厕所粪便与粗甘油共液化制备生物原油研究

水热液化是处理湿有机废弃物并实现能源化的技术之一。以厕所粪便和粗甘油为原料进行水热液化,探究了不同质量比例的厕所粪便和粗甘油(1∶0、3∶1、2∶1、1∶1、1∶2、1∶3、0∶1)对产物分布和油品特性的影响。粪便与粗甘油的比例混合为1∶3时,生物原油的产油率最高为40.6%,液化率最高为94.8%,相比单组分厕所粪便分别提高了18%和15%,表明粗甘油对粪便水热液化的产物转化具有促进作用。当在粪便中添加粗甘油时,水热液化生物原油的热值变化了0.27%～8.88%,含水率降低了11.5%～85.2%;所含烃类物质高达21.1%,酸类物质降低到14.4%,表明生物原油更稳定;增加了生物原油中的轻组分成分,残渣含量降低了25.2%～53.2%,进一步表明粗甘油可以改善粪便水热液化生物原油的油品质量。     

互花米草在乙醇-水体系中直接液化制备生物油

生物质因其储量丰富、来源广泛、碳中和等优势被认为是最具有应用前景的生产替代燃料的原料。在容积50 m L的小型高温高压反应釜中,利用醇-水共溶剂直接液化互花米草制备生物油,考察反应温度、醇-水共溶剂中乙醇体积分数、液料比对液化产物分布的影响,分析了原料的热重特性及生物油的主要成分。结果表明:随着升温速率的增加,互花米草的热失重曲线(thermogravimetric,TG)和微分热重曲线(differential thermogravimetric,DTG)基本保持不变,但却发生了不同程度的横向移动,出现明显的滞后现象,这是由温度和时间共同作用的结果;正交优化操作条件为温度340℃、乙醇体积分数50%、液料比10 m L/g,此时生物油产率高达44.2%,而残渣率仅为12%;与单一溶剂相比,醇-水共溶剂对互花米草的液化具有明显的协同作用,在提高产油率的同时能够显著改善生物油的品质;生物油的气相色谱-质谱分析表明生物油是一种组分复杂的含氧有机混合物,包括酸类、酚类、酯类、呋喃等,主要成分为酚类和酯类,相对含量分别为29.62%和11.27%;乙醇能够与酸发生酯化反应生成酯类,而酚类主要来自原料中木质素的降解;以乙醇体积分数为50%的醇-水共溶剂作为液化介质时,生物油的能量回收率为76.5%,明显高于以水或乙醇作为单一溶剂时液化所得生物油的能量回收率,因而醇-水共溶剂是生物质直接液化中非常有前景的液化介质。     

玉米秸在亚/超临界乙醇-水中液化的初步研究

在间歇高压釜实验装置上，采用环境友好的溶剂(乙醇和水)在亚/超临界状态下对玉米秸秆进行液化反应，考察了乙醇摩尔含量对玉米秸秆在超/亚临界乙醇-水中萃取过程的影响，并对液化产物进行了初步分析。研究结果表明，随着乙醇摩尔分数的增加，玉米秸液化的转化率和萃取率呈现先增加后减少的趋势，在乙醇摩尔分数为0.09～0.35范围内，存在一个最优值。在本实验条件下，乙醇摩尔分数为0.21时，玉米秸秆的转化率和萃取率均达到最高值，分别为88.51%，52.52%。利用极性不同的有机溶剂对液化产物进行分离，得到有机水溶物，油溶物和残渣。结果表明，随着乙醇含量的增加，油溶物含量增大，有机水溶物含量减小。     

