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- Chronakis, I S, et al.
(författare)
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Complex formation in aqueous medium of partially hydrolysed oat cereal proteins with sodium stearoyl-2 lactylate (SSL) lipid surfactant and implications for bile acids activity
- 2004
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Ingår i: Colloids and Surfaces B: Biointerfaces. - : Elsevier BV. - 1873-4367 .- 0927-7765. ; 35:3-4, s. 175-184
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Tidskriftsartikel (refereegranskat)abstract
- Sodium stearoyl-2 lactylate (SSL) lipid surfactant molecules specifically bind partially hydrolysed oat proteins in aqueous medium and significantly enhance the dispersion stability of oat cereal preparations. The proposed complexation is composition dependent and a greater understanding of the role of both oat proteins and lipid surfactant in the effect was gained with data from high performance liquid chromatography (HPLC-UV), viscometry and differential scanning micro calorimetry. The effect of the lipid surfactant on the degree of association is primarily governed by the conformational activity of oat protein molecules related to the extent of protein hydrolysed state, as well as protein unfolded and subsequent aggregated structures. SSL does not dissociate oat proteins into subunits or destroy important hydrophobic contacts already stabilising the protein molecules. Although the exact mode of association is unknown, the present study demonstrates that such interactions occur in a specific manner and suggest selectivity of oat proteins for individual fatty acids. The effect of various amounts of bile acids on SSL-oat protein interaction was also investigated, as a first attempt to investigate the role of lipid surfactant molecules in the known cholesterol-lowering action of oat cereal ingredients and to elucidate favourable conditions by which oat cereal can elicit hypocholesterolemic effects. (C) 2004 Elsevier B.V. All rights reserved.
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| 2. |
- Chronakis, I S, et al.
(författare)
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Solid-state characteristics and redispersible properties of powders formed by spray-drying and freeze-drying cereal dispersions of varying (1→3,1→4)--glucan content
- 2004
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Ingår i: Journal of Cereal Science. - : Elsevier BV. - 0733-5210. ; 40:2, s. 183-193
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Tidskriftsartikel (refereegranskat)abstract
- Cereal powders containing 33, 18 and 4% (w/w) (1→3,1→4)--glucan, prepared from cereal suspensions, had distinct differences in surface morphology as observed by scanning electron microscopy, depending both on the drying process (spray- or freeze-drying) and the dietary fibre level. Freeze-drying produced powders with a ‘flake-like’ matrix, without particle formation and similar matrix morphology independent of the (1→3,1→4)--glucan content, in contrast to spray-drying, which gave powders with morphologies that were (1→3,1→4)--glucan-dependent and consisted of aggregated particles and microspheres. Choosing the concentration of (1→3,1→4)--glucans permits control of the particle size and particle size distribution of the spray-dried cereal powders. pH-dependent zeta () potential measurements of re-dissolved powders indicated that the isoelectric point was in the pH range of 3.8–4.8 and that it increased at higher pH as the (1→3,1→4)--glucan content of the powders was decreased from 33 to 4% (w/w). The absolute value of the zeta () potential fell with increasing pH and was largest for the powder dispersion with the lower (1→3,1→4)--glucan content, leading to the greatest dispersion stability. The importance of particle size, net surface charge and (1→3,1→4)--glucan and protein content in controlling the surface activity at the air–water interface of cereal powder dispersions is also discussed. Author Keywords: Spray-drying; Freeze-drying; (1→3,1→4)--glucan; Morphology; Particles; Zeta potential; Surface activity
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