Background: Fiber regulates the rate and site of lipid and carbohydrate digestion and absorption and thus can modify the alimentary responses to a meal. When fiber sources containing viscous polysaccharides are included in a meal, a slower rate of carbohydrate and lipid absorption will modify the alimentary hormone and lipid responses. Objective: We investigated in 11 healthy men the response of insulin, glucose, cholecystokinin, and lipid to 2 test meals containing ␤-glucan. Design: One of the meals was high in fiber (15.7 g) and the other meal was low in fiber (5.0 g). The low-fiber meal contained pasta made with wheat flour. The high-fiber meals contained pasta prepared by replacing 40% of the wheat with 2 types of barley flour: barley naturally high in ␤-glucan and the other a flour enriched in ␤-glucan during processing. Results: Plasma glucose and insulin concentrations increased significantly after all meals but the insulin response was more blunted after the barley-containing meals. The test meals were low in fat (25% of energy) but elicited an increase in plasma triacylglycerol and cholecystokinin. Cholecystokinin remained elevated for a longer time after the barley-containing meals. After the low-fiber meal, plasma cholesterol concentrations did not change significantly; however, 4 h after the barley-containing meals, the cholesterol concentration dropped below the fasting concentration and was significantly lower than that after the lowfiber meal. Conclusions: Carbohydrate was more slowly absorbed from the 2 high-fiber meals. Consumption of the barley-containing meals appeared to stimulate reverse cholesterol transport, which may contribute to the cholesterol-lowering ability of barley.Am J Clin Nutr 1999;69:55-63.

Cereal Chem. 74(3):293-296

5c+Cholestan-5,6ol-epoxy-3p-ol (cholesterol a-oxide) and Sp-cholestan-5,6fi-epoxy-3fl-o1 (cholesterol p-oxide) were isolated from freshly dehydrated commercial whole egg and yolk powders. The isolates were shown to have identical HPLC retention volumes to those of synthesized cholesterol 01-and p-oxides, respectively. Their mass (MS), nuclear magnetic resonance (NMR) and infrared (IR) spectra were also proven to be identical. Cholesterol oxides found in dehydrated egg products may have been formed during the commercial drying process since no oxides were found in fresh shell eggs nor in the egg samples lyophilized in the laboratory.

A method for the quantitation of cholesterol α‐oxide in egg and egg products is described. Total lipids extracted from dry egg samples were fractionated on a silicic acid column to concentrate cholesterol oxides which were then quantitatively determined by gas liquid chromatography (GLC). Those samples which showed cholesterol oxides by GLC were further analyzed by high pressure liquid chromatography (HPLC) for the ratio of cholesterol α‐oxide and cholesterol β‐oxide. Cholesterol α‐oxide content was calculated from the combined results of GLC and HPLC.

In 1996, U.S. Food and Drug Administration regulations mandated the fortification of enriched cereal-grain products with folic acid, thereby emphasizing the need for validated methods for total folates in foods, particularly cereal products. The AOAC Official Methods (944.12, 960.46) currently used for the analysis of folate in foods for compliance purposes are microbiological methods. When the fortification regulations were finalized, no Official AOAC or Approved AACC methods for folate in cereal-grain products were in place. The AOAC Official Method (992.05) for folic acid in infant formula does not incorporate important improvements in the extraction procedure and was not considered suitable for the analysis of folates in foods in general. Amicrobiological assay protocol using a trienzyme extraction procedure was prepared and submitted for comments to 40 laboratories with recognized experience in folate analysis. On the basis of comments, the method was revised to have the conjugase (gamma-glutamyl-carboxy-peptidase) treatment follow a protease treatment, to include the use of cryoprotected inoculum, and to include the spectroscopic standardization of the standard and optional use of microtiter plates. Thirteen laboratories participated in a collaborative study of 10 required and 10 optional cereal-grain products, including flour, bread, cookies, baking mixes, and ready-to-eat breakfast cereals. The majority of the participating laboratories performed the assay by the standard test tube method; others used the microtiter plate modification for endpoint quantitation with equal success. For the required products, the relative standard deviation between laboratories (RSDR) ranged from 7.4 to 21.6% for 8 fortified (or enriched) products compared with expected (Horwitz equation-based) values of 11–20%. RSDR values were higher (22.7–52.9%) for 2 unfortified cereal-grain products. For the optional products, the RSDR ranged from 1.8 to 11.2% for 8 fortified products. RSDR values were higher (27.9–28.7%) for 2 unfortified cereal-grain products. Based on the results of the collaborative study, the microbiological assay with trienzyme extraction is recommended for adoption as Official First Action.