Effect of chemical treatments of sugar beet fibre on their physico-chemical properties and on their in-vitro fermentation

Chemically treated and dried sugar beet fibres were fermented in vitro in order to study the effects of chemical and physico-chemical parameters of dietary fibre on their colonic fermentation. Sugar beet fibre was treated with dilute alkali, removing mainly acetyl and methyl ester groups, and/or with dilute acids eliminating arabinose, galactose and certain uronic acid residues. The chemical treatments led to an increase in the hydration properties and fermentability by improvement of the accessibility of the remaining polysaccharides. However, if the chemically treated fibres were dried under harsh conditions (100°C), their hydration properties and their fermentability were limited, probably because of structural collapse of the fibre matrix. Whatever the conditions for chemical treatments and drying of the sugar beet fibres, it was possible to predict their fermentability from the water-binding capacity. Because of the relationship between the physiological effects of dietary fibres and the extent to which they are fermented, this result underlines the importance of the physico-chemical characterisation of the fibre in order to acquire a better knowledge of their physiological effects.     

大孔吸附树脂对茶多酚和咖啡碱吸附及洗脱性能的研究

利用绿茶茶汤为实验材料,通过超滤浓缩后,选择不同型号的大孔吸附树脂,进行静态吸附、静态洗脱实验和动态吸附实验。结果表明:聚酰胺对茶多酚有较好的吸附性,3×10-4mol.L-1酒石酸和85%食用酒精是较好的洗脱剂,建立聚酰胺树脂吸附茶多酚过程的传质模型,计算出传质区长度和传质系数,得出最佳上样流速为1.4×10-4m.s-1,最佳上样体积为30BV。     

Effect of various chemical decontamination treatments on natural microflora and sensory characteristics of poultry

Regulation (EC) No. 853/2004 of the European Parliament and of the Council provides a legal basis permitting the use of antimicrobial treatments to remove surface contamination from poultry. This paper reports the results of research into the effects on natural microflora, pH, and sensorial characteristics achieved by dipping chicken legs (15 min, 18+/-1 degrees C) into solutions (wt/vol) of 12% trisodium phosphate (TSP), 1200 ppm acidified sodium chlorite (ASC), 2% citric acid (CA), 220 ppm peroxyacids (Inspexx 100; PA), and water. Samples were collected immediately after evisceration, subjected to the treatments listed or left untreated (control) and tested after 0, 1, 3 and 5 days of storage (3 degrees C+/-1 degrees C). For most microbial groups similar counts were observed on water-dipped and on untreated legs. All the chemical compounds were effective in reducing microbial populations throughout storage, with TSP, ASC and CA showing the strongest antimicrobial activity. The average reductions (mean+/-standard deviation) relative to untreated samples caused by chemical treatments when considering simultaneously all storage days ranged (log(10) cfu/g skin) from 0.53+/-0.83 (PA) to 1.98+/-0.62 (TSP) for mesophilic aerobic counts, from 0.11+/-0.89 (PA) to 1.27+/-1.02 (CA) (psychrotrophs), from 1.34+/-1.40 (PA) to 2.15+/-1.20 (CA) (Enterobacteriaceae), from 1.18+/-1.24 (PA) to 1.98+/-1.16 (CA) (coliforms), from 0.66+/-0.99 (PA) to 1.86+/-1.80 (TSP) (Micrococcaceae), from 0.54+/-0.74 (TSP) to 2.17+/-1.37 (CA) (enterococci), from 0.72+/-0.66 (TSP) to 2.08+/-1.60 (CA) (Brochothrix thermosphacta), from 0.78+/-1.02 (PA) to 1.99+/-0.96 (TSP) (pseudomonads), from 0.21+/-0.61 (PA) to 1.23+/-0.60 (TSP) (lactic acid bacteria), and from 1.14+/-0.89 (PA) to 1.45+/-0.61 (ASC) (moulds and yeasts). The microbial reductions throughout storage increased, decreased, or did not vary, in accordance with microbial group and chemical involved. Similar pH values were observed for untreated samples and for those dipped in PA and water on all sampling days. ASC-treated samples showed a lower pH than controls to day 1. TSP-treated legs exhibited the highest pH values and CA-treated ones the lowest, throughout storage. Hedonic evaluation (nine-point structured scale, untrained panellists) showed similar colour, smell and overall acceptability scores for dipped and untreated samples on day 0 and day 1. From day 3 sensorial attributes scored lower for untreated, PA- and water-dipped legs, as compared to legs treated with TSP, ASC and CA. Only for these three groups of samples were average scores higher than 6 (shelf-life limit value) observed by the end of storage. Results from the present study suggest that the treatments tested improve the microbial quality of chicken without adverse sensorial effects.     

