Abstract Rosmariquinone (RQ), an ortho ‐quinone diterpenoid found in rosemary, was shown to act as a hydrogen‐donating antioxidant. The proposed mechanism is based on the isolation of the catechol intermediate arucadiol (AD) in methyl oleate test systems. AD was also observed in a bulk soybean oil oxidation experiment, which supports the observation that RQ is converted to AD during oxidation of the oil. Because AD was found in both light‐induced oxidation and autoxidation test systems, the antioxidant mechanism proceeds in a similar manner. The antioxidant activities of RQ and AD were not significantly different in the autoxidation experiments, while AD was a significantly better ( P <0.05) antioxidant than RQ in the light‐induced oxidation.
Egg yolk was spray-dried under conditions to produce a small particle size powder and a large particle size powder. Particle size was determined using a Nikon Optiophot microscope. Spray-dried egg yolk was also adjusted to various moisture levels as follows: control (2 to 4% moisture), 7% moisture, and 12% moisture. Supercritical carbon dioxide extraction (SCE) of each of these moisture treatments at 45 C/306 atm using 30 g CO2/g of sample was completed. For the particle size study, 45 g CO2/g of sample at 45 C/306 atm was utilized. Particle size exhibited a significant effect on cholesterol and lipids extracted using SCE. As moisture content of dried egg yolk increased to 7%, there was a significant increase in lipids extracted using supercritical carbon dioxide. Moisture content had no significant effect on cholesterol extraction. After extracting SCE higher moisture spray-dried egg yolk, sponge cake volume was significantly reduced compared to that of the control. The reduced sponge cake volume may be due to protein denaturation.
Abstract Improved knowledge of the properties, composition, and analysis of grain sorghum wax would assist in efforts for industrial application of this product. Wax extracted from grain sorghum, harvested in 1996 in Nebraska, using hot hexane was fractionated with silica gel column chromatography using a series of mixtures of hexane, chloroform, methanol, and acttic acid. During TLC analysis of the sorghum wax, a dark band, which did not appear in carnauba wax, was found between was esters and TAG. This dark band fraction was the primary component, representing more than 40% of the total sorghum wax weight. The purpose of this study was to chemically characterize the dark band. The fraction containing the dark band was subjected to borohydride reduction and autoxidation by exposure to air. The borohydride reduction gave a dark band at the fatty alcohol position on TLC, whereas the oxidized sample showed a dark band at the FA position, strongly suggesting the original dark band contained aldehydes. NMR and GC‐MS data confirmed that this fraction contained a saturated C 28 aldehyde.
ABSTRACT Grain sorghum can be a major source of policosanols, long‐chained alcohols, that have beneficial physiological activities. Sorghum dried distillers grains (DDG), a by‐product of ethanol production from grain sorghum, contain a large amount of policosanols. Content and composition of policosanols in long‐chained lipids extracted from grain sorghum kernels and DDG were determined. Long‐chained lipids were extracted using hot hexane or hot ethanol. The major components of the long‐chained lipids extracted from grain sorghum kernels, as determined using HPLC, were policosanols (37–44%), aldehydes (44–55%), and acids (4–5%). Long‐chained lipids from DDG contained 52% policosanols, 23% aldehydes, 6.4% acids, and 17% wax esters/steryl esters. Composition of policosanols in DDG matched the composition in grain sorghum kernels, as determined by gas chromatography, even though the content of policosanols in DDG was greater than the content in grain sorghum kernels. Policosonal composition ranges were 0–1% C22:0, 0–3% C24:0, 6–8% C26:0, 1% C27:0, 43–47% C28:0, 1–2% C29:0, 40–43% C30:0, and 1–4% C32:0.
Near-infrared (NIR) spectroscopic methods for measuring degradation products, including total polar materials (TPMs) and free fatty acids (FFAs), in soy-based frying oil used for frying various foods have been successfully developed. Calibration models were developed using forward stepwise multiple linear regression (FSMLR) and partial least-squares (PLS) regression techniques and then tested with an independent set of validation samples. The results show that the quality of oil used for frying different foods can be measured with a single model. First-derivative treatments improved results for TPM measurement. In addition, PLS models gave better prediction results than FSMLR models. For PLS models, the best correlations (r) between the NIR-predicted data and the chemical method data for TPMs and FFAs in oils were 0.995 and 0.981, respectively. For FSMLR models, the best r values for TPMs and FFAs in oils were 0.993 and 0.963, respectively.
ABSTRACT A comparison of the effectiveness of two procedures, ammonium sulfate fractionation and concanavalin A affinity (Con A) chromatography, for the purification of β‐conglycinin from soy flour was made. In addition, the effect of toasting on the effectiveness of these two procedures for purifying β‐conglycinin was studied. Results indicated that Con A affinity chromatography was less effective than the ammonium sulfate fractionation for the purification of β‐conglycinin. The ammonium sulfate fractionation produced nearly homogeneous β‐conglycinin; however, the yield from this procedure was very low (4.1%). Toasting the soy flour decreased the purification effectiveness of both procedures.
This study was performed to develop HPLC methods for determining the composition of grain sorghum wax using a silica column and an ELSD. The method development emphasized separation of aldehydes from wax esters (WE) and steryl esters (SE). Gradient mobile systems using 0.2% (v/v) acetic acid and 0.02% (v/v) methyl tert-butyl ether (MTBE) in hexane and 0.2% (v/v) acetic acid in MTBE or hexane and 0.2% (v/v) acetic acid in MTBE separated aldehydes, acids, and alcohols, as well as minor components such as mixtures of WE and SE, and triacylglycerols (TG). Grain sorghum wax was composed of 46.3% (w/w) fatty aldehydes, 7.5% fatty acids, 41.0% fatty alcohols, 0.7% hydrocarbons, 1.4% WE and SE, and 0.9% TG, based on HPLC data. The gradient HPLC systems were also useful for compositional analysis of carnauba wax. Carnauba wax contained of 34.3% (w/w) WE, 5.1% fatty acids, undetermined amount of fatty alcohols, and 3.0% TG.
Both fresh and frozen asparagus rapidly deteriorate in quality due, in part, to the formation of oxidative off-flavors. Anti-oxidants and chelating agents prevent lipid oxidation in vegetables, but increasing the levels of such compounds in whole vegetables is difficult. Vacuum infusion was optimized to saturate asparagus spears with ascorbic acid without damaging tissues. The combination of vacuum infusion of ascorbic acid and thermal blanching effectively prevented the formation of oxidative off-flavors and hexanal during frozen storage. Sensory evaluations correlated with hexanal levels following frozen storage.
