Oxidation mechanisms in real food emulsions: oil-water partition coefficients of selected volatile off-flavour compounds in mayonnaise.

摘要

A method for determination of oil/water partition coeff., Po/w, for volatile lipid oxidation products in mayonnaise enriched with fish oil was developed. Selected volatile off-flavour compounds (2-pentenal, 3-heptanone, octanal, 1-octen-3-ol, 2,4-hepta-dienal and 2-nonanone) were added in levels ranging from 80 to 480 ng/g mayonnaise. Mayonnaises were separated by a procedure involving freezing, centrifugation and ultracentrifugation. Po/w values were then determined from the concn. of volatilesquantified by dynamic headspace GC on the separated lipid and aqueous phases. Po/w values for the selected volatiles ranged from 4.9 to infinity. Increased addition levels of the 6 volatile compounds resulted in an increase of the apparent Po/w valuesand higher recoveries of the volatiles. Effects of adding an extra emulsifier (Panodan TR) and 3 different antioxidant systems (Grindox 1032, Toco 70 and ascorbic acid) on Po/w values of the different off-flavour compounds in mayonnaise samples were also studied. Addition of ascorbic acid seemed to increase recoveries, which resulted in higher Po/w values. In contrast, addition of Panodan TR and a water dispersible tocopherol preparation such as Grindox 1032 resulted in lower Po/w values and lower recoveries for analysis. It is proposed that the effect of Grindox 1032 addition may be due to the ability of this antioxidant, via its emulsifier content, to promote increased binding or entrapment of volatile compounds at the oil/water interface of mayonnaise. These data may be useful for selecteing antioxidant and emulsifier systems to mask off-flavour development in food emulsion systems. [Formerly Zeitschrift fuer Lebensmittel-Untersuchung und-Forschung A/Food Research and Technology up to and including Volume 208. From En summ.]