Un procedimiento simple para evaluar el comportamiento de aceites y grasas a temperaturas de fritura

5 pages, 5 tables.[EN] A standard procedure is proposed to evaluate the performance of fats and oils at frying temperatures, taking the advantages provided by the Rancimat apparatus, i. e., standard vessels, temperature correction and temperature homogenity in all vessels resulting from the particular characteristics of the heating block. The results obtained in oil samples of 8 g heated at 180° C for 10 h in triplicate gave coefficients of variation lower than 6% for total polar compounds and polymers. In case of limited amount of oil, it is additionally proposed to use only 2 g of sample provided that a similar surface-to-oil volume ratio is maintained, and coefficients of variation of the same order than those for 8 g samples were thus obtained. Advantages of the procedure as well as potential applications for evaluation of frying fats and oils are Included. As an example, the effect of a-tocopherol on performance of sunflower oils was analyzed.[ES] Se propone un procedimiento estándar para evaluar el comportamiento de aceites y grasas a temperaturas de fritura. En este procedimiento se utilizan las ventajas del aparato Rancimat, que permite el uso de tubos estándar, la corrección de la temperatura, en su caso, y la igualdad de temperatura en todos los tubos dadas las características del bloque de calentamiento. De los resultados obtenidos en muestras de 8 g de aceite calentadas a 180° C durante 10 h, analizadas por triplicado, se obtuvieron coeficientes de variación inferiores al 6% para la determinación de compuestos polares y polímeros. En caso de limitación en la cantidad de aceite, se propone utilizar 2 g de muestra, manteniendo similares valores para la relación superficie a volumen de aceite, lo que permite obtener valores de alteración y coeficientes de variación del mismo orden. Se analizan finalmente las ventajas globales del procedimiento y sus distintas posibilidades en la evaluación de grasas de fritura. Como ejemplo, se aplica el procedimiento a la evaluación del efecto de los antioxidantes naturales de los aceites de girasol.This study was funded by CICYT (Project ALI-95- 0736). Daniel Barrera Arellano was supported by a postdoctoral fellowship (95/9304-2) from Fundaçao de Apoío à Pesquisa do Estado de Sao Paulo (FAPESP).Peer reviewe

Risk/benefit considerations of a new formulation of wheat-based biscuit supplemented with different amounts of chia flour

The incorporation of Chia (Salvia hispanica L.) in the formulation of certain foods may be particularly desirable from a nutritional and healthy point of view. The effect of addition of chia flour on the nutritional properties and the formation of process contaminants in wheat flour-based biscuits was investigated. Higher percentage of chia flour in the formula increased the antioxidant capacity, phenolic compounds, protein, fiber and polyunsaturated fatty acids content, then resulting in a nutritionally enhanced product. However levels of process contaminants were also increased and thus acrylamide, hydroxymethylfurfural and furfural ranged between 151 and 1188 mg/kg, 22.8e71.4 mg/kg and 1.3 e5.6 mg/kg, respectively, when chia was added in a range of 0e20% of the total weight. In parallel, the formation of dicarbonyl compounds, such as methylglyoxal and glyoxal, were significantly increased with addition of 5%. Lipid oxidation, particularly polymerization compounds, was accelerated in chiaenriched biscuits, which decreased the shelf-life of the product by promoting a rapid rancidity under accelerated storage conditions. Therefore, although nutritional properties are improved by the incorporation of chia into the biscuits, the increase in the content of process contaminants and the extent of the lipid oxidation should be carefully considered in a context of risk/benefit. © 2016 Elsevier Ltd. All rights reserved.This work was funded by projects S1013/ABI-3028-AVANSECAL (CAM) and CSIC-201370E027.Peer reviewe

Método rápido para la determinación de compuestos polares en aceites y grasas de fritura

