Characterization of Enzymatically Interesterified Canola Oil and Fully-Hydrogenated Canola Oil Blends Under Supercritical CO2

Blends of canola oil and fully-hydrogenated canola oil (FHCO) containing 10, 30, and 50 wt% FHCO were interesterified enzymatically using Lipozyme TL IM (6 % of initial substrates, w/v) under supercritical CO₂ at 10 MPa and 65 °C for 2 h. Changes in polymorphic behavior and crystal morphology of non-interesterified initial blends (NIB) and purified enzymatically interesterified products (PEIP) were studied using X-ray diffraction spectroscopy (XRD) and polarized light microscopy. As well, the effects of blend ratio and enzymatic interesterification on rheological behavior were investigated. XRD analysis demonstrated the predominance of α form in FHCO while blending it with canola oil induced the formation of β form after crystallizing the samples at 24 and 5 °C for 12 h. Enzymatic interesterification caused the appearance of β′ forms and dramatically changed crystal morphology. The PEIP samples contained fewer crystal particles compared to NIB, but the crystals were more symmetrical. The elastic modulus (solid-like behavior) (G′) was lower in NIB with 30 wt% FHCO compared to the one with 50 wt% FHCO. Enzymatic interesterification also had a strong effect on G′ of the samples as it decreased after interesterification. The results of this study will help the development of conversion technologies under supercritical conditions in order to formulate more healthy fats having appropriate functional properties to address the industrial demand for the production of margarine and pastry shortenings.     

The Certification of the Identity of Individual Sterols in Three BCR Oil and Fat Reference Materials by GC-MS

The sterols of three Reference Materials: a vegetable oil (RM162: a mixture of Soya oil and Maize oil) and two animal fats (RM163: a blend of Pig and Beef fats and RM164: Milkfat) were identified by GC-MS in two experienced laboratories. The techniques used were practically the same nevertheless, Lab. 1 and 2 used respectively an HPLC and a classical TLC method to isolate the sterols from the unsaponifiable matter. Many minor components were detectable when the high efficient HPLC fractionation technique was used but the only molecules similarly identified by the two Labs were considered for the certification of sterol identities. In this article, we present the results of the certification study together with the interpretation of mass spectra.     

Determination of Fecal Sterols Following a Diet with and without Plant Sterols

The aim of this study was to develop a method for neutral fecal sterols determination in subjects receiving a normal diet with or without a plant sterols-enriched beverage using gas chromatography–mass spectrometry (GC/MS). Sample preparation conditions (homogenization of lyophilized feces with water) were evaluated. Sterol determination required direct hot saponification, unsaponifiable extraction with hexane, and the formation of trimethylsilyl (TMS) ether derivatives. The method allows the quantification of cholesterol, plant sterols and their metabolites (coprostanol, coprostanone, cholestanol, cholestanone, methylcoprostanol, methylcoprostanone, ethylcoprostenol, stigmastenol, ethylcoprostanol and ethylcoprostanone). Good linearity was obtained (r > 0.96) and interference was only observed for coprostanone, where the standard addition method proved necessary for quantification. The limits of detection (LOD) ranged from 0.10 to 3.88 µg/g dry feces and the limits of quantitation (LOQ) from 0.34 to 12.94 µg/g dry feces. Intra- and inter-assay precision (RSD %) were 0.9–9.2 and 2.1–11.3, respectively. Accuracy, expressed as percentage recovery (80–119%) was obtained for all determined sterols.     

Synthesis and Characterization of Canola Oil Alkyd Resins Based on Novel Acrylic Monomer (ATBS)

A water-reducible alkyd resin was synthesized using the renewable resource canola oil and then chemically modified with styrene and the novel monomer acrylamido tertiary butane sulfonic acid (ATBS). Infrared spectroscopy and nuclear magnetic resonance techniques were used for structural elucidation of newly synthesized resins. Analyses of their physico-chemical and thermal properties revealed that styrene and ATBS-grafted water-reducible polymers have better thermal, chemical and coating properties than canola oil alkyd resins.     

