The effects of dairy ingredients on the pasting, textural, rheological, freeze-thaw properties and swelling behaviour of oat starch

Abstract

The effects of milk ingredients, whey protein concentrate (WPC), whey lactalbumin (WLAC) and skim milk powder (SMP) on oat starch characteristics in terms of pasting, rheological, freeze-thaw and swelling behaviour, were investigated. Oat starch was extracted from oat flour and different proportions of dairy ingredients were mixed with oat starch. Substitution of oat starch with milk components increased hot paste stability and reduced peak viscosity using the RVA method of assessment. Furthermore, thermal processing affected the granules size, swelling power and flow behaviour of the mixtures containing oat starch in combination with different dairy ingredients. Oat starch illustrated reduced swelling and breakdown properties when pasted in the presence of WPC and SMP. This study also showed that addition of SMP resulted in an increase in freeze-thaw syneresis and reduction in starch granule size. SMP was found to affect the oat starch properties more significantly in comparison with WPC and WLAC.

Keywords: Oat starch; Skim milk powder; Starch granule size; Whey protein.