bluuebunny/crossref_metadata_2025_split huggingface dataset:
Antioxidant activity of phenolic compounds in 2,2′‐azobis (2‐amidinopropane) dihydrochloride (AAPH)‐induced oxidation: Synergistic and antagonistic effects
Authors: Peyrat‐Maillard M. N. , Cuvelier M. E. , Berset C. 
Published: November 2006

AbstractInteractions between phenolic antioxidants in binary systems were determined by adding two antioxidants simultaneously in equimolar proportions to an aqueous dispersion of linoleic acid that was then subjected to 2,2′‐azobis (2‐amidinopropane) dihydrochloride‐induced oxidation and by evaluating the protective effect of the antioxidant mixture. The antioxidant power of the mixture was then compared with the expected antioxidant activity calculated by the sum of efficiencies of each compound separately, relative to their proportions in the mixture. If it was higher, a synergy was pointed out whereas a lower value was representative of an antagonism. Thus, synergistic effects were observed between rosmarinic acid and quercetin, or rosmarinic acid and caffeic acid, whereas antagonistic effects were obtained with the following mixtures: α‐tocopherol/caffeic acid; α‐tocopherol/rosmarinic acid; (+)‐catechin/caffeic acid; and caffeic acid/quercetin. These mixture effects are partly explained by regeneration mechanisms between antioxidants, depending on the chemical structure of molecules and on the possible formation of stable intermolecular complexes.
Dependence of oil stability index of fatty compounds on their structure and concentration and presence of metals
Authors: Knothe Gerhard , Dunn Robert O. 
Published: November 2006

AbstractDuring storage and use, vegetable oil‐derived industrial products such as biodiesel and biodegradable lubricants can be subjected to conditions that promote oxidation of their unsaturated components. The materials arising during oxidation and subsequent degradation can seriously impair the quality and performance of such products. Therefore, oxidative stability is a significant issue facing these vegetable oil‐derived products, and enhanced understanding of the influence of various components of vegetable oils and storage parameters is necessary. In this work, the oil stability index (OSI) was used for assessing oxidation of monoalkyl esters of FA by varying several parameters. Neat fatty compounds and prepared mixtures thereof were studied for assessing the influence of compound structure and concentration. Small amounts of more highly unsaturated compounds had a disproportionately strong effect on oxidative stability. The recently developed concept of bis‐allylic equivalents correlated more closely than the iodine value with the OSI times of mixtures of fatty esters. The OSI times of free acids were shorter than those of the corresponding alkyl esters. The presence of copper, iron, and nickel also reduced oxidative stability, but their effect was less than the presence of more highly unsaturated fatty compounds. Of these metals, copper had the strongest catalytic effect on OSI time. OSI may be an alternative to long‐term storage tests for determining the influence of extraneous materials such as metals on oxidative stability.
Screw pressing of whole and dehulled flaxseed for organic oil
Authors: Zheng Yun‐ling , Wiesenborn Dennis P. , Tostenson Kristi , Kangas Nancy 
Published: November 2006

AbstractFlaxseed oil, a rich source of dietary n−3 FA, is commonly obtained by cold pressing whole seed. Furthermore, flaxseed hulls are emerging as a valuable lignan‐rich product for functional food use; therefore, the pressing characteristics of dehulled seed need to be understood. Screw press performance was measured for pressing of whole and dehulled flaxseed. When whole Omega flaxseed was pressed through a 6‐mm choke, an inverse relationship between seed moisture content (6.1–11.6% range) and oil recovery (70.1–85.7%) was observed. However, peak oil recovery from pressing dehulled Omega flaxseed of 72.0% was found at 10.5% moisture content in the moisture content range of 7.7–11.2%. Although oil recovery from dehulled Omega flaxseed was lower than from whole Omega flaxseed, the weight of oil produced from dehulled Omega flaxseed per unit time was higher. The dependence of capacity on moisture content was less evident with the 6‐mm choke than with the 8‐mm choke. An inverse relationship between moisture content of whole flaxseed and oil and meal temperature was observed. The oil and meal temperatures from pressing dehulled flaxseed were significantly lower than those from whole flaxseed. Therefore, pressing dehulled flaxseed appears to offer advantages in organic flaxseed oil production.
Use of phenylselenyl chloride in the preparation of methyl 11‐phenylseleno‐10‐acetamido‐ and ethyl phenylselenoethoxy fatty alkanoates
Authors: Ahmad Shabana , Rauf Abdul 
Published: November 2006