Sterols of eustigmatophytes

The oyster cannot synthesize sterols from smaller molecules but must obtain them from its diet, which consists of detritus and small organisms, i.e., mostly single-celled algae. Algae differ widely in their effectiveness as oyster food. Small (<5 μm) algae which are abundant in sterols and polyunsaturated fatty acids appear to be most effective. Recent studies have shown the occurrence of cholesterol in strains of the unicellular algaeTetraselmis, Chaetoceros andSkeletonema, sometimes in large quantities. In the study reported here, six isolates of a recently constructed algal class, the Eustigmatophyceae, have been examined for sterols and fatty acids by gas chromatography and gas chromatography/mass spectrometry. All strains were shown to contain cholesterol as the principal sterol. Two isolates contained large amounts of total sterol (400–1000 fg/cell), and one (Sticho 0–18) also contained large amounts of eicosapentaenoic acid (20∶5n−3). These biochemical characteristics are desirable in a potential food source for oysters.     

Canola oil processing in Canada

Canola is the registered trademark of the Canola Council of Canada for the seed, oil and meal derived from rapeseed cultivars low in erucic acid and low in glucosinolates. Conversion to canola cultivars on a commercial scale started in 1976; in 1981, ca. 87% of the brassica-based oil crop in Canada was of canola quality. Canola oil is the most important oil in Canada. Processing of the oil is, in its essentials, conventional. A few problems not usually encountered with other oils are its chlorophyll content which requires extra processing and analytical effort, and certain limitations in crystallization behavior when highly hydrogenated. Advantages are that stable oils can be produced at moderate degree of hydrogenation, and without hydrogenation in the case of salad oil. New developments in processing of the oil have led to the production of acid-degummed, crude oil on a commercial scale. This opens the possibility to apply physical refining to the oil.     

Enrichment of Lysophosphatidylcholine in Canola Lysolecithin

Lysophosphatidylcholine (LPC) possesses excellent oil‐in‐water emulsifying properties and health benefits. The objective of this study was to produce an LPC‐enriched fraction from lysolecithin generated during enzymatic degumming of crude canola oil. Three alcohols (methanol, ethanol and isopropanol) were evaluated for their effectiveness at enriching LPC. A 3 × 3 full factorial design was employed to study the effects of two processing parameters (temperature and alcohol/lysolecithin ratio) on three responses (yield and LPC concentration of alcohol soluble fraction, and LPC recovery) with the most effective alcohol. Ethanol was found to be the best solvent to enrich LPC in lysolecithin. An ethanol soluble fraction with more than 50 % LPC was produced. Quadratic models with R² > 0.9 were developed to describe the relationship between the processing parameters and the responses in the 3 × 3 full factorial experiment. Both ethanol soluble fraction yield and LPC recovery increased with increasing temperature and ethanol/lysolecithin ratio. LPC concentration in the ethanol soluble fraction was enhanced with decreasing temperature and ethanol/lysolecithin ratio. According to the analysis, ethanol soluble fractions with LPC concentration higher than 66 % could be obtained at temperatures of 0–40 °C and an ethanol/lysolecithin ratio of 2:1 (v/w).     

Sterols in pumpkin seed oil

The sterol fraction of unsaponifiable matter obtained from a Yugoslav pumpkin seed ripening was investigated by gas liquid chromatography on a glass capillary column. It contained at least 14 different sterols ten of which were identified primarily by combined gas chromatography-mass spectrometry as cholesterol, brassicasterol, campesterol, stigmasterol, 24-methylcholest-7-en-3β-ol, Δ^7,22,25-stimastatrien-3β-ol, α-spinasterol, Δ^7,25-stigmastadien-3β-ol, Δ^7,25-stigmastenol, and Δ⁷-avenasterol. It was shown that the unidentified sterols in the oil obtained from a Chinese pumpkin seed were Δ^7,25-stigmastadien-3β-ol, and Δ^7,22,25-stigmastatrien-3β-ol,. There was practically no difference in the composition of Yugoslav and Chinese pumpkin seed oil, the main characteristic of which was the presence of Δ⁷-sterols as was already stated by Sucrow.     

