Detecting vegetable oil adulteration in hazelnut paste (Corylus avellana L.)

The possibilities of detecting hazelnut paste adulterated with refined and non-refined vegetable oils have been studied. Research was focussed mainly on peanut, high oleic-acid sunflower, corn and soybean oils which have a similar composition to hazelnut oil. The analytical procedures to detect fatty acid (FA), triacylglycerol (TAG) and tocopherol profiles as indicators of adulteration were determined. The better indicators experimentally determined were seven FA (palmitic, stearic, linoleic, linolenic, arachidonic, behenic and lignoceric acids) and different TAG with three unsaturated FA (the code letters used for FA are: P = C_16:0; S = C_18:0; O = C_18:1; L = C_18:2;; L_n = C_18:3) (LLL_n, LLL and OOO), two unsaturated FA (POL, PLL and SOO), and one unsaturated FA (PPL). As expected, when refined vegetable oils were added to hazelnut paste, the increment of stigmasta-3,5-diene allowed detection at levels of 2% oil added. Limits of detection were measured using standard and adulterated hazelnut with different amounts of non-refined vegetable oils added (5%, 10%, 20% and 30%). The distribution of tocopherols and tocotrienols is highly useful, except in the case of added sunflower oil. The differences between the experimental and theoretical values of the TAG with equivalent carbon number (ΔECN) of 42 does not improve the detection limit of hazelnut paste adulterated with peanut or sunflower oils. Similarly, tocopherols usually added to refined vegetable oils as an antioxidant were also determined.     

The influence of dietary hazelnut kernel oil on the performance and fatty acid composition of broilers

A total of 360 one‐day‐old broilers (Ross 308) were allocated to three treatment groups with four replicates each of 30 chicks to evaluate the effects of the dietary hazelnut kernel oil (HKO) inclusion on the performance and the composition of fatty acid of meat in broilers. Treatments were diets with (1) soybean oil (SO), (2) HKO, or (3) HKO + SO (in equal amount, HKSO) added to the basal diets. There were no significant differences in weight gain, feed per gain, dressing percentage, abdominal fat weight, and mortality among the different dietary oil sources. Dietary HKO decreased (P < 0.01) linoleic and linolenic acids contents and the ratio of SFA:MUFA (saturated fatty acids:unsaturated fatty acids) of breast meats in broiler, and increased oleic acid content compared to SO. The result indicates that meat from broiler chickens fed diets containing HKO, singly or combined with SO could be an important source of oleic acid for human diets. Copyright © 2007 Society of Chemical Industry     

Differential scanning calorimeter application to the detectionof refined hazelnut oil in extra virgin olive oil

The potential application of differential scanning calorimetry (DSC) to verify adulteration of extra virgin olive oil with refined hazelnut oil was evaluated. Extra virgin olive oil and hazelnut oil were characterised by significantly different cooling and heating DSC thermal profiles. Addition of hazelnut oil significantly enhanced crystallisation enthalpy (at hazelnut oil ?20%) and shifted the transition towards lower temperatures (at hazelnut oil ?5%). Lineshape of heating thermograms of extra virgin olive oil was significantly altered by hazelnut oil addition: a characteristic exothermic event originated at −27 °C in extra virgin olive oil and progressively disappeared with increasing hazelnut oil content, while the major endothermic peak at −3.5 °C broadened (at hazelnut oil ?40%) and the minor endothermic peak at 8 °C shifted toward lower temperatures (at hazelnut oil ?5%). The preliminary results presented in this study suggest that DSC analysis may be a useful tool for detecting adulteration of extra virgin olive oil with refined hazelnut oil.     

榛子乳饮料加工工艺及其稳定性研究

榛子是一种营养价值很高的补品,其综合利用价值也很高.研究了以榛子为主要原料的植物蛋白饮料的加工工艺及其稳定性.着重对CMC、卡拉胶、黄原胶等、单甘脂、蔗糖脂、吐温 80 等稳定剂、乳化剂及乳化稳定剂在榛子乳饮料中的稳定效果进行了研究.实验结果表明,在榛子乳饮料中添加0.08%卡拉胶、0.08%瓜尔豆胶、0.1%蔗糖脂、0.15%复分稳定剂,稳定效果最佳;70℃、35MPa的均质条件有较好的效果;采用121℃、20min 的高温高压杀菌,效果最好.     

