26-3 |
Studies on the foaming character of sweet whey powders |
D. S. BANAVARA and S. A. Rankin. Dept. of Food Science, Univ. of Wisconsin, Madison, 1605 Linden Dr., 218 Babcock Hall, Madison, WI 53706-1519 Sweet whey powder (SWP) is a byproduct of cheese manufacturing and is valued as a nutritive additive with specific functional characteristics. SWP is not manufactured under a standard protocol resulting in a large degree of variability in product character and functional properties. Potential sources of SWP functional variation include raw milk quality, cheese type, extent of heat treatments, final whey composition, and storage conditions. However, little is known about the relationship of these sources of variation with specific functional properties such as foaming behavior. The objective of this work was to characterize the variability of foaming properties amongst commercially available samples of SWP and to correlate that variation to inherent attributes or properties of SWP. Published procedures used to characterize foaming properties were adapted to evaluate 20% w/v SWP dispersions. Assays included foaming capacity and stability in the native sample and after heating to 80°C for 15 minutes. Additional data collected included pH, total protein, soluble protein, lipid content, and cheese origin. Several dozen commercial samples representing different manufacturers, processes, and cheese types were evaluated. The foaming capacities varied from 0 to 200% overrun. The foam stability (interval for a 50% reduction in foam volume) varied from 0 to 11 minutes. Both foam capacity and stability values grouped within relatively discrete categories, suggesting that such grouping was correspondingly caused by a non-linear variable. Heating effected a marked increase in both foaming capacity and stability for previously low foaming samples. For high foaming samples (>200% overrun), foaming stability improved substantially after heat treatment without minimal increase in foaming capacity. With application in foods where foaming is of significance, SWP manufacturing may be optimized to select for specific foaming character.
Session 26, Dairy Foods: General developments in dairy technology
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