生物质水热液化产物特性与利用研究进展

近年来,由于水热液化技术可以将高含水率的生物质直接转化为生物原油而极具潜力,引起了人们的广泛关注。该文综述了生物质水热液化研究的最新进展,简述了生物质水热液化的产物分离流程,着重分析了水热液化4种产物(生物原油、水相产物、固体残渣和气体)的产物特性及其利用方式。在4项产物中,生物原油可作为燃料或者从中提炼高附加值产品,水热液化水相可以进行微藻养殖、经厌氧发酵产甲烷或者利用微生物电解池产生氢气等,固体残渣通过进一步处理后可作为生物炭使用,气相产物可作为温室的气体肥料。另外,该文总结了生物质中关键元素在水热液化产物中的分布规律,展望了水热液化技术未来研究方向,以期能为生物质水热液化研究提供参考与借鉴。     

苹果渣中不同极性多酚的分离及体外抗氧化活性研究

为了优化苹果多酚提取工艺,进而提高苹果多酚提取物中强效多酚的含量,该文采用液-液萃取方法按极性大小对果渣多酚进行分离,进而采用1,1-二苯基-2-苦苯肼自由基法和铁离子还原/抗氧化力法对不同极性多酚体外抗氧化活性进行评价.结果表明:液-液萃取方法,可以实现不同极性多酚的有效分离,不同极性苹果多酚,其体外抗氧化活性有显著差异,水层多酚活性最强,其次为正丁醇层,乙酸乙酯层相对较弱,即多酚的抗氧化性与其极性呈正相关.因此,工业化提取苹果渣中多酚时,增大提取溶剂的极性有利于强效多酚的获取.     

鸡粪发酵液培养的小球藻水热液化制备生物原油及其特性

为探索沼液资源再利用,以鸡粪沼气发酵液培养的小球藻为原料,采用水热液化技术制备生物原油。采取正交试验,在温度250~330℃、时间30~90 min及含固量15%~25%下,探讨了水热反应后各相产物特性及元素回收效率。生物原油产率为13.23%~23.83%,最高产油率在330℃、60 min、15%时取得。生物原油中碳、氢及氮回收率分别是16.13%~31.14%、19.18%~34.89%及5.97%~14.32%,最高碳回收率及最低氮回收率分别在330℃、60 min、15%及250℃、30 min、15%时获得。水热液化各相产物中,碳、氢及氮回收率在水相中占主导地位,分别为48.74%~60.43%、46.81%~62.13%及74.84%~82.67%。热重分析暗示生物原油可能适合制备润滑油。此外,GC-MS分析表明生物原油中烃类物质质量分数为16.14%~24.91%,主要为低碳链烃类,如甲苯及二氢茚等。     

夹带剂对超临界CO2萃取结晶穿心莲内酯的影响

以穿心莲内酯粗品和高纯品(纯度分别为30%和95%)为原料,采用超临界CO2萃取结晶法,考察了乙醇、丙酮、异丙醇与乙酸乙酯四种夹带剂对超临界CO2萃取结晶穿心莲内酯的结晶率、纯度、晶型和形貌等的作用规律.结果:因乙酸乙酯分离纯化综合效果较好,且既能与前处理工序中选择的浸提溶剂相统一,减少采用多种溶剂存在的污染,又能保持晶体优良晶型和结晶品质,所以优先选择了乙酸乙酯为夹带剂.     

小球藻粉水热催化液化制备生物油

为探索新型生物质燃油的开发,该文以小球藻粉为原料,采用水热催化液化方法制备生物油。研究了液化温度,液化时间,催化剂等因素对液化率的影响,在此基础上采用正交试验,以液化率为指标,探讨了生物油优化的制备工艺;利用傅里叶红外光谱(FTIR)和气相色谱-质谱联用(GC/MS)技术分析了小球藻粉生物油的基团结构与组成。结果表明,小球藻粉优化的液化反应条件为:采用质量分数5%的Ce/HZSM-5为催化剂,在300°C水热条件下催化液化20min,小球藻粉和溶剂料液比为1:10g/mL,液化率达39.87%。在此条件下制备的小球藻粉生物油的主要成分为醇类,酯类以及部分碳氢化合物,热值达26.09MJ/kg。和传统木质纤维素类生物质相比,小球藻粉制备的生物油成分更接近传统化石燃油且热值更高,显示了良好的应用前景,为微藻生物质液体燃料的制备提供参考。     