AbstractReaction of methyl 10‐undecenoate (I) with phenylselenyl chloride in acetonitrile furnished methyl 11‐phenylseleno‐10‐acetamido‐undecanoate (II) as a major product, and a similar reaction of I with phenylselenyl chloride in absolute ethanol gave ethyl 11‐phenylseleno‐10‐ethoxy‐undecanoate (III) as a sole product. A similar reaction of methyl octadec‐cis‐9‐enoate (IV; oleate) with phenylselenyl chloride in absolute ethanol was conducted and resulted in the formation of ethyl 10(9)‐phenylseleno‐9(10)‐ethoxy‐octadecanoate (V).
Influence of soybean protein isolates‐phosphatidycholine interaction on the stability on oil‐in‐water emulsions
Authors: Scuriatti M. P. , Tomás M. C. , Wagner J. R. 
Published: November 2006

AbstractSoybean protein isolates and phospholipids present specific surface properties with synergistic or antagonistic effects on emulsion stability. Oil‐in‐water emulsions (25∶75 w/w) were prepared using native and denatured soybean isolates (NSI and DSI, respectively) with the addition of phosphatidylcholine (PC) (protein/PC ratio 100∶1 to 10∶1). The effect of ionic strength was also studied by adding sodium chloride (0–100 mM) to the aqueous phase. Analysis of NSI/PC and DSI/PC emulsions showed that the creaming rate diminished upon addition of PC, with the creamed phase showing more stability than those of the control systems. In DSI/PC systems, the coalescence process was partially controlled, as evidenced by a decrease in the size of oil droplets. Both systems were altered by the presence of sodium chloride, with an increase in the creaming rate attributable to flocculation and the coalescence of droplets. Under these conditions, DSI/PC emulsions exhibited a stronger protein‐phospholipid interaction than those of NSI/PC.
Genotype and growing location effects on phytosterols in canola oil
Authors: Hamama Anwar A. , Bhardwaj Harbans L. , Starner David E. 
Published: November 2006

AbstractThere is little information available about phytosterols in canola (Brassica napa L.) oil and the effects of genotype and growing locations from Virginia and the mid‐Atlantic region of the United States, a potential area for the establishment of domestic production to provide edible oil. Our objectives were to characterize the phytosterols, phospholipids, unsaponifiable matter, and FA in oil from Virginia‐grown canola. Among 11 canola genotypes grown at two locations during 1995–1996 significant variations existed for oil content and FA profiles, but not for contents of phospholipids, unsaponifiable matter, total phytosterols, campesterol, stigmasterol, and β‐sitosterol, Total phytosterol content in the oil of Virginia‐grown canola varied from 0.7 to 0.9% with a mean of 0.8%. This concentration compared favorably with oil from Canadian canola, which typically contains 0.5 to 1.1% total phytosterols. The mean contents of brassicasterol, campesterol, stigmasterol, β‐sitosterol, Δ5‐avenasterol, and Δ7‐stigmatenol as percentages of total phytosterols in Virginia‐grown canola were: 9.7, 32.0, 0.6, 49.3, 4.99, and 3.5%, respectively. Growing location did not affect phytosterols in Virginia‐grown canola oil but had significant effects on contents of phospholipids, and saturated (myristic, stearic, and arachidic) and unsaturated (palmitoleic, linoleic, linolenic, eicosenoic, and erucic) FA.
Molecular exchange in thermal equilibrium between dissolved and crystalline tripalmitin by NMR
Authors: Löfborg Negin , Smith Paul , Furó Istvan , Bergenståhl Björn 
Published: November 2006

AbstractAn NMR technique to measure exchange kinetics at thermal equilibrium in dispersions of moderately soluble crystalline material is presented. By monitoring the exchange of molecules between pools in solid and dissolved form, one can characterize the surface specific exchange rate. Illustrative experiments were performed in a model system with β‐type crystals of tripalmitin as the solid phase and tripalmitin, a fraction of it deuterated, dissolved in a medium‐chain TG oil as the liquid phase. The concentration of deuterated tripalmitin in the solvent was followed by 2H NMR after the crystals, which initially lack deuterated tripalmitin, were immersed in the liquid. The variation of the 2H concentration in the solvent provided the surface specific exchange rate. No systematic errors, due to the slight difference in properties of the deuterated tripalmitin compared to hydrogenated tripalmitin, were observed. The methodology worked well between crystal concentrations of 2 and 4 wt%.
Multivariate determination of cloud point in palm oil using partial least squares and principal component regression based on FTIR spectroscopy
Authors: Setiowaty G. , Che Man Y. B. 
Published: November 2006