树脂整理对含棉织物吸湿速干性能的影响

对含棉织物进行树脂整理,测试了树脂整理对织物吸湿、速于性能的影响.结果表明,树脂整理可降低棉纤维表面能,降低其吸水性,防止其吸水后膨润;若同时进行亲水整理,则有利于提高其水滴扩散速率及蒸发速率,从而显著提高含棉织物的吸湿速干性能.树脂整理有利于提高含棉织物的吸湿速干性能,适合在大量出汗条件下服用,且穿着舒适.     

仓储粮堆内热湿耦合传递的数值模拟

本文通过理论分析与数值模拟相结合的方法,以典型吸湿性多孔介质—小麦为研究对象,根据小麦吸湿和解吸湿曲线,建立了吸湿性多孔介质内部热湿耦合传递的数学模型,通过与相关实验数据比较验证了数学模型的合理性。基于有限元的方法模拟分析了外界气温和小麦分别为273K(0℃)和293K(20℃),小麦初始水分为14%和18%时直径为10m高度为10m的充满小麦的圆柱仓内部热湿迁移过程,重点探究了近似冬季和夏季仓储粮堆内部温度和水分的动态变化规律。研究结果表明,冬季工况下水分从粮堆内部向顶部和右侧壁面迁移,聚集在相对狭窄的壁面边界附近,形成低温高水分区域,最大水分值出现在右上部侧壁面附近。夏季工况下水分从顶部和侧面向内迁移,而内部又朝右上部区域扩散,形成较宽的高温高水分区域(r <4.5m, 8.0m 相似文献   

Ft-ir spectroscopy as a tool for the study of biological and chemical treatments of barley straw

Diffuse reflectance Fourier transform infrared (FT-IR) spectroscopy has been used to characterise the changes in barley straw when subjected to biological and chemical treatments. The untreated and treated straws were also analysed by traditional analytical techniques for neutral sugar residues and lignin. A comparison between the spectroscopic data and the chemical analyses showed that FT-IR spectroscopy was a quick and non-destructive analytical technique which could be used to assess the efficacy of treatments applied to annual plants.     

海藻纤维针刺复合医用敷料吸湿透气性能的研究

采用海藻纤维、黏胶纤维、涤纶的纤网,通过针刺工艺制备一种新型复合医用敷料。研究不同海藻纤维含量、不同纤网结构的复合医用敷料对液体的吸收性、扩散性以及透湿性和透气性的影响。结果表明:随着海藻纤维含量的增加,复合敷料的吸液量、透湿量及透气性有所提高,防止液体扩散的性能也有所提高;杂乱排列的纤网结构相对于平行排列的纤网结构,吸湿和透气性能都明显提高。     

改善纸浆模塑餐具透气度和挺度的研究

为降低纸浆模塑餐具的透气度和提高其挺度,本文研究了不同浆料和增加打浆度、增加湿压压强、增加干压温度、浆内添加增强剂和表面施胶剂处理等方法对纸浆模塑制品的透气度和挺度的影响。结果发现:半纤维素含量高的纸浆,更容易打浆,对降低透气度也有帮助;打浆度在40°SR时,有利于保证纸餐具具有好的挺度和较低的透气度。增加湿压,能降低透气度;但是挺度也出现了一定程度的下降,压力增加到0.5MPa比较合适。干压处理时,随着温度的增加,纸盘厚度下降,纸盘的透气度下降明显;但温度过高会使纸盘表面变色,建议干压处理温度在400℃左右。表面施胶剂表面处理纸餐盘比浆内添加有效。     

Influence of moderate heat pre-treatments on physical and chemical characteristics of kiwifruit slices

The effect of mild heat treatments, applied to whole kiwifruit, on physical characteristics and chemical composition of minimally processed fruit was studied. Fruits were subjected to heat treatments at 45 °C for 25 and 75 min, cooled for 24 h, minimally processed and stored at 4 °C for 12 days. Heat-treated fruits showed increased respiration rates in the first 2 days of storage. Samples colour was marginally affected either by heat treatments or by minimal processing. The application of heat treatments leads to an increment of slices firmness due to cross linking between demethylated galacturonic acid chains and endogenous calcium. An increment in sucrose, L-malic, citric, quinic and ascorbic acids was observed as a consequence of applied heat treatments. Heat treatment at 45 °C for 25 min applied to whole fruits allows quality retention of minimally processed fruit during 9 days at 4 °C.     

