Many vegetable oils are marketed as specialty oils because of their retained flavors, tastes and distinct characteristics. Specialty oil samples which were commercially produced and retailed were purchased from local superstores in Reading, UK, and Uppsala, Sweden and profiled for detailed lipid composition and oxidative status. These oil samples include: almond, hazelnut, walnut, macadamia nut, argan, avocado, grape seed, roasted sesame, rice bran, cold pressed, organic and cold pressed, warm pressed and refined rapeseed oils. The levels of PV were quite low (0.5-1.3mEq O₂/kg) but AV and Rancimat values at 100 °C (except for rapeseed oils) varied considerably at (0.5-15.5) and (4.2-37.0 h) respectively. Macadamia nut oil was found to be the most stable oil followed by argan oil, while walnut oil was the least stable. Among the specialty oils, macadamia nut oil had the lowest (4%) and walnut oil had the highest (71%) level of total PUFA. The organic cold pressed rapeseed oil had considerably lower PUFA (27%) compared with other rapeseed oils (28- 35%). In all the samples, α- and γ- tocopherols were the major tocopherols; nut oils had generally lower levels. Total sterols ranged from 889 to 15,106 μg/g oil. The major sterols were β-sitosterol (61-85%) and campesterol (6-20%). Argan oil contained schottenol (35%) and spinasterol (32%). Compared with literature values, no marked differences were observed among the differently processed, organically grown or cold pressed rapeseed oils and other specialty oils in this study.<br><br>Muchos aceites vegetales se venden como aceites especiales debido a su flavor, gusto y características distintas. Muestras de aceites especiales de almendra, avellana, nuez, nuez de macadamia, argán, aguacate, semillas de uva, de sésamo tostadas, salvado de arroz, y aceites orgánico de semillas de colza prensado en frío y, prensado caliente, y refinados que se producen y comercializan al por menor, se obtuvieron en comercios de grandes superficies en Reading, Reino Unido, y Uppsala, Suecia, y se les determinó su composición detallada de lípidos y su estado oxidativo. Los niveles de peróxidos (PV) fueron bastante bajos (0,5 a 1,3 mEq O₂/kg), pero la acidez (AV) y los valores de la estabilidad oxidativa Rancimat a 100 °C (excepto los aceites de colza) variaron considerablemente (0,5-15,5%) y (4,2 a 37,0 h), respectivamente. El aceite de nuez de macadamia se encontró que fue el aceite más estable, seguido por el aceite de argán, mientras que el aceite de nuez fue el menos estable. Entre los aceites especiales, el aceite de nuez de macadamia, presentó el menor nivel de ácidos grasos poliinsaturados (AGPI) (4%) y aceite de nuez el más alto (71%). El aceite ecológico de colza prensado en frío tenía un contenido considerablemente menor de AGPI (27%) en comparación con otros aceites de colza (28-35%). En todas las muestras, α-y γ- fueron los principales tocoferoles, y el aceite de nuez presentó los niveles más bajos. Los esteroles totales variaron desde 889 hasta 15.106 mg/g de aceite. ...

No abstract

1,3-Diacylglycerol is known to reduce body weight and fat deposits in humans. α-Lipoic acid is a potent antioxidant and effective against many pathological conditions, including obesity and related metabolic syndromes. The present work is based on the hypothesis that the hybrid molecules of 1,3-diacylglycerol and lipoic acid possess synergistic and/or additive effects compared with the parent compounds against obesity, overweight, and related metabolic syndromes. Laboratory scale synthesis of 1,3-dioleoyl-2-lipoyl-sn-glycerol (yield 80%) and 1,3-dioleoyl-2-dihydrolipoyl-sn-glycerol (yield 70%) was performed for the first time and supported by NMR and MS data. Free radical scavenging capacity of the conjugates was assayed using DPPH test. A remarkably high in vitro free radical scavenging capacity was demonstrated for the 1,3-dioleoyl-2-dihydrolipoyl-sn-glycerol (EC50 value 0.21). RP-HPLC-MS-APCI analysis showed satisfactory separation between the conjugates (R~1). Protonated molecular ion of the conjugates at m/z 809 and m/z at 811, respectively, and their characteristic fragment ions were abundant.

Plant sterols (PS) are bioactive compounds effective in reducing plasma cholesterol. Fatty acid esters of PS have improved solubility and blending properties when utilized in various food products. Naturally occurring α-lipoic acid (LA) and its reduced form dihydrolipoic acid (DHLA) are known for their antioxidant activity. In addition, they have shown an array of health benefi cial properties against obesity, diabetes, cancer, cardiovascular and infl ammatory diseases etc. Different LA conjugates have been reported to have increased bioactivity compared to the parent compounds. The objective of this study was to synthesize PS esters of LA (PSLA) and DHLA (PSDHLA) in order to increase their cholesterol lowering effect and reducing the risk of atherosclerosis with additional health benefi ts e.g. against oxidative stress.Synthesis of PSLA and PSDHLA was performed with a pure PS mixture of β-sitosterol, stigmasterol, campesterol and brassicasterol. The free radical scavenging capacity of the conjugates was assessed by the DPPH method. Remaining percentage of DPPH free radicals was measured at the steady state for different concentrations of PSLA and PSDHLA. High free radical scavenging capacity was observed for PSDHLA compared with PSLA. Effi cient concentration EC 50 as a molar ratio for PSDHLA was 0.43. The derivatives were analyzed by RP-HPLC-MS-APCI. The order of the elution times of the compounds observed in HPLC-MS analysis was PS< PSDHLA< PSLA. Baseline separation was not achieved between campesterol and stigmasterol and their derivatives. These compounds could be identifi ed by their characteristic fragment ions from the mass spectral data.