Functional properties of ultrasonically generated flaxseed oil-dairy emulsions.
This study reports on the functional properties of 7% flaxseed oil/milk emulsion obtained by sonication (OM) using 20 kHz ultrasound (US) at 176 W for 1-8 min in two different delivery formulae, viz., ready-to-drink (RTD) and lactic acid gel. The RTD emulsions showed no change in viscosity after sonication for up to 8 min followed by storage up to a minimum of 9 days at 4±2 °C. Similarly, the oxidative stability of the RTD emulsion was studied by measuring the conjugated diene hydroperoxides (CD). The CD was unaffected after 8 min of ultrasonic processing. The safety aspect of US processing was evaluated by measuring the formation of CD at different power levels. The functional properties of OM gels were evaluated by small and large scale deformation studies. The sonication process improved the gelation characteristics, viz., decreased gelation time, increased elastic nature, decreased syneresis and increased gel strength. The presence of finer sono-emulsified oil globules, stabilized by partially denatured whey proteins, contributed to the improvements in the gel structure in comparison to sonicated and unsonicated pasteurized homogenized skim milk (PHSM) gels. A sono-emulsification process of 5 min followed by gelation for about 11 min can produce gels of highest textural attibutes.
School of Chemistry, University of Melbourne, Victoria 3010, Australia.
Akalya
A
Shanmugam
School of Chemistry, University of Melbourne, Victoria 3010, Australia; Adjunct Professor, Chemistry Department, King Abdulaziz University, Jeddah, Saudi Arabia. Electronic address: masho@unimelb.edu.au.
Muthupandian
M
Ashokkumar
D000818:Animals; D003611:Dairy Products / Q000032:analysis* / Q000528:radiation effects*; D004548:Elasticity / Q000528:radiation effects; D004655:Emulsions; D005782:Gels / Q000737:chemistry / Q000528:radiation effects; D006861:Hydrogen Peroxide / Q000737:chemistry / Q000528:radiation effects; D006863:Hydrogen-Ion Concentration; D019344:Lactic Acid / Q000737:chemistry / Q000528:radiation effects; D008043:Linseed Oil / Q000737:chemistry* / Q000528:radiation effects*; D008892:Milk / Q000737:chemistry / Q000528:radiation effects; D008894:Milk Proteins / Q000737:chemistry / Q000528:radiation effects; D010084:Oxidation-Reduction; D014465:Ultrasonics / Q000379:methods*; D014783:Viscosity; D000067816:Whey Proteins
D004655:Emulsions; D005782:Gels; D008894:Milk Proteins; D000067816:Whey Proteins; D019344:Lactic Acid; D008043:Linseed Oil; D006861:Hydrogen Peroxide
Acid gel; Emulsion; Flaxseed oil; Rheology; Syneresis; Ultrasound