56 research outputs found

    Erträge und Qualitäten von Saflor (Carthamus tinctorius L.) im ökologischen Landbau

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    Due to the high nutritive value of safflower oil, its weed suppressing capacities, its earlier ripening time compared to sunflowers and the potential of breeding success, safflower could be an interesting crop for organic farmers in future. Yield and qualities of the variety ‘Sabina’ at different organic sites in Germany are reported. Kernel yield, oil and raw protein contents were dependant from site conditions. Average yield levels between 0.2-2.8 t ha-1 with oil contents between 5.5-23.7 % were found

    Propiedades fisicoquímicas, ácidos grasos y tocoferoles de aceites obtenidos de plantas y semillas de Sudán

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    Seven oils, obtained from seven Sudanese oil bearing sources that are Albizia lebbek Oil (ALO), Cassia obtusifolia Oil (COO), Cassia occidentalis Oil (CCO), Abutilon pannosum Oil (APO), Mitracarpus villous Oil (MVO), Ipomea indica Oil (IIO) and Sesamum alatum Oil (SAO), were investigated. The seeds were collected in Sudan from Ghibaish, North Kordofan state. In addition to the oil content, the fatty acid was determined by capillary gas chromatography and the tocopherols were evaluated by highperformance liquid chromatography. The oil content of the seven seeds amounted to 12.8, 7.0, 3.2, 7.1, 11.5, 8.8, and 21.3%, respectively.The oils contained 16.4, 20.0, 14.3, 16.8, 19.4, 19.9 and 10.9 % palmitic acid and 21.0, 24.4, 22.1, 10.9, 27.7, 34.0, 45.1 % oleic acid, and 43.8, 38.2, 45.0, 63.9, 34.6, 33.5, 36.3 % linoleic acid and traces of linolenic acid, respectively.The tocopherol content of these oils amounted to 85.6, 48.2, 32.7, 163.5, 52.5, 30.9, and 26.4 mg/100 g oil, respectively. Alpha-tocopherol was the predominant tocopherol in the oil of Albizia lebbek, Cassia obtusifolia, Cassia occidentalis, and Abutilon pannosum, while gamma-tocopherol was the predominant tocopherol in the oil of Mitracarpus villous, Ipomea indica and Sesamum alatum.Se analizan siete aceites procedentes de plantas y semillas de Sudán: Albizia lebbek Oil (ALO), Cassia obtusifolia Oil (COO), Cassia occidentalis Oil (CCO), Abutilon pannosum Oil (APO), Mitracarpus villous Oil (MVO), Ipomea indica Oil (IIO) y Sesamum alatum Oil (SAO). Las semillas se recolectaron en el estado de Ghibaish, North Kordofan. Además del contenido en aceite (12.8, 7.0, 3.2, 7.1, 11.5, 8.8, y 21.3 %, respectivamente), se determinaron los ácidos grasos mediante cromatografía de gases y los tocoferoles mediante HPLC. Los aceites contenían, respectivamente, 16.4, 20.0, 14.3, 16.8, 19.4, 19.9 y 10.9 % de ácido palmitito, 21.0, 24.4, 22.1, 10.9, 27.7, 34.0, 45.1 % de ácido oleico, 43.8, 38.2, 45.0, 63.9, 34.6, 33.5 y 36.3 % de ácido linoleico y trazas de ácido linolenico. El contenido en tocoferol total fue de 85.6, 48.2, 32.7, 163.5, 52.5, 30.9, y 26.4 mg/100 g oil, respectivamente. Alfa-tocopherol fue el predominante en los aceites de Albizia lebbek, Cassia obtusifolia, Cassia occidentalis, y Abutilon pannosum, mientras gamma-tocopherol fue el mayoritario en los aceites de was the predominant tocopherol in the oil of Mitracarpus villous, Ipomea indica y Sesamum alatum

    Actividad antioxidante de extractos de torta de aceite de semilla de Sclerocarya birrea

