Sterol content in sunflower seeds (Helianthus annuus L.) as affected by genotypes and environmental conditions

Phytosterols play essential roles in many plant cell mechanisms. They are of industrial interest since, as part of the diet, they can reduce low density lipoprotein cholesterol. An increase in plant sterol contents, by improved crop varieties or crop management, could help to answer industrial demands and also to develop environmentally friendly extraction methods. The aim of this study was to evaluate genotypic variability of sterol content in cultivated sunflower and, in particular, effects of sowing date. Results showed large variability among a collection of sixteen sunflower inbred lines and hybrids. Total sterols varied almost twofold between extreme genotypes. A delay of sowing, giving higher temperatures during seed formation, induced a general increase in total sterol concentration by up to 35%, as well as variation in sterol composition according to genotype. These results are considered with an aim of improving sterol content by sunflower breeding programmes.     

Total and partial erucate of pentaerythritol. Infrared spectroscopy study of relationship between structure, reactivity, and thermal properties

Esters of neopentylpolyols are an important starting base for synthetic lubricants. These bulky esters are generally prepared by an esterification reaction between a carboxylic acid and a neopentylpolyol. Because neopentylpolyols have a number of primary alcohol sites, a variety of partial esters is formed before total esters. In the present study, we investigated the reaction between pentaerythritol and erucic acid. The composition of the reaction mixture in erucic acid, partial esters, and total esters was monitored by thin-layer chromatography, coupled with flame-ionization detection. The pure esters and the esters in solution at different concentrations in xylene at different temperatures were analyzed by Fourier transform infrared spectroscopy. Erucic acid and partial esters in xylene coexist in the free form and as bound complexes. These findings furthered understanding of the reactivity and thermal properties of the partial esters.     

Effect of Cooking on Moisture Sorption Isotherms of Shea Nut (Vitellaria paradoxa Gaertn.) Kernels Part II: Modelling and Properties of Sorbed Water

An investigation was undertaken in this work to model the sorption isotherms of cooked and raw shea nut kernels determined by the standard static gravimetric method. The GAB, Halsey and Caurie models were validated and used in describing the sorption behaviour of the kernels. The monolayer moisture contents derived from Caurie’s equation for the desorption of cooked and raw kernels at 40, 50 and 60 °C were 5.49, 4.40 and 2.65 % and 5.22, 3.68 and 2.47 %, respectively. Monolayer moisture contents obtained from the GAB model showed a similar variation. As the temperature of sorption increased from 40 to 60 °C, the number of adsorbed monolayers (N), the surface area of adsorbent (A) and the percent bound water decreased significantly (p?<?0.05). It is suggested that the sorption process at all temperatures is multilayered. Desorption isosteric heats were lower for cooked kernels than the raw ones, while the reverse phenomenon was obtained for the adsorption process. It was established that, during storage, cooked kernels adsorbed moisture more slowly, suggesting that they could be stored for a longer period compared to the raw ones.     

A twin-screw extruder for oil extraction: II. Alcohol extraction of oleic sunflower seeds

Our work is about the extraction of sunflower seed oil in a twin-screw extruder with or without the injection of 2-ethylhexanol and acidified 2-ethylhexanol. 2-Ethylhexanol is mixed with phosphoric acid. The oil recovery is increased to 90% by the co-injection of acidified alcohol. Mixing phosphoric acid with the alcohol enhances the lability of the oily spherosomes. Its addition increases the destruction of the membranes enveloping the lipid-containing organelles to release the oil more easily. Phosphoric acid exhibits an extracting and a degumming role. The best oil quality was obtained at a low extraction temperature (80°C), when 88% of the oil was removed. After alcoholic distillation, the oil exhibited a total acid value (mineral acidity plus organic acidity) of 4 mg KOH/g of oil and an organic phosphorus content below 30 ppm. This work was presented as an oral communication at the 2nd American Oil Chemists’ Society Europe Symposium, October 1–4, 1998, at Cagliari, Italy.     

