Physicochemical characteristics and storage stability of clarified butter fat « smen » produced from pasteurized and non-pasteurized milk

Document Type: Original Article

Authors

1 department of biologie, Laboratoire Analyses, Valorisation et Sécurité des Aliments (LAVASA), ENIS, BP 3038, Université de Sfax, Tunisia.

2 Laboratoire Analyses, Valorisation et Sécurité des Aliments (LAVASA), Ecole Nationale d’Ingénieurs de Sfax, Université de Sfax, Route de Soukra, 3038 Sfax, Tunisia.

Abstract

Smen is a milk fat isolated by ‘boiling-off’ water. Milk fat was first converted into butter and then into smen. Smen product is utilized for culinary cooking and frying of different food. Smen has better shelf-life than other indigenous dairy products due to its lower moisture content. However, it undergoes deterioration (lipolysis and oxidation of milk fat) causes flavor impairment, lowers nutritional quality and creates serious problems for storage stability. Objectives of this work were studying physicochemical characteristics and oxidative stability of clarified butter fat “smen” produced from non-pasteurized and pasteurized cow’s milk. A sensorial evaluation was applied to select more appreciate “smen” by consumers. An oxidative procedure was applied to test the stability of smen. Samples were kept in glass bottles and heated at 100°C. The resistance to oxidation of smen samples was studied by measuring Peroxide value (PV), Thiobarbituric acid (TBA), Free Fatty Acid (FFA), Specific absorptivity at 232 and 270 (K232 and K270) values and change in fatty acid composition, color, polyphenol contents and oxidation induction time in the Rancimat. Differences between the two clarified butter fat “smen” products are indicative for their comparison in terms of their thermal stability, consequently for their shelf-life determinations. Therefore, effect of processing methods and storage conditions were evaluated. When compared, smen produced from pasteurized milk has higher thermal stability than smen produced from non-pasteurized milk. All studies indicated that, smen produced from non-pasteurized cow’s milk was more prone to oxidation than smen produced from pasteurized cow’s milk. Regarding these specificities, the value of this product in food formulation may be justified.

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