期刊名称：Advance Journal of Food Science and Technology
印刷版ISSN：2042-4868
电子版ISSN：2042-4876
出版年度：2015
卷号：8
期号：6
页码：383-393
DOI：10.19026/ajfst.8.1531
出版社：MAXWELL Science Publication
摘要：The objective of this study was to monitor and model the texture changes of foxtail millet extrudates with different structural properties as a function of water activity ( a w). Four extrudates, after equilibrated at a w of 0.113-0.97, were compressed using a TA.XT2 Texture Analyzer. Two force-related texture parameters, Peak Force (PF) and Total Work (TW) and two jaggedness-related, Number of Spatial Ruptures (NSR) and Specific Ling Length (SLL), were extracted from their force-displacement curves. Water sorption led to loss of jaggedness of their force-displacement curves. All the four texture parameters decreased when a a w increased to a certain value. Before the decrease occurring, TW and PF increased for all the extrudates with a a w increase, while SLL increase was observed only for two extrudates and no NSR increase was observed for all extrudates. The critical water activity ( a wc) where texture parameters decreased rapidly ranged between 0.42 and 0.83 depending mainly on the kinds of the extrudates and to some extent on the texture parameters studied. The extrudates with coarse structure exhibited lower force-related values, while the extrudates with fine structure exhibited lower jaggedness-related values. Crispness index, a combination of force- and jaggedness-related texture criteria, decreased almost linearly as a a w increase up to 0.61~0.66 for all the extrudtes. The Peleg-Fermi equation can satisfactorily model the changes in jaggedness-related texture parameters as a function of a w. A modified form of the Peleg-Fermi equation, proposed in this study, was needed to model the changes of force-related parameters better.
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