The determination of polar compounds by adsorption chromatography is the most accepted method for the analysis of used frying fats due to its high precision and accuracy. However, this method is expensive and time consuming. In this study, a rapid analytical method to determine polar compounds is proposed. Starting from milligrams of sample dissolved in a solution of hexane containing methyl oleate as internal standard, the nonpolar fraction, which comprises the non-altered triglycerides (TG) and the internal standard, is obtained by solid phase extraction. Then, the non polar fraction is quantitatively analyzed in 15 min by high-performance size-exclusion chromatography (HPSEC) and the polar fraction is determined by difference of weight. Response factors for pure TG and FAME were calculated. Six samples of sunflower oils of different degrees of unsaturation were analyzed in triplicate and the results were compared with those obtained by the gravimetric method based on silica classical column chromatography. Results showed no significant differences between the two methods. In addition, the repeatability of the proposed method was excellent, as the coefficient of variation ranged from 1.5 to 13% depending on the contents of polar compounds.La determinación de compuestos polares mediante cromatografía de adsorción es el método más aceptado en el análisis de aceites y grasas de fritura debido a su elevada exactitud y precisión. Sin embargo, la determinación es costosa, debido al elevado consumo de sílice y disolventes, y son necesarias varias horas para la obtención del resultado. En este estudio se propone una determinación alternativa rápida. Partiendo de miligramos de muestra disueltos en una solución de hexano con oleato de metilo como patrón interno, la fracción no polar, que contiene los triglicéridos no alterados y el patrón interno, es aislada mediante extracción en fase sólida. Posteriormente, la fracción no polar se analiza cuantitativamente en 15 min mediante cromatografía líquida de exclusión y la cantidad de fracción polar se determina por diferencia de peso. Se han calculado los factores de respuesta de triglicéridos y ésteres metílicos. El método se ha aplicado a seis muestras de aceites de girasol de distinto grado de insaturación evaluadas por triplicado y los resultados se han comparado con los obtenidos mediante la determinación gravimétrica basada en cromatografía en columna clásica de sílice. No se han encontrado diferencias significativas entre los dos grupos de resultados. Por otra parte, la repetibilidad fue excelente ya que los coeficientes de variación oscilaron entre 1.5 y 13% dependiendo del contenido en compuestos polares de los aceites.This research work was supported by Junta de Andalucía and Ministerio de Educación y Ciencia (Project AGL 2004-00148).Peer reviewe

An investigation of process contaminants ’ formation during the deep frying of breadcrumbs using a bread coat model

The formation of acrylamide, hydroxymethylfurfural (HMF) and furfural was investigated in a deep fried breadcrumb coat model resembling the coat batter of breaded foods. The influence of the composition of the breadcrumb and the frying conditions on the formation of these contaminants was evaluated. Six wheat-based flour formulations of breadcrumbs were deep fried in sunflower oil at temperatures between 170–200 °C and for frying times of 1–5 minutes. Results showed significant differences in the levels of contaminants according to the concentration of the potential precursors in the breadcrumbs. HMF was influenced by the sugar content in the breadcrumbs whereas levels of acrylamide were significantly correlated with the ratio between asparagine and reducing sugars. Acrylamide, HMF and furfural were directly related to the frying time and temperature. The composition of the breadcrumb and the compounds formed during frying contributed to the total antioxidant capacity of the fried samples. The bread coat model is a useful tool in the formulation of breaded foods since it allows the evaluation of the contribution of breadcrumbs in the formation of process contaminants after frying.This research was partly funded by projects S1013/ABI-3028-AVANSECAL (Comunidad Autonoma of Madrid and FEDER program) and Spanish National Research Council (CSIC-201370E027).Peer reviewe

LAS MICRORREGIONES UNA ALTERNATIVA PARA LA PRODUCCIÓN Y COMERCIALIZACIÓN EN BASE A SU VOCACIÓN PRODUCTIVA

En esta ponencia se plantea la necesidad de hacer investigación a nivel microrregional con tendencia a la integración territorial, por la biodiversidad que se presentan entre cada una de las microrregiones de México, no tan solo desde el punto de vista de sus recursos naturales sino también de sus recursos humanos, lo cual ha constituido desde siempre un gran obstáculo para la integración regional, a pesar de los múltiples esfuerzos que se han hecho con diferentes programas, que han fracasado por muchas razones, pero una de las principales es la falta de continuidad de estos, lo cual permitirá una base conceptual para comercial los productos de cada centro integrador aprovechando su vocación productiva

New Analytical Evidence of Discontinuous Oxidation in Dried Microencapsulated Lipids

