Evidence that dietary lycopene decreases the risk for a number of health conditions has generated new opportunities for the addition of lycopene to functional foods. This work examined the potential of oil-in-water emulsions as a lycopene delivery system for foods. Oil-in-water emulsions containing lycopene were prepared using different kinds of surfactant (cationic, anionic, and nonionic) and oil types (corn oil, stripped corn oil, and hexadecane). The formation of fatty acid oxidation products and the degradation of lycopene and tocopherol were then monitored. Fatty acids and lycopene had greater stability in oil-in-water emulsions stabilized by cationic dodecyltrimethylammonium bromide (DTAB) or nonionic polyoxyethylene (23) lauryl ether than by anionic sodium dodecyl sulfate (SDS). Oxidative stability in the corn oil-in-water emulsions stabilized by SDS was in the following order: tocopherolhexadecane>tocopherol-stripped corn oil. Lycopene degradation rates were similar in emulsions with and without fatty acids, suggesting that lycopene loss was independent of the presence of fatty acids. These results suggest that the stability of lycopene in oil-in-water emulsions could be inhibited by altering the emulsion droplet interface and by the presence of tocopherols.

Thermal stability of 10 anthocyanins found in a bilberry extract was studied at different heating temperatures and times. Degradation of the 10 anthocyanins, delphinidin, cyanidin, petunidin, peonidin, and malvidin derivat with different conjugated sugars, followed 1st-order reaction kinetics at heating temperatures 80, 100, and 125 degrees C. Though the degradation rate constants of anthocyanins were not significantly different from each other at the same heating temperature, they increased drastically when heating temperature was increased to 125 degrees C. At that temperature, the half-lives for all anthocyanins were less than 8 min. The degradation rate constants followed the Arrhenius equation. The trend of lower activation energy of the anthocyanins with arabinoside than with galactoside or glucoside was observed. These conjugated sugars were cleaved from the anthocyanins to produce their corresponding anthocyanidins or aglycones during heating. The production of anthocyanidins increased con stantly and was converted from approximately 30% of the degraded anthocyanins when heated at 100 degrees C for up to 30 min. At 125 degrees C, the increase of anthocyanidins lasted for 10 min, after which the degradation rate of anthocyanidins exceeded the production rate. Antioxidant activities of the heated extracts were estimated by measuring DPPH (2, 2'-diphenyl-1-picrylhydrazyl) free radical scavenging activity. The extracts heated at 80 degrees C for 30 min, 100 degrees C for 10 and 20 min, and 125 degrees C for 10 min had higher free radical scavenging capability than unheated extract.

Soy isoflavones in the cotyledon, coat and germ of four soybean varieties from the southern U.S.A. were determined and compared. Isoflavones with aglycone, daidzein, genistein, glycitein and aglycone, withβ‐glucoside, genistin, daidzin and glycitin, were found in the four varieties. The range of total soy isoflavones in cotyledon, coat and germ extracts from the varieties was 2.73–9.71, 5.56–16.94 and 27.76–81.43 mg/g, respectively. Soy germ was the richest source of isoflavones among the three soybean parts. Distribution of the isoflavones in soy cotyledon was different from that in soy coat or germ. Daidzin and glycitin were the major isoflavones in the germ and coat, while daidzin and genistin led in the cotyledon. Compared with theβ‐glucoside forms isoflavones, the aglycone isoflavones were at a much lower level in all three soy parts. The difference of the distribution profiles may reflect different isoflavone biosynthesis preference between soy cotyledon and coat or germ. Total phenolic content of the three soy part extracts from high to low was germ, cotyledon and coat. Antioxidant activity of the three part extracts from each variety was measured using 2,2′‐diphenyl‐1‐picrylhydrazyl free radical scavenging method. The order of the antioxidant activity was germ = cotyledon > coat. This study demonstrated that soy germ could be a good source rather than whole soy flour for preparing highly concentrated soy isoflavones extract. It provided useful information for effectively utilizing each part of soybean based on their different compositions, and maximizing the economic value of soybean. PRACTICAL APPLICATIONS This study presented the distribution of isoflavones and their antioxidant activity in soybean cotyledon, coat and germ. The information would be useful in preparing soy products with higher level of isoflavones and antioxidant activity retained. It could also be used in developing soy isoflavone concentrate for food antioxidants or nutritional supplements. These value‐added post‐harvest applications will increase the economic value and potential utilization of soybean.

