The effect of roasting on the chemical composition and oxidative stability of pumpkin oil

This study is concerned with the effect of the process of roasting of naked pumpkin seeds prior to their pressing on the chemical composition and oxidative stability of the extracted oil. Ground seeds were roasted at temperatures of 90, 110, and 130°C for 30 and 60 min, according to the traditional technology of production of roasted pumpkin oil. Depending on the roasting conditions of the seeds, this treatment resulted in a significant increase of the contents of phospholipids (from 0.005 to 0.463%), total phenolic compounds (from 4.63 to 19.60 mg/kg), and total tocopherols (from 265.79 to 350.98 mg/kg) in oil. Higher contents of these minor components enhanced the oxidative stability of the oil, i.e., increased the induction period (from 4.50 to 12.93 h). However, at the same time, the applied thermal treatment generated an increase in the primary and secondary oxidation products, resulting in higher Totox values that could lower the quality of the oil.     

Phenolic compounds and some quality parameters of pumpkin seed oil

Pumpkin seed oil has become a recognized source of phenolic compounds. The main aim of this paper was to evaluate the concentration of phenolic compounds and their extraction from pumpkin seed oil. The total phenolics content (TPC) measured in the pumpkin seed oil samples ranged from 24.71 to 50.93 mg GAE/kg of oil. The individual phenolics were tyrosol, vanillic acid, vanillin, luteolin and sinapic acid. Hexane and acetone were the best solvents for the washing step, and methanol for the elution of the phenolics in the solid‐phase extraction (diol‐SPE), whereas bleaching caused a significant increase in the TPC obtained (24.5–30.7%). Additionally, some other oil characteristics were evaluated. The mean oxidative stability of the oils (OSI) was around 4 h, with 5.43 h for the most stable oil. The maximum antioxidant capacity measured by the reduction of the DPPH radical was 62%, which was comparable to 0.16 mM Trolox equivalent. The color of the oil was expressed by L*a*b* coefficients and its hue and saturation. Whereas all samples had similar lightness, their rates of green, red, yellow and blue color were different. Moreover, TPC correlated negatively with lightness, b* and saturation (–0.49, –0.48, and –0.43), and positively with a* and hue (0.58 and 0.52).     

Study of the convective drying of pumpkin (Cucurbita maxima)

The main goals of the present work are, on one hand to study the influence of drying operation in some chemical properties of pumpkin, and, on the other hand, to study the drying kinetics, by applying different kinetics models to the experimental drying data.In this way, pumpkin was dried by convection for different air temperatures, ranging between 30 °C and 70 °C. The chemical properties that were analysed in the fresh and dried pumpkin were: moisture content, total and reducing sugars, acidity, proteins, lipids, crude fibre and ash.The results enable concluding that the convective drying at the lowest temperature, 30 °C, induces reductions of 14% in proteins, 65% in total sugars and 36% in fibre. Furthermore, the drying temperature seems to have a negligible effect on the nutritional characteristics of the pumpkin, since the results for the drying at 30 °C are quite similar to those for the drying at 70 °C.With respect to the other subject analysed, the drying kinetics, the results show that the increase on the operating temperature strongly accelerates the drying process, so that the process at 30 °C takes 8 h while at 70 °C the drying is finished after only 2 h. The experimental data for moisture ratio was fitted to different models, and the best were Page and modified Page.     

Frying stability of canola oil in presence of pumpkin seed and olive oils

Frying performance of canola oil (CO) was investigated in the presence of 5, 10, and 15% levels of virgin olive oil (VOO) and pumpkin seed oil (PSO) during frying of potatoes at 180°C. Acid value, carbonyl value, total polar compounds content, and total tocopherols content of the oil samples were determined during the frying process. VOO and PSO addition improved the frying stability of the CO. Frying performance of the CO increased more in the presence of PSO than in the presence of the VOO. The PSO levels higher than 5% exerted pro‐oxidant effects, indicating the necessity of investigation at lower levels. The better antioxidative effect of PSO was attributed to its probably different phenolic composition.     

