Effects of alkalization on the properties of Ensete ventricosum plant fibre

Ensete ventricosum (EV) fibre is a lignocellulosic plant fibre hitherto, to the best of our knowledge, unexplored in terms of its response to alkali treatment at room temperature. The chemical compositions as well as physical and tensile properties of this fibre were evaluated after alkali treatment (in 2–15%w/v NaOH at 23 ± 2 °C for 1 h). Effects of alkali concentration on fibre properties were analysed and compared with that of untreated fibres. EV fibres treated with alkali solutions between 2 and 10% (w/v NaOH) exhibited all round improvement in physical, morphological, tensile, structural and thermal properties as compared to that of untreated EV fibres. Unlike the cellulose content, hemicellulose content of alkalized fibres decreased substantially with increase in alkali concentration. The 10% NaOH treated fibres showed the highest improvement in tenacity (9.1 gf/den), crystallinity index (71%) and other properties. Changes in fibre properties were further confirmed by SEM, XRD and TGA.     

Comparison of the performance of kenaf fiber using different reagents presoak combined with steam explosion treatment

To enhance the degumming effect of steam explosion on kenaf fiber, different chemical reagents including hydrogen peroxide (H₂O₂), sulfuric acid (H₂SO₄), and sodium hydroxide (NaOH) presoak combined with steam explosion were used and compared in this article. Distilled water coupled with steam explosion treatment and kenaf raw samples were used as control. The fiber morphology, chemical composition, crystalline structure, degree of fineness, and breaking tenacity of kenaf fibers after treatment were studied. The results showed that hydrogen peroxide (H₂O₂) performs better on removing lignin. It not only splits fibers, but also keeps the fiber’s tenacity during steam explosion treatment. Dilute sulfuric acid (H₂SO₄) performs better on hemicellulose removal, but it damages the fiber cellulose during steam explosion treatment and cause the fiber strength decrease a lot. Sodium hydroxide (NaOH) performs the best on removing hemicellulose and lignin, and splits fiber well. However, the breaking tenacity of the fiber is lower than the fiber pretreated by H₂O₂. Besides, NaOH is a pollutant to the environment. In conclusion, H₂O₂ could be considered as the most promising reagent to be used in combined presoak-steam explosion system.     

Effect of Alkali Treatment on Alfa Fibers Behavior

The object of this study is to characterize of Algerian Alfa (Esparto grass or Stipa tenacissima L), and also to examine the effect of chemical treatment on different properties of this fiber. The surface of the Alfa vegetable fibers was modified by alkali treatment in 5% (NaOH) aqueous solution for 2, 4, 6, 8, 16, 24, 48, and 72 h. The chemical, physical, and morphological properties of the Alfa fibers were investigated. The results show that the Alfa fibers are composed of 39% cellulose, 33% hemicelluloses, 20% lignin, and certain minerals (e.g., SiO₂, K₂O, and CaO). The alkali treatment of the fibers contributes to a decrease in the rate of moisture absorption and to an increase the crystallinity and stiffness. The processing time for adequate alkali treatment is observed at 6 h.     

The biosorptive effect of untreated and chemically modified fir cone powder on Pb(II) removal

In this work, the main aim was to investigate the adsorption potential of untreated and chemically modified (sodium hydroxide and hydrogen peroxide treatment) fir cone powder (Abies alba) for the removal of Pb(II) from aqueous solutions. The effect of contact time, initial concentration of Pb(II), initial pH and temperature was studied in a batch process mode. Adsorption isotherm models (Langmuir, Freundlich, Dubinin–Radushkevich (D–R) and Temkin) and kinetics (pseudo-first-order and pseudo-second-order) models for both processes (treated and untreated) were used to analyse the equilibrium data. The kinetic data were found to fit better the pseudo-second-order. Maximum adsorption capacities calculated using the Langmuir model are 4.8 and 2.9 mg/g for NaOH and H₂O₂ treated fir cone powder, respectively, and 3.7 mg/g for untreated fir cone powder. The results indicate that the NaOH treatment increases the fir cone powder adsorption capacity, while the H₂O₂ treated biomass showed a slight decrease in its adsorption capacity in comparison to the untreated one.     

