Reinforcement of Polypropylene Composites Based on Recycled Wool or Cotton Powders

This article addresses the preparation and characterization of polymer composites of polypropylene (PP) containing recycled wool or cotton micro-powder. The PP composites were produced in a lab-scale twin-screw extruder. The recycled wool or cotton powder was obtained from wool and cotton waste fibers (from textile industry) by freeze milling technique. The amount of powder (wool or cotton) was varied from 1% to 10 %. Cotton and wool powders were homogenously distributed in the polymer matrix, as observed from scanning electron microscopic (SEM) images. Thermal, physical, and mechanical properties of the obtained composites were investigated by differential scanning calorimetry (DSC), Thermogravimetric analysis (TGA), tensile strength, dyeability as well as the moisture uptake behavior is also explored. The overall results clarify that wool or cotton powders could be used as effective reinforcing materials for the production of PP composites with enhanced properties.     

Effect of milling and sieving processes on the physicochemical properties of okra seed powders

The aim of this work was on one hand to investigate the influence of milling speed and mean particle size of granulometric classes of okra (Abelmoschus esculentus (L.) Moench) seed powders on proximal composition (related to nutritional potential). On the other hand, it was tried to relate flow properties to powder physicochemical characteristics, namely particle size distribution and proximal composition. Then, dry okra seeds were ground with an ultra-centrifugal mill at three rotational speeds, 6 000, 12 000 and 18 000 r.p.m., corresponding to circa 990, 3 958 and 8 906 g , respectively. Each powder was separated into four granulometric classes: ≥500, 315–500, 180–315 and ≤180 µm. Milling speed affected the particle size distribution of dry okra seed powders: on one hand, the higher the milling speed, the lower the mean particle size, mainly because of the higher the proportion of fine particles (<100 µm); on the other hand, at low milling speed, dry okra seed powders were rather monomodal and constituted of large particles, whereas at high milling speed they were bimodal and composed of two populations (fine and large particles). In granulometric classes, fat and protein contents were significantly higher for fine particles, unlike carbohydrate and ash contents that were lower. This differential distribution of macronutrients within granulometric classes was enhanced at higher milling speed. Finally, the ≤180 µm granulometric class, corresponding to the smallest mean particle size, had a low flowability, confirmed by their high cohesion and compressibility, which can be related to its high fat content making it sticky. On the contrary, the ≥500 µm granulometric class was not cohesive, leading to good flow properties.     

Assessment of the Anti-Microbial Activity of Dried Garlic Powders Produced by Different Methods of Drying

The anti-microbial activity of a range of garlic products including dried garlic powder produced by different methods, commercial garlic products, and garlic oil was determined against a range of selected bacteria. The bacteria included food borne pathogens, spoilage agents, and health-beneficial agents, namely Staphylococcus aureus, Escherichia coli, Salmonella typhimurium, Bacillus cereus, and a mixed lactic culture consisting of Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus. The dried powders were produced using air-drying at both 60 and 80°C, vacuum-drying at 50 and 60°C, and freeze-drying at ?20°C. In addition, five commercial products were tested, two of which are used as spices, and three as food supplements. Before testing, the moisture content of the dried garlic powders was raised to that of fresh garlic before drying. Garlic oil was used without any addition of water. In general, the results showed that the lactic culture was the most sensitive to the growth inhibitory active compound of garlic used in this study, followed by Staphylococcus aureus. In contrast Salmonella typhimurium and Bacillus cereus demonstrated the greatest resistance to garlic. Generally, fresh garlic produced the greatest inhibition followed by freeze-dried powder. The anti-microbial activity decreased with decreasing dried garlic powder concentration. The results showed that both drying temperature and time have major effects on retaining the active components responsible for the inhibition of microbial growth. The anti-microbial substances in the moist fresh garlic were also affected by moist-heating temperatures and time. Higher heating temperatures caused faster loss of anti-microbial activity. The decrease in growth-inhibition zones for moist-heated fresh garlic followed zero-order kinetics.     