夹带剂对超临界CO2萃取结晶穿心莲内酯的影响

以穿心莲内酯粗品和高纯品(纯度分别为30%和95%)为原料，采用超临界CO₂萃取结晶法，考察了乙醇、丙酮、异丙醇与乙酸乙酯四种夹带剂对超临界CO₂萃取结晶穿心莲内酯的结晶率、纯度、晶型和形貌等的作用规律。结果：因乙酸乙酯分离纯化综合效果较好，且既能与前处理工序中选择的浸提溶剂相统一，减少采用多种溶剂存在的污染，又能保持晶体优良晶型和结晶品质，所以优先选择了乙酸乙酯为夹带剂。     

木屑快速热裂解生物油特性及其红外光谱分析

该文以杨木木屑快速热裂解制取的生物油为原料,对其进行了理化特性研究及傅立叶变换红外光谱（FTIR）分析,同时和甜高粱茎秆残渣热裂解生物油的特性进行了比较。结果表明,木屑生物油含水率较低（25.01%）,热值较高（20.62 MJ/kg）,常温下运动黏度为3.44 mm2/s,密度、灰分含量和残炭值分别为1072 kg/m3,0.305%,12.74%,且呈明显的酸性（pH=3.07）。随着温度的升高（25～100℃）,木屑生物油运动黏度明显降低。木屑生物油的较低含水率和较高热值,使其在应用方面优于甜高粱茎秆残渣生物油。然而,从傅立叶变换红外光谱图上不同位置的吸收峰可以判断木屑生物油含有多种官能团,实际应用之前需要进一步的精制。     

Heterogeneous aspects of lipid oxidation in dried microencapsulated oils

This work was aimed at studying lipid oxidation in dried microencapsulated oils (DMOs) during long-term storage. Samples were prepared by freeze-drying of emulsions containing sodium caseinate and lactose as encapsulating components. Evaluation of lipid oxidation was approached by quantitative analysis of nonvolatile lipid oxidation products and tocopherol. Lipid oxidation products were analyzed by separation of polar compounds by adsorption chromatography followed by HPSEC with refraction index detection for quantitation of oxidized triglyceride monomers, dimers, and oligomers. The analytical method applied enabled the detection of different oxidative patterns between the free and encapsulated oil fractions. The free oil fraction of DMOs showed a typical oxidative pattern for oils in continuous phase, which consisted of a clear induction period, in which hydroperoxides (oxidized triglyceride monomers) accumulated, before oxidation accelerated. The end of the induction period was marked by the total loss of tocopherol and the initiation of polymerization. On the contrary, the encapsulated oil showed a pattern characteristic of a mixture of oils with different oxidation status. Thus, high contents of advanced oxidation compounds (polymerization compounds) were detected when the antioxidant (tocopherol) was still present in high amounts. It is concluded that the encapsulated oil was comprised of oil globules with very different oxidation status. The results obtained in this study gave evidence of heterogeneous aspects of lipid oxidation in a dispersed-lipid food system.     

脉冲强光处理对菜籽油储藏稳定性的影响

为探索脉冲强光(IPL)处理对富含油脂食品的影响,采用化学滴定和分光光度法研究了IPL处理对菜籽油储藏稳定性及其酚类物质的影响。结果表明,在试验储藏期内IPL处理5 次和15 次的菜籽油储藏稳定性与对照组相比显著降低(P<0.05),但IPL处理25 次的菜籽油储藏稳定性显著优于对照组(P<0.05)。同时,油脂氧化与酚类物质含量的相关性研究表明,在试验储藏期内IPL处理对菜籽油储藏稳定性的影响与酚类物质含量呈良好的相关性(r²>0.89),可推知IPL处理25 次使菜籽油中酚类化合物的稳定性增加,从而使得油脂储藏稳定性增加。本研究结果为IPL技术在富含油脂食品中的应用提供了一定的理论依据。     

