烤烟烟叶中游离氨基酸与内在质量关系的研究

系统地分析了烤烟烟叶中游离氨基酸与内在质量的关系，参试材料31份，每个样品分析鉴定25项指标，对试验数据分别进行简单相关分析，多元回归和偏相关分析以及典型相关分析。简单相关分析结果表明，游离氨基酸组分与内在质量之间存在一定的相关关系，其中缬氨酸、酪氨酸和游离氨含量较高，则烟叶香气较好，亮氨酸含量较高，烟叶杂气较少，丝氨酸，甘氨酸和游离氨含量高，则烟叶评吸总分较高，烟叶品质相对较好，多元回归和偏相关分析系统地分析了游离氨基酸组分对内在质量的贡献大小。其中对香气贡献较大的有精氨酸，苯丙氨酸和游离氨；对吃味贡献较大的有甘氨酸，对减少杂气贡献较大的是游离氨和脯氨酸，对评吸总分贡献较大的有精氨酸。苯丙氨酸、丝氨酸，总游离氨基酸和酪氨酸。典型相关分析结果表明，游离氨基酸与内在质量间的典型相关主要是由酷氨酸，蛋氨酸，苯丙氨酸，精氨酸，丝氨酸，脯氨酸，亮氮酸，苏氨酸，氨与香气，吃味，杂气，刺激性相关显著引起的。     

抗静电阻燃混纺纱的纺制及其主要性能

研究不锈钢纤维阻燃粘胶纤维混纺纱的纺纱工艺及产品的主要性能.对不锈钢纤维与阻燃粘胶纤维的基本性能进行了分析,设计生产了不锈钢纤维含量在1%～40%的10种抗静电阻燃混纺纱,测试分析了不锈钢纤维含量与混纺纱的燃烧、电学等主要特性间的关系.结果表明:不锈钢纤维在混纺纱中的含量决定纺纱细度;不锈钢纤维含量增加,混纺纱强伸度均降低,纱线燃烧平均摧毁长度减小,燃烧时间缩短,燃烧速率基本相同;不锈钢纤维含量为1%时抗静电性能较好;纱线色泽与不锈钢纤维含量近似呈线性关系.     

Chemical composition and antioxidative activity of Moldavian balm (Dracocephalum moldavica L.) extracts

Moldavian balm (Dracocephalum moldavica L., Lamiaceae) is a perennial herb native to central Asia and naturalized in eastern and central Europe. It is commonly consumed as a food-related product and as a herbal preparation because of its reputed medicinal properties. Despite its importance, few reports exist in the literature regarding the chemistry or antioxidant activity of this species. In this study, the aerial material of Moldavian balm collected from Iran was extracted by Soxhlet using seven solvents of different polarity, viz., petroleum ether, dichloromethane, acetonitrile, ethyl acetate, methanol, n-butanol and water. The qualitative-quantitative chemical composition of each extract was determined using high-performance liquid chromatography coupled to photodiode array detection. For each extract, the total phenolic content was estimated as was the in vitro antioxidant activity using the iron(III) reduction assay, the β-carotene-linoleic acid bleaching assay and the 1,1-diphenyl-2-picrylhydrazyl and 2,2′-azinobis(3-ethylbenzothiazoline-6-sulphonate) free radical scavenging assays. Hydroxylated cinnamic acids, their derivatives and flavonoids were identified and quantified within the extracts, with rosmarinic acid being the most abundant component identified. The extracts demonstrated different degrees of potency within each assay, however, the observed pattern was not necessarily replicated between assays indicating the importance of the use of more than one screening technique to estimate the antioxidant activity of plant extracts.     

The determination of frying oil quality using Fourier transform infrared attenuated total reflectance

The possibility of using the whole spectra (wave numbers between 4000 and 850 cm⁻¹) from Fourier transform infrared attenuated total reflectance spectroscopy (FTIR-ATR) to differentiate between good, marginal and unacceptable oils with regard to various intensities of oil rancidity was investigated. Fresh, used, and discarded oils were collected from several fast food restaurants from each frying cycle for 4 weeks. Dielectric constant, peroxide value, free fatty acid content, and density of oil samples significantly (P<0.01) increased with frying time. The correlation (r) between FTIR absorbance at 3300 cm⁻¹ and free fatty acid content was from 0.84 to 0.94 for oils from the three restaurants. Similarly, the correlation between FTIR absorbance at 3471 cm⁻¹ and peroxide value was from 0.90 to 0.97. The results of principal component analysis using the whole spectra (4000-850 cm⁻¹) showed good discrimination and stability for identification between acceptable, marginal and unacceptable frying oils.     