An overview of the chemical composition of biomass

An extended overview of the chemical composition of biomass was conducted. The general considerations and some problems related to biomass and particularly the composition of this fuel are discussed. Reference peer-reviewed data for chemical composition of 86 varieties of biomass, including traditional and complete proximate, ultimate and ash analyses (21 characteristics), were used to describe the biomass system. It was shown that the chemical composition of biomass and especially ash components are highly variable due to the extremely high variations of moisture, ash yield, and different genetic types of inorganic matter in biomass. However, when the proximate and ultimate data are recalculated respectively on dry and dry ash-free basis, the characteristics show quite narrow ranges. In decreasing order of abundance, the elements in biomass are commonly C, O, H, N, Ca, K, Si, Mg, Al, S, Fe, P, Cl, Na, Mn, and Ti. It was identified that the chemical distinctions among the specified natural and anthropogenic biomass groups and sub-groups are significant and they are related to different biomass sources and origin, namely from plant and animal products or from mixtures of plant, animal, and manufacture materials. Respective chemical data for 38 solid fossil fuels were also applied as subsidiary information for clarifying the biomass composition and for comparisons. It was found that the chemical composition of natural biomass system is simpler than that of solid fossil fuels. However, the semi-biomass system is quite complicated as a result of incorporation of various non-biomass materials during biomass processing. It was identified that the biomass composition is significantly different from that of coal and the variations among biomass composition were also found to be greater than for coal. Natural biomass is: (1) highly enriched in Mn > K > P > Cl > Ca > (Mg, Na) > O > moisture > volatile matter; (2) slightly enriched in H; and (3) depleted in ash, Al, C, Fe, N, S, Si, and Ti in comparison with coal. The correlations and associations among 20 chemical characteristics are also studied to find some basic trends and important relationships occurring in the natural biomass system. As a result of that five strong and important associations, namely: (1) C-H; (2) N-S-Cl; (3) Si-Al-Fe-Na-Ti; (4) Ca-Mg-Mn; and (5) K-P-S-Cl; were identified and discussed. The potential applications of these associations for initial and preliminary classification, prediction and indicator purposes related to biomass were also introduced or suggested. However, future detailed data on the phase-mineral composition of biomass are required to explain actually such chemical trends and associations.     

贝壳的化学成分及其结构特征

以扇贝和珍珠母贝壳为研究对象,对其化学成分、微观结构以及热分解行为进行研究,结果表明,扇贝和珍珠母贝壳都是由95%左右的CaCO₃和5%左右的有机质组成。其中,扇贝的无机相几乎由100%的方解石组成,而珍珠母贝壳的无机相由4.96%的方解石和95.04%的文石组成。且两者所含有机质的成分存在很大的差异。热分析表明,热分解分为两个阶段,第一阶段为有机质的变性和分解,第二阶段为碳酸钙分解为二氧化碳和氧化钙的过程。有所不同的是,珍珠母贝壳在400~500℃出现了由文石转变为方解石的晶型转换,可为生物矿化等提供参考。     

Chemical characteristics of oils from naked and husk seeds of Cucurbita pepo L.

Pumpkin seed oils from naked and husk pumpkin seeds, produced by an industrial process and by laboratory extraction, were evaluated for fatty acid composition, tocopherol, sterol and squalene content. The major fatty acids in the oils from both varieties were oleic, linoleic and palmitic acid, followed by stearic acid. The ratios of monounsaturated to polyunsaturated fatty acids for husk and naked seed oils were about 0.60 and 0.75, respectively. Analysis of tocopherols in industrially pressed and laboratory‐extracted oils showed that husk seed oils had higher amounts of total tocopherols than naked seed oils. Oils extracted in the laboratory had higher amounts of tocopherols than industrial oils. Pumpkin seed oil, in general, had a high level of squalene, which was higher in husk seed oils than in naked seed oils and in extracted than in pressed oils. The total amount of sterols was higher in husk than in naked seed oils and in extracted oil samples. The main sterols were Δ7‐sterols and their content was similar in all samples, but the content of Δ5‐sterols was higher in oil samples of husk pumpkin seed and in extracted than in pressed oils.     

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.     