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    The antioxidant activity of methanolic extracts from Sclerocarya birrea kernel oil meal, extracted using two different methods was evaluated. The extraction was carried out using magnetic stirring of the material in methanol/water (80:20 v/v) overnight followed by two ultra-sonic treatments for 45 min. (Overnight extract, ONEXT) and three ultra-sonic treatments for 45 min. only (Ultra-sonic extract, USEXT), respectively. Three fractions were obtained from each extract and the contents of total phenolic compounds were determined in each fraction according to the Folin-Ciocalteau method as 34.6, 54.8, and 58.6 mg/g of dry product in ONEXT and 29.6, 84.8, 143.9 mg/g in USEXT, respectively. The antioxidant activity of the extracts was evaluated according to the β-carotene-linoleic acid assay, where the extracts and their fractions showed significant effect (pSe ha evaluado la actividad antioxidante de extractos metanólicos de torta de aceite de semilla de Sclerocarya birrea extraídos usando dos métodos diferentes. La extracción se llevó a cabo mediante agitación magnética del material en metanol/agua (80:20 v/v) durante toda la noche seguida de dos tratamientos con ultrasonidos durante 45 min. (extracto ONEXT) y solo tres tratamientos con ultrasonidos durante 45 min. (extracto USEXT), respectivamente. Se obtuvieron tres fracciones de cada extracto y el contenido total de compuestos fenólicos se determinó en cada fracción según el método de Folin-Ciocalteau como 34.6, 54.8 y 58.6 mg/g de producto seco en ONEXT y 29.6, 84.8 y 143.9 mg/g en USEXT, respectivamente. La actividad antioxidante de los extractos fue evaluada mediante el ensayo del β-carotenoácido linoleico donde los extractos y sus fracciones mostraron efectos significativos (

    Effect of maturity stage on the chemical composition of argan fruit pulp

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    Argan tree, a species endemic to Southern Morroco, is well known for its kernel oil used in cosmetics and health-food, but the corresponding pulp attracted less interest from researchers and little is known about its chemical composition and evolution during maturation. The pulp of argan fruits monthly harvested during the ripening period based on fruit color (April to July), was analyzed. With progressing ripeness various changes were observed in the chemical composition, such as (i) a four-fold increase of total soluble sugars content (glucose, fructose and saccharose), and of Fe (75–165 ppm), but also (ii) a drop of many components, such as proteins (10.1–6.4%), and cell wall polymers, lignin (14.9–5.9%) and hemicellulose and cellulose. Hexane-soluble compounds found in substantial amount (10.7% in April) also decreased with time: the pulp oil peak (8.3%) was in April and June, and that of polyisoprene in June (3.6%). Therefore the stage of maturity (harvest date) is to be considered, without affecting the quality of the argan oil

    The German National Reference Centre for Authentic Food (NRZ-Authent)☆

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    The present report describes the establishment, structure and objectives of the recently established German National Reference Center for Authentic Food (NRZ-Authent). The NRZ-Authent is completely integrated into the Max Rubner-Institut (MRI), the Federal Research Institute of Nutrition and Food in Germany. Various different departments of MRI have a long experience regarding the analysis of the quality of food in general and the testing of food authenticity in particular. Therefore, a close interaction between these food-related departments and the NRZ-Authent is a basic requirement for the successful work of this newly created centre. The addressees of the NRZ-Authent are the official food authorities and laboratories in the German states. In this context, the NRZ-Authent will establish a platform for providing quick access to updated, reliable and consistent technical data, research findings, new techniques and expertise necessary for the correct application of European Union legislation. The MRI has been working on the authenticity of edible oils for a number of years now, and some examples of this successful work are presented

