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Effects of Microencapsulated High-Fat Powders on the Empirical and Fundamental Rheological Properties of Wheat Flour Doughs

¹National Food Biotechnology Centre, National University of Ireland, Cork. ²Dept. Food Science and Technology, National University of Ireland, Cork. ³Teagasc, Dairy Products Research Centre, Moorepark, Femoy, Co. Cork. ⁴Electron Microscopy Unit, National University of Ireland, Cork. ⁵Corresponding author. E-mail: e.arendt@ucc.ie Phone: + 353-21-902064. Fax: + 353-21-276138.

Microencapsulated high-fat powders are a healthy and convenient alternative to fats normally used in cereal-based products. In powder form they are easier to use than block fat. Microencapsulation involves dispersion of the fat using homogenization. The globules are then fixed by spray-drying. Empirical and fundamental rheological tests were conducted on doughs containing commercial vegetable fat and four microencapsulated high-fat powders. The doughs were compared with a standard dough containing no fat. The powders contained 70% vegetable fat or milk fat. The encapsulating agent used was either sodium caseinate or whey protein concentrate (5–10%). Sucrose or lactose were also present in the powders (20–25%). The powders were manufactured at low- or high-pressure homogenization. Farinograph and extensigraph tests were performed on all doughs. Dynamic oscillation tests were conducted in the linear visco-elastic region of the dough. Addition of fat and microencapsulated high-fat powders produced using low-pressure homogenization reduced the complex modulus of the doughs. The results showed an increase in phase angle with incorporation of commercial fat and the microencapsulated high-fat powders. Scanning electron microscopy was conducted to examine the effects of the additives on dough structure. This study demonstrated that microencapsulated high-fat powders, especially powders produced using low-pressure homogenization, had some beneficial effects on dough rheology when compared with doughs produced with commercial fat.