Determination of fat in olestra-containing savory snack products by capillary gas chromatography

A quantitative method to determine fat in olestra-containing savory snack products was validated within the AOAC Peer-Verified Methods Program. The method may be used to demonstrate compliance with the guidelines of the U.S. Nutrition Labeling and Education Act for labeling products as "fat free" or "low fat." The method can measure total and saturated fat in savory snacks when present at levels of 0.2-10 g total fat and 0.1-3 g saturated fat per 30 g serving. The method is standardized to measure C6-C24 fatty acids. Extraction of olestra-containing savory snack samples with chloroform-methanol (modified AOAC Official Method 983.23) yields a lipid extract containing the total fat and olestra. The extracted lipid is hydrolyzed by lipase, yielding fatty acids and unreacted olestra. The fatty acids are precipitated as calcium soaps. Olestra is extracted from insoluble soaps with hexane and then discarded. The isolated soaps are converted back into fatty acids with hydrochloric acid and extracted with hexane. The isolated fatty acids are converted to methyl esters with boron trifluoride-methanol and quantitated by capillary gas chromatography using internal standard. Test samples were prepared by blending olestra-containing and full-fat (triglyceride) snacks to obtain 6 levels of spiking (0-10 g total fat added/30 g serving) in potato chips, potato crisps, cheese puffs, and nacho cheese-flavored corn chips. Results were linear (r2 > 0.997) between 0 and 10 g fat/30 g serving for each product matrix. Mean recovery was 101 +/- 6% standard deviation (SD) for total fat and 104 +/- 6% SD for saturated fat. Mean recovery by peer laboratory was 88 +/- 5% SD for total fat and 95 +/- 4% SD for saturated fat in potato chips (0-3 g total fat added/30 g serving). Two sets of 10 replicates of potato chips (0.5 g total fat/30 g serving and 0.16 g saturated fat/30 g serving) and potato crisps (0.5 g total fat/30 g serving and 0.16 g saturated fat/30 g serving) were analyzed by submitting and peer laboratories. Repeatability relative standard deviations ranged from 3.90 to 7.33% for total fat and from 4.01 to 11.53% for saturated fat. Reproducibility relative standard deviations were 7.33% (total fat, potato chips), 7.15% (total fat, potato crisps), 11.36% (saturated fat, potato chips), and 13.50% (saturated fat, potato crisps).     

A test of the withdrawal theory for ellis fluids

The Ellis withdrawal theory is shown to be a eubstantial improvement for predicting film thickness as compared to the previous theory for pseudo-plastic fluids. The two-term Ellis power-law theory ie shown to be a good approximation to the Ellis theory. The relative deviations between data and Ellis theory become larger at lower speeds.     

Characterization of used frying oils. Part 2: Comparison of olestra and triglyceride

In this study, the analytical scheme presented in our previous paper [Gardner, D. R., R. A. Sanders, D. E. Henry, D. H. Tallmadge and H. W. Wharton,J. Am. Oil Chem. Soc. 69:499 (1992)] was used to provide a detailed qualitative comparison between a heated olestra and a heated triglyceride that had been used to fry potatoes. The purpose was to determine if unique components are created in olestra when it is exposed to typical frying conditions. Prior to their analysis, the heated and unheated olestra and triglyceride were converted to their corresponding fatty acid methyl esters (FAMEs) by transesterification. The FAMEs obtained were separated by degree of polarity by means of adsorption chromatography and solid-phase extraction. High-resolution capillary gas and liquid chromatography were used to profile isolated fractions, and detailed comparisons of these profiles were carried out in an effort to disclose components only present in the heated olestra. Spectroscopic data confirmed that by the methods employed, the only detectable qualitative differences between heated triglyceride and heated olestra were attributable to components also observed in unheated olestra. These species are generated during the manufacture of olestra and are not uniquely created by its use as a frying oil. In those chromatographic fractions containing altered fatty acids, no components were observed to be generated at levels ⩾5 ppm upon heating olestra that were not also generated upon heating triglyceride.     

Characterization of used frying oils. Part 1: Isolation and identification of compound classes

In this study, an analytical scheme is presented for detailed qualitative comparisons between heated and unheated oils. This scheme is less subject to loss or alteration of sample components when compared with methods that characterize the distillable non-urea adducting portion of heated oils. In this work, oils were first converted to their corresponding fatty acid methyl esters (FAMEs) by transesterification. These FAMEs were then separated by degree of polarity by means of adsorption chromatography and solid-phase extraction. High-resolution capillary gas and liquid chromatography were used to profile isolated fractions. Mass spectrometric and infrared analyses of major chromatographic features were used to identify the presence of aldehydes, epoxides, ketones, alcohols, phytosterols and dimer methyl esters down to 5 ppm in the original sample.     

Increasing productivity in public works maintenance: The effects of job estimates based on engineered performance standards.

Data regarding the size of conventional labor hour estimates based on Engineered Performance Standards (EPS), and labor hours expended in completing jobs were collected from a carefully selected sample of Navy Public Works offices. An analysis of 266 work orders sampled from 12 Navy activities revealed that EPS estimates were significantly lower than conventional estimates but that the difference diminished with time from between 35% to 40% early in the EPS program (1958) to between 5% to 7% in 1963. This reduction was attributed to a learning effect which caused a lowering of conventional estimates as they were shown to be excessively high. Other analyses showed that estimated hours were consumed on the job regardless of how grossly they appeared to overestimate actual requirements, indicating that EPS utilization increased productivity by an amount roughly corresponding to the initial difference between EPS and conventional estimates. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A review of acrylamide: an industry perspective on research, analysis, formation, and control

Acrylamide is a synthetic monomer with a wide scope of industrial applications, mainly as a precursor in the production of several polymers, such as polyacrylamide. The main uses of polyacrylamides are in water and wastewater treatment processes, pulp and paper processing, and mining and mineral processing. The announcement by the Swedish National Food Administration in April 2002 of the presence of acrylamide predominantly in heat-treated carbohydrate-rich foods sparked intensive investigations into acrylamide, encompassing the occurrence, chemistry, agricultural practices, and toxicology, in order to establish if there is a potential risk to human health from the presence of this contaminant in the human diet. The link of acrylamide in foods to the Maillard reaction and, in particular, to the amino acid asparagine has been a major step forward in elucidating the first feasible chemical route of formation during the preparation and processing of food. Other probably minor pathways have also been proposed, including acrolein and acrylic acid. This review addresses the analytical and mechanistic aspects of the acrylamide issue and summarizes the progress made to date by the European food industries in these key areas. Essentially, it presents experimental results generated under laboratory model conditions, as well as under actual food processing conditions covering different food categories, such as potatoes, biscuits, cereals, and coffee. Since acrylamide formation is closely linked to food composition, factors such as the presence of sugars and availability of free amino acids are also considered. Many new findings that contribute towards a better understanding of the formation and presence of acrylamide in foods are presented. Many national authorities across the world are assessing the dietary exposure of consumers to acrylamide, and scientific projects have commenced to gather new information about the toxicology of acrylamide. These are expected to provide new scientific knowledge that will help to clarify whether or not there is a risk to human health from the consumption of foods containing low amounts of acrylamide.