24 Páginas; 4 FigurasFormation of hydroperoxy-, keto- and hydroxy-dienes was studied at 40 °C in fatty acid methyl esters (FAME) microencapsulated in a dairy-like matrix formed by lactose and sodium caseinate. The FAME were obtained from conventional sunflower oil and the microcapsules were prepared by freeze-drying of an oil-in-water emulsion. For comparative purposes a neat sample of FAME was also tested. Results showed that for a given content of hydroperoxydienes much more elevated amounts of secondary products were detected in the microencapsulated sample compared to the neat sample of FAME. The contents of keto- and hydroxy-dienes found in the microencapsulated FAME ranged as a whole between 6 and 31 wt% of the analyzed compounds, while the neat sample showed values lower than 1.5 %. Along with the fact that relatively higher contents of polymers were also found in the encapsulated sample, these results can be attributed to lipid droplets with very different oxidation states. On the one hand, the extract would be formed from droplets in early stages of oxidation containing hydroperoxides and very low contents of secondary products and, on the other, from droplets in advanced stages with decreased hydroperoxides and substantial contents of secondary products. Unlike the neat sample, hydroxy-dienes formed with significantly higher amounts than keto-dienes in the microencapsulated FAME, suggesting a possible chemical role of the encapsulation matrix.This work was funded by the “Ministerio de Economía y Competitividad” through project AGL2013-45110-R, “Junta de Andalucía” through project P09-AGR-4622 and CSIC through a PIE project with reference 201270E134.Peer reviewe

Inhibition of hydroperoxy-, keto- and hydroxy-FAME by alpha- and delta-tocopherol at Rancimat conditions

The effects of alpha- and delta-tocopherol on inhibition of hydroperoxides, keto and hydroxy compounds at Rancimat conditions, i.e. 100 ºC and air bubbling, were studied in samples of fatty acid methyl esters (FAME) obtained from high linoleic (HL) and high oleic (HO) sunflower oils. Simple hydroperoxides from methyl linoleate and oleate and keto and hydroxy compounds derived from methyl linoleate hydroperoxides were analyzed by HPLC-UV-ELS. Different tocopherol concentrations, namely, 10, 50, 100, 500 and 1000 mg/kg, were tested. Irrespective of the lipid substrate and the initial concentration of tocopherol, results showed that the content of hydroperoxides accumulated during the induction period was remarkably higher in the samples containing delta-tocopherol. The relative concentrations of oleate hydroperoxides in the HO samples were also higher in the presence of delta-tocopherol. Alpha-tocopherol was more effective in inhibiting hydroperoxides at low levels, being 100 mg/kg its optimal concentration, while delta-tocopherol displayed optimal protection at 1000 mg/kg. Under the oxidation conditions applied, neither alpha- nor delta-tocopherol showed a protective effect on hydroperoxide decomposition at any level assayed. Formation of keto- and hydroxy-dienes was more related to the concentration of their hydroperoxide precursors. Furthermore, both tocopherols gave rise to increased concentrations of ketodienes at 500 and 1000 mg/kg compared to the controls. Such an effect was more pronounced for alpha-tocopherol and in the HL samples.This work was Funded by the Spanish Ministry of Economy and Competitiveness through project AGL2013-45110-R and CSIC through a PIE project with reference 201270E134. The authors also thank the Spanish Ministry of Economy and Competitiveness for supporting Susana Marmesat with a “Juan de la Cierva” contract with reference JCI-2011-08874.Peer Reviewe

Assessment of Discontinuous Oxidation in Microencapsulated FAME based upon Analysis of Hydroperoxy-, Keto- and Hydroperoxydienes