Capabilities of crude soy oil, degummed oil, gum, and defatted soy flour extract in preventing the oxidation of menhaden oil and its omega-3 fatty acids, DHA (docosahexaenoic acid) and EPA (eicosapentaenoic acid), during heating were evaluated. The menhaden oil mixed with defatted soy flour extract demonstrated the greatest stability by producing the lowest TBA reactive oxidation products and retaining the highest concentrations of DHA and EPA after heating at 150 degrees C for 30 min. A range of 62.8% to 71.5% of DHA and 67.7% to 75.9% of EPA remained in the fish oil with defatted soy flour extract, while only 29.9% of DHA and 37.2% of EPA were retained in the fish oil with no addition. Stabilizing capability from highest to lowest was defatted flour extract > gum > degummed oil = crude oil. The defatted flour extract had the highest level of total phenolic content (11.3 microg catechin equivalent/g), while crude oil, degummed oil, and gum contained 7.1, 6.1, and 6.0 microg catechin equivalent/g, respectively. The level of isoflavones in the defatted soy flour extract was 55 mg/g, which was over 100 times higher than in the crude oil or gum. Although isoflavones were not detected in the degummed oil, it contained the highest level of tocopherols (414 mug/g), whereas the lowest level (215 microg/g) was found in the defatted flour extract. The order of free radical scavenging capability measured from high to low was the defatted soy flour extract, crude oil, degummed oil, and gum.

Extraction yields of lutein from egg yolk using both hexane solvent (SOL) and ultrasound‐assisted solvent (UA‐SOL) extraction methods at different levels of saponification were compared. The yields obtained with SOL and UA‐SOL were significantly different. The broad range of extraction yield in the SOL method at different levels of saponification was from 6.3 to 63.8 μg/g. Compared to the SOL method, the extraction yield using UA‐SOL was significantly higher at each corresponding saponification level. The yield of the UA‐SOL method without alkaline solution was the highest (89.9 μg/g) of all. The yield of the UA‐SOL decreased as the level of saponification increased. The results indicated that alkaline significantly affected stability of lutein in egg yolk and resulted in underestimation of its concentration. Compared with the traditional saponification solvent extraction method, the UA‐SOL extraction method was more effective in extracting lutein from the sample matrix, and presumably by avoiding degradation reactions.

Thermal stabilities of major soya isoflavones at different dry-heating temperatures were determined in this study. The conversion of glucoside isoflavones to aglycone isoflavones was monitored as well. The thermal degradation of the isoflavones: glucoside form daidzin, glycitin, and genistin and aglycone form daidzein, glycitein, and genistein followed first-order reaction kinetics at heating temperatures 100, 150, and 200°C. The degradation rate constants of the six isoflavones were not significantly different at 100°C. However, the constants increased with increasing heating temperature. The half-life for the glucoside and aglycone isoflavones was from 144 to 169 min and 139 to 176 min at 100°C, respectively. They decreased rapidly to 15.7-54.7 and 36.0-90.7 min when temperature increased to 150°C. When heated at 200°C, they further decreased to 5.8-6.0 and 15.7-21.2 min, respectively. The order of thermal stability from lowest to highest was glycitin < genistin < daidzin < glycitein < genistein < daidzein at temperature below 150°C. However, their thermal stabilities were not different at 200°C. The conjugated glucosides were cleaved from the isoflavones to produce their corresponding aglycones when heated at 150°C or higher. The production of glycitein increased constantly and was the highest among the three aglycone isoflavones.

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