Soybean seed protein and oil contents and fatty acid composition adjustments by drought and temperature

Environmental stress during soybean [Glycine max (L.) Merr.] seed fill can alter the chemical composition of the seed and reduce yield, viability, and vigor. The effect of drought and high air temperature (AT) on soybean seed protein and oil contents have not been reported. The objective of this study was to characterize the protein and oil contents and fatty acid composition of soybean seeds after exposure to drought and high AT during seed fill. Experiments were conducted during two years, in which three drought-stress levels were maintained throughout seed fill. In Experiment I, “Gnome” soybeans were grown at daytime AT of 20 and 26°C, and in Experiment II “Hodgson 78” were grown at 27, 29, 33, and 35°C. Across experiments, severe drought increased protein content by 4.4 percentage points, while oil content decreased by 2.9 percentage points. As drought stress increased, measured by accumulating stress degree days, protein content increased linearly and oil content decreased linearly at each AT. Seeds from plants exposed to 35°C during seed fill contained 4.0 percentage points more protein and 2.6 percentage points less oil than those exposed to 29°C when averaged across drought stress levels. Drought had little effect on the fatty acid composition of the oil, but high AT reduced the proportion of the polyunsaturated components.     

TAG composition and solid fat content of palm oil, sunflower oil, and palm kernel olein belends before and after chemical interesterification

Modification of the characteristics of palm oil (PO), sunflower oil, and plam kernel olein (PKOo) according to conventional three-component mixture designs was undertaken by a combination of blending and chemical interesterification (CIE) techniques. TAG composition and solid fat content (SFC) profile of the starting blends were analyzed and compared with those of the interesterified blends. Upon CIE, extensive rearrangement of FA among TAG was evident. Concentrations of several TAG were increased, some were decreased, and several new TAG were formed. The resulting changes in TAG profile were reflected in the SFC of the blends. The SFC values of the chemically interesterified blends, except binary blends of PO/PKOo, revealed that they were softer than their respective starting blends. SFC data also indicated that eutectic interaction occurred between PO and PKOo in the starting blends and that this interaction was diminished after CIE.     

The significance of chemical markers in the bioprocessing of fossil fuels

Biochemical conversion of crude oils is a multi-step process proceeding through a series of biochemical reactions. These reactions can be characterized by a set of chemical markers which are associated with the chemical composition of crude oils. Reactions with heavy crude oils indicate that there is an overall decrease in the concentration and chemical speciation of organic sulfur compounds, and a redistribution of hydrocarbons and organometallic species. The contents of trace metals in the crude oils, such as nickel and vanadium, also decrease. Further, heavy ends of crudes, containing the asphaltenes and the polar nitrogen, sulfur, and oxygen containing fractions, as well as the organometallic compounds and complexes, are biochemically converted to lower molecular weight chemical species. In the studies reported in this paper, microorganisms used to mediate such reactions were thermophilic ( > 60°C) and pressure tolerant (up to 2500 psi). These organisms are also capable of biochemical conversion of bituminous and lignite coals in an analogous manner to their action on crude oils and follow similar trends characterized by chemical markers. For example, X-ray absorption near-edge structural (XANES) analyses of biotreated crude oils and low grade coals show that biochemical reactions lead to decreases in organic sulfides and thiophenes with a concurrent increase in sulfoxide contents. Chemically related constituents present in heavy crude oil fractions and low grade coals are the asphaltenes. Asphaltenes are complex structures containing heteroatoms and metals involved in inter- and intra-molecular bridges and stereochemical configurations. The chemical markers associated with the biochemical conversion of oils and coals indicate multiple biochemical processes involving chemical reactions at sites containing heteroatoms and metals leading to a breakdown of the structure(s) to smaller molecular weight units. Thus, using chemical markers as diagnostic tools, the extent and the efficiency of fossil fuel bioconversion may be predicted and monitored, allowing for better cost-efficient field trials. Recent results in this area will be presented and discussed in this paper.     

漆籽中漆籽油和漆蜡的提取和初步表征(英文)

研究漆籽油和漆蜡提取的最佳工艺,进行单因素实验,对不同品种漆油进了红外分析。结果表明:漆蜡的最佳工艺条件是:石油醚(30℃～60℃)作为提取剂,提取温度为50℃,固液比为1∶20,提取时间12h,漆籽皮的目数是大于100目;漆油的最佳工艺条件是:石油醚(30℃～60℃)作为提取剂,提取温度为50℃,固液比为1∶30,提取时间3h,漆籽皮的目数是大于100目。通过萃取所得的漆油在红外图谱上出峰位置基本一致,表明其化学成分基本相同。     