Oxidative stability of algal oils as affected by their minor components

Algal oils, namely, arachidonic acid single-cell oil (ARASCO), docosahexaenoic acid single-cell oil (DHASCO), and a single-cell oil rich in both docosahexaenoic acid and docosapentaenoic acid (OMEGA-GOLD oil), were evaluated for their oxidative stability, as such and after stripping of their minor components, in the dark at 60 degrees C and under fluorescent light at 27 degrees C. Several analytical methods were used to assess the oxidative stability of these oils. Oil extracts were also investigated for their scavenging of 1,1-diphenyl-2-picrylhydrazyl radical by a spectrophotometric method and by measuring their total phenolic contents. The results indicated that minor oil constituents play a major role in their oxidative stability in the dark as well as under fluorescent light. The stability of the oils was dictated by their fatty acid composition, total tocopherols, and the type of pigment present. DHASCO contained a significant level of natural radical scavengers and phenolic compounds that contributed to its higher stability compared to the ARASCO and OMEGA-GOLD oils. Thus, the importance of minor components in the stability of the oils examined was demonstrated.     

Quantitation of short-chain glycerol-bound compounds in thermoxidized and used frying oils. A monitoring study during thermoxidation of olive and sunflower oils

Major short-chain glycerol-bound compounds were investigated in olive oil (OO) and conventional sunflower oil (SO) during thermoxidation at 180 degrees C for 5, 10, and 15 h. These compounds included methyl heptanoate (C7:0), methyl octanoate (C8:0), methyl 8-oxo-octanoate (8-oxo-C8:0), methyl 9-oxononanoate (9-oxo-C9:0), dimethyl octanodiate (C8:0 diester), and dimethyl nonanodiate (C9:0 diester), which were analyzed by GC after derivatization of triacylglycerols to fatty acid methyl esters. An acceptable linear correlation (r = 0.967) was found between the total content of these compounds and the total content of polar compounds, suggesting that quantitation of the major short-chain glycerol-bound compounds provides a good indication of the total alteration level of oils heated at frying temperature. Samples with levels of polar compounds around 25% on oil showed total contents within 2-3 mg/g of oil. To determine the content of these compounds in used frying oils, 10 samples from restaurants and fried-food outlets in Spain were analyzed. Results showed total levels between 2.13 and 7.56 mg/g of oil in samples with contents of polar compounds ranging from 18.8 to 55.5% on oil. Samples with levels of polar compounds of approximately 25% showed total contents of the short-chain compounds similar to those found in the thermoxidized oils, that is, within 2-3 mg/g of oil.     

Influence of deep frying on the unsaponifiable fraction of vegetable edible oils enriched with natural antioxidants

The influence of deep frying, mimicked by 20 heating cycles at 180 °C (each cycle from ambient temperature to 180 °C maintained for 5 min), on the unsaponifiable fraction of vegetable edible oils represented by three characteristic families of compounds (namely, phytosterols, aliphatic alcohols, and triterpenic compounds) has been studied. The target oils were extra virgin olive oil (with intrinsic content of phenolic antioxidants), refined sunflower oil enriched with antioxidant phenolic compounds isolated from olive pomace, refined sunflower oil enriched with an autoxidation inhibitor (dimethylpolysiloxane), and refined sunflower oil without enrichment. Monitoring of the target analytes as a function of both heating cycle and the presence of natural antioxidants was also evaluated by comparison of the profiles after each heating cycle. Identification and quantitation of the target compounds were performed by gas cromatography-mass spectrometry in single ion monitoring mode. Analysis of the heated oils revealed that the addition of natural antioxidants could be an excellent strategy to decrease degradation of lipidic components of the unsaponifiable fraction with the consequent improvement of stability.     