Prediction of effect of natural antioxidant compounds on hazelnut oil oxidation by adaptive neuro-fuzzy inference system and artificial neural network

In this study, natural compounds including gallic acid, ellagic acid, quercetin, β-carotene, and retinol were used as antioxidant agents in order to prevent and decrease oxidation in hazelnut oil. Quercetin showed the strongest antioxidative effect among the antioxidative agents, during storage. The accuracy of adaptive neuro-fuzzy inference system (ANFIS) and artificial neural network (ANN) models was studied to estimate the oil samples' peroxide value (PV), free fatty acid (FFA), and iodine values (IV). The root mean square error (RMSE), mean absolute error (MAE), and determination coefficient (R(2)) statistics were used to evaluate the models' accuracy. Comparison of the models showed that the ANFIS model performed better than the ANN and multiple linear regressions (MLR) models for estimating the PV, FFA, and IV. The values of R(2) and RMSE were found to be 0.9966 and 2.51, 0.6269 and 88.55, 0.5120 and 101.8 for the ANFIS, ANN, and MLR models for PV in testing period, respectively. The MLR was found to be insufficient for estimating various properties of the oil samples.     

大黄鱼鱼卵磷脂抗油茶籽油氧化作用的研究

目的　研究大黄鱼鱼卵磷脂对油茶籽油的抗氧化作用。方法　利用Schaal烘箱法, 将含有不同质量分数鱼卵磷脂(0.05%、0.10%、0.20%、0.40%)的油茶籽油放置在(60±0.5) ℃烘箱中加速氧化21 d, 同时做空白对照组, 以及大豆卵磷脂、特丁基对苯二酚(tert-butyl hydroquinone, TBHQ)两组阳性对照组, 测定加速氧化期间油脂的过氧化值(peroxide value, POV)与酸价(acid value, AV), 分析鱼卵磷脂对油茶籽油氧化酸败的抑制效果, 结合范特霍夫(van’t Hoff)定律进行货架期预测, 探究鱼卵磷脂对油茶籽油的抗氧化作用。结果　鱼卵磷脂能够有效抑制油茶籽油过氧化值和酸价的升高, 与空白对照组相比差异显著(P<0.05), 与其他两组对照组相比,鱼卵磷脂的抑制效果优于大豆卵磷脂,但劣于TBHQ; 货架期预测结果显示, 鱼卵磷脂可将油茶籽油在20 ℃下的保质期最多延长96 d。结论　大黄鱼鱼卵磷脂能够有效抑制油茶籽油的氧化酸败, 提升油茶籽油的抗氧化稳定性, 具有较好的油脂天然抗氧剂开发前景。     

The effect of preultrasonic process on oil content and fatty acid composition of hazelnut,peanut and black cumin seeds

In this study, the effect of different sonication times (10, 20, and 30 min) on oil yields, extracted by using soxhlet together with preultrasonic treatment, and fatty acid composition of seed/kernels were investigated. The sonication of samples for 30 min caused the highest increase in oil yield of hazelnut (from 62.38 to 63.60%) and black cumin (from 27.90 to 31.80%) (p < .05). The appropriate sonication time for oil yield of peanut was 10 min, with the range of 51.50%. After sonication process, the dominant fatty acid contents of all samples showed a change and the major decrease in oleic acid amount of hazelnut (from 75.20 to 74.27%) and peanut oils (from 57.10 to 56.69%) and linoleic acid content of black cumin (from 58.38 to 57.50%) were determined when samples sonicated for 30 min (p < .05). Sonication process caused a decreasing in black cumin oil, and the reduction increased with sonication time.

Practical applications

Ultrasound‐assisted extraction method can be used as an alternative extraction method for conventional extraction. Ultrasonic‐assisted extraction has some advantages as being efficiency, speed and using low temperatures, which prevents thermal damage. The ultrasound process enables to greater influence of solvent into the sample matrix and increases mass transfer. Thereby, the higher extract yield, almost 23%, provided with ultrasonic‐assisted extraction in comparison to soxhlet extraction.     