Yield,viscosity, and gel strength of wami tilapia (Oreochromis urolepis hornorum) skin gelatin: Optimization of the extraction process

A factorial design and response surface methodology were used to optimize the extraction process of tilapia skin gelatin (Oreochromis urolepis hornorum). The concentrations of NaOH (0.15%–0.35%) and H₂SO₄ (0.15%–0.35%), the extraction temperature (40°C–60°C), and the extraction time (3–15 h) were independent variables. Response variables were yield (%), viscosity (mPa·s), and gel strength (g). The NaOH (%) and H₂SO₄ (%) concentrations had significant influences (p<0.05) on viscosity and gel strength, while the extraction temperature (°C) and the extraction time (h) showed significant influences (p<0.05) on all dependent variables. Increasing the temperature and extraction time provided higher yields with a reduction in the gelatin viscosity and gel strength. Tilapia fish skin can be used as a source for production of gelatin.     

杨木APMP制浆化学预处理废液中有机物的分析

研究了不同化学预处理条件对APMP废液中木素和糖类物质浓度的影响。结果表明,化学预处理过程中化学药剂NaOH用量、H₂O₂用量和Na₂SiO₃用量对化学预处理废液中木素和糖类物质浓度的变化有不同影响,影响程度由大到小依次为NaOH用量＞H₂O₂用量＞Na₂SiO₃用量,其中NaOH用量和H₂O2用量对木素和糖类物质浓度的变化有重要影响,Na₂SiO₃用量无明显影响。化学预处理温度对化学预处理废液中木素和糖类物质浓度的影响程度明显大于化学预处理时间。在化学预处理过程中,NaOH用量、H₂O₂用量和化学预处理温度是影响杨木APMP制浆化学预处理废液中木素和糖类物质浓度的重要因素。     

Technical note: A comparison of alkali treatment methods to improve neutral detergent fiber digestibility of corn stover

The objective of this study was to compare neutral detergent fiber (NDF) digestibility of corn stover that had been treated by 2 alkali treatment methods. Two experiments were conducted to test a sodium hydroxide (NaOH) treatment method that uses an ethanol/water co-solvent (NaOH/ethanol-H₂O, United States Patent No. 20140220228) and a calcium hydroxide (CaOH) treatment method, which uses water as a solvent (CaOH/H₂O). An in situ trial was conducted to compare NDF digestion kinetics between NaOH/ethanol-H₂O-treated stover, CaOH/H₂O-treated stover, untreated corn stover, and soy hulls. The digestion rate of potentially digestible NDF (k_d) of NaOH/ethanol-H₂O-treated corn stover (5.36%/h) was higher than CaOH/H₂O-treated stover (2.27%/h), or untreated corn stover (1.76%/h) and similar to the k_d of soy hulls (4.93%/h). The indigestible NDF (iNDF) fraction of untreated corn stover (35.1% of NDF) was reduced by CaOH/H₂O treatment (27.3% of NDF) and by NaOH/ethanol-H₂O treatment (2.8% of NDF). The iNDF fraction in soy hulls (3.6% of NDF) was similar to iNDF of NaOH/ethanol-H₂O-treated stover. An in vivo digestibility trial was also conducted to compare fiber digestibility of diets supplemented with untreated corn stover, NaOH/ethanol-H₂O-treated corn stover, or soy hulls. Total-tract apparent dry matter (DM) and NDF digestibility were measured with 8 lactating Holstein cows in a replicated 4 × 4 Latin square with four 21-d periods. Apparent DM digestibility (DMD) was improved when supplemental soy hulls were added to the base diet (60.0% DMD) compared with the base diet with no supplemental fiber (57.7% DMD). Apparent DM digestibility was reduced when diets were supplemented with untreated stover (52.4%). Dry matter digestibility of NaOH/ethanol-H₂O-treated stover was similar (54.8% DMD) to all other treatments. Digestibility of NDF was lowest when cows were fed the diet with supplemented untreated stover (35.5% of NDF), and improved when soy hulls (40.6% of NDF) or NaOH/ethanol-H₂O-treated stover (43.8% of NDF) were added to the diets. The NaOH/ethanol-H₂O treatment process improves the DM and NDF digestibility of corn stover to values similar to those of soy hulls.     

Optimization of the Strength Properties of Waste Oil Palm (Elaeis Guineensis) Fronds Fiber

In this study, Box-Behnken design (BBD) and response surface methodology (RSM) was applied to study the effects of alkaline peroxide treatment variables (cooking time, sodium hydroxide concentrations, and hydrogen peroxide concentrations) on the pulp and paper strength properties (screened pulp yield, kappa number, tensile index, tear index, burst index), which are considered dependent variables or response variable of the extracted cellulose from oil palm (Elaeisguineensis) fronds (OPF) vascular bundle fibers. The results indicated that at the optimum operating conditions of 2.35% NaOH, 5.00% H₂O₂ and a 53.41 min cooking time, resulting maximum strength properties (tensile index, burst index, tear index,) gave 9.92 Nm/g, 6.55 KPam²/g, 6.22 mNm²/g, respectively. The study revealed that alkaline peroxide pulped fibers of oil palm frond vascular bundles could be considered a suitable alternative for paper qualities with moderate strength requirements.     