Antioxidant Properties of Cocoa Beans (Theobroma cacao L.): Influence of Cultivar and Roasting Conditions

Effects of various roasting conditions on antioxidant properties of five Theobroma cacao L. varieties were investigated. The cocoa beans were roasted at four different temperatures (110–150°C) and three different air humidities (0.3–5.0%). The raw cocoa beans were characterized by high antioxidant activities. The antioxidant properties of the roasted cocoa beans varied markedly among the analyzed cultivars and geographical regions and were affected by roasting conditions. Generally, cocoa beans of the cv. Forastero from Brazil exhibited higher total phenolic content, free radical scavenging activity, and metal chelating ability than samples of the other analyzed cocoa varieties. Roasting at 110°C caused negligible changes in total phenolics content and antioxidant activity of cocoa beans, while almost all samples tended to have lower antioxidant potential when roasting temperature increased. The air humidity used in roasting did not affect the total phenolics content and antioxidant activity for lowest roasting temperature (110°C). Moreover, the obtained results revealed that thermal processing at the higher temperatures and elevated air humidity resulted in the higher antioxidant capacities. It was also found that the ferrous ion chelating activity of cocoa beans increased with the roasting temperature (in the range from 110 to 150°C), with the exception of cv. Trinitario from Papua New Guinea. The data showed that roasting at lower temperatures with humid air are more favorable in terms of preserving the bioactivity of roasted cocoa beans.     

Lipolysis,lipid peroxidation and texture of Serrano ham processed under different ripening temperature conditions

Lipolysis, lipid peroxidation, texture and rancid taste were investigated in Serrano hams processed under low, medium and high ripening temperature conditions (RTC) for 15 months. Medium RTC hams showed the highest contents of saturated and monounsaturated free fatty acids (FFAs) from month 5 to 15 and of polyunsaturated FFAs from month 7 to 12. The primary peroxidation index decreased during ripening in all hams, with higher levels for low RTC hams from month 5 onwards. Contrarily, the secondary peroxidation index increased during ripening in all hams, with higher levels for medium RTC hams from month 7 onwards. Texture parameters varied significantly among ham muscles. Shear force increased during ripening in all hams, with higher values for medium RTC hams, whereas cutting force was not influenced by RTC or ripening time. Rancid taste scarcely developed during ripening and was not affected by RTC.     

Antioxidant and antiproliferative activities of mango (Mangifera indica L.) flesh and peel

The antioxidant and antiproliferative properties of flesh and peel of mango (Mangifera indica L.) were investigated. The cytoprotective effect of mango flesh and peel extracts on oxidative damage induced by H₂O₂ in a human hepatoma cell line, HepG2, were determined, and the underlying mechanism was examined by a single-cell electrophoresis assay (comet assay). Treatment of HepG2 cell with mango peel extract prior to oxidative stress was found to inhibit DNA damage. The free radical scavenging activities of mango flesh and peel extracts were evaluated by electron spin resonance (ESR). The mango peel extract exhibited stronger free radical scavenging ability on 1,1-diphenyl-2-picrylhydrazyl (DPPH) and alkyl radicals than mango flesh extract, regardless of ripeness. Similarly, peel extract exhibited significant antiproliferative effect against all tested cancer cell lines, compared to that of flesh extract, in a dose-dependent manner. The result also showed that the antiproliferative activity of mango flesh and peel extracts correlated with their phenolic and flavonoid contents. Thus, mango peel, a major by-product obtained during the processing of mango product, exhibited good antioxidant activity and may serve as a potential source of phenolics with anticancer activity.     

热镀钢丝膜层的冷凝计算

分析了热镀钢丝自液池引出过程中的热传导，得出了温度分布的解析解，从而计算钢丝表面膜层达到凝固温度时的提抽高度，为结构设计及确定冷却装置的合理位置提供依据。     

新型选择性减害滤棒的研制

为了利用天然植物活性成分的抗氧化性,对抗氧化剂葡萄多酚(PT)、苹果多酚(PG)、茶多酚(CY)进行了筛选,采取直接添加、依托载体添加及制备成颗粒复合添加等多种添加工艺,并通过对抗氧化剂改性提高其在卷烟中的添加量,制备了新型选择性减害滤棒并卷制成样品烟支,对滤棒的各项常规物理指标和卷烟烟气的常规化学指标及自由基含量的变化进行测试。同时,采用加速氧化法对该种减害滤棒的抗氧化性能的稳定性进行了检测和评价。结果表明:采用直接添加和复合添加相结合的加工工艺,当有效成分含量为90%的改性抗氧化剂CY1在滤棒中的添加量达到3.0mg/支后,能够实现选择性显著降低烟气自由基近30%,同时不影响烟支外观和烟气常规技术指标,卷烟吸味也未因此有明显改变。     

Innovation in milk powder technology

Global trade in preserved milks is on the increase as new markets open up in regions of the world that have not been traditionally associated with milk consumption. Equally, a rise in world milk production is forecasted to continue, and the indications are that significant quantities of the extra milk produced will be converted to commodity products such as butter and powders. Consequently, on-going investment in new spray drying capability is likely to track geographical shifts in milk production. Successful application of advanced process control to the operation of large scale drying plant is both a priority and a challenge.
  Meanwhile, opportunities for the exploitation of milk as a source of functional ingredients are being availed of by the dairy industry as it continues to achieve added value and unique key selling points. Recent research on the role of spray drying, along with other processes in the development of dairy ingredients for applications in chocolate and the preparation of microencapsulated powders, is reviewed.