3种脂溶性酚类对紫苏籽油的抗氧化作用研究

采用Schaal烘箱法,以过氧化值和α-亚麻酸含量为指标,比较了3种脂溶性酚类及人工合成抗氧化剂对紫苏籽油的抗氧化效果。结果表明,当抗氧化剂添加量为100 mg/kg时,基于过氧化值的抗氧化效果为香芹酚百里香酚、丁香酚BHT、BHA。低添加量抗氧化剂(1~100 mg/kg)紫苏籽油中α-亚麻酸含量均高于不添加抗氧化剂的处理组。香芹酚的最适添加量为5 mg/kg,α-亚麻酸含量为6.399 mg/g,与4℃保存的紫苏籽油含量相近;BHT的最适添加量为50 mg/kg,α-亚麻酸含量为6.987 mg/g,高于4℃保存的紫苏籽油;分别添加100 mg/kg的香芹酚与100 mg/kg的BHT的紫苏籽油中α-亚麻酸含量相近,说明二者抗氧化能力相当。研究结果证实了香芹酚、百里香酚、丁香酚对紫苏籽油具有较好的抗氧化作用,为安全高效的天然酚类抗氧化剂的筛选及其在油脂食品中的应用提供理论参考。     

A green separation process for recovery of healthy oil from pumpkin seed

In this study, pumpkin seeds, called as “Ürgüp Sivrisi” and grown in Cappadocia region, were used as plant materials because of high aroma contents. In the supercritical fluid extraction of pumpkin seed oil, the effect of main process parameters as the particle size (250-2360 μm), the volumetric flow rate of supercritical solvent (0.06-0.30 L/h), the operating pressure (20-50 MPa), the operating temperature (40-70 °C), the type of entrainer (ethanol and n-hexane) and those concentrations (0-10 vol.%) on the extraction yield, the oil solubility and the initial extraction rate were investigated. A cross-over effect for the extraction of pumpkin seed oil using supercritical CO₂ was determined at the operating pressure of 20-30 MPa. The maximum extraction yield obtained with entrainer free was reached 0.50 g oil/g dry seed at 600-1180 μm, 0.12 L/h, 50 MPa and 70 °C for the operation time of 5 h. The maximum extraction yield obtained with ethanol as an entrainer in the experiments was reached 0.54 g oil/g dry seed at the conditions of 600-1180 μm, 0.12 L/h, 30 MPa, 40 °C and 8 vol.% for the operating time of 2 h. The oil compositions were determined by gas chromatography analysis and the results showed that the compositions of pumpkin seed oil which were obtained by means of organic solvent extraction and supercritical fluid extraction were similar. The average oil compositions determined as 9.3 (±0.43)% palmitic acid, 7.5 (±0.6)% stearic acid, 32.3 (±0.6)% oleic acid, 48.1 (±0.6)% linoleic acid and 0.7 (±0.3)% linolenic acid. The morphological changes in the seeds were determined by the scanning electron microscopy analysis.     

Fatty acid profiles from forty-nine plant species that are potential new sources of γ-linolenic acid

Forty-nine plant species from Spain, belonging to the Boraginaceae, Scrophulariaceae, Onagraceae, and Ranunculaceae families, were surveyed in a search of new sources of γ-linolenic acid (18∶3ω6, GLA). Fatty acid profiles from seeds, stems, roots, flowers and leaves were determined. GLA was detected mainly in seed and root tissues. High GLA amounts were found in seeds of Boraginaceae species, with a maximum of 20.25% of total fatty acids in Myosotis nemorosa. Within the Scrophulariaceae the highest GLA content (10.17%) was found in Scrophularia sciophila. Variable amounts of stearidonic acid, (18∶4ω3, SDA) were present in Boraginaceae species, ranging from 0.08% of total seed fatty acids in Anchusa azurea to 21.06% in Echium asperrimum. SDA was also very abundant in all organs of Asperugo procumbens. A multivariate analysis was performed using our results and those reported for other plant species belonging to the same families in order to investigate a possible correlation between the fatty acid profile and the genera within these families.     

Formation of Benzo(a)pyrene in Sesame Seeds During the Roasting Process for Production of Sesame Seed Oil

The main aim of this research was to enhance the understanding of the formation mechanisms of benzo(a)pyrene (BaP) during roasting of sesame seeds (SS). BaP levels in hot‐ and cold‐pressed sesame seed oil (SSO) were evaluated to correlate oil technology and BaP formation. Extracted principal components from SS were roasted either singly or in mixtures at 230 °C for 30 min. BaP was measured by HPLC with fluorescence detection. The results showed that BaP levels in hot‐pressed SSO were significantly higher than those in cold‐pressed SSO (p < 0.05), BaP formation mostly occurred during SS roasting and increased with roasting temperature (between 80 and 280 °C) and time (from 10 to 50 min). Furthermore, the BaP level in the roasted hulled SS (3.64 μg/kg) was higher than it was in roasted whole SS (1.63 μg/kg). The maximum BaP level observed (5.03 μg/kg) was detected in a roasted mixture of SS protein and SSO. The addition of sesame protein to protein‐free SSO promoted the formation of BaP, which suggests that the pyrolysis products of protein and triacylglycerols are probably important precursors in BaP formation.     

