Dietary fiber fractions (DFF) were fermented in vitro with human fecal inocula to study fiber fermentability and production of short-chain fatty acids (SCFA). Amylolytic and proteolytic enzyme treatment using the Association of Official Analytical Chemists enzymatic-gravimetric procedure reduced processed food fiber products to DFF by removing gastric enzyme-digestible (nonresistant) components. Total 24-h SCFA production from DFF decreased in the following order:  fig > oat = soy > pea > apple > corn = wheat > pear. SCFA production was proportional to the fermentability of these fibers. Fermentation of DFF from fruits such as pear, apple, and fig produced low amounts of butyrate. In contrast, less acetate and more propionate and butyrate were produced by fermentation of oat and soy DFF. Major fiber constituents, resistant starch (RS), β-glucan, and pectin were also fermented. RS, isolated from starch, produced acetate more slowly than the starch. β-Glucan produced propionate and butyrate in higher amounts than did pectin, starch, and RS. This study demonstrates that the fermentability of DFF and the production of SCFA differ among food products. In vitro fermentation of DFF is useful in estimating SCFA production in the human colon. Keywords: Dietary fiber fractions; fermentation; short-chain fatty acids

On July 11, 2003, the U.S. Food and Drug Administration published a final rule amending its food-labeling regulations to require that trans FA be declared in the nutrition label of conventional foods and dietary supplements. The effective date of this final rule is January 1, 2006. This places some urgency on increasing the number and types of currently available foods for which there are trans-fat data. Compositional databases on trans fat content of food are currently limited. The purpose of this study was to determine the trans-fat content of a wide range of foods prior to the effective date of the new regulation. AOAC Official Method of Analysis 996.01 was modified for the analysis of trans fat in noncereal products. Food products for analysis were selected on the basis of market share and data from the USDA's 1994-1996 Continuing Survey of Food Intake by Individuals. Foods were purchased from local supermarkets, weighed, hydrolyzed, converted to FAME, and analyzed by GC. The results showed that trans fat (g/100 g fat) ranged from 0.0 to 48.8 in bread, cake, and related products; from 14.9 to 27.7 in margarines; from 7.7 to 35.3 in cookies and crackers; from 24.7 to 38.2 in frozen potatoes; from 0.0 to 17.1 in salty snacks; from 0.0 to 13.2 in vegetable oils and shortenings; from 0.0 to 2.2 in salad dressings and mayonnaises; and from 0.0 to 2.0 in dry breakfast cereals. Serving sizes for the foods included in this survey ranged from 12 to 161 g, and trans-fat levels ranged from 0.0 to 7.2 g/serving. The significant differences in trans-fat content in products within each food category are due to differences in the type of fats and oils used in the manufacturing processes.

No abstract

The accuracy, repeatability, and reproducibility characteristics of a method using multitoxin immunoaffinity column cleanup with liquid chromatography (LC) for determination of aflatoxins (AF; sum of aflatoxins B1, B2, G1, and G2) and ochratoxin A (OTA) in powdered ginseng and ginger have been established in a collaborative study involving 13 laboratories from 7 countries. Blind duplicate samples of blank, spiked (AF and OTA added) at levels ranging from 0.25 to 16.0 g/kg for AF and 0.25 to 8.0 g/kg for OTA were analyzed. A naturally contaminated powdered ginger sample was also included. Test samples were extracted with methanol and 0.5 aqueous sodium hydrogen carbonate solution (700 + 300, v/v). The extract was centrifuged, diluted with phosphate buffer (PB), filtered, and applied to an immunoaffinity column containing antibodies specific for AF and OTA. After washing the column withwater, the toxins were eluted from the column with methanol, and quantified by high-performance LC with fluorescence detection. Average recoveries of AF from ginseng and ginger ranged from 70 to 87 (at spiking levels ranging from 2 to 16 g/kg), and of OTA, from 86 to 113 (at spiking levels ranging from 1 to 8 g/kg). Relative standard deviations for within-laboratory repeatability (RSDr) ranged from 2.6 to 8.3 for AF, and from 2.5 to 10.7 for OTA. Relative standard deviations for between-laboratory reproducibility (RSDR) ranged from 5.7 to 28.6 for AF, and from 5.5 to 10.7 for OTA. HorRat values were 2 for the multi-analytes in the 2 matrixes.