树脂对大豆异黄酮吸附与洗脱性能的研究

利用HPD-600大孔吸附树脂对大豆异黄酮的吸附与洗脱性能进行了研究.测定其静态吸附率为53.30%,静态解吸率为95.36%.吸附时间2 h时,吸附基本达到最大,解吸时间为2.4h时,解吸基本达到最大.上样量45mL时,吸附效果最佳.经吸附-解吸和干燥后,产品纯度达到39.7%.     

毛织物孔隙特征与透湿性关系

为探索毛织物的孔隙特征对其透湿性的作用机制,建立毛织物孔隙特征与其透湿性的经验关系模型,采用体积孔隙率、表面孔隙率和平均孔径分别从不同角度对毛织物的孔隙特征进行表征,用湿阻表征织物透湿性;分别测试了24种毛织物试样的孔隙指标和湿阻;最后分别建立各孔隙特征指标与湿阻的多项式回归模型。得到的经验关系曲线表明:3个织物孔隙特征指标分别与湿阻呈一定程度的非线性相关性,且都呈先正相关后负相关的特征,即湿阻在一定区域存在最高值;当体积孔隙率为60%时湿阻进入最高值区域;当表面孔隙率超过1.5%时,其对湿阻的影响关系开始明显,表面孔隙率在3%附近湿阻呈最高值;当平均孔径在45 μm左右时,湿阻到达最高区域。     

大孔树脂对菥蓂总黄酮的静态吸附分离特性研究

采用静态法考察了10种大孔树脂对菥蓂总黄酮的吸附和解吸性能,筛选出较优的3种树脂HPD722、D101和AB-8,并进一步研究这3种树脂的静态吸附和解吸动力学特性,其中HPD722树脂略优于另外2种树脂。HPD722树脂静态吸附行为结果表明,平衡数据符合Langmuir等温吸附方程和Langmuir平衡吸附速率方程。      

大麻与棉及其混纺纱线吸放湿性能研究

纱线的吸湿透湿性能是影响纺织品舒适性的基本条件和重要因素。测试大麻、棉、棉/大麻和棉/大麻/莫代尔这4种纱线在不同温湿度条件下的吸放湿性能。结果表明：大麻纱线的毛效数值最高,可达11.0cm,说明大麻纱线具有很好的吸湿性能;同一温湿度条件下,当纱线吸湿达到平衡时,大麻、棉和棉/大麻混纺纱线的回潮率接近,棉/大麻/莫代尔混纺纱线的回潮率明显比前3种纱线高;棉/大麻/莫代尔混纺纱线的吸湿放湿速率最大,吸湿放湿速率减小的最快;大麻纱线的吸湿放湿速率比棉、棉/大麻混纺纱线快。     

Effect of chemical treatments on tensile properties and interfacial shear strength of unsaturated polyester/fan palm fibers

Surface treatment of fan palm fibers (FPFs) was investigated as a means of improving fiber tensile strength (FTS) and interfacial shear strength (IFSS) of unsaturated polyester (UPR)/FPFs samples. The fibers were treated with sodium hydroxide, silane, and a combined sodium hydroxide and silane. FT-IR spectra and SEM observation indicated the removal of hemicellulose and lignin components after chemical treatments. The alkaline treatment of FPF resulted in the highest tensile strength of 816 MPa. The interfacial shear strength of FPF/UPR samples was increased for all treated FPF. The highest IFSS (4.1 MPa) was obtained for the alkaline-treated FPF/UPR sample.     

