Thermal Degradation of p-Hydroxybenzoic Acid in Macadamia Nut Oil,Olive Oil,and Corn Oil

p-Hydroxybenzoic acid (PHBA) plays a significant role in sustaining the oxidative stability of macadamia nut oil (MNO). However, PHBA undergoes thermal decarboxylation and loses its bioactive antioxidant properties. In this study, we determine PHBA degradation kinetics in oils at various heating temperatures, which provides fundamental understanding of PHBA thermal degradation in oils and oil quality changes during high-temperature processing. PHBA degradation kinetics in MNO, olive oil, and corn oil were evaluated at temperatures typical for cooking and frying. PBHA headspace concentration was measured using selected ion flow tube mass spectrometry. PHBA decarboxylation followed a zero-order reaction, where degradation could be affected by factors such as the type of oil matrix having different FA compositions, antioxidants, and component interactions. PHBA degradation activation energies (E _a) showed that PHBA was more stable against thermal decarboxylation in MNO (85 kJ mol^–1) than in olive oil (40 kJ mol⁻¹) or corn oil (22 kJ mol⁻¹). The higher enthalpy () of decarboxylation in MNO (82 kJ mol⁻¹) indicates that PHBA is more inhibited from decomposition than olive oil (37 kJ mol⁻¹) or corn oil (19 kJ mol⁻¹). Moreover, the negative entropy values () of PHBA degradation from MNO (−192 J mol⁻¹ K⁻¹), olive oil (−277 J mol⁻¹ K⁻¹), and corn oil (−325 J mol⁻¹ K⁻¹) indicates that these oils impart some inhibitory properties against PHBA thermal decarboxylation.     

双马来酰亚胺树脂扩链增韧改性研究

研究了采用腰果壳油增韧改性双马来酰亚胺树脂的方法，双马来酰树脂虽具有突出的耐热性，良好的机能及加工性能，但其最大不足是固化物脆性大，因此必须引进长链的柔性分子或分合物对双马来酰亚胺树脂加以改性，增加其韧性，改善其机械性性能，扩大其应用邻域，腰果壳油具有柔性长链分子，而且还有不饱和双键，能与双马来酰亚胺树脂的不饱和双键反应，它是一种良好的改性剂，本篇论文探讨了双马来酰亚胺树脂与腰果壳油长链分子反应机理，考察了改性树脂的力学性能和热学性能，对其工艺和配方也作了初步探讨。     

妥尔油和腰果油改性酚醛补强树脂对全钢载重子午线轮胎三角胶性能的影响

考察妥尔油改性酚醛补强树脂SL-2101和腰果油改性酚醛补强树脂SL-2201对全钢载重子午线轮胎三角胶性能的影响。结果表明：与补强树脂SL-2101相比,补强树脂2201对胶料的补强性能好;随着2种补强树脂用量增大,胶料物理性能提高;采用补强树脂SL-2201替代补强树脂SL-2101,需适当调整硫化体系。     

Bioactive Compounds in Virgin Olive Oil of the PDO Montoro-Adamuz

Virgin olive oil (VOO) is generally recognized as a healthy fat because of its fatty acid composition and content in minor compounds but a wide range of these substances can be found in commercial oils. The concentration of compounds with attributed health benefits were analyzed in VOO of the PDO Montoro‐Adamuz. Oleic acid represented around 79 % of the total fatty acids, and the mean squalene and tocopherols concentrations were 5800 and 247 mg/kg respectively. Despite the changes found in polyphenols concentration in the oils analyzed for six consecutive crops, these substances accounted for more than 700 mg/kg. Moreover, the effect of irrigation regime and sun radiation on the content in bioactive substances of these oils was also assessed. No significant differences were detected between oils from trees irrigated ad libitum or rain‐feed. In contrast, the level of tree radiation exerted a great effect on the concentration of bioactive substances in oils. Oils from trees cultivated in a sunny area (south orientation) had a higher percentage of oleic acid and concentration in phenolic compounds than those from shady areas (north orientation). The opposite was detected for tocopherols and squalene which were more concentrated in oils from olives of the shady area. The results obtained in this study point out VOO of the PDO Montoro‐Adamuz as a very healthy fat due to their composition in bioactive substances, in particular their richness in phenolic compounds.     

Influence of Water Deficit in Bioactive Compounds of Olive Paste and Oil Content

The main objective of this study was to evaluate the effect of different deficit irrigation treatments (control, regulated deficit irrigation [RDI]‐1, RDI‐2, and RDI‐3) on the phenolic profile of the olive paste and oil content. Irrigation treatments with more stress water led to a considerable increase in the phenolic compounds of olive paste, especially in oleuropein (60.24%), hydroxytyrosol (82%), tyrosol (195%), and verbascoside (223%) compared to control. A significant increase in the content of total flavonoids and phenolic acids was also observed for these samples. In virgin olive oils (VOO) elaborated from the most stressed olive trees (RDI‐2 and RDI‐3), a noticeable increase in phenolic substances with antioxidant properties (oleuropein, hydroxytyrosol, tyrosol, secoiridoid derivatives, and o‐vanillin) was observed. Consequently, water stress conditions improved antioxidant activity of VOO.     

Differentiation of Mechanically and Chemically Extracted Hazelnut Oils Based on their Sterol and Wax Profiles

The sterol and wax content of solvent extracted (SEHO) and cold pressed hazelnut oils (CPHO) were compared. A total of 48 samples from 19 hazelnut varieties were collected for two successive crop years from four different geographical districts in Turkey. Hazelnuts were processed to oil with a laboratory scale press, than the remaining oil in cake was extracted with n‐hexane. CPHO and SEHO were evaluated for their wax, sterol and squalene contents. Results showed that sterol, squalene and wax contents of all individual cultivars were higher in SEHO than those of CPHO, indicating the higher solubility of these compounds in solvent. Total sterol contents ranged between 1088.56 (Kargalak)—1609.39 mg/kg (Mincane) for CPHO and 1590.86 (Çak?ldak)—2897.26 mg/kg (Mincane) for SEHO. Hazelnut oils were found to be richer of C36‐38 esters than C40‐46 group. Total wax content was between 24.19 (Kargalak)—94.58 mg/kg (Ku?) for CPHO and 81.46 (Kargalak)—160.92 mg/kg (Akçakoca) for SEHO. The squalene amounts of the samples obtained by hexane extraction were between 499.75 (Allahverdi)—885.36 mg/kg (Cavcava), while it varied between 288.55 (Kargalak)—647.68 mg/kg (Mincane) in cold pressed oils. Significant and obvious variations between SEHO and CPHO were verified by principal component and hierarchical cluster analysis. Geographical discrimination was also achieved by discriminant analysis.     

Optimization of Ultrasound-Assisted Alkali Neutralization in the Refining of Safflower Oil to Minimize the Loss of Bioactive Compounds

In this study, ultrasound-assisted (UA) neutralization parameters are optimized using the response surface methodology to develop a novel alkali neutralization method based on the minimal refining concept. Sodium hydroxide (NaOH), magnesium oxide (MgO), and calcium hydroxide (Ca(OH)₂) are used in both the traditional (TR) and UA neutralizations. Optimum probe depth, duration, and intensity levels are calculated as 3.7 cm, 25 s, and 54.3%, respectively, for UA neutralization with NaOH, which is more successful at free fatty acid (FFA) reduction and total phenolic content (TPC) retention than MgO and Ca(OH)₂. Validation results of optimum conditions show that lowest average FFA content (0.29%) and highest average TPC (211.2 mg kg⁻¹) are determined for the UA-neutralized safflower oil samples. The comparison of all the neutralization experiments reveal that the UA neutralization under optimum conditions using NaOH reduced 82.8% of the FFA content, whereas the TR alkali neutralization reduced the FFA content at a maximum of only 47.8%. Practical Applications: From the results, it can be inferred that the UA neutralization exhibits good performance in FFA content reduction and bioactive compound retention while offering a good solution within the concept of minimal refining.     

高压玻璃钢管道的研制及在油田中的应用

本文介绍了高压玻璃钢管道的特性及在我国油田的应用情况。     

固定床渣油加氢工艺发展与运行问题研究

近年来,随着我国国民经济的迅猛增长及石油价格的不断攀升,重油轻质化的要求越来越迫切,同时为了符合国家相关环保要求,渣油的回收再利用成为炼化界普遍关注的热点。渣油加氢工艺是处理渣油最有效的工艺方案,其能够较为彻底地去除渣油中的硫、氮、金属及残炭等杂质对环境的污染。本文从渣油加氢工艺的发展、反应原理及运行问题等方面分析入手,简要说明了渣油加氢工艺的应用现状。     

腰果壳油改性酚醛树脂在轿车子午线轮胎高硬度三角胶中的应用

对比研究4种不同牌号酚醛补强树脂的理化性能及其对轿车子午线轮胎高硬度三角胶性能的影响。结果表明:国外A与国内2201牌号腰果壳油改性酚醛树脂的相对分子质量和软化点相近,使用这两种树脂的胶料性能相当;国外B与国内2201H牌号腰果壳油改性酚醛树脂的相对分子质量和软化点较高且相近,酚醛树脂2201H胶料的加工安全性更好,其他性能与酚醛树脂B胶料相当。     

Profile of Bioactive Compounds in Avocado Pulp Oil: Influence of the Drying Processes and Extraction Methods

The influence of different procedures of pulp drying and oil extraction methods on the concentrations of α-tocopherol, squalene and several phytosterols in avocado oil was evaluated. Pulp portions of Fortune variety avocados were dried either by lyophilization or under circulating air at 40 or 70 °C. For lyophilization and for each air drying temperature, the oil was obtained either by cold pressing or with Soxhlet extraction using petroleum ether. The dehydrated pulp (73 % of the pulp weight) yielded 25–33 % oil by cold pressing, and 45–57 % oil by Soxhlet extraction. Infrared spectroscopy and gas chromatography with FID and mass spectrometry detection were used to analyze the oils. α-Tocopherol, squalene, cycloartenol acetate, β-sitosterol, campesterol and stigmasterol were present in all the oil samples. In comparison to lyophilization, hot air drying resulted in smaller concentrations of α-tocopherol, squalene and β-sitosterol, and larger relative concentrations of campesterol and cycloartenol acetate. On the other hand, extraction by cold pressing produced a smaller amount of oil, with greater concentrations of α-tocopherol and squalene, and lower contents of campesterol and cycloartenol acetate, than Soxhlet extraction. Thus, the oil yield was maximal with lyophilization and Soxhlet extraction, but lyophilization and cold pressing produced oils which had greater concentrations of antioxidants and other bioactive compounds.     

Bioactive Compounds,Antioxidant Activities and Heat Stability of Corn Oil Enriched with Tunisian Citrus aurantium L. Peel Extract

This study was designed to examine physicochemical composition, antioxidant activities and heat stability of corn oil enriched with bitter orange peel. Volatile compounds composition of corn oil flavored with Citrus aurantium peel was investigated. Flavored oil total aroma content (2.6 mg/mg oil) was mainly represented by monoterpene hydrocarbons and limonene was the major one (2.49 mg/mg oil). Flavored oil methanolic extract was characterized by total phenol content of 1.22 mg GAE/kg. Chlorogenic, ferulic and p-coumaric acids were the major phenolic components of the flavored oil extract (34.33, 30.24 and 19.39 %, respectively). It was also characterized by a higher chlorophylls and carotenoids contents than the refined one. Antioxidant activities of methanolic extracts of both samples were determined using four assays: DPPH, reducing power, β-carotene bleaching and metal chelating tests. In β-carotene bleaching and DPPH radical scavenging assays, flavored oil methanolic extract showed higher activities than the control. It was characterized by a total antioxidant activity of 4.08 mg GAE/kg and an EC₅₀ value of 3.14 mg/mg oil. Its concentration providing 50 % inhibition (IC₅₀) was 0.53 mg/mg oil in the DPPH test and 4.08 mg/mg oil in the β-carotene bleaching test. However, refined corn extract showed significantly lower antioxidant activities (p < 0.05). Results of the oxidative stability index showed bitter orange peel effectiveness against thermal oxidation based on the increased induction time observed in flavored oil (5.95).     

Effect of Industrial Chemical Refining on the Physicochemical Properties and the Bioactive Minor Components of Peanut Oil

The effect of the industrial chemical refining process on the physicochemical properties, fatty acid composition, and bioactive minor components of peanut oil was studied. The results showed that the moisture and volatile matter content, acid value, peroxide value, and p‐anisidine value were significantly changed (P < 0.05) after the complete refining process. No significant variation (P > 0.05) in the iodine value was observed among all the peanut oil samples. Similar changes were observed in the DPPH radical scavenging activity and the total tocol content during chemical refining. In addition, chemical refining did not have much effect on the fatty acid composition, except for certain changes of several individual fatty acids. Moreover, the chemical refining resulted in 23.6, 23.1, and 9.5 % losses of squalene, total phytosterols, and total tocols (α, β, γ, δ‐tocopherols and α, β, γ, δ‐tocotrienols), respectively. The degumming–neutralization step caused the greatest overall reduction of these bioactive minor components. However, the concentrations of α‐tocotrienol and γ‐tocotrienol increased after full refining. Furthermore, chemical refining slightly changed the relative proportions of individual phytosterols and individual tocols.     

Effects of Vegetable Oil Composition on Epoxidation Kinetics and Physical Properties

In this article, we investigate the role of triacylglycerol composition on the properties of epoxidized vegetable oils and the kinetics of the epoxidation process under conditions comparable to commercial epoxidation. Commodity soybean oil (24% oleic acid, 50% linoleic acid, and 7% linolenic acid), high‐oleic soybean oil (75% oleic acid, 8% linoleic acid, and 2.5% linolenic acid), and linseed oil (11% oleic acid, 15% linoleic acid, and 64% linolenic acid) were each epoxidized to various extents. Epoxidation rate, viscosity, differential calorimetry, and X‐ray diffraction data are presented for these oils and interpreted in the context of their fatty acid profile (mostly oleic, linoleic, or linolenic). While fully epoxidized soybean oil is widely commercially available and used in an increasing array of industrial applications, information relating to partially epoxidized oils and epoxidized oils of other cultivars is less well known.     

循环氢夹带高分油的分离研究

以夹带有重烃、水组分的循环氢混合气为对象,在150万t/a加氢裂化循环氢脱硫系统中开发了旋流脱烃器工业实验装置,利用气相色谱法考察了旋流脱烃器进、出口中C5＋以上的重烃组分的含量。结果表明,旋流脱烃器对循环氢中重烃组分的平均脱除率为86.1%,水组分的平均脱除率为75.6%,压缩机的总能耗降低了10.1%。     

注入水对地层油高压物性影响实验研究

为揭示注入水对地层油高压物性的影响规律,采用从油田获取的油、气、水样品,开展了不同含水百分比条件下地层流体高压物性模拟实验。结果表明:随着水或聚合物溶液的注入,模拟地层油的饱和压力和溶解气油比都降低,且降低的幅度随含水百分比的增大而增大。当含水百分比为80%时,注水使模拟地层油的饱和压力降低10.33%、溶解气油比减小16.00%,注聚合物溶液使模拟地层油的饱和压力降低8.75%、溶解气油比减小12.93%。不同含水百分比条件下,注水时气水比平均值为2.09 cm3/g,注聚时气水比平均值为2.01 cm3/g。注入水进入油藏与地层油充分接触后会从油相夺取部分气体成为含气水。     

Changes in Volatile Compounds of Black Cumin Oil and Hazelnut Oil by Microwave Heating Process

Black cumin and hazelnut oils were subjected to a heating process in a microwave oven for a duration of 2, 4, 6 and 8 min at a constant frequency of 2450 MHz and a power of 0.45 kW. The ultraviolet absorption and volatile products of the oils were investigated in detail during the processes. The experimental evidences obtained show that K₂₃₂ and K₂₇₀ parameters reach values of 4.69 and 1.30 for black cumin oil, 3.22 and 1.75 for hazelnut oil, respectively with the increment of heating time. The headspace SPME method was used to analyze volatile compounds extracted from black cumin and hazelnut oils being exposed to the microwave heating process. The SPME–GC/MS method allowed the detection of 17 identified volatile compounds (hexanal, α‐thujene, α‐pinene, sabinene, β‐pinene, 2‐heptenal, α‐terpinene, limonene, p‐cymene, γ‐terpinene, E‐2‐octenal, nonanal, 4‐terpineol, thymoquinone, E,E‐2,4‐decadienal, α‐longipinene and isolongifolene) in black cumin oils. Of the products, hexanal, 2‐heptenal, E‐2‐octenal, nonanal and E,E‐2,4‐decadienal were determined to be the predominant volatile oxidation products. In fact, the hexanal was found as a major volatile oxidation compound and reached a local maximum point of 7.41 × 10⁶ AU at the end of heating. On the other hand, only 8 volatile oxidation products (hexanal, heptanal, 2‐heptenal, nonanal, E‐2‐decenal, E,Z‐2,4‐decadienal, E,E‐2,4‐decadienal and E‐2‐tridecenal) were identified in hazelnut oils as a consequence of the heating process. Based on the experimental evidence observed, it is reasonable to conclude that the nonanal content dramatically increased at the end of heating and reached a value of 9.22 × 10⁶ AU.     

Extraction and Identification of Phytosterols in Manketti (Schinziophyton rautanenii) Nut Oil

Phytosterols of manketti (Schinziophyton rautanenii) nut oil extracted by Soxhlet, mechanical shaking using hexane, screw press and supercritical carbon dioxide, were analyzed by gas chromatography with flame ionization detection and identified by gas chromatography–mass spectrometry. The presence of several phytosterols (campesterol, stigmasterol, β‐sitosterol, Δ⁵‐avenasterol, 22‐dihydrospinasterol and Δ⁷‐avenasterol) previously reported in manketti oil, was confirmed. In addition, another fourteen phytosterols (lanosterol, Δ^5,23‐stigmastadienol, Δ⁷‐campesterol, clerosterol, obtusifoliol, Δ^5,24(25)‐stigmastadienol, α‐amyrin, gramisterol, cycloeucalenol, cycloartenol, stigmasta‐8,24‐dienol‐3‐β‐ol, 28‐methylobtusifoliol, 24‐methylenecycloartenol and citrostadienol) were identified. The phytosterols, β‐sitosterol, Δ⁵‐avenasterol and campesterol, had the highest concentrations in oils extracted by all the methods, whereas stigmasterol and cycloartenol were abundant in oils extracted by mechanical shaking and supercritical carbon dioxide. Total phytosterols and the quantities of individual phytosterols differed significantly (p ≤ 0.05) in oils from the four extraction methods. Mechanical shaking extracted the highest levels of total sterols (22,100 mg/100 g oil), followed by supercritical fluid extraction (9,550 mg/100 g oil). Screw press and Soxhlet extracted oils contained the lowest levels of total sterols, 3,810 mg/100 g oil and 3,350 mg/100 g oil, respectively.