AbstractA rapid FTIR spectroscopic method was developed for quantitative determination of the cloud point (CP) in palm oil samples. Calibration samples were prepared by blending randomized amounts of palm olein and palm stearin to produce a wide range of CP values ranging between 8.3 and 47.9°C. Both partial least squares (PLS) and principal component regression (PCR) calibration models for predicting CP were developed by using the FTIR spectral regions from 3000 to 2800 and 1800 to 1600 cm−1. The prediction capabilities of these calibration models were evaluated by comparing their standard errors of prediction (SEP) in an independent prediction set consisting of 14 palm oil samples. The optimal model based on PLS in the spectral range 1800‐1600 cm−1 produced lower SEP values (2.03°C) than those found with the PCR (2.31°C) method. FTIR in conjunction with PLS and PCR models was found to be a useful analytical tool for simple and rapid quantitative determination of CP in palm oil.
Shear and longitudinal ultrasonic measurements of solid fat dispersions
Authors: Saggin Raffaella , Coupland John N. 
Published: November 2006

AbstractDispersions of coating fat in corn oil (2.5–12.5 wt%) were prepared following two different protocols: Type A dispersions had an average crystal size of 30–36 μm, whereas type B dispersions were less than 1 μm. In both dispersions the fat crystals were aggregated into larger structures (up to 80 μm). The longitudinal ultrasonic properties (i.e., velocity, attenuation, and reflectance) were linearly related to the solid fat content, but only attenuation was sensitive to the different microstructures. The velocity and reflectance measurements were modeled using the Urick equation. Shear ultrasonic reflectance and oscillatory viscometry were used to measure the dynamic viscosity of all dispersions. According to both methods, type B samples were always more viscous than type A at a similar solids content. The correlation between the two techniques was good (r2>0.99), but the numeric agreement was different for both systems.
Reaction selectivity of rhizomucor miehei lipase as influenced by monoacylation of sn‐glycerol
Authors: Fu Xun , Parkin Kirk L. 
Published: November 2006

AbstractReaction selectivities were determined in multicompetitive reactions mediated by Rhizomucor miehei (RM) lipase at water activity of 0.19 in hexane. Saturated FA (C4–C18 even chain) and oleic acid (C18∶1) were reacted with a single alcohol, glycerol, or α‐or β‐MAG containing C4, C10, C16, or C18∶1 individually as alcohol cosubstrate. Similar patterns of broad FA selectivity toward C8–C18 FA were generally observed for esterification into specific acylglycerol (AG) pools with the different α/β‐CX‐MAG cosubstrates. Exceptions were enrichment of C18 in the MAG pool with α‐C16‐MAG substrate, and a general suppression of C4/C6 FA reactivity and a specific discrimination toward >C8 FA incorporation into the TAG pool, both for reactions with α‐C10‐ and α‐C16‐MAG. RM lipase selectivity toward MAG was in descending order: β‐C18∶1‐MAG>α/β‐C4‐MAG∼β‐C10‐MAG∼β‐C16‐MAG>α‐C18∶1‐MAG >α‐C10‐MAG∼α‐C16‐MAG. Selectivity in channeling CX of the original CX‐MAG substrates into higher AG species was in descending order: α‐C10‐MAG∼α‐C16‐MAG>β‐C10‐MAGβ‐C16‐MAG>α‐C18∶1‐MAG>β‐C18∶1‐MAG∼ α/β‐C4‐MAG. Aside from their characteristic FA selectivity, Burkholderia cepacia (PS‐30) and RM lipases behaved similarly in terms of MAG selectivity as well as a general conservation of FA selectivity throughout the sequential steps of TAG assembly from FA and glycerol for processes designed to yield specifically structured TAG.
Characterization of soybean protein isolates The effect of calcium presence
Authors: Scilingo A. A. , Añón M. C. 
Published: November 2006

AbstractResults of a study of the effect of calcium addition on polypeptide composition, hydrophobicity, sulfhydryl content, thermal stability, enthalpy of denaturation, and water solubility of soybean protein isolates suggest that the addition of small amounts of calcium (1.23–5.0 mg/g protein) induced the formation of α, α′ soluble aggregates, whereas large amounts (5.0–9.73 mg/g protein) induced the selective insolubilization of the glycinin fraction. The addition of this ion also produced thermal stabilization of the soybean proteins, mainly the glycinin fraction, and increased the enthalpy of denaturation. A decrease in the surface hydrophobicity of proteins with increasing calcium content was also observed. The results obtained suggested the existence of specific calcium‐soy protein interactions, especially with the glycinin fraction.
Evaluation of virgin olive oil bitterness by quantification of secoiridoid derivatives
Authors: Mateos Raquel , Cert Arturo , Pérez‐Camino M. Carmen , García José M. 
Published: November 2006

