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。     

Synergistic effect of nanoparticles and Thalassospira sp. isolated from Bahregan area in biodegradation of oil sludge

Oil sludge is obtained from the contaminated site of Bahregan area in the Persian Gulf in Iran. Chemotaxis was used for the isolation of alkane-degrading bacteria from oil sludge and the alk genes were determined with specific primers. bac1 identified in Thalassospira was selected as a powerful strain for biodegradation of oil sludge. Biodegradation of oil sludge by bac1 in the presence of nanoparticles was investigated by GC-MS analysis. Synergistic effect of Fe₂O₃ and Fe₃O₄ nanoparticles on bacteria increases the biodegradation of oil sludge and produces cyclosiloxane compound which is used in the field of medicine; however, the Thalassospira reduced its toxicity in the environment.     

Thermal degradation of corn starch based biodegradable plastic plates and determination of kinetic parameters by isoconversional methods using thermogravimetric analyzer

Oil shortage and awareness of environment pollution leads to the extensive use of biodegradable starch-based materials against synthetic plastics. The accumulated wastes of these plastics takes more time for natural recycling and the process is complex. Therefore the best option of recycling would be to convert these polymers into a source of energy by pyrolysis. So to understand the pyrolytic behaviour, kinetics of such waste plastics is studied by using thermogravimetric analysis at different heating rates of 10 °C, 20 °C, 40 °C, 60 °C, 80 °C and 100 °C in nitrogen atmosphere followed by characterization of the pyrolysis products. The kinetic parameters are obtained for two major stages of decomposition in two different temperature ranges 250–620 °C and 620–855 °C by iso-conversional methods such as Friedman, Coats-Redfern, FWO and Kissinger methods. The regression coefficient data (>0.9) of kinetic plots obtained for different methods best fits to the kinetic equation. Empirical formula of the compound is determined by ultimate analysis is CH_2.214S_0.0018O_0.6910. Proximate analysis gives the idea of volatile component which is74.33%. The range of average value of activation energy is 120.7013 kJ/mol to 140.7707 kJ/mol for the biodegradable plastic plate with different conversion (0.1–0.6) and (0.1–0.3) respectively at two different temperatures. The pyrolysis products obtained using a semi-batch reactor are characterized to know their composition and other properties.     

Investigating volatile compounds’ contributions to the stale odour of green tea

This study aimed to characterise the volatiles that contribute to stale odour of green tea. Volatiles were extracted using headspace solid-phase microextraction (HS-SPME) and analysed using gas chromatography-mass spectrometry (GC-MS) and gas chromatography-olfactometry (GC-O). Results showed that a total of ninety-six volatiles were identified by GC-MS, in which forty-four volatiles were screened out based on Principal component analysis (PCA) and orthogonal projections to latent structures–discriminant analysis (OPLS-DA), and thirty-nine volatiles had a significant variation at the level of 0.05 by analysis of variance (anova ). From GC-O analysis, fifty-four aromatic volatiles with strong aroma intensity (aroma intensity above 2) were perceived. Further investigation revealed that fifteen volatiles, including 1-octen-3-ol, benzyl alcohol, benzaldehyde, safranal, β-cyclocitral, (E,E)-3,5-octadien-2-one, (Z,E)-3,5-octadien-2-one, dimethyl adipate, dihydroactinidiolide, β-ionone, α-ionone, geranyl acetone, phenylethyl alcohol, methyl decanoate and α-terpineol were responsible for stale odour, besides the former nine compounds were only found in stored tea.     

涂料中溶剂定性定量测定方法的探讨

以实际经验为基础并结合具体实例,探讨了涂料中溶剂定性定量的测定方法,包括内标物、稀释剂的选择以及其中可能发生的问题,并提出建立相应的记录方法。     

Bio-oil extraction and physicochemical characterization of Caesalpinia pulcherrima plant seed oil

Dwarf Poinciana (Caesalpinia pulcherrima) seeds are studied for first time for the extraction of bio-oil. The dried and crushed seeds are optimized for maximum yield of bio-oil with a series of polar and nonpolar solvents and recovered by a simple distillation process. Methanol is found to yield the maximum bio-oil. The fatty acid analysis of bio-oil reveals the prevalence of linoleic acid (54.67%), followed by palmitic acid (16.9%), stearic acid (12.5%), and oleic acid (10.32%). Basic fuel properties like specific gravity, viscosity, refractive index, iodine value, saponification value, fire point, flash point, pour point, and calorific value are studied.     

Real-time monitoring of hemicellulose liquefaction in ethylene glycol

Xylan was used as a model material to study the liquefaction of hemicellulose in the presence of ethylene glycol. The ReactIR^TM reaction analysis system was used to monitor the entire liquefaction process online. The results showed that xylan was decomposed and transferred to liquid phase. The gel permeation chromatography results of the liquid products showed that the weight average molecular of xylan decreased signi?cantly to around 1728 g/mol after liquefaction. Gas chromatography-mass spectrometry revealed that the ethylene glycol liquefaction products from xylan include ethylene glycol and its derivatives, alcohols, aldehydes, ketones, some acids and their esters.     

一种未知涂料的化学成分剖析

采用红外光谱、气质联用仪对一种未知涂料的化学成分进行分析,对涂料的红外光谱进行解析、联机检索并定性,用气质联用数据进行验证、补充,确定出该涂料的主要成分。     

Stability Studies of Ozonized Sunflower Oil and Enriched Cosmetics with a Dedicated Peroxide Value Determination

Ozonized oils have interesting applications in the cosmetic industry and several patents on enriched products were developed in the last years. Ozonides are known for their high reactivity and stability data are required for enriched cosmetic products during storage. In this paper a dedicated determination of Peroxide Value (PV) was performed on ozonized sunflower oil (Neozone 4000) and on some enriched cosmetics, in order to control their stability during storage. The optimal conditions of the PV method were determined, following the decomposition reaction of ozonides with KI utilizing ¹H-NMR and GC/MS techniques.