Effect of Ball-Milling Treatment on Physicochemical and Structural Properties of Chitosan

In this study, chitosan flake was micronized in a ball mill to make fine powder. The effects of the milling on properties of chitosan, such as particle size, molecular parameters, bulk density, crystalline structure, color, chemical structure, and solubility, were investigated. Results showed that the volume weight mean diameter (D[4 Rabea, E.I., Badawy, M.E.I., Steurbaut, W. and Stevens, C.V. 2009. In vitro assessment of N-(benzyl) chitosan derivatives against some plant pathogenic bacteria and fungi. European Polymer Journal, 45: 237–245. [Crossref], [Web of Science ®] , [Google Scholar],3 Kumar, M.N.V.R. 2000. A review of chitin and chitosan applications. Reactive and Functional Polymers, 46: 1–27. [Crossref], [Web of Science ®] , [Google Scholar]]) of chitosan was reduced to 37.53 μm after 8 h of milling and extended milling did not cause a further decrease in particle size. After milling, the viscosity average molecular weight (Mv) of chitosan was decreased, but the degree of acetylation (DD) remained nearly unchanged. The bulk density of chitosan increased with increasing milling time. The crystalline structure of chitosan was destroyed by the milling. The ball-milling treatment deepened the color of chitosan. UV-vis spectra showed that new C=O groups might be formed during the milling process. Further, the micronized powders showed high dissolution rates in simulated gastric juice.     

Effect of superfine grinding on properties of <Emphasis Type="Italic">Vaccinium bracteatum</Emphasis> Thunb leaves powder

Vaccinium bracteatum Thunb, have been widely used in various traditional medicines and food products. The narrow and uniform particle size distribution in V. bracteatum Thunb leaves (VBTL) can be achieved through a new emerging type of foodstuff processing and superfine grinding. The VBTL powders were subjected to four particle sizes as followed: 300–125, 125–75, 75–40, and <40 μm. The VBTL powders were observed to be with smaller size and bulk density, greater surface area, tapped density and the angle of repose. Water solubility index, water holding capacity and total flavonoid extraction increased slightly with the decrease in particle size. Differential scanning calorimetry showed that the VBTL exhibiting particle size of <40 μm had the lowest peak temperature; whereas, powder with a particle size of 125–300 μm displayed the largest endothermic enthalpy. Our results of the properties of VBTL superfine powder supplied the basis for VBTL in potential industrial applications of foods.     

Physicochemical and in vitro digestion characteristics of size-different red ginseng powders

The aims of the present study were to prepare different-sized red ginseng powders and investigate the particle size effect on the release property of ginsenosides in in vitro digestion conditions. Ultrafine powder showed bimodal particle size distribution with a large peak at around 100 μm and small peak at around 10 μm, differently from fine powder showing unimodal distribution at 100 μm. The specific surface areas of fine- and ultrafine powders were 48.72 ± 6.41 and 86.74 ± 5.96 m²/g, respectively. Time-dependent release property of the powders in the simulated gastrointestinal fluids was determined by quantifying ginsenoside Rg1 released. The initial and final concentrations of ginsenoside Rg1 released was higher in ultrafine powder than fine one. It is expected that particle size reduction and corresponding increase in the specific surface area have a potential to improve the release of ginsenosides in the gastrointestinal tract and enhance the chances to be absorbed in human body.     

Effect of particle size on flow behaviour and physical properties of semi-ripe plantain (AAB Musa spp) powders

This work was conducted to study the influence of particle size and shape on the flow behaviour of semi-ripe plantain powders. An improved plantain variety (Big Ebanga), two hybrids (FHIA 21 and PITA 3), and a local variety (Corne 1, as reference material) were powdered by successive drying, milling, and sieving into three granulometric classes: unsieved (<500 µm), fine fraction (<180 µm; class 1), and coarse fraction (between 180 and 500 µm; class 2), thus differing in particle size distribution. Physical properties (water activity, particle size distribution, shape factors) were characterised and flow properties (basic flowability energy, compressibility, fluidisability, cohesion, etc.) were investigated using the FT4 powder rheometer. Convexity of unsieved and fine powders was slightly higher than for coarse powders. Fine powders of all plantain varieties were found to have the lowest water activity and the lowest flowability in unconfined conditions. Unsieved and fine powders presented a fluidised state at the end of the FT4 standard aeration test and their minimum fluidisation velocity was low, confirming the good fluidisability of these powders.     