AbstractThe bitterness of the main compounds identified in the phenolic extract of virgin olive (Olea europaea L.) oils has been sensory‐tested. The aldehydic form of oleuropein aglycone (AOA) was responsible for this attribute. Correlations between the sensory bitterness and concentrations of secoiridoid derivatives, analyzed separately or in different combinations, were obtained for olive oils from different olive varieties. The best correlation obtained corresponds to AOA content (r=0.96; P=1.83×10−17) in the concentration range of 0.03 to 0.5 mmol/kg. AOA concentrations ≥0.5 mmol/kg produce sensory saturation of this attribute. The correlation with AOA concentration was better than that with the absorbance of the phenolic extract at 225 nm. Therefore, the equation obtained allows the evaluation of the bitterness in virgin olive oils by HPLC analysis of the phenolic extract using detection at 280 nm.
Application of phospholipids extracted from bovine milk to the reconstitution of cream using butter oil
Authors: Miura Susumu , Tanaka Miyako , Suzuki Asuka , Sato Kaoru 
Published: November 2006

AbstractPhospholipid (PL) extracted from bovine milk was tested for its emulsifying properties in conjunction with the reconstitution of cream using butter oil. PL from bovine milk dispersed in the oil phase was found to stabilize the cream, whereas PL extracted from soybean oil was found to solidify the cream. Different PL species purified from bovine milk PL were tested for their emulsifying properties. PC from bovine milk dispersed in butter oil was shown to stabilize the cream, whereas PE and sphingomyelin had no such effects. PC from soybean oil also was found to have emulsifying abilities. It was suggested that PC stabilized the reconstituted cream, regardless of its origin.
GC‐MS method for characterization and quantification of sitostanol oxidation products
Authors: Soupas Laura , Juntunen Laura , Säynäjoki Suvi , Lampi Anna‐Maija , Piironen Vieno 
Published: November 2006

AbstractA new GC‐MS method for characterization and quantification of phytosterol oxidation products was developed. Applicability of this method was tested by characterizing sitostanol oxides formed in bulk and then quantifying selected oxides in purified rapeseed oil and tripalmitin matrices in which the complex matrix made oxide analysis difficult. In bulk, nine different sitostanol oxides were characterized, including epimers of 7‐ and 15‐hydroxysitostanol and 6‐ and 7‐ketositostanol. In both lipid matrices, the amounts of sitostanol oxides generated in thermo‐oxidation were very low. According to statistical analyses, depending on the oxide, the GC‐MS results were the same or slightly higher than those quantified by the more common GC‐FID method. Thus, GC‐MS provides a powerful alternative for characterization and quantification of phytostanol oxides found in low amounts in complex matrices and is a promising method for future phytosterol oxide studies.
Recovery of phytosterols from sunflower oil deodorizer distillates
Authors: Moreira Eduardo A. , Baltanás Miguel A. 
Published: November 2006

AbstractPhytosterols are usually recovered by crystallization from the deodorizer distillate (DD) of vegetable oils. In this work, the impact of the principal process variables (viz., solvents and cosolvents, cooling rate, crystallization temperature, and ripening time) on the quality and yield of the recovered phytosterols was studied by using a sunflower oil DD “enriched” (i.e., preconcentrated) via transesterification with ethanol (EDD) as a feedstock and commercial hexane as solvent (S), with S/EDD mass ratios of 3 to 5. Water (0 to 4.5 wt%) and ethanol (0 to 10 wt%) were used as cosovents, with crystallization temperatures between 0 and −20°C and crystallization times from 4 to 96 h. The cooling rate was either −20°C/h or “brisk chilling” from 40 to −5°C. The nature and composition of the EDD solvent and cosolvent composite arose as the most important process variable, strongly influencing both the percentage of sterol yield and the purity of the crystals, as well as their filterability and washability. Water‐saturated hexane sufficed to give good crystallization, yet the beneficial effect of adding water as the single cosolvent was enhanced by adding small and precise amounts of ethanol. A recovery of sterols as high as 84% (with 36% purity) was achieved by using a single‐stage batch crystallization of the S/EDD mixture (S/EDD=mass ratio 4).
Evolution of the oxidation process in olive oil triacylglycerol under accelerated storage conditions (40–60°C)
Authors: Gómez‐Alonso S. , Salvador M. D. , Fregapane G. 
Published: November 2006

