食用植物油中酸价测量结果的不确定度评估

应用不确定度评定方法对酸价测量结果进行不确定度分析与评估,得出样品中酸价的合成标准不确定度和扩展不确定度。根据油脂中酸价测定的原理和步骤建立数学模型,对不确定度进行评估。该方法测定油脂中酸价的合成不确定度u（X）=0.03,扩展不确定度U=0.06,滴定终点判断引入的标准不确定度影响较大。     

工业硫磺酸度测量不确定度的评估

应用不确定度评定方法对硫磺酸度测量进行不确度分析与评估,得出样品中酸度值的合成标准不确度和扩展不确定度。根据硫磺酸度测定的原理和步骤建立数学模型,对不确定度进行评定,找出主要影响因素,以进一步提高酸度测定的准确性,EXCEL表在评估中的使用,使评定中的计算更直观更灵活。     

Color determination in olive oils

Color characterization of olive oil may be of great importance to the industry. To determine the color of a solution, it is necessary to accurately measure a series of tristimulus coordinates for which several methods exist. This study analyzes the errors in the calculation of tristimulus values of olive oil color based on methods, by using several selected ordinates and an increasing number of weighted ordinates, and how these errors affect the values of the chromatic parameters defined in the various chromatic systems. The above analysis shows that the use of a large number of ordinates will lead to better results in the color definition of oils. For its determination, we have used the CIE 1931, CIELUV 1976 and CIELAB 1976 spaces; the latter yields the best results.     

希腊橄榄油的加工技术

介绍希腊橄榄油加工和市场现状,关键技术及其特征,主要设备,橄榄油的等级、质量指标和感官评价,化学组成及分析方法,影响橄榄油质量的因素,废水和果渣的组成及其副产物的开发利用以及橄榄油的食用及药用功能等,提出油橄榄的综合利用和加工方向。     

Effects of free fatty acids on oxidative stability of vegetable oil

The effect of free fatty acid (FFA) content on the susceptibility to thermooxidative degeneration of vegetable oils was determined by Rancimat analysis. A prooxidant effect of FFA was observed in all filtered oils, independently of lipidic substrate and of its state of hydrolytic and oxidative alteration. The intensity of this effect was related to FFA concentration, but regression analysis of the experimental data did not show a general correlation law between FFA concentration and induction time (I _t). Different results were obtained for freshly processed virgin olive oils, characterized by postpressing natural suspension-dispersion: opposite behavior was observed of FFA content as regards oxidative stability, depending on the presence of suspended-dispersed material. This fact is of interest because the dispersed particles play a double stabilizing effect on both oxidative and hydrolytic degradation. These results showed that avoidance of oil filtration is highly desirable to extend olive oil’s shelf life.     

Interfacial tension of edible oils in supercritical carbon dioxide

Interfacial properties essentially influence fluid‐liquid separation processes. Thereby, interfacial tension is an important parameter that is associated with mass transfer and mutual solubility of participating compounds. For this reason, interfacial tension of a virgin olive oil with a known amount of free fatty acids was measured in supercritical carbon dioxide atmosphere at 313 K and 353 K and pressures up to 40 MPa. The obtained values were compared to different oils some of which contain appreciable amounts of volatile components. In general, interfacial tension behaviour is dominated by the effect of pressure, whereas differences between oil compositions are secondary. Besides mutual solubility interfacial tension is supposed to be associated with the compressibility of the dense fluid phase. For predicting mass transfer area some general comments on the colloidal behaviour of systems containing supercritical CO₂ are made     

