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.     

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。     

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.     

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。     

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%.     

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.     

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.     

Effect of combined treatments of high-pressure and natural additives on carotenoid extractability and antioxidant activity of tomato puree (<Emphasis Type="Italic">Lycopersicum esculentum</Emphasis> Mill.)

High-pressure is a new food processing technology aimed at achieving consumer demands for fresher products with reduced microbiological levels. The objective of this work was to evaluate the effect of combined treatments of high-pressure and natural additives (citric acid and sodium chloride) on lutein, lycopene, lycopene epoxide, - and -carotene content, and vitamin A value, and on the in vitro antioxidant activity of tomato puree. The methods used to evaluate the antioxidant activity were the measurement of the DPPH· radical scavenging and the inhibition of lipid oxidation (linoleic acid/CuSO₄ system). The experimental design comprised a response surface methodology according to a central composite face-centred design. The variable ranges were 50–400 MPa, sodium chloride 0–0.8%, and citric acid 0–2%. Total carotenoid content showed the best extraction when pressure was increased up to 400 MPa without sodium chloride and citric acid. The effect of the moderately high-pressure treatment (under 200 MPa) on the structure of the cellular tomato matrix may lead to the different release of various carotenes on the basis of their chemical features and chromoplast location. Radical scavenging activity was higher in the aqueous extract than the organic extract of tomato puree. Significant correlation (P<0.05) was found between the total carotenoid content and the radical scavenging activity and inhibition of lipid oxidation by the organic extract of tomato puree. In conclusion, applying the highest range of pressures (without additives) increased the carotenoid extractability. Further human studies are needed to clarify the effect of high-pressure treatment on the bioavailability of tomato puree constituents.     

Effect of vacuum cooking treatment on physicochemical and structural characteristics of purple‐flesh potato

Cook‐vide (CV, vacuum boiling) and sous‐vide (SV, cooking in a vacuum‐sealed pouch) have been applied to cook purple‐flesh potatoes. Response surface methodology (RSM) sets up the work conditions of temperatures (78–92 °C) and times (16–44 min). Textural parameters, colour and anthocyanins have been measured in cooked samples, and microstructure of cooked tissues was observed with cryo‐SEM technique. CV and SV provided similar hardness (P > 0.05), while SV treatments provided samples more adhesive and cohesive than CV ones (P ≤ 0.05). Micrographs of cooked samples showed rounder cells in cook‐vide samples and higher swelling than in sous‐vide ones. SV treatment avoided the leaching into the water of anthocyanins (chromophore) retaining more of them in potatoes (P ≤ 0.05), as a consequence of which total colour difference was lower in SV samples compared with CV ones (P ≤ 0.05). Particularly, CV samples were lighter (higher values of L*) and less reddish (lower values of +a*) than SV ones (P ≤ 0.05).     

PLA表面温敏性互穿网络水凝胶的UV接枝及其透湿性

为制备一种温度响应型智能调湿织物,采用丙烯酸间苯二酚二缩水甘油酯在聚乳酸(PLA)非织造布表面通过热处理引入不饱和双键,在紫外光照射下引发聚丙烯酰胺/聚(N-异丙基丙烯酰胺)(PAAM/PNIPAAM)互穿网络水凝胶体系接枝于PLA非织造布表面.分析接枝后织物的化学结构、形貌,探究PNIPAAM用量在不同温度下对织物透...     

Comparative study of natural carob fibre and psyllium husk in rats. Influence on some aspects of nutritional utilisation and lipidaemia

The effects of the addition of 100 g kg⁻¹ of psyllium husk (PSY), cellulose (CEL) or natural carob fibre (NCF) to a semi‐synthetic diet on fat (FD) and nitrogen (NF) digestibility coefficients, metabolic nitrogen utilisation (MNU), net nitrogen utilisation (NNU) and total serum cholesterol and triglyceride levels, were studied in male ‘Wistar’ rats. No significant differences were observed between the three fibres with respect to the weight increase of the animals or MNU. Significant differences were recorded for the FD of the NCF group (0.91±0.01) compared to the CEL group (0.95±0.01), as well as on ND (0.88±0.00 NCF group, 0.88±0.00 PSY group and 0.95±0.00 CEL group) and NNU. None of these indexes showed differences between the groups PSY and NCF. For the serum cholesterol levels, there were no significant differences between the non‐hypercholesterolaemic groups fed PSY, CEL or NCF; in those in which hypercholesterolaemia was induced (cholesterol and bile bovine 8.3 g kg⁻¹), significantly lower values were found in the NCF group (166±17 mg dl⁻¹ ) than in the PSY group (343±61 mg dl ⁻¹) and in the CEL group (386±48 mg dl⁻¹). © 1999 Society of Chemical Industry     

Effects of continuous flow microwave treatment on chemical and microbiological characteristics of milk

Raw cows' and goats' milks were heated by microwave in a continuous flow unit up to temperatures ranging from 73.1 to 96.7°C. The effects of the heat treatments were estimated by measurements of lactose isomerization, protein denaturation, inactivation of alkaline phosphatase and peroxidase and the total bacterial count. Negative phosphatase tests and low bacterial counts, together with low degrees of whey protein denaturation, were achieved under several temperature/time combinations. The results indicate that continuous microwave processing may be an efficient and mild approach for the pasteurization of milk.     

有机硅-酚醛树脂共聚物的合成与应用研究

该文利用酚醛树脂与有机硅化合物的接枝共聚反应制备了有机硅改性酚醛树脂,并将其与聚氧化乙烯(PEO)组成双元助留体系,应用于废纸脱墨浆的助留实验。实验结果表明,该双元体系能显著提高细小组分的一次留着率,而影响助留效果的主要因素有助剂的用量、有机硅改性酚醛树脂与PEO的比率、剪切力等。     

Dietary fiber from coconut residue: effects of different treatments and particle size on the hydration properties

The present work is aimed at the production of dietary fiber from underutilized coconut residue left after the extraction of milk, by subjecting it to physical treatments such as water washing, hot water washing, boiling water washing and pressure cooking, as well as solvent extraction. The fat content was reduced from 62% to 45% and 41% by treatment with boiling water and pressure-cooking, respectively. Water-holding, water retention and swelling capacities increased with decreasing fat content. A marked increase was observed in hydration properties when the fat content decreased from 10 to 2%. The hydration properties were maximum for 550 m particle size coconut fiber. For the higher particle size (1,127 m), the oil was trapped inside the fiber matrix, resulting in decreased hydration properties, whereas for the lower particle size (390 m) the rupture of the fiber matrix was responsible for low hydration properties. An attempt was made to compare the hydration properties of coconut dietary fiber with other commercially available dietary fibers.     

Influence of green banana pulp on the rheological behaviour and chemical characteristics of emulsions (mayonnaises)

The influence of green banana pulp (GBP) on rheological behaviour and chemical characteristics of emulsions (mayonnaises) was investigated in this work. Five formulations were developed, using an experimental design for constrained surfaces and mixtures, with the following proportions (water/soybean oil/GBP): F1 (0.10/0.20/0.70), F2 (0.20/0.20/0.60), F3 (0.10/0.25/0.65), F4 (0.20/0.25/0.55) and F5 (0.15/0.225/0.625). Rheological properties of the emulsions were obtained with a rotational Haake Rheostress 600 rheometer and a cone and plate geometry sensor (60 mm diameter, 2° cone angle), with a gap distance of 1 mm. The samples presented high values for mineral salts and low calories. The emulsions showed pseudoplastic behaviour at 10 and 25 °C and rheological data were well described by the Herschel-Bulkley model. Formulations with high GBP content (F1 and F3) presented higher yield stress and apparent viscosity values. The results obtained with the response surface methodology, which were adjusted by the quadratic model, showed that GBP had a significant influence on the increase of yield stress and apparent viscosity. The consistency coefficient increased with an increase in soybean oil concentration and water contributed to high values of flow behaviour index in all emulsions samples.