铜柱凸块生产关键工艺技术研究

讨论了铜柱凸块生产工艺中籽晶层厚度和电镀电流密度等关键制程因素对铜柱凸块共面性、晶圆应力、凸块剖面结构和电镀效率等方面的影响.研究结果表明增加电镀籽晶层厚度可以提高凸块共面性;在相同电镀电流密度下,籽晶层越厚,晶圆应力越大;相同的籽晶层厚度下,随着电镀电流密度增加,晶圆应力增加,但增加速率逐渐变慢;低电流密度下铜柱凸块顶部形成盘碟形状的剖面结构,而高电流密度容易使铜柱顶部形成圆拱剖面结构;采用阶梯电镀速率电镀方法与均一慢电镀速率电镀出的铜柱凸块共面性一致,而采用阶梯电镀法既能够提高电镀效率又可以得到较好的铜柱顶部盘碟形剖面结构.     

Hemp seed oil: Minor components and oil quality

Owing to its high content of omega‐6/omega‐3 fatty acids and bioactive minor components with antioxidant activities, hemp seed oil is now recognized for its health benefits by a large number of consumers. This paper primarily discusses the profile of minor components in hemp seed oil and their beneficial and adverse effects on oil quality. While tocopherols, polyphenols and phytosterols prevent oxidative deterioration of hemp seed oil, the high amount of chlorophyll can be detrimental to oil quality.     

Effect of air temperature and velocity on moisture diffusivity in relation to physical and sensory quality of dried pumpkin seeds

Understanding the effect of drying process parameters on food quality is helpful in process optimization and control. The objective of this work is to understand the effect of mild and harsh effective moisture diffusivity (D_eff), varied by air temperature and velocity, of drying processes on the physical and sensory quality of flat food products. Pumpkin seeds were selected as a food representative. It was found that increments of air temperature and velocity resulted in increased D_eff and brown color on seed hull surfaces and embryos, but decreased hardness of seed embryos. Changes in taste and aroma of seed embryos were able to be sensed. Indicating that D_eff is related to seed physical quality. Similar phenomena occurred with both tray and fluidized bed drying. Air temperature, velocity, and D_eff should be controlled to ensure the best dried flat food products. Mild drying conditions are potentially preferred for good physical and sensory quality.     

桐油基水性光固化树脂的合成及性能研究

以生物质资源桐油（TO）、马来酸酐（MA）为原料,通过Diels-Alder反应合成了桐油酸酐,再以其与丙烯酸羟乙酯（HEA）反应,经中和水化制备了桐油基水性光固化树脂。通过红外光谱（FTIR）、核磁共振氢谱（1H NMR）表征了合成产物的分子结构。考察了TO、MA以及HEA的比例对桐油基水性光固化树脂的乳液性质、光固化活性以及涂膜性能的影响。研究结果表明,当n(TO):n(MA):n(HEA):n(TEA)= 1:2.5:2.5:2.5时,合成的桐油基水性光固化树脂的稳定性、光固化活性以及涂膜性能最优异。     

Physicochemical Properties and Fatty Acid Profile of Phoenix Tree Seed and its Oil

Various components of Phoenix tree (Firmiana simplex) seed were determined. Oil, protein, moisture, ash, and fiber accounted for 27.8 ± 0.3, 19.7 ± 0.4, 7.5 ± 0.2, 4.4 ± 0.3, and 31.23 ± 0.93 % (w/w) of the seed, respectively. The acid value, peroxide value, saponification value, and unsaponifiable matter content of Phoenix tree seed oil extracted using the Soxhlet method were 3.73 ± 0.02 mg KOH/g, 1.97 ± 0.21 mmol/kg, 183.74 ± 2.37 mg KOH/g, and 0.90 ± 0.05 g/100 g, respectively. The total tocopherol content was 54.5 ± 0.5 mg/100 g oil, which consisted mainly of δ‐tocopherol (29.5 ± 0.6 mg/100 g oil) and γ‐tocopherol (13.8 ± 0.8 mg/100 g oil). Linoleic acid (L, 30.2 %), oleic acid (O, 22.2 %), and sterculic acid (S, 23.2 %) were the main unsaturated fatty acids of Phoenix tree seed oil. The saturated fatty acids included palmitic acid (17.4 %) and stearic acid (St, 2.9 %). The work shows the first report of sterculic acid in seeds of this species. This oil can be used as a raw material to produce sterculic acid.     

Experimental investigation of injection timing on the performance and exhaust emissions of a rubber seed oil blend fuel in constant speed diesel engine

An experimental study is conducted to evaluate the use of rubber seed oil with diesel at a proportion of 20% by volume (RSO20) in a constant speed (1500?rpm) direct injected four-stroke air-cooled single-cylinder compression ignition engine at different injection timings (24°, 27°, 30°, 33° bTDC (before top dead centre)). A series of tests were conducted at various engine load conditions at the rated power of 5.9?kW. The injection pressure was maintained at 200?bar. As a result of investigations, at the full load condition, the brake thermal efficiency of RSO20 at 30° bTDC is high compared with other injection timings and brake energy fuel consumption is increased when advancing injection timing. There is a significant reduction in unburned hydrocarbon emission and carbon monoxide emission, and the oxides of nitrogen emission (NO_x) is increased when advancing the injection timing.