Solvent-assisted extraction of oil from papaya (Carica papaya L.) seeds: evaluation of its physiochemical properties and fatty-acid composition

ABSTRACT

The present work reports the solvent-assisted extraction of oil from papaya (Carica papaya L.) seeds. Various operating parameters such as solid solvent ratio, temperature and time on oil yield, and its effects have been investigated using response surface methodology. The experimental oil yield (20.30 ± 0.03%) at optimal condition was well agreed with the predicted value. The compositions from GC-FID results showed saturated fatty acid (20.94%), monounsaturated fatty acid (73.12%), and polyunsaturated fatty acid (4.96%). It was also found that the solvent-assisted extraction is a simple and effective method for extraction of oil from papaya seeds.     

Effect of drying method and wall material composition on the characteristics of camellia seed oil microcapsule powder

Camellia seed oil (CSO) is one of the richest sources of oleic acid (75–80%) and it is considered to provide beneficial health effects to humans. However, its susceptibility to oxidative degradation prevents its widespread use in the food industry. This study was aimed to improve the stability of camellia seed oil by microencapsulation. CSO was microencapsulated using whey protein concentrate (WPC) and maltodextrin (MD) or starch sodium octenylsuccinate (SSOS) as wall materials. The produced oil-in-water emulsion was subsequently dehydrated to produce microcapsule powder using spray and freeze drying techniques, respectively. Various characteristics of oil-in-water emulsion and final microcapsule powder including particle size distribution, encapsulation efficiency, morphology, rheological properties of reconstituted emulsions, in vitro digestion behavior and oxidative stability were determined to investigate the effect of wall material composition and drying method on these microcapsule powder characteristics. The spray-dried powder had significantly higher bulk density and smoother surface compared to freeze-dried powder while the freeze-dried CSO microcapsule powder with WPC/SSOS as wall material had the highest encapsulation efficiency and the lowest surface oil. The subsequent in vitro digestion test suggested the microencapsulated CSO could be successfully controlled-released in the simulated gastric (10.28–13.03%) and the subsequent intestinal fluid (72.89–89.61%). Oxidative stability of camellia seed oil was significantly improved by microencapsulation. The freeze dried CSO microcapsule powder in WPC/SSOS wall material exhibited highest encapsulation efficiency (95.17%) and best oxidative stability (peroxide value and p-anisidine values of 3.57 meq/kg oil and 3.01, respectively, during the 45 days storage at 25°C.     

化学组成对合成堇青石显微结构和高温性能的影响

研究了化学组成对合成堇青石材料显微结构和高温性能的影响。研究发现 ,当配料中的Al2 O3含量在理论组成的 5 %范围内变化时 ,对合成堇青石材料的显微结构和高温性能产生明显影响。其中Al2 O3与SiO2 或Al2 O3与MgO的质量比的增大有利于改善堇青石材料的显微结构和提高其高温性能。合成的堇青石材料在 12 5 0℃下的高温抗折强度为 16～ 18MPa ,0 .2MPa荷重下 10h后的蠕变率为 - 0 .0 79%。     

Morphology and chemical composition of Si-ion-irradiated zirconolite glass-ceramic

Evaluation of the radiation resistance of zirconolite glass-ceramic is significant to it serves as the first barrier for high-level waste (HLW). The evolutions in the morphology and chemical composition of a Ce-bearing zirconolite glass-ceramic induced by 15 MeV Si-ion-irradiation were studied in this paper. The swelling of the glass matrix, amorphization, and shape change of the zirconolite phase were identified after irradiation. The chemical compositions of both zirconolite and glass matrix were changed and more Ce was incorporated into the glass. These modifications induced by ion irradiation were discussed in detail combined with thermal-spike model calculations, suggesting that the electronic energy deposition also can play a dominant role in the evolutions of both the morphology and the chemical composition of the ion irradiated zirconolite glass-ceramic. These results are extremely important for understanding the microstructural evolutions of zirconolite glass-ceramic in a strong radiation environment.     

树立和落实科学的发展观规范有序推进炼油和化工园区建设

以科学的发展现，从5个方面阐述了建设炼油和化工园区的重要意义，以翔实的数据重点讨论了我国炼化企业及化工园区建设方面存在的问题，对建设布局合理的炼油和化工园区提出了可行性建议。