Harmonization of methods for analysis of cholesterol oxides in foods--the first portion of a long road toward standardization: interlaboratory study.

A compilation of literature data on the content of cholesterol oxidation products (COP) in various food products and in blood demonstrates a large variation in content in products or tissues of very similar nature when analyzed in different laboratories according to a large number of methods. The lack of validated, internationally recognized methodology with published accuracy and precision has so far hindered such assessments. Hence an interlaboratory comparision of methodologies of COP analysis was undertaken on egg yolk powders (EYP), whole milk powders (WMP), skim milk powders (SMP), and lard (L).

Corn and sesame oils increase serum gamma-tocopherol concentrations in healthy Swedish women.

We studied the effects of dietary intervention with three vegetable oils (Linola, corn or sesame oil, all good sources of gamma-tocopherol) on absolute and relative concentrations of alpha- and gamma-tocopherol in human serum. The oils contained only small amounts of linolenic acid but varying amounts of oleic and linoleic acids, and they had different concentrations of alpha-tocopherol. Forty healthy female students (mean age 26 y) were randomly assigned to one of three groups and consumed a diet that contained one of the three oils for 4 wk.

The chemistry and antioxidant properties of tocopherols and tocotrienols.

This article is a review of the fundamental chemistry of the tocopherols and tocotrienols relevant to their antioxidant action. Despite the general agreement that alpha-tocopherol is the most efficient antioxidant and vitamin E homologue in vivo, there was always a considerable discrepancy in its "absolute" and "relative" antioxidant effectiveness in vitro, especially when compared to gamma-tocopherol. Many chemical, physical, biochemical, physicochemical, and other factors seem responsible for the observed discrepancy between the relative antioxidant potencies of the tocopherols in vivo and in vitro.

Sesamin (a compound from sesame oil) increases tocopherol levels in rats fed ad libitum.

Six groups of rats were fed diets low, but adequate, in alpha-tocopherol but high in gamma-tocopherol. The six diets differed only in their contents (0, 0.25, 0.

Gravimetric determination of ash in foods: NMKL collaborative study.

A gravimetric method for the determination of ash was collaboratively studied in 14 laboratories. The food is ashed at 550 degrees C to constant weight and the ash is determined by weighing. Seven samples of various food commodities with estimated ash contents varying between low and high (0.