Use of nitrogen to improve stability of virgin olive oil during storage

Experiments were carried out to study the possibility of improving the stability of extra virgin olive oil by using nitrogen as a conditioner gas during storage. With this aim, virgin olive oil samples, obtained from Leccino and Coratina cultivars, were stored in the dark, in closed bottles conditioned with air or nitrogen at 12–20 and 40°C. Results indicated that the FFA percentage increased over 1% only when oils were stored at 40°C. The PV and the K ₂₃₂ value (light absorbance at 232 nm) of oils increased over the limit value allowed by European Union law when the bottles were only partly filled and air was the conditioner gas. The use of nitrogen as conditioner gas helped to avoid this risk during 24 mon of storage at 12–20°C. The total phenolic content of both cultivars oils decreased during storage because their oxidation protected the oils from autoxidation. The content of total volatile compounds in oils decreased continuously during storage at 12–20°C, whereas it increased over 10 (Coratina cv.) and 15 (Leccino cv.) mon and then diminished when the storage temperature was 40°C. The same behavior, i.e., increase then decrease, was ascertained for trans-2-hexenal. The hexanal content of oils increased continuously during storage because this compound is formed by the decomposition of the 13-hydroperoxide of linoleic acid.     

UPLC-MS/MS法测定食用植物油中15种全氟化合物

建立了UPLC-MS/MS同时测定食用植物油中15种全氟化合物(包括全氟烷基羧酸类、全氟磺酸类、全氟磺酰胺、全氟调聚醇)的检测方法.采用ACQUITY UPLC BEH-C18(1.7μm,2.1 mm×100 mm)色谱柱,以5 mmol/L乙酸铵的5％甲醇水溶液和95％甲醇水溶液为流动相,梯度洗脱,流速为0.3 m...     

橄榄油表面活性剂的体外刺激性研究

PEG－7橄榄油羧酸钠（SPOC）和PEG－7橄榄油酯（OPE）是新型的由橄榄油衍生而来的温和型表面活性剂,它们不同于硫酸盐、醇醚硫酸盐和磺基琥珀酸酯,但具有相同的起泡能力,且对皮肤无刺激作用。第一种含有洗涤活性并有较高的皮肤相容性;第二种具有润肤特性,还能够修复皮肤的氢化类脂层。通过进行体外溶解红血细胞的实验研究来证实其所具有的良好性能。     

以橄榄油为模拟食品测定微波加热容器的总迁移量

本文以橄榄油为脂肪食品模拟物,对市售微波适用塑料容器中有害物质的总迁移量进行了测定。对照我国现行标准中正己烷模拟物的测定结果,发现以橄榄油为模拟物的方法测得样品合格率为20%,而以正己烷为模拟食品测得样品合格率为100%。说明我国现行的相关标准对评价微波加热容器的安全性还存在不足之处。     

Characteristics of tea seed oil in comparison with sunflower and olive oils and its effect as a natural antioxidant

A comparison of iodine values showed that the degree of saturation of tea seed oil (Lahjan variety) was intermediate between the oils of sunflowerseed (Fars variety) and olive (Gilezeytoon variety), and the saponification values of these three oils were similar. Tea seed oil consisted of 56% oleic acid (C18∶1), 22% linoleic acid (C18∶2), 0.3% linolenic acid (C18∶3), and therefore, on the basis of oleic acid, occupied a place between sunflower and olive oil. In studies at 63°C, the shelf life of tea seed oil was higher than that of sunflower oil and similar to olive oil. Tea seed oil was found to have a natural antioxidant effect, and it enhanced the shelf life of sunflower oil at a 5% level. In this study, tea seed oil was found to be a stable oil, to have suitable nutritional properties (high-oleic, medium-linoleic, and lowlinolenic acid contents), and to be useful in human foods.     

Low molecular weight polypeptides in virgin and refined olive oils

Twenty-eight virgin olive oils—from different regions of Spain and prepared from olive drupes of different varieties—and six refined olive oils were analyzed to determine the presence of proteins in these oils. All oils studied showed the presence of proteins in the range of 7–51 μ/100 g of oil. There were no significant differences in protein content in oils from different varieties or between virgin or refined oils. In addition, all oils exhibited analogous amino acid patterns, suggesting a similarity among protein fractions obtained from different oils. A polypeptide with an apparent M.W. of 4600 Da was common to the isolated protein fractions. These results suggest that this polypeptide is a previously unknown minor component in olive oils. No clear influence of this component on oil stability was observed when oil stabilities were estimated as a function of phenol, tocopherol, phosphorus, and protein contents of the oils.