Theoretical and Kinetic Analysis of the Esterification of Undecylenic Acid with Glycerol

The synthesis of undecylenic acid partial esters can be performed at mild temperature with a classical esterification reaction catalyzed by dodecylbenzene sulfonic acid (DBSA). A semi-empirical molecular modeling on the different reaction intermediates indicates that DBSA can strongly decrease their heats of formation through hydrogen bonding. Diester formation seems to be thermodynamically favored with a selectivity for alpha, alpha, or alpha, beta forms that depend on the geometry of the catalyst-intermediate configuration. Triesters are not favored but a high selectivity for monoesters requires a kinetic control. Experimental approach, considering different DBSA concentrations and temperature partially confirms the theoretical predictions but surfactant properties of DBSA and monoesters may induce nonpredicted geometries. Global apparent activation energies are calculated, corresponding to the formation and hydrolysis of mono and diesters. If water trapping allows the decrease of hydrolysis reaction constants, the presence of water and subsequent phase separation may explain differences between theoretical and experimental results and could help increasing monoester selectivity.     

Influence of physical pretreatments of sheanuts (Vitellaria paradoxa Gaertn.) on butter quality

Shea butter, usually extracted from kernels of Vitellaria paradoxa Gaertn. by rural women in Sub‐Saharran Africa, has multiple traditional and industrial uses. Traditional processing methods are not standardized and often lead to the production of poor quality butter, which attract low market prices. The aim of this work was to study the different pretreatments locally applied to sheanuts during processing in order to identify those that can affect butter quality. The effect of cooking, soaking as well as drying on the amount of butter extracted and its minor constituents were investigated. All these pretreatments significantly affected oil quality. The effect of soaking of the kernels on improving oil extraction yields (55%) was comparable to that of kernels digested with α‐amylase, acid protease, cellulase/hemicellulase, pectinase, and glucanase enzymes before oil extraction reported in the literature. Drying had a significant negative effect on tocopherol contents of the oil. However, residual amounts of tocopherols in the oil after drying were high enough to suggest that it may still confer anti‐oxidant activities. Soaking, cooking, and drying are important pretreatments involved in the production of shea butter locally that need to be standardized in order to produce better quality butter. Practical applications: In this work, we carried out scientific analysis of methods already used by rural women to process shea fruits into shea butter. This work should be useful for establishing processing conditions for obtaining good quality shea butter.     

Management of environmental crop conditions to produce useful sunflower oil components

The objective of this study was to investigate the impact of water availability and temperature after flowering on oil, major fatty acid and sterol contents in seeds of standard and oleic sunflower genotypes, under managed and controlled field conditions. When water deficit was effective from the beginning to the end of anthesis, it modified the fatty acid composition of standard hybrids. When water was supplied, a major enhancement of oleic acid content was associated with a concomitant reduction of linoleic acid content and a decrease in saturated fatty acid contents. Higher temperatures increased the oleic acid content in seeds of standard hybrids. Oil content was enhanced under colder temperature and irrigation. The content of minor oil components, phytosterols, was also enhanced when seed development occurred under high temperature and severe water stress. As a whole, the data showed that combining water management, sowing date and choice of genotype may orientate the biosynthesis of seed components and thus generate seed composition variability suitable for industrial purposes.     

Aframomum stipulatum (Gagnep) K. Schum and Aframomum giganteum (Oliv. & Hanb) K. Schum as Aroma Tincto Oleo Crops resources: essential oil,fatty acids,sterols, tocopherols,and tocotrienols composition of different fruit parts of Congo varieties

BACKGROUND: Today, few known plant species provide both an essential oil (EO) and a vegetable oil (VO). Seed and husk of two Aframomum species were investigated and compared in terms of EO, fatty acids, tocopherols, and tocotrienols. RESULTS: EO yield reaches 15.3 g kg⁻¹ in the seeds and 3.2 g kg⁻¹ in the husks, while VO yield is 180.0 g kg⁻¹ in the seeds and 25.0 g kg⁻¹ in the husks. β‐Pinene, 1,8‐cineol, α‐selinene, terpine‐4‐ol, linalool, myrtenal and β‐caryophyllene are the major compounds of seed and husk EO. Fatty acid analysis of two Aframomum species shows that oleic, linoleic, and palmitic acids were the major compounds of VO. Total sterol contents reached 4.3 g kg⁻¹ in seed VO and 8.5 g kg⁻¹ in husk VO. An appreciable amount of tocopherols (0.52 g kg⁻¹) was found in seed VO. CONCLUSION: The seed and husk oil of A. stipulatum and A. giganteum fruits are rich sources of many bioactive constituents such as fatty acids, sterols, tocopherols and tocotrienols. These tropical wild fruits can be considered as new Aroma Tincto Oleo Crops (ATOC) resources that contain both EOs and VOs. Copyright © 2012 Society of Chemical Industry     