Sterols and Oxidized Sterols in Feed Ingredients Obtained from Chemical and Physical Refining Processes of Fats and Oils

The by-products obtained from conventional chemical and physical refining processes for edible fats and oils are important sources of valuable fatty components such as sterols, tocopherols, fatty acids, etc., and are also used as ingredients in animal feed formulations. Reports on sterol composition and content are limited, and the levels of oxidized sterols in these valuable by-products are unknown. This study analyzed by-product fractions from European refineries intended for use as ingredients in animal feeds for their content and composition of sterols and sterol oxidation products. The complex mixtures of sterol oxidation products were separated and quantified by multidimensional capillary columns, a medium polar DB-17MS and an apolar DB-5MS, in GC and GC–MS. Sterol content ranged from 0.l to 3.4 and 0.03 to 5.0 g/100 g in the by-product fractions collected from chemical and physical refining processes, respectively, while the corresponding ranges for sterol oxidation products were 0.02–17 and 0.02–1.5 mg/100 g.     

Sterols in five coastal spermatophytes

Sterolic fractions ofRuppia maritima L.,Diplanthera wrightii Aschers,Halophila engelmanni Aschers,Syringodium filiforme Kutzing andThalassia testudinum Konig have been isolated. The sterolic fractions were characterized by IR spectroscopy and tentative identities of their components were determined by gas chromatography and mass spectrometry.     

Sterols in yeast subcellular fractions

Yeast is the most primitive organism synthesizing substantial amounts of sterols. Because of this eucaryotic organism's versatility in growth conditions, ease of culture, well-defined genetic mechanism, and characteristic subcellar architecture, it is readily applied to studies of the role of sterols in the general economy of the cell. Sterols exist in two major form, as the free sterol, or esterified with long chain fatty acids. The importance of sterols for this organism can be demonstrated using a naturally occurring antimycotic azasterol. This agent inhibits yeast growth. Three effects are seen on sterol synthesis: inhibition of the enzymes Δ¹⁴-reductase, sterol methyltransferase, and methylene reductase. Cells cultured on respiratory substrates are more sensitive to inhibition than are cells growing on glucose. We have demonstrated a relationship between respiratory competency and sterol biosynthesis in this organism. Many mutants altered in sterol synthesis are respirationally defective and must growth fermentatively. One clone has temperature conditional respiration. Experiments with purified mitochondria, perpared from this mutant and its isogenic wildtype, show that the mutant organism is able to respire at the higher temperature but lacks the ability to couple respiration to phosphorylation. No similar loss is seen in the wild-type clones. Data are given which support the proposal that, for inclusion in mitochondrial structures, yeast cells may discriminate among sterols available from the total sterol pool in favor of ergosterol.     

Antioxidant Activity of Piceatannol in Canola Oil

Piceatannol has shown to be a strong antioxidant in vivo, however, its ability to suppress lipid oxidation in foods has not been examined. The present study is to examine the antioxidant effect of piceatannol on heated canola oil compared with that of butylated hydroxytoluene (BHT). The oxidation of canola oil is conducted at 60, 90, 120, and 150 °C by monitoring the depletion of oxygen, the decrease in unsaturated fatty acids, and the changes of primary and secondary oxidation products. Results demonstrated that piceatannol can suppress lipid oxidation of canola oil in a dose-dependent manner with its effect being more effective than BHT. Practical Applications: Lipid oxidation is a major factor in the deterioration of food quality. Synthetic antioxidants, such as BHT and butylated hydroxyanisole, are used to inhibit oxidation in foods, but their safety has been always concerned. Piceatannol has exhibited a strong antioxidant activity to attenuate lipid oxidation and it should be further explored for use as a natural antioxidant in foods.     

