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Optimisation of a baking procedure for incorporation of a microencapsulated high fat powder into wheat
bread in comparison to a vegetable shortening using experimental design. C. M. O'BRIEN (1), D. P.
Neville (2), M. K. Keogh (2), and E. K. Arendt (1). (1) Department of Food Science and Technology,
University College Cork, Ireland; (2) Teagasc, Dairy Products Research Centre, Moorepark, Fermoy, Co.
Cork, Ireland.
Response surface methodology was used to examine the effects of five
input variables on the performance of a microencapsulated high fat powder and a commercial shortening in
wheat bread. Two separate central composite designs were used and the results were compared. The input
variables selected for both designs were water addition (WA), mix time (MT), rest time (RT), proof time
(PT) and the level of fat (FL) or powder (PL) added. The response variables selected to evaluate the effects
of the high fat powder and the shortening were loaf volume yield (VY), bake loss (BL), crumb hardness
(CH) and crumb chewiness (CC). The effects on image characteristics such as total cell area and total
number of cells were also evaluated using an in-house image analysis system. WA and MT were found to be
the primary and secondary influences on VY, BL, CH and CC for the loaves containing the shortening, but
WA and PL were found to be the primary and secondary influences on VY, BL, CH and CC for the loaves
containing the high fat powder. Loaf VY did not vary significantly between the two designs, however
significant differences (P < 0.05) were found for BL, CH and CC. Significant differences (P < 0.001) were
also detected for total cell area and total number of cells for loaves containing the high fat powder and the
shortening.
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