Ionizability and Bioaccessibility of Externally Added Iron in Legumes and Their Water Soluble Protein Fractions

The present investigation focused on determining ionizable iron from legumes, their water soluble protein fraction (albumin), and enzyme hydrolyzed albumin in the presence and absence of external iron. The legumes chosen were decorticated chick pea (Cicer arietinum), green gram (Phaseolus aureus Roxb), lentil (Lens esculenta), and defatted soy (Glycine max merr). Total iron, protein, and ionizable iron were estimated in samples with and without added iron (500 and 1000 μg/g of protein). Protein content of legumes ranged between 22.5–28.5 g/100 g for all except soy (59.6 g/100 g); that of albumin fractions and enzyme hydrolyzed albumin was 82.5–89.1 and 82.5–94.1 g/100 g, respectively. Total iron contents were 5.6, 8.13, 6.25, and 15 mg/100 g for chick pea, green gram, lentil, and soy, respectively, whereas ionizable iron ranged between 0.625–0.813 μg/100 g. On adding external iron, the ionizable iron increased to 719–1445 μg (500 μg/g protein) and 1219–1545 μg (1000 μg/g protein). In albumin fraction of legume, the ionizable iron range (as % of total iron) observed were 28.7–68.0 (500 μg added iron) and 25.0–37.3 (1000 μg added iron). On enzyme hydrolysis of albumin, these ranges were between 256–464 μg/g protein for both levels of added iron. Overall results indicate that ionizable iron from legumes was very low. On adding iron an increase could be seen; however, it was not proportionate to added levels. Better ionizability was observed at a lower level of addition than at higher levels in all samples indicating existence of an optimum level of iron for absorption.     

Dielectric Behaviour of Whole-Grain Wheat with Temperature at 27.12 MHZ: A Novel Use of a Liquid Dielectric Test Fixture for Grains

This paper is a step towards fulfilling the gap seen in temperature dependence of permittivity (?) of grains at radio frequencies. A commercial device especially built for liquids was exploited for the first time in measuring ? of bulk wheat samples at various temperatures. The dielectric constant (?′) of the wheat increased almost linearly with temperature, and varied between 3.82 and 5.95. The loss factor (?″) increased non-linearly with temperature with values between 0.07 and 0.93. Regression models predicted ?′ and ?″ of the wheat with RMSE of 0.14 and 0.034, and R² values of 0.97 and 0.99, respectively.     

Characterization of Rosehip (Rosa canina L.) Seed and Seed Oil

In this study, the nutritional composition and phytochemical composition of the rosehip seed, and the fatty acid and sterol compositions of the seed oil were investigated. The rosehip seed contained valuable phytochemicals such as phenolic compounds (2554 μg/g), carotenoids (2.92 μg/g), and ascorbic acid (1798 μg/g). Furthermore, the rosehip-seed oil was rich in polyunsaturated fatty acids, linoleic acid (54.05%), linolenic acid (19.37%), and phytosterols, mainly β-sitosterol (82.1%). The rosehip seed and seed oil were found to have antioxidant activity measured by trolox equivalent antioxidant capacity assay. It can be concluded that the rosehip seed and seed oil may be utilized as a source of phytonutrients.     

Characterization of Enzyme Released Antioxidant Phenolic Acids and Xylooligosaccharides from Different Graminaceae or Poaceae Members

Xylooligosacchrides (XOS) and phenolic acids were simultaneously produced from hemicelluloses using crude enzyme mixture synthesized by a novel Bacillus subtilis KCX006. The strain synthesized XOS-forming endo-xylanase and de-branching α-L-arabinofuranosidase and esterase but not β-xylosidase. This enzyme mixture can improve the yield of XOS and phenolic acids from xylan due to the absence of hydrolysis of XOS by β-xylosidase and release of phenolic acids by esterase. Hence, the enzyme mixture was tested for simultaneous production of XOS and phenolic acids from xylan (28–35%)-rich Graminaceae or Poaceae plant biomass, such as wheat bran, sugarcane bagasse, bamboo, and rise husk. Hemicellulose fractions of the biomasses were extracted by alkaline treatment and hydrolyzed using crude xylanase mixture. The profiles of XOS and phenolic acids formed were analyzed by HPLC. The lyophilized hydrolytic products were further analysed by ¹H NMR to identify the substitutions in XOS. The observed profile of XOS and phenolic acids varied with the biomass sources. Maximum amounts of XOS (665.2 mg/g dwt) and phenolic acids (89.69 μg/g dwt) were produced from hemicellulose A fractions of sugarcane bagasse and bamboo bagasse, respectively. HPLC and ¹H NMR analysis of XOS revealed the formation of free- and arabino-XOS. Phenolic acids consisted of hydroxycinnamic and hydroxybenzoic acids and the antioxidant activity correlated well with hydroxