Nohemí Gámez-Meza

Concentration of eicosapentaenoic acid and docosahexaenoic acid from fish oil by hydrolysis and urea complexation

Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) derived from chemically or enzymatically hydrolyzed from sardine oil were concentrated by urea complexation. The enzymatic hydrolysis was effected in aqueous emulsion using five commercial lipases from Pseudomonas, three immobilized (PS-CI, PS-CII and PS-DI) and two soluble lipases (AK-20 and PS-30). EPA and DHA were determined by gas–liquid chromatography as methyl esters. Results showed that an immobilized lipase preparation (PS-CI) produced the highest degree of hydrolysis for EPA and DHA (81.5 and 72.3% from their initial content in the oil) after 24 h. After complexation of saturated and less unsaturated free fatty acids, the highest concentration of EPA (46.2%) and DHA (40.3%) was obtained using an ethanolic solution with 20% (w/w) urea and 12% (w/w) PS-CI hydrolyzed with a 78% yield. Combination of enzymatic or chemical hydrolysis with urea complexation is a promising method to obtain highly concentrated n-3 PUFA from sardine oil.

Antioxidant Activity and Diffusion of Catechin and Epicatechin from Antioxidant Active Films Made of Poly(l-lactic acid)

Active membranes and food packaging containing antioxidants like catechin and epicatechin, combined with the use of materials made of biopolymers obtained from renewable sources, could create a novel alternative to reduce oxidation in food, pharmaceutical, and cosmetic products. Poly(94% L-lactic acid) films containing 1.28% catechin and 1.50% epicatechin were extruded in a pilot plant-scale extrusion machine. The diffusion kinetics of catechin and epicatechin into 95% ethanol at 20, 30, 40, and 50 °C and 50% ethanol at 40 °C displayed Fickian release behavior and diffusion coefficients between 0.5 and 50 × 10(-11) cm(2)/s. According to the Arrhenius equation, the energy of activation for the diffusion of catechin and epicatechin in the films was 110.43 and 98.92 kJ/mol, respectively. The antioxidant activity of the films was measured in methanol extracts containing 46.42 μg/mL of catechin and 57.52 μg/mL of epicatechin as 32.90 and 36.68% of scavenging the 2,2-diphenyl-1-picrylhydrazyl radical, respectively.

Oil production from sardine (Sardinops sagax caerulea).

Sardine (Sardinops sagax caerulea) oil was refined and the fatty acid composition as well as the physical and the chemical quality variables were monitored. The refining of crude sardine oil was carried out in three stages: alkali-refining, clay-bleaching, and steam-deodorizing. Results show that the refining process significantly improved (p < 0.05) the chemical quality of the oil, by decreasing its peroxide value (from 10.05 to 0.81 meq/kg), p-anisidine value (from 3.67 to 1.63 mmol/kg), and free fatty acids content (from 0.21 to 0.052% as oleic acid). The oxidative stability increased from 10.39 to 17.55 h (using Rancimat at 60°C, and 7 L/h air flow). These values are within the acceptable standards for edible fish oils. No significant differences (p < 0.05) were observed in fatty acids composition. The notable improvement in the physical properties of refined sardine oil produced high quality fish oil in terms of color (golden yellow) and odor (odorless).

Compuestos fenólicos y actividad antioxidante de cáscara de uva (Vitis vinifera L.) de mesa cultivada en el noroeste de México Phenolic compounds and antioxidant activity of table grape (Vitis vinifera L.) skin from northwest Mexico

The evaluation of the antioxidant capacity of table grape cultivars is important, because it varies according to the production area. In this work, the content of phenolic compounds and total antioxidant capacity (TAC) of skin of 4 table grapes (Vitis vinifera L.) cultivars, two green (Perlette and Sugra One) and two red (Flame and Red Globe) and one industrial variety (Carignane) was evaluated. The total phenol content was determined by Folin-Ciocalteau and TAC of the grape skin extracts by the methods of radicals scavenging ABTS•+ and DPPH•. The TAC (ABTS•+) of extracts was increased (P < 0.05) in the following order: Sugra One < Flame < Perlette and Red Globe < Carignane. The higher contents of gallic acid, resveratrol and rutin were found in the extracts with the higher TAC, which correspond to the cultivars Carignane, Red Globe and Perlette.

Optimisation of Bleaching Conditions for Soybean Oil Using Response Surface Methodology

The refining process applied to soybean oil (SBO) in order to obtain the desirable purity characteristics as edible oil, produces chemical changes by partially removing desirable components such as tocopherols. In this study, the effect of temperature (76.4-143.6°C), contact time (6.4-73.6min) and clay amount (0.16-1.84% w/w) on tocopherol content and quality of SBO were evaluated. Neutralised soybean oil was subjected to bleaching using different clay amounts (Tonsil Optimum 320 FF), stirring (250rpm), and partial vacuum (60mmHg). A response surface methodology (RSM) was used to find the parameters that produce bleached oil with minimum peroxide value (PV), maximum tocopherol retention (TOCR) and light colour. The optimal bleaching conditions for SBO were: temperature, 96°C; time, 23min; clay amount, 1.4% w/w oil. Under these conditions, a bleached soybean oil with 0.1meq/kg of PV, 91.74% of TOCR, and colour 1.53 Lovibond red value units was obtained.

Development of an antioxidant biomaterial by promoting the deglycosylation of rutin to isoquercetin and quercetin.

Quercetin-3-O-rutinoside (rutin), quercetin-3-O-glucoside (isoquercetin) and quercetin have shown antioxidant, cytoprotective, vasoprotective, antiproliferative and antiinflammatory properties. The aim of this work was to determine the conversion of rutin to isoquercetin and quercetin during the production of poly(l-lactic acid) films with potential to deliver these flavonoids toward tissues, pharmaceuticals or food matrices. Three poly(l-lactic acid) formulations with 17.7, 39.6 and 39.1mg/g of rutin were prepared by the extrusion process. Processing temperatures (130-165°C) promoted the deglycosylation of rutin to produce isoquercetin and subsequently quercetin, identified by high performance liquid chromatography coupled to mass spectrometry. The effect of the process on the antioxidant activity of the films was determined by measuring the capacity to scavenge 2,2 diphenyl-1-picrylhydrazyl radicals. The material with the highest proportion of quercetin showed the highest antioxidant activity which could be used to produce delivering devices of the flavonoids to tissues, pharmaceuticals or food matrices.

Chemical characterisation of kernels, kernel meals and oils from Jatropha cordata and Jatropha cardiophylla seeds.

BACKGROUND Jatropha cordata and Jatropha cardiophylla are native to northwestern Mexico and are adapted to arid and semi-arid conditions (<500 mm of precipitation and temperatures from 8 to 45 °C). The aim of this study was to evaluate the chemical composition of J. cordata and J. cardiophylla kernels and oils as well as antinutrients in the defatted kernel meals of these species. RESULTS Kernels of J. cordata and J. cardiophylla seeds analysed in this study were rich in crude protein (283 and 289 g kg(-1) respectively) and lipid (517 and 537 g kg(-1) respectively). The main fatty acids in J. cordata and J. cardiophylla oils were linoleic and oleic acids. High levels of trypsin inhibitor and phytates and low levels of saponins were present in the meals. The phorbol ester contents in J. cordata and J. cardiophylla kernel meals were 2.73 and 1.46 mg g(-1) respectively. CONCLUSION For both J. cordata and J. cardiophylla it could be inferred that (a) the oil and kernel meal were toxic and the kernel meal could be used as livestock feed only after detoxification, (b) the oil could be used for non-alimentary purposes, i.e. biodiesel production, and (c) the seed or oil could be used for isolating various bioactive compounds for pharmaceutical and agricultural applications.

Effect of Refining Process and Use of Natural Antioxidants on Soybean Oil

Soybean (Glycine max L. Merril.) is an annual plant of Asian origin, adapted to temperate climates. This plant is a member of the family Fabaceae, subfamily Papilionoideae, tribe Phaseoleae, genus Glycine and subgenus Soja (Hymowitz, 2004). One of the most important agronomic characteristics of soybean is that it can take nitrogen from the air and fix it to be used as nutrient by the plant. The symbiotic relationship between the soybean plant and its modulation by bacterium (Rhixobium japonicum) is responsible for the conversion of atmospheric nitrogen into plant-available nitrogen. This also makes to soybean a good rotational plant for use with high nitrogen-consuming crops. Another important benefit of this nitrogen fixation is that it helps to keep the production cost of soybeans relatively low compared to other crops that competing for the same land area (Erickson, 1995). Among the factors that allow the soybean to be a dominant crop could be mentioned some of the most important agronomic traits: good profits for producers and processors, as well as the possibility of obtaining high-protein quality meal, which are used as ingredient in food animal. These characteristics have allowed the soybean oil is consumed more than other vegetable oils. Soybean is the most important crop in the world because of its high quality protein and edible oil products. World production of oilseeds during 2009-2010 was 403.58 million metric tons (tons), from which 60% corresponded to soybean, 13.74% to rapeseed, 10.23% to cottonseed, 8.30% to peanut and 7.87% to sunflower (Soya & Oilseed Bluebook, 2010). Others factors that have contributed to soybean worldwide importance are the high demand of meal and oil. The main consumer of these meals is the agricultural sector. World production of vegetable meals during 2009-2010 was 237 million tons; soybean meal represented 67%, rapeseed 13.6% and cotton 6.2% (Soya & Oilseed Bluebook, 2010). Oil is a byproduct of meals production, which has a great demand. In this situation of soybean oil domain in fat total supplies, is extremely important to take advantage of its nutritional properties, such as its high content of polyunsaturated fatty acids essential for humans(n-6 and n-3), and their contents of tocopherols (vitamin E) (Emken, 1995).

Kinetics of Peroxides Degradation to Hexenal During Bleaching of High Oleic Safflower Oil

Bleaching is an important step of the vegetal oil refining for the removal of impurities. Some of the reactions that take place during this stage can be explained by the catalytic properties of bleaching clays. The most important reaction is the decomposition of peroxides to secondary oxidation products, mainly trans-2-hexenal. Therefore, in the present study, empirical and mathematical models were applied to predict the kinetic parameters of peroxide reduction and the formation of trans-2-hexenal during bleaching of high oleic safflower oil. For this, neutralized high oleic safflower oil was mixed with bleaching clay (Tonsil Optimum 320 FF) at three different concentrations (0.5%, 1.0%, and 1.5% based on the weight of the oil), in a laboratory reactor with agitation at 90 °C, 100 °C, and 110±1 °C during 60 min. Results showed that the first-order mathematical model is suitable to predict both peroxide reduction and formation of trans-2-hexenal (R2 > 0.90). Kinetics parameters of initial rate (k0) and the decontamination constant (kd) suggest a high correlation between peroxide reduction to trans-2-hexenal and clays used for bleaching high oleic safflower oil. This information may be used to design particular bleaching conditions for high oleic safflower oil.

Lignin and holocellulose from pecan nutshell as reinforcing fillers in poly (lactic acid) biocomposites

Lignocellulose from agro-food biowaste represents a valuable source of cost-effective structural fillers for wholly renewable polymer composites. In this work, pecan (Carya illinoinensis) nutshell (NS) fiber and its structural components, holocellulose (HC) and acid insoluble lignin (AIL), were isolated, characterized and used as reinforcing fillers to manufacture poly(lactic acid) (PLA) based biocomposites. Thermal, morphological and mechanical properties of the prepared materials were analyzed. NS and HC acted as heterogeneous nucleating agents, potentially able to control PLA physical aging. Moreover, they significantly enhanced the viscoelastic response of PLA, mainly restricting the melt molecular mobility due to hydrodynamic effects and the formation of a three-dimensional particulate network. Flexural tests demonstrated that HC induced a 25% increase in modulus compared to the plain polymer. AIL, conversely, conferred higher ductility to the PLA matrix producing an increase in stress and strain at break of 55% and 65%, respectively. Finally, all the biocomposites showed lower resilience with respect to plain PLA due to the lack of chemical adhesion between filler and matrix. These results emphasize the potential of NS as a source of reinforcing filler in polymer-based biocomposites.