New Environmentally Friendly Oxidative Scission of Oleic Acid into Azelaic Acid and Pelargonic Acid

Oleic acid (OA) is a renewable monounsaturated fatty acid obtained from high oleic sunflower oil. This work was focused on the oxidative scission of OA, which yields a mono-acid (pelargonic acid, PA) and a di-acid (azelaic acid, AA) through an emulsifying system. The conventional method for producing AA and PA consists of the ozonolysis of oleic acid, a process which presents numerous drawbacks. Therefore, we proposed to study a new alternative process using a green oxidant and a solvent-free system. OA was oxidized in a batch reactor with a biphasic organic-aqueous system consisting of hydrogen peroxide (H₂O₂, 30 %) as an oxidant and a peroxo–tungsten complex Q₃{PO₄[WO(O₂)₂]₄} as a phase-transfer catalyst/co-oxidant. Several phase-transfer catalysts were prepared in situ from tungstophosphoric acid, H₂O₂ and different quaternary ammonium salts (Q⁺, Cl^–). The catalyst [C₅H₅N(n-C₁₆H₃₃)]₃{PO₄[WO(O₂)₂]₄} was found to give the best results and was chosen for the optimization of the other parameters of the process. This optimization led to a complete conversion of OA into AA and PA with high yields (>80 %) using the system OA/H₂O₂/[C₅H₅N(n-C₁₆H₃₃)]₃{PO₄[WO(O₂)₂]₄} (1/5/0.02 molar ratio) at 85 °C for 5 h. In addition, a new treatment was developed in order to recover the catalyst.     

Uptake and utilization of trans octadecenoic acids in lactating dairy cows

Trans fatty acids (FA) arise in ruminant-derived foods as a consequence of rumen biohydrogenation and are of interest because of their biological effects and potential role in chronic human diseases. Our objective was to compare 2 trans FA, elaidic acid (EA; trans-9 18:1) and vaccenic acid (VA; trans-11 18:1), with oleic acid (OA; cis-9 18:1) relative to plasma lipid transport and mammary utilization for milk fat synthesis. Three ruminally cannulated, Holstein dairy cows, 259 ± 6 DIM (mean ± SEM), were randomly assigned in a 3 × 3 Latin square design. Treatments were a 4-d abomasal infusion of 1) OA (45.5 g/d), 2) EA (41.7 g/d), and 3) VA (41.4 g/d). Milk samples were collected at each milking and blood samples were collected at the start and end of each treatment period. The proportions of total plasma FA associated with each plasma lipid fraction at baseline (pretreatment) were 62.6 ± 0.6% phospholipids, 26.1 ± 0.6% cholesterol esters, 9.8 ± 0.4% triglycerides, and 1.5 ± 0.1% nonesterified fatty acids; these values were unaffected by treatment. There were striking differences in the FA composition of the individual plasma lipid fractions and in the distribution of specific 18-carbon FA among the lipid fractions. Infusion of treatment isomers caused their specific increase in the various plasma lipid fractions but had no effect on milk production variables, including milk fat yield and content. Transfer efficiency of infused OA, EA, and VA to milk fat averaged 65.5 ± 3.0%, 59.7 ± 1.5%, and 54.3 ± 0.6%, respectively. For the VA infusion, 24.6 ± 1.1% of the transfer was accounted for by the increased yield of cis-9, trans-11 conjugated linoleic acid in milk fat, consistent with its endogenous synthesis from VA via the mammary enzyme Δ⁹-desaturase. Notably, linoleic acid (18:2n-6) and linolenic acid (18:3n-3) accounted for 47.7% of total plasma FA, but only 2.6% of FA in milk. Overall, results demonstrate clear differences in plasma transport and mammary uptake and utilization of 18-carbon FA, and these relate to the location, orientation, and number of double bonds.