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Title:Improved stabilization of 2-acetyl-1-pyrroline zinc chloride complex using spray chilling encapsulation and its practical application in foods
Author(s):Yin, Yun
Director of Research:Cadwallader, Keith R.
Doctoral Committee Chair(s):Feng, Hao
Doctoral Committee Member(s):Lee, Youngsoo; Bohn, Dawn
Department / Program:Food Science & Human Nutrition
Discipline:Food Science & Human Nutrition
Degree Granting Institution:University of Illinois at Urbana-Champaign
Zinc chloride complex
Spray chilling
Abstract:2-Acetyl-1-pyrroline (2AP) is an important and characteristic odorant in aromatic rice and a multitude of other foods. Despite its desirable aroma attributes, the great instability of 2AP has hindered its widespread commercial use by the flavor industry. Various approaches have been attempted to increase its stability; however, none of them showed potential for real applications in foods. Our lab pioneered a stabilization method whereby 2AP is complexed with a zinc halide. This complexed form of 2AP maintains excellent stability under anhydrous conditions. However, it degrades rapidly when moisture is present. The overall objective of this study was to improve the stability of 2AP zinc halide complex by use of spray-chilling encapsulation, and to demonstrate the practical application of the stabilized microcapsules as flavoring agents in foods. First, the use of 2AP-ZnCl2 complex itself as a flavoring agent in instant rice was evaluated and high flavor recovery of 2AP (92%) was found in the final product. Secondly, the feasibility of encapsulating 2AP-ZnCl2 by a modified spray-chilling encapsulation process using paraffin wax (octacosane) was achieved. The physical properties of the microcapsules were measured by scanning electron microscopy (SEM) and X-ray micro-computed tomography (CT). The microcapsules were shown to have matrix type structure and possess other preferred characteristics. The chemical properties were measured by gas chromatography (GC) and by absorbance spectroscopy, whereby the 2AP retention after spray chilling process was shown to be 65.26%. Additionally, the 2AP stability in both microcapsule and unprotected complex forms were monitored under ambient temperature (at 0%, 22.5%, or 43.2% relative humidity) conditions for more than three months. The results demonstrated significantly enhanced stability in the microcapsule form under all storage conditions. Finally, the controlled release and flavoring properties of the 2AP-ZnCl2 microcapsules were verified by full flavor recovery after cooking in instant rice. The results showed that the loss of 2AP in microcapsule form during cooking was negligible (not statistically significant). Overall, the aims of the study were achieved and the application of the 2AP-ZnCl2 microcapsules as a flavoring agent in foods was examined to be feasible.
Issue Date:2017-06-26
Rights Information:Copyright 2017 Yun Yin
Date Available in IDEALS:2017-09-29
Date Deposited:2017-08

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