Antioxidant Activity of Sesamin in Canola Oil

The present study presents the antioxidant activity of sesamin in canola oil compared with that of butylated hydroxytoluene (BHT) by monitoring the oxygen consumption and the decrease in linoleic acid and α-linolenic acid. The oxidation of canola oil was conducted at 35, 60, 90, 120 and 180 °C with addition of 50–400 ppm sesamin. Results from the oxygen consumption test showed that sesamin dose-dependently inhibited the oxidation of canola oil at concentrations of 50–200 ppm at temperatures of 60–180 °C, however, sesamin lost its antioxidant activity at a low temperature of 35 °C. The fatty acid analysis also demonstrated that sesamin at 50, 100 and 200 ppm dose-dependently prevented the oxidation of linoleic acid and α-linolenic acid in canola oil. Both the oxygen consumption and the fatty acid analysis demonstrated sesamin was less effective than BHT as an antioxidant at temperatures of 60–180 °C. It was therefore concluded that sesamin could prevent the lipid oxidation of frying fats and oil, however, its antioxidant activity was not as potent as that of BHT.     

Sterols and their biosynthesis in some freshwater bivalves

A number of free sterols and sterol esters of three freshwater mussels was separated and identified. A slow rate of biosynthesisde novo of sterols was demonstrated inAnodonta cygnea. Injected cholesterol was found to undergo esterification, oxidation, Δ²²-dehydrogenation and C-24 alkylation. Methyl-[¹⁴C]methionine was proved to be incorporated in C-24 alkylsterols. Abnormally large amounts of cholesterol injected inA. cygnea were metabolized toward restoration of the normal composition of sterols. This was achieved by intensified metabolism of cholesterol, mainly by conjugation, oxidation and Δ²²-dehydrogenation.     

Sterols in mollusks and crustacea of the Pacific Northwest

There are at least eight major sterols in mollusks and cholesterol predominates in shrimp and crab of the Pacific Northwest. Depending on the analytical method used, significantly different values for total sterols in mollusks are obtained. Using combined gas liquid chromatography for Δ⁵ sterols and a modified Liebermann-Burchard reaction for Δ^5,7 sterols, an average total sterol and cholesterol content in oysters (Crassostrea gigas) of 170±21 mg and 51±10 mg/100 g, respectively were found. Approximately one-half these amounts were found in 7 other mollusks. Dungeness Crab (Cancer magiter) and Pacific shrimp (Pandalus joradani) contain 50 and 144 mg cholesterol/100 g, respectively. For these crustacea, this represents 99% of the total sterols present. In mollusks, the percent non-esterified sterols ranges from 49.6 to 100%, with a mean of 73%. Only free cholesterol is present in Dungeness crab. Proximate composition of all samples, including oysters analyzed over a 9-month period is reported. Portions of this paper were presented at the AOCS Meeting, San Francisco, CA, April, 1979.     

两个多羟基甾醇的分离与结构鉴定

研究刺柳珊瑚Echinogorgia sp的化学成分。各种色谱方法进行分离纯化,理化性质和光谱数据鉴定结构。从中国南海硇洲岛刺柳珊瑚Echinogorgia sp中分离得到两个多羟基甾醇：胆甾-3β,5α,6β,11β-四醇;胆甾-22（23）-烯-3β,5α,6β,11β-四醇,这些化合物均为首次从该属珊瑚中获得。     

9-芴甲氧羰基-对甲磺酰氨-(L)-苯丙氨酸的全合成

(L)-苯丙氨酸经硝化、酯化、叔丁氧羰基(Boc)保护α-氨基、Pd/C还原对位硝基、对甲磺酰氯(MSCl)保护对位氨基、经水解反应后,在酸性条件下脱去叔丁氧羰基(Boc)基团,碱性条件下引入9-芴甲氧羰基琥珀酰亚胺(Fmoc-osu),最终生成标题化合物,并且对所合成标题化合物进行了HNMR结构确证。