Effects of mechanical treatments and moisture enhancement on the processing characteristics and tenderness of beef semimembranosus roasts

The combined effect of blade tenderization (TD,NTD), pre-massaging (0 and 30min), moisture enhancement and post-injection tumbling (2h) on the chemical, binding and textural characteristics of pre-cooked roasts made from beef top round was investigated. Properties of the beef roasts were determined by measuring processing (i.e., cooking yield, expressible moisture (EM)) and textural characteristics (Warner-Bratzler shear, Kramer shear (KS), texture profile analysis). Brine injection helped to improve the cook yield and had the largest effect on tenderness of semimembranosus muscles. Post-injection tumbling did not significantly improve yield and textural properties of roasts; however, combined with the tenderization, it had beneficial effects on water holding and moisture retention. Pre-tumbling and blade tenderization treatments prior to injection generally were found to be beneficial for textural characteristics; pre-tumbling also tended to improve cook yield, but did not influence EM. However, no synergistic effect between these two variables was observed. An interaction between injection/tumbling and pre-tumbling was observed for KS. There was a significant improvement of KS values of roasts due to pre-tumbling observed for either non-injected roasts or those injected but without tumbling. However, no additional reduction in shear force was observed with pre-tumbling when roasts were tumbled after injection. This suggests that pre-tumbling may not be necessary to ensure more tender roasts when post-injection tumbling is applied, but would be beneficial for non-injected roasts or when tumbling is not applied after injection.     

浓缩方式对慕萨莱思品质及香气成分的影响

研究4种处理方式慕萨莱思的品质及香气成分的差异,并对其进行QDA统计分析。结果表明:冷浓缩处理组的慕萨莱思中总糖、还原糖、可溶性固形物、pH、澄清度及生物活性指标均显著高于热浓缩慕萨莱思组;4种酒样中酯类物质种类最多,高达65种,为主要呈香物质。冷浓缩慕萨莱思中酯类物质相对含量最高,占总挥发性物质相对含量的48.77%,热浓缩慕萨莱思中酯类物质相对含量略低于冷浓慕萨莱思,为36.95%。QDA统计结果表明:冷浓缩慕萨莱思色泽鲜亮均一、口感柔滑、酸甜适口,具有明显的花果香味,且余香、余味时间长,其感官评价最高,风味最佳。     

大孔树脂对长坝柚汁脱苦工艺的研究

利用国产优质大孔树脂对长坝沙田柚汁进行脱苦工艺的研究。选择树脂添加量、树脂保留时间、吸附温度以及pH等因素研究非极性D101树脂对长坝沙田柚汁脱苦的最佳工艺。在单因素实验的基础上,通过响应面优化树脂对长坝沙田柚汁脱苦的工艺。结果表明,D101树脂脱苦最佳工艺条件为树脂添加量6.04%,树脂保留时间15min,吸附温度44.4℃,摇床转速200r/min,柚汁pH5.0,在此条件下,实际测出的脱苦率96.31%,与模型预测值96.80%基本一致,且柚汁的柚皮苷与柠檬苦素含量均显著下降,接近阈值。柚汁感官评价分值较高,达4.6分,无明显感官苦味。      

木材树脂组分之间的相互作用及其对体系稳定性的影响

首先研究了在钙离子存在条件下,三种模型物乳液(树脂酸R、脂肪酸O,甘油三酯TG)的稳定性,结果发现,中性的甘油三酯TG乳液的稳定性最差.接着,研究了树脂模型物各组分之间的相互作用对体系稳定性的影响.结果发现,乳液的制备方法不同,三者在体系中的相互作用也不同.     

大孔树脂对二角菱壳多酚的吸附及解吸性能研究

研究了大孔树脂分离纯化二角菱壳乙酸乙酯萃取液中多酚的方法.对7种大孔树脂进行了静态吸附和解吸的研究,筛选出了效果最佳的大孔树脂D101.对D101大孔树脂进行动态吸附和解吸条件的优化,最佳条件为:上样固形物质量浓度5 mg/mL,上样流速1 mL/min,洗脱溶剂乙醇体积分数70％,洗脱流速4 m L/m in,洗脱体...     

The effect of different dietary treatments on volatile organic compounds and aromatic characteristics of buffalo Mozzarella cheese

The objective of this study was to evaluate the effect of two dietary treatments, ryegrass hay (RH) and wrapped ryegrass silage (WRS) on the volatile organic compounds (VOCs) of buffalo Mozzarella cheese. The primary data were collected from 40 female buffaloes. Twenty animals were fed RH, and other twenty received WRS. Volatile organic compounds were identified using a mass selective detector after extraction with a ‘purge and trap’ system and a gas chromatographic analysis. Our results showed differences in the aromatic profile of Mozzarella cheese samples obtained from buffaloes receiving different feed. In particular, 5 VOCs allowed the discrimination between cheese samples.