Today there are a number of formulated food o/w emulsions that are dehydrated such as infant formulae and others containing polyunsaturated lipids and oils of nutritional value. As a result of drying, the lipids are microencapsulated in the carbohydrates and/or proteins formerly present in the aqueous phase. Evaluation and control of lipid oxidation in such products are of great significance because of losses of quality and the formation of compounds that may even be detrimental to health. Oxidized droplets may occur in different conditions and complex mixtures of primary, secondary and even advanced oxidation compounds may be detected in quite different proportions to those found in continuous phase. In these cases evaluation of oxidation would be possible by applying a novel HPLC method. In the present study formation of hydroperoxy-, keto- and hydroxy- dienes was studied at 40 ºC in fatty acid methyl esters (FAME) microencapsulated in a dairy-like matrix. The FAME were obtained from conventional sunflower oil and the microcapsules were prepared by freeze-drying of an oil-in-water emulsion containing sodium caseinate and lactose. For comparative purposes a neat sample of FAME was also assayed. Results showed that for a given content of hydroperoxydienes much more elevated amounts of secondary products, i.e. keto- and hydroxy- dienes, were detected in the microencapsulated sample, ranging as a whole between 6 and 31 wt% of the analyzed compounds, compared to the neat sample, which showed values lower than 1.5%. Along with the fact that relatively higher contents of polymers were found in the encapsulated sample, these results can be attributed to lipid droplets with very different oxidation states. On the one hand, the extract would be formed from droplets in early stages of oxidation containing hydroperoxides and very low contents of secondary products and, on the other, from droplets in advanced stages with decreased hydroperoxides and substantial contents of secondary products. Unlike the neat sample, hydroxydienes formed at significantly higher amounts than ketodienes in the microencapsulated FAME, suggesting a possible chemical role of the encapsulation matrix.This work was funded by the Spanish Ministry of Economy and Competitiveness through project AGL2013-45110-RPeer Reviewe

Variables que intervienen en la oxidación lipídica de aceites microencapsulados

Dried microencapsulated oils are powdery foods or ingredients, prepared by drying natural or formulated emulsions, wherein the oil globules are dispersed in a matrix of saccharides and/or proteins. The study of lipid oxidation in microencapsulated oils is a very difficult task since, in addition to the numerous variables normally involved in lipid oxidation, mainly unsaturation degree, oxygen, light, temperature, prooxidants and antioxidants, other factors exert an important influence in these heterophasic lipid systems. In this paper, the present state of the art on lipid oxidation in dried microencapsulated oils is reviewed, focused on the variables specifically involved in oxidation of these lipid systems. Such variables include those pertaining to the preparation process (type and concentration of the matrix components and drying procedure) and those related to the physicochemical properties of microencapsulated oils (particle size, oil globule size, lipid distribution, water activity, pH and interactions between matrix components).Los aceites microencapsulados son alimentos o ingredientes en polvo preparados mediante secado de emulsiones naturales o formuladas, donde los glóbulos de aceite se encuentran dispersos en una matriz de hidratos de carbono y/o proteínas. El estudio de la oxidación lipídica en aceites microencapsulados es muy difícil ya que, además de las numerosas variables implicadas normalmente en la oxidación lipídica, principalmente el grado de insaturación, oxígeno, luz, temperatura, prooxidantes y antioxidantes, en estos sistemas lipídicos heterofásicos existen otros factores que ejercen una importante influencia. En este trabajo, se revisa la situación actual del conocimiento sobre oxidación lipídica en aceites microencapsulados en relación con las variables que intervienen específicamente en la oxidación de estos sistemas lipídicos. Concretamente, dichas variables incluyen las implicadas en el proceso de preparación (tipo y concentración de los componentes de la matriz y procedimiento de secado) y las relacionadas con las propiedades físico-químicas de los aceites microencapsulados (tamaño de partícula, tamaño de glóbulo de aceite, distribución lipídica, actividad del agua, pH e interacciones entre los componentes de la matriz)

LOS HUERTOS FAMILIARES COMO ESTRATEGIA PARA LA EDUCACIÓN AMBIENTAL EN EL DESARROLLO

La educación ambiental a través del sistema de producción de huertos familiares, que son los que mayor sustentabilidad ha mostrado a lo largo de la historia. Esto se debe a su semejanza con los ecosistemas tropicales en cuanto a biodiversidad, partiendo de que la agricultura es una actividad basada en los conocimientos empíricos, milenarios de culturas autóctonas en que destaca la destreza del agricultor (Hernández Xolocotzi, Efraín, et al., 1977). Este sistema de producción se considera junto con la “milpa” como un sistema sustentable. Además, la biodiversidad y el uso intensivo de los estratos vertical, horizontal y temporal, lo hacen altamente eficiente, porque minimiza el problema de plagas y enfermedades y prácticamente elimina la necesidad de aplicación de fertilizantes inorgánicos. Pero con la entrada de gran‐ des centros comerciales que ofertan todo tipo de productos del campo, el modelo tradicional de producción basado en huertos familiares ha ido desapareciendo paulatinamente