Comparing antioxidant effectiveness of natural and synthetic free radical scavengers in thermally-oxidized lard using DPPH method.

Antioxidant effectiveness of free radical scavengers (FRSs) of alpha-tocopherol, sesamol, butylated hydroxytoluene (BHT), and tert-butylhydroquinone (TBHQ) were evaluated in thermally-oxidized lard using methods of 2,2-diphenyl-1-picrylhydrazyl (DPPH), conjugated dienoic acid (CDA), and p-anisidine value (p-AV). Absorbance of DPPH with lard containing 2.5 micromol/g FRSs were low before oxidation while those with control lard was high due to the hydrogen atom donating ability of FRSs.

Formation of succinyl genistin and succinyl daidzin by Bacillus species.

6''-O-Succinyl-4'-hydroxyisoflavone-7-O-beta-D-glucopyranoside (succinyl-beta-daidzin) and 6''-O-succinyl-6,4'-dihydroxyisoflavone-7-O-beta-D-glucopyranoside (succinyl-beta-genistin), 2 new isoflavone metabolites, are found in cheonggukjang or natto, traditional soy-based foods fermented with Bacillus species. Standard isoflavones including daidzin, genistin, daidzein, and genistein, and mixtures of isoflavones extracted from roasted soybeans were added to the medium growing Bacillus subtilis or B. subtilis natto and formation of succinyl-beta-daidzin and succinyl-beta-genistin were monitored by high-performance liquid chromatography (HPLC).

Changes of headspace volatiles in milk with riboflavin photosensitization.

Effects of fluorescent light, riboflavin, ascorbic acid, sodium azide, and butylated hydroxyanisole (BHA) on the volatiles in milk at 4 degrees C were determined using a combination of headspace-solid phase microextraction (HS-SPME), gas chromatography (GC), and mass spectrometry (MS). Pentanal, hexanal, heptanal, and dimethyl disulfide were formed only in the milk stored under light and increased significantly as the duration of light exposure increased from 0 to 8 h and the concentration of added riboflavin increased from 5 to 50 ppm (P < 0.05).

Effects of riboflavin photosensitization on the degradation of bisphenol A (BPA) in model and real-food systems.

Effects of riboflavin photosensitizations on the stability of bisphenol A (BPA), a well-known endocrine disrupting chemical, were studied in model and real-food systems by high-performance liquid chromatography (HPLC). Concentration of BPA was significantly decreased under light exposure (P < 0.05) as the concentration of riboflavin increased while those without riboflavin under light or those with riboflavin in the dark did not change significantly (P > 0.

Stability of isoflavone daidzein and genistein in riboflavin, chlorophyll b, or methylene blue photosensitization.

Effects of photosensitizers including riboflavin, chlorophyll b, or methylene blue on the stability of daidzein and genistein were studied in model systems by high-performance liquid chromatography (HPLC). Concentration of daidzein and genistein in 80% methanol with riboflavin under light for 7 h was significantly decreased with the apparent 1st-order rate constants of 0.234 and 0.