, Cairo, Egypt. | ||||
| Abstract | ||||
| Kinetics of isothermal crystallization of butter oil (BO) and interesterified butter oil (IEBO) with gamma-linolenic acid (GLA; C18:3 ω-6) at 10 °C were evaluated by applying Avrami equation. Differential Scanning Calorimeter (DSC) analysis of Avrami parameters revealed significant differences (P < 0.05) between BO and IEBO samples obtained at 1, 8, and 24 h of interesterification. Results of crystallization rate constant (k), Avrami exponent (n), and half-time of crystallization (t1/2) indicated different crystallization mechanisms for BO and IEBO samples. BO illustrated the lowest (P < 0.05) induction time of nucleation with a value of 8.93 min corresponding to its high peak melting temperature (Tp < /sub>) of 30.54 °C which was converse to IEBO samples. The results were ascribed to alteration (P < 0.05) of fatty acids (FAs) composition of IEBO occurred by lipase-catalyzed acidolysis of BO and GLA. | ||||
| Keywords | ||||
| Avrami equation; milk fat; crystallization kinetics; gamma-linolenic acid; interesterification | ||||
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