The activity of healthy olive microbiota during virgin olive oil extraction influences oil chemical composition

The activity of olive microbiota during the oil extraction process could be a critical point for virgin olive oil quality. With the aim to evaluate the role of microbiological activity during the virgin olive oil extraction process, just before oil extraction freshly collected healthy olive fruits were immersed in contaminated water from an olive mill washing tank. The oils extracted were then compared with control samples from the same batch of hand-picked olives. The presence of lactic and enteric bacteria, fungi and Pseudomonas on the surface of olives was proved to be much higher in washed than in control olives, with increments in cfu/g between 2 and 3 orders of magnitude. The biogenesis of volatile compounds and the extraction of olive polyphenols and pigments were significantly influenced by the microbiological profile of olives even without any previous storage. In most cases the effect of olive microbiota on oil characteristics was greater than the effect exerted by malaxation time and temperature. Oils from microbiologically contaminated olives showed lower amounts of C5 volatiles and higher levels of C6 volatiles from the lipoxygenase pathway and some fermentation products. On the other hand, a decrease of chlorophylls, pheophytins, xanthophylls and the ratio chlorophyll/pheophytin was observed in these oils. Likewise, the microbiological activity during oil extraction led to significantly lower amounts of polyphenols, in particular of oleuropein derivatives. These differences in olive oil chemical composition were reflected in oil sensory characteristics by the decrease of the green and bitter attributes and by the modification of the oil color chromatic ordinates.     

Quantitative analysis of anti-inflammatory and radical scavenging triterpenoid esters in evening primrose oil

Cold pressed, nonraffinated evening primrose oil (EPO) was recently found to contain lipophilic triterpenoidal esters with radical scavenging and anti-inflammatory properties. A simple and robust method for the quantitative analysis of these 3-O-trans-caffeoyl derivatives of betulinic, morolic, and oleanolic acid was developed and validated. Separation was achieved by normal phase chromatography on a Diol column and with hexane/ethyl acetate (50:50) as eluent. The analytes could be determined directly in the oil matrix, without need of a previous removal of the triglycerides. Normal phase LC ESI-MS with a makeup flow of polar modifier was used for checking the identity and purity of analyte peaks. Samples from 22 commercially available EPOs were analyzed. The average caffeoyl ester contents were 58 mg/100 g in cold pressed oils and 4.7 mg/100 g in partially raffinated oils. In fully raffinated EPO samples, the concentration was below the limit of detection. The influence of extraction temperature on the content of caffeoyl esters in nonraffinated EPO was investigated with seeds of Oenothera biennis and Oenothera lamarckiana, respectively. With O. lamarckiana, the concentration of caffeoyl esters in the oil increased with rising pressure and temperature, whereas no such dependency was found with O. biennis. Microscopic analysis revealed some differences in the histology of the seed testa, which may explain in part the differing behaviors in the extraction experiments. There was a difference between O. biennis and O. lamarckiana oils with respect to the relative amounts of the three esters. The temperature of the extraction process had no effect on the ratio of the compounds.     

水媒法提取食用油技术研究进展

该文提出了水媒法提油技术的概念。水媒法提油技术是指以水为主要媒介的提油技术(水媒法),可辅以或不辅以与水互溶的可食用物质(例如乙醇)、食品级酶、超声波、微波等处理以破坏油料细胞壁和/或破乳的食用油提取方法。水媒法的提油过程主要分为分成破碎、提取、破乳和分离四个阶段。水媒法发展至今60余年,已全面发展了水代法、水酶法和乙醇水提法等多种制油技术。目前水媒法的产业化还存在一些问题,如油料的预处理、酶的种类与成本等。但是,水媒法绿色健康、符合可持续发展要求,随着工艺设备、分离技术等的发展,该技术将更加完善,成为未来未来取代传统工艺的新主流。该文将水媒法研究领域的成果进行归纳总结并为其未来发展提供理论参考。