    The impact of fat deterioration on formation of acrylamide in fried foods

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    The current study investigates to what extent the reaction products of thermal degradation directly influence acrylamide formation in French fries. The frying tests at 170 and 180 °C are carried out with rapeseed oil for 32 h with 128 frying cycles. Acrylamide content in French fries is determined by LC-MS/MS. Oxidative and thermal degradation is followed by measuring total polar compounds (TPC), di- and polymerized triacylglycerols (DPTG), monomer oxidized triacylglycerols (MONOX), p-anisidine value (AnV), mono and di-acyl-glycerols (MAG and DAG), acid value (AV), epoxy fatty acids, iodine value (IV), saponification value, and fatty acid composition. During frying, the nature and degradation level of the frying medium have a direct impact on acrylamide formation. It can be shown that the pH-dependent reaction is strongly inhibited at acid values above 0.5 mg KOH g−1 oil. Acidity measured as AV or FFA is mainly caused by oxidation, and less so by hydrolysis of triacylglycerols (TAG) as assumed up to now. Obviously, acid functional groups formed by oxidation of unsaturated fatty acids bound in TAG can act not only as catalyst for dimerization of TAG but also interact with asparagine as most important precursor for acrylamide formation so that no reaction with carbonyl groups for the formation of acrylamide is necessary. Practical applications: The same acidic functional groups that are known to catalyze the formation of dimeric TAG under frying conditions (160–190 °C, access of oxygen) in a nonradical mechanism apparently can also deactivate asparagine by protonization as a potential precursor for the formation of acrylamide. It is recommended not to reduce acidity of used frying oil by active filter aids below AV ≥ 0.5 as it helps to reduce acrylamide contamination of fried food

    Conservación a largo plazo de tres aceites no convencionales

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    Three samples, Sclerocarya birrea oil (SCO), Melon bug oil (Aspongubus viduatus) (MBO), and Sorghum bug oil (Agonoscelis pubescens) (SBO), were stored (autoxidized) in the dark at 30±2 °C for 24 months. Oil aliquots were withdrawn every 2-4 month for analyses of changes in four quality indexes, namely fatty acid composition, tocopherol content, peroxide value and oxidative stability index by Rancimat. After 24 months of storage the fatty acid composition of the three oils showed no change while tocopherol contents were decreased. SCO and MBO showed only slight changes in their oxidative stability as indicated by the peroxide value and induction period during the 24 months of storage. Sorghum bug oil showed a periodical increase in the peroxide value and had less stability as measured by the Rancimat in comparison to other oils.Tres muestras de aceite, Sclerocarya birrea oil (SCO), Melon bug oil (Aspongubus viduatus) (MBO), and Sorghum bug oil (Agonoscelis pubescens) (SBO), fueron almacenadas en la oscuridad a 30±2 °C durante 24 meses. Cada 2- 4 meses se toman alícuotas para analizar los cambios de calidad. Se determinaron la composición en ácidos grasos, el contenido en tocoferol, el índice de peróxidos y la estabilidad oxidativa mediante el aparato Rancimat. Después de 24 meses de almacenamiento, la composición en ácidos grasos no experimentó variación mientras que el contenido en tocoferol disminuyó en los tres aceites. SCO y MBO mostraron cambios minoritarios como se comprobó por los indices de peroxides y estabilidad a los 24 meses. SBO fue el menos estable de los tres aceites

    It is not just a ‘trade‐off’: : indications for sink‐ and source‐limitation to vegetative and regenerative growth in an old‐growth beech forest

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    Summary Controls on tree growth are key issues in plant physiology. The hypothesis of our study was that the interannual variability of wood and fruit production are primarily controlled directly by weather conditions (sink limitation), while carbon assimilation (source limitation) plays a secondary role. We analyzed the interannual variability of weather conditions, gross primary productivity (GPP) and net primary productivity (NPP) of wood and fruits of an old‐growth, unmanaged Fagus sylvatica forest over 14 yr, including six mast years. In a multiple linear regression model, c . 71% of the annual variation in wood‐NPP could be explained by mean air temperature in May, precipitation from April to May (positive influence) and fruit‐NPP (negative influence). GPP of June to July solely explained c . 42% of the variation in wood‐NPP. Fruit‐NPP was positively related to summer precipitation 2 yr before ( R 2 = 0.85), and negatively to precipitation in May ( R 2 = 0.83) in the fruit years. GPP had no influence on fruit‐NPP. Our results suggest a complex system of sink and source limitations to tree growth driven by weather conditions and going beyond a simple carbon‐mediated ‘trade‐off’ between regenerative and vegetative growth
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