AbstractThis paper presents an analysis of oxidation in olive oil TAG at different temperatures within a range of 40–60°C in darkness, as measured by the rate of formation of hydroperoxides, their decomposition products, and sensory and chemical flavor deterioration. At 60°C, the oxidation process was relatively fast, and all the indexes of the extent of oxidation behaved in a very similar way. The behaviors of the rate of formation of conjugated dienes (measured as the K232), of oxidized TAG (determined by HPLC), and of carbonyl compounds (measured as anisidine value) were very similar to that of the PV. The induction periods (IP) of the four indexes were less than 36 h. Nevertheless, the IP for K270 and the sum of oxidized TAG dimers and polymers were 5 d. At 50 and 40°C, the rate of formation of secondary oxidation products was lower. Residual linolenic acid or PUFA as determined by GC showed correlation coefficients higher than 0.999 with the Totox index at all of the assayed temperatures. The rancid recognition threshold corresponded to lower values of the oxidation indexes at lower temperature. Moreover, at all assayed temperatures, the rancidity threshold apparently coincided with the IP for the kinetics of 2,4‐decadienal formation.
Effects of antioxidants and humidity on the oxidative stability of microencapsulated fish oil
Authors: Baik M. ‐Y. , Suhendro E. L. , Nawar W. W. , McClements D. J. , Decker E. A. , Chinachoti P. 
Published: November 2006

AbstractThe effects of various antioxidants and RH on the oxidative stability of microencapsulated fish oil powder were investigated using PV and thiobarbituric acid tests. The micorencapsulation process provided high encapsulation efficiency (≥88% of extractable fish oil). Without antioxidants, the encapsulated fat was 10 times more stable against oxidation than the surface fat, as determined by PV. α‐Tocopherol, which is a lipophilic antioxidant, showed a greater antioxidative effect in both surface and encapsulated fats than ascorbyl palmitate, which is an amphiphilic antioxidant. According to TBARS values, the longest lag period was observed at 0% RH. Addition of >200 ppm α‐tocopherol in a 10–30% RH range prolonged the oxidative stability of the microencapsulated fish oil powder.
Phospholipids from palm‐pressed fiber
Authors: Choo Yuen May , Bong Siow Ching , Ma Ah Ngan , Chuah Cheng Hock 
Published: November 2006

AbstractPalm‐pressed fiber, a by‐product of palm oil milling, was extracted successively with hexane and 95% ethanol; the ethanol extracts yielded 46,800 ppm of phospholipids. The phospholipid composition, as analyzed by HPLC coupled with an ELSD, was found to be predominantly PC, PE, phosphatidylglycerol, and PA; as expected, the FA were more unsaturated than the TAG. Palm‐pressed fiber is estimated to be able to provide 21,645 tonnes of palm lecithin based on the present total world production of fresh fruit bunches and thus be an alternative source of lecithin, which is normally obtained from soybeans.
Adsorption of FFA in crude catfish oil onto chitosan, activated carbon, and activated earth: A kinetics study
Authors: Sathivel Subramaniam , Prinyawiwatkul Witoon 
Published: November 2006

AbstractThe feasibility of using chitosan, activated carbon, and activated earth to remove FFA from crude catfish visceral oil, and the adsorption kinetics of the procedure were evaluated. The effect of adsorbents on water activity and the 18∶3 and 22∶6 content of crude catfish visceral oil was also studied. The initial adsorption kinetic coefficients of FFA (mL g−1 min−1) were 0.1, 0.07, and 0.03 for chitosan, activated carbon, and activated earth, respectively. The external film mass‐transfer coefficient (0.001 mL s−1) was similar for the three adsorbents. The adsorption capacity of FFA at saturation (mg g−1) was 71.2 for chitosan, 65.5 for activated carbon, and 57.0 for activated earth. The intraparticular diffusion coefficients (mg mL−1 min−0.05) were 0.14, 0.12, and 0.09 for chitosan, activated carbon, and activated earth, respectively. Water activity of the crude oil decreased with increased contact time of the adsorbents. Results indicated that chitosan was a better adsorbent than activated carbon and activated earth for FFA removal from crude catfish visceral oil.