Total dietary fiber was determined in Japanese foods by the Prosky-AOAC method. To accomplish the analyses of unsuitable samples, we introduced a few minor modifications to the versions for (i) seaweed and fruits, (ii) cereals, and (iii) fish and meats. These modified methods were used together with the standard method to obtain results with reasonably good relative standard deviation for 231 foods and 21 groups of mixed foods. In this study, dietary fiber was defined so as not to exclude the nondigestible polysaccharide portions of animal foods. A method was proposed which could estimate more accurately the fiber components of animal foods by measuring the "nondigestible protein" of the fiber sample of the fiber sample by the Biuret colorimetric method, instead of the Kjeldahl method, to avoid deducting the values for aminopolysaccharides. In Japanese diets, the amount of fiber obtained from animals foods was less than 5% of the total intake of dietary fiber.

Dietary Fiber↗

PubMedDate not supplied

Enzyme immunoassay for hen egg white lysozyme used as a food additive.

An indirect competitive enzyme immunoassay for hen egg white lysozyme (HEL) used as a food additive was investigated. Anti-HEL antibodies were obtained from B10A mouse ascites immunized by intraperitoneal injection of HEL. HEL samples to be assayed were extracted from foods with 1% gelatin in borate buffer. Goat anti-mouse IgG (H+L)-peroxidase complex was used as a second antibody, and 3,3',5,5'-tetramethylbenzidine was used as a substrate for the peroxidase. The working range for quantitative analysis was 1-50 ng/mL, because in this range the binding inhibition curve of anti-HEL antibodies to HEL-coated plates by HEL was linear. Even after losing the lysozyme activity by heat treatment, HEL could be detected by indirect competitive enzyme immunoassay. Recoveries of HEL by this assay were greater than 85% for Japanese noodles and Japanese traditional-style confectioneries, 53-95% for Miso and cooked beans, and 30-85% for fried fish pastes. HEL contents of 55 commercial foods were determined; HEL was detected in 19 samples in the range 25-20,000 ng/g. HEL as a food additive was detected more frequently in plant-derived foods than in foods of animal origin.

Animals↗

PubMedDate not supplied

Enzyme immunoassay for carminic acid in foods.

A competitive enzyme immunoassay (EIA) for carminic acid was investigated. Monoclonal anticarminic acid antibody was obtained from A/J mice immunized with carminic acid-human immunoglobulin G (IgG) conjugate. Carminic acid was extracted with distilled water from beverage, jelly, candy, pasta sauce, yogurt, or ice cream samples. Ham or fish paste samples were digested with pronase, then carminic acid was extracted from samples with sodium hydroxide solution. The extract was diluted more than 10-fold with 1% gelatin in borate buffer solution. Microtiter plates were coated with carminic acid-bovine serum albumin (BSA) conjugate or just BSA. Goat anti-mouse IgG(H+L)-peroxidase complex was used as a second antibody, and 3,3',5,5'-tetramethylbenzidine was used as a substrate for the peroxidase. The working range for quantitative analysis was 0.3-10 ng/mL, and the detection limit was 0.2 micrograms/g original sample. Recoveries of carminic acid by this assay were > 95% for milk beverage and jelly, and > 85% for yogurt and fish paste. Carminic acid was detected in 7 of 26 red-colored commercial food products and ranged from 3.5 to 356 micrograms/g. This EIA system also responded to the structural analogue of carminic acid, laccaic acid.

Animals↗