响应面法优化提取油茶籽壳棕色素与抗氧化活性研究

为综合开发利用油茶资源,采用响应面法优化油茶籽壳棕色素提取工艺。以提取温度、液料比、乙醇浓度、提取时间为自变量,以油茶籽壳棕色素提取含量为响应值,进行响应面分析,并研究油茶籽壳棕色素体外抗氧化活性。结果表明,影响油茶籽壳棕色素提取含量高低的因素主次顺序为提取时间乙醇浓度温度液料比。油茶籽壳棕色素最佳提取工艺条件为提取温度35℃、液料比11∶1、乙醇体积分数65%、提取时间2 h。在此条件下,油茶籽壳棕色素提取率为15.09%,与预测值基本一致。体外抗氧化活性试验表明,油茶籽壳棕色素有一定的清除O~-_2·、H_2O_2的能力和还原能力。     

Ultrasonic-Assisted Extraction of α-Tocopherol Antioxidants from the Fronds of Elaeis guineensis Jacq.: Optimization, Kinetics, and Thermodynamic Studies

This article presents the first report on the extraction and quantification of α-tocopherol from the fronds of the oil palm (Elaeis guineensis Jacq). In this study, the optimization, kinetic, and thermodynamic data of α-tocopherol extraction by sonication are presented. Response surface methodology coupled with central composite design was used to optimize the experimental conditions for α-tocopherol extraction. Three independent variables, namely sample/solvent ratio (1:20–1:40 g/ml), extraction temperature (30–50 °C), and extraction time (20–50 min) were studied. For optimum conditions of 39.31 °C (~40 °C), 50 min, and 1:23.63 g/mL (~1:20 g/mL), total tocols and α-tocopherol optimal concentrations were 346.49 μg/g oil palm fronds (OPFs) by dry weight (DW) and 28.41 μg/g OPF DW, respectively. The effects of extraction temperature and tocol concentrations on the extraction kinetics and thermodynamic parameters were also studied. From the mass transfer rate equation, the kinetic and thermodynamic data obtained from the ultrasonic-assisted extraction (UAE) of α-tocopherol from OPF were activation energy, E _a (104.6 kJ mol^?1), UAE rate constant, k (6.886?×?10^?3 min^?1), ΔH (+0.818 kJ mol^?1), ΔS (+27.22 J mol^?1 K^?1), and ΔG (?8.52 J mol^?1). According to this study, the UAE of α-tocopherol from OPF is endothermic, irreversible, and spontaneous.     

Microwave Assisted Modulation of Vat Dyeing of Cellulosic Fiber: Improvement in Color Characteristics

The role of radiations in textile processing is gaining attention due to its low cost, energy effectiveness and eco-friendly process. This study is concerned with the improvement in modulation of microwave assisted vat dyeing of cellulosic fiber. It was found that radiation treatment of both cotton fabric and dye solution for 1 min gives good color strength, while for redox reaction, 2.5 g of NaHSO₃, 2 mL of CH₃COOH, and 1.5 mL of H₂O₂ are the optimized conditions which show it is a cost-effective tool. Good color strength was obtained at 65 °C for 1 h dyeing using 50 mL of optimal solution in dye bath at pH 9. Finally, ISO standards for color fastness to light, washing, rubbing and perspiration were applied at 0.5–2.5% of shade at optimal conditions which showed that microwave treatment has enhanced the color characteristics. Hence, the technique can successfully and easily be employed for surface modification of fabric for good quality dyeing with various classes of dyes.     

Enhanced Chemiluminescence Determination of Hydrogen Peroxide in Milk Sample Using Metal–Organic Framework Fe–MIL–88NH<Subscript>2</Subscript> as Peroxidase Mimetic

The presence of hydrogen peroxide (H₂O₂) in milk is a major concern because it constitutes a public health hazard. Here, a sensitive flow injection chemiluminescence method was established for the detection of H₂O₂. As a peroxidase mimetic, metal–organic framework Fe–MIL–88NH₂ was found to significantly enhance the chemiluminescence of luminol–H₂O₂ reaction. The enhancement mechanism could be attributed to peroxidase-like activity of Fe–MIL–88NH₂, which effectively catalyzed the decomposition of H₂O₂ into hydroxyl radical. The experimental conditions for the chemiluminescence reaction were thoroughly investigated. The chemiluminescence intensity was proportional to the concentration of H₂O₂ in the range of 0.1–10.0 μmol/L. The detection limit was 0.025 μmol/L H₂O₂, and the relative standard deviation was 2.6 % for 11 replicated measurements of 1.0 μmol/L H₂O₂ solution. The practicability of this method was demonstrated by determining H₂O₂ in milk samples.     

