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Effects of Physicochemical Characteristics and Lipid Distribution in Algerian Durum Wheat Semolinas on the Technological Quality of Couscous

¹Département de Technologie des IAA, Institut National Agronomique, Hassan Badi, 16200 Alger, Algérie. ²Corresponding author. E-mail: ounaneg@yahoo.fr ³UMR Ingéniérie des Agropolymè reset Technologies Emergentes (IATE), 2 place Viala, 34060 Montpellier, Cedex 1, France. ⁴Département de Phytotechnie, Institut National Agronomique; Hassan Badi, 16200 Alger, Algérie.

Semolinas milled from 18 Algerian durum wheat cultivars cropped over a two-year period (1999-2000) were used for making couscous. This study was designed to determine the impact of lipid components of durum wheat semolina on the quality of the couscous end product. Lipids were extracted from semolina by various techniques and classified as free or bound lipids, polar or apolar lipids, and glycolipids or phospholipids. An analysis of the overall results clearly revealed that the cooking quality of couscous made from different durum wheat semolinas was partially dependent on the semolina free lipid content and composition. We have shown that this is mainly a varietal characteristic (53.4%). The surface state of the couscous, i.e., caking index (r = -0.48) and cooking loss (r = -0.54), thus depends on the apolar lipid content. Polar lipids, and especially glycolipids, affect couscous texture in terms of firmness (r = 0.57 and r = 0.63, respectively). Polar bound lipids also contribute to couscous swelling (r = 0.53) and caking index (r = 0.70). Moreover, we obtained no correlation between cooked couscous quality and the semolina total lipid content (r < 0.3). We also showed that couscous characteristics were not significantly related to the semolina protein and dry gluten contents or gluten index (r < 0.3).