响应面法优化碱性蛋白酶提取榛子油工艺

采用Alcalase碱性蛋白酶水酶法提取榛子油,以提油率为指标,对影响提油率的各个因素进行了研究,并用响应面法优化了提油工艺.F检验可以得到因素影响大小顺序为:酶解时间＞加酶量＞料液比＞酶解温度＞酶解pH.得到优化酶解条件为:加酶量1.6％,酶解温度51℃,酶解时间1.9h,料液比1∶5.6,酶解pH 10.在优化酶解条件下,榛子提油率可达92.92％.同时测得榛子油的棕榈酸含量4.33％,油酸67.10％,亚油酸0.09％,亚麻酸0.09％,硬脂酸1.165％.     

南极磷虾油磷脂富集工艺的优化

借鉴水化脱胶原理,对南极磷虾油磷脂富集工艺进行优化。通过单因素实验考察了反应溶液类型、质量分数、加入量,反应温度,反应时间及搅拌速度对南极磷虾油磷脂富集效果及富集后各功能成分的影响,得到南极磷虾油磷脂富集的最佳工艺条件为南极磷虾油中加入4倍南极磷虾油磷脂量的2%柠檬酸溶液、反应温度60 ℃、搅拌速度60 r/min、反应时间30 min。在最佳条件下磷脂富集效果明显,分离得到的磷脂溶液经冻干后磷脂含量可达70.78%,EPA和DHA含量分别为151.93 mg/g和113.70 mg/g;而分离得到的甘油三酯中虾青素含量最高可达780.49 mg/kg。     

Influence of hazelnut flour and skin addition on the physical, chemical and sensory properties of vanilla ice cream

The effect of hazelnut flour (1.5, 3 and 4.5%) and hazelnut kernel skin (1, 2 and 3%) on the physical, chemical and sensory properties of vanilla ice cream was examined. All samples were analysed for pH, titratable acidity, total solids, nitrogen, fat, ash, overrun, viscosity, meltdown, Hunter L‐, a‐ and b‐values, flavour, body and texture, and appearance. The samples with hazelnut flour exhibited higher pH, nitrogen, ash, viscosity, and L‐, flavour, body and texture, and appearance values than the samples with kernel skin. Samples with hazelnut flour and skin can be added to the ice cream mix to produce a non‐fat ice cream at 3% and 1% levels in combination with maltodextrin, respectively.     

Review of the use of phytosterols as a detection tool for adulteration of olive oil with hazelnut oil

Adulteration of virgin olive oil with less expensive oils such as hazelnut oil is a serious problem for quality control of olive oil. Detection of the presence of hazelnut oil in olive oil at low percentages (<20%) is limited with current official standard methods. In this review, various classes of phytosterols in these two oils are assessed as possible markers to detect adulterated olive oil. The composition of 4-desmethyl- and 4-monomethylsterols is similar in both oils, but the 4,4′-dimethylsterols differ. Lupeol and an unknown (lupane skeleton) compound from 4,4′-dimethylsterols are exclusively present in hazelnut oil and can be used as markers via GC–MS monitoring to detect adulteration at levels as low as 2%. The phytosterol classes need to be separated and enriched by a preparative method prior to analysis by GC or GC/MS; these SPE and TLC methods are also described in this review.     

超声波对磷脂酶A1脱除油中非水化磷脂的影响

以菜籽四级油为原料,研究了超声波对磷脂酶A1脱除油中非水化磷脂的影响。结果表明,适宜的超声辐射可显著提高磷脂酶A1对油脂的酶处理脱胶速度;超声波对磷脂酶A1的作用效果与超声功率、超声时间和超声频率密切相关;超声作用没有改变磷脂酶A1对油脂脱胶的最适pH,但使磷脂酶A1对油脂脱胶的最适温度明显增高。     

微波对植物油品质的影响

基于微波加热原理，并通过分析植物油中主要化学成份的介电特性，说明植物油受微波作用时，其品质会受到一定程度的影响，而且，用微波干燥油料，能较好地保持毛油的品质。本文重点综述这一领域的研究进展。     

Detection of hazelnut oil in virgin olive oil by a spectrofluorimetric method

The possibilities of a spectrofluorimetric method joined to multivariate analysis to assess the genuineness of olive oil in admixtures with hazelnut oils were studied. Virgin olive, virgin hazelnut and refined hazelnut oil samples and admixtures between them at 5, 10, 15, 20, 25 and 30% adulteration were analysed at _ex=350 nm. The precision of the method, in terms of repeatability and internal reproducibility, was established by means of the analysis of a virgin olive oil sample under different conditions, the RSD showing values less than 10%. Raw data of the spectra were subjected to mathematical treatment by calculation of the first derivative, selection of the maximum values and application of one-way ANOVA, to assess the most prominent variables in the discrimination process. The response to the addition of adulterant was linear, adjusted-R²=0.99 for virgin olive and refined hazelnut oil mixtures, and 0.98 for virgin olive and virgin hazelnut oil mixtures. Stepwise linear discriminant analysis applied to each admixture separately and to the whole set of samples allowed 100% correct classifications.     

Evaluation of the bellier test in the detection of olive oil adulteration with vegetable oils

Virgin olive oil was mixed with eight vegetable oils (sunflower, soya bean, palm, linseed, cottonseed, corn, sesame, and olive residue) at various levels. The Bellier test was applied to find the minimum detectable adulteration level and the ‘sensitivity score’ for each oil. The test was inapplicable to sunflower and linseed oils regardless of the level in olive oil. It was successful in detecting olive residue, soya bean, palm, cottonseed, corn, and sesame oils at minimal levels of 730, 150, 130, 90, 60 and 10 g kg^?1, respectively. The rancidity level of the adulterant oils did not affect the performance of the test in the case of sunflower, linseed and sesame oils. The sensitivity of the test decreased considerably with increasing peroxide value of the adulterant oil: soya bean, palm, cottonseed, corn and olive residue. However, the change in sensitivity level commenced at so high a peroxide value that it has no significance for practical purposes; at such levels of peroxidation the adulterated olive would be unmarketable and rejected by inspectors due to its poor sensory quality.     

Characterisation of oil oxidation,fatty acid,carotenoid, squalene and tocopherol components of hazelnut oils obtained from three varieties undergoing oxidation

Hazelnut oils obtained from three varieties of Chinese hybrid hazelnuts (cv. ‘Liaozhen 3 (LZ)’, ‘Pingou 21’ (PG) and ‘Yuzhui’ (YZ)) were used to compare the lipid oxidation characteristics (peroxide value, p-anisidine value and conjugated diene value), fatty acid profiles and major active components (squalene, carotenoids and tocopherols) under oxidation condition at 60 °C for 40 days, in addition, the molecular structure changes in the three hazelnut oils were monitored by Raman spectroscopy. The lipid oxidation of the three hazelnut oils had similar tendencies, and the oxidation rate was slower in the early stage and faster in the later stage. Polyunsaturated fatty acids (PUFAs) tended to decrease mainly due to the decrease in linoleic acid. LZ had higher contents of tocopherol, carotenoids and PUFAs than the other varieties, while YZ owned the highest content of squalene. Tocopherol and carotenoids of the three hazelnut oils showed easy loss, while squalene was relatively stable. Raman spectroscopy can effectively indicate the degree of oxidation and carotenoid levels of hazelnut oil. This study can provide a scientific basis for variety selection in planting and utilisation of active ingredients for the hazelnut industry.     

磷脂酶Lecitase Ultra脱除大豆油中非水化磷脂研究

在单因素的基础上,选取酶浓度、酶解温度、酶解时间、p H四个因素为自变量,以脱胶后油脂中的磷含量为响应值,根据中心组合设计原理,利用Design–Expert 7.0软件设计响应面试验及对数据进行处理,优化酶解工艺,确定最佳工艺参数为:酶浓度0.045%、反应时间3.5 h、反应温度44.0℃、p H为4.8。在此条件进行磷脂酶Lecitase Ultra脱除大豆油中非水化磷脂实验,3次平行实验所得到的磷含量的平均值为6.2 mg/kg。