Similar Reduction of Salmonella enterica Typhimurium on Grape Tomatoes and Its Cross-Contamination in Wash Water by Washing with Natural Antimicrobials as Compared with Chlorine Treatment

Thymol (THY), a generally recognized as safe (GRAS) compound found in thyme oil, has inhibitory effects against foodborne pathogens including Salmonella. Hydrogen peroxide (H₂O₂) is another GRAS agent to effectively inactivate Salmonella. The aim of the current study was to develop a GRAS wash solution containing THY (or H₂O₂) and other GRAS antimicrobials (organic acids and food surfactants) that would effectively reduce Salmonella enterica on grape tomatoes and minimize cross-contamination in washing water. A systematic approach including minimum inhibitory concentration and minimum bactericidal concentration tests, inhibition zone tests, and small-scale and scaled-up tomato washing tests was used to develop such wash solutions. Grape tomatoes surface-inoculated with S. enterica Typhimurium were washed with selected solutions containing combination of 0.2 mg/ml THY, 5 % sodium dodecyl sulfate (SDS) and 2 mg/ml acetic acid (AA), 800 ppm H₂O₂, combination of 200 ppm H₂O₂ with 4 % SDS, or 200 ppm chlorine for 2 min. THY 0.2 mg/ml + SDS 5 % + AA 2 mg/ml, 800 ppm H₂O₂, or 200 ppm chlorine achieved around 7.5 log reductions of Salmonella on the tomatoes as compared to the control in tests involving 10 or 100 g tomatoes. More than 5.0 log reductions in the spent washing solutions (0.2 mg/ml THY + SDS 5 %?+?2 mg/ml AA; 800 ppm H₂O₂) was observed. None of these antimicrobial washes changed the color, pH, texture, sensory quality of the tomatoes during 16-day storage at 4 and 22 °C. These treatments also achieved a 1.3 log reduction of total aerobic bacteria. Thus, washing with 0.2 mg/ml THY + SDS 5 %?+?2 mg/ml AA and 800 ppm H₂O₂ as alternative to chlorine-based washing could be an effective method to inactivate Salmonella on tomatoes and reduce the transmission of pathogens from tomatoes to washing solutions.     

Hydroxyl Radical-Stressed Whey Protein Isolate: Functional and Rheological Properties

The objective of the study was to examine the sensitivity of whey protein functionality to oxidizing radicals. Whey protein isolate (WPI) was oxidatively stressed by incubation at 20 °C for 3, 5, and 10 h in hydroxyl radical-generating media containing 0.1 mM ascorbic acid, 0.1 mM FeCl₃, and 1–10 mM H₂O₂. Protein solubility decreased (P?<?0.05) with increasing H₂O₂ concentrations and oxidation time. Surface properties of WPI, including both emulsifying and foaming activities, exhibited significant improvements (P?<?0.05) at H₂O₂ concentrations up to 5 mM and oxidation time up to 5 h. The longer oxidation time or higher H₂O₂ concentrations tended to diminish the surface functionality. However, the oxidative stress, though decreasing the onset gelling temperature, had a general detrimental effect on WPI gelation (hardness, springiness, and storage modulus). The results indicated opposing effects of oxidation on WPI: detrimental to hydrodynamic properties (solubility, gelation) but beneficial to surface properties (emulsification, foaming).     

Scope of Sustainable Pretreatment of Cotton Knit Fabric Avoiding Major Chemicals

ABSTRACT

The present effort attempted to avoid basic chemicals, namely NaOH and H₂O₂ in scouring and bleaching of cotton knit fabric in order to reduce the chemical load and processing cycles without compromise of dyeing performance. Single jersey single lacoste cotton knit fabrics treated with detergent and wetting agent at 120°C temperature for 20 minutes revealed 5.8% weight loss. FTIR graphical data validated the weakening and moving out of characteristic bands of wax and pectin-based cotton impurities in the region of 1740–1200 cm^?1. The color differences of 1.5% and 1% dyed samples confirmed pass value (CMC ΔE ≤ 1) when treated at 105°C temperature for 20 minutes. The grading for color fastness to wash, perspiration, rubbing and light was 4–5 to 5. No deterioration in strength and morphological changes were experienced for the treated samples.     

H2O2/NOBS活化体系在棉织物冷轧堆漂白中的应用

 针对传统棉织物冷轧堆漂白法耗时长和耗碱高等问题,研究H₂O₂/NOBS活化体系在纯棉织物冷轧堆漂白中的应用。通过单因素试验和正交试验法分析各工艺因素对漂白效果的影响,探讨其作用原理,开发了整套的应用工艺技术。合适的工艺条件为:H₂O₂质量浓度30 g/L,NOBS与H₂O₂物质的量比1∶4,NaOH质量浓度6 g/L,堆置时间6 h。结果表明:该活化漂白工艺在改善漂白织物品质的前提下能够大大减少耗碱量,缩短冷轧堆时间,具有生态环保和高效节能的优势。     

Effect of alkali treatment on mechanical properties of woven jute composites

The effect of alkali treatment on the jute fabrics and its influence on jute composites properties has been studied. The plain woven jute fabrics were manufactured using handloom. The alkali treatment was optimized using Box and Benkhen experimental design using time, temperature and concentration as independent variables and water absorbency, weight loss percentage as dependent variables. The fabric treated with optimized condition of 5% NaOH for 4 h at 30 °C was made into a composite of [0°]₄ lay-up sequence by means of compression moulding technique using vinyl ester resin. The composites were characterized for various mechanical properties such as tensile, flexural and impact strength. It is observed from the results that the alkali-treated samples show increased mechanical properties of the composites which may be due to the better adhesion between the fabric and the resin because of the removal of lignin and hemicellulose.     

Effect of controlled atmospheres with varying O2/CO2 levels on the postharvest senescence and quality of broccoli (Brassica oleracea L. var. italica) florets

Controlled atmosphere (CA) has been widely used to help extend the shelf life and maintain the quality of horticultural products. In the present study, broccoli (Brassica oleracea L. cv. Youxiu) florets were stored under CA with high levels of O₂/CO₂ at 15 °C, including 100 % O₂, 80 % O₂ + 20 % CO₂, 60 % O₂ + 40 % CO₂, 40 % O₂ + 60 % CO₂, and air (control), to determine the effects of CA on storage period and on some physiological properties during storage. The results showed that compared with the control, the treatments combining O₂ and CO₂ effectively extended the storage period and inhibited respiration rate, ethylene production, and reductions in weight loss, chlorophyll, and ascorbic acid levels. Moreover, the CA treatments inhibited the increases in both superoxide radicals (O ₂ ^?· ) production rate and hydrogen peroxide (H₂O₂) level and reduced malondialdehyde accumulation, which could be beneficial in delay of senescence by alleviation of oxidative damage. In addition, broccoli florets exposed to CA conditions maintained lower activities of superoxide dismutase and peroxidase that are responsible for scavenging of O ₂ ^?· and H₂O₂ and alleviating lipid peroxidation. Among the treatments, the maximum efficacy was observed with a CA of 40 % O₂ + 60 % CO₂, which prolonged the storage period of broccoli heads to 17 days (d) compared with 4 d under air treatment. Conversely, 100 % O₂ treatment accelerated senescence and deterioration in the quality of broccoli, resulting in a shorter storage period. These results suggest that the establishment of an appropriate CA condition with high levels of O₂/CO₂ may be an ideal strategy for maintaining the quality of broccoli florets during storage.     

葡萄糖酸钠发酵废弃菌丝体提取壳聚糖的研究

以产葡萄糖酸钠的废弃菌丝体为原料,探究了从废弃黑曲霉（Aspergillus niger）菌丝体提取壳聚糖的工艺条件。对废弃菌丝体进行了各组分分析后,在单因素的基础上对提取工艺进行优化,得出了碱法提取壳聚糖的最佳优化条件：料液比为1∶30（g∶mL）,6% NaOH处理2 h,反应温度为95 ℃时,菌体蛋白去除率达到77.26%;碱（NaOH）浓度为30%,处理温度为120 ℃,脱蛋白处理后样品采用重复碱处理的方式脱乙酰,样品分两次重复用30% NaOH溶液在120 ℃下各处理1 h,得到壳聚糖的脱乙酰度为78.85%,壳聚糖得率为10.53%;后续用12%醋酸纯化处理,得到脱乙酰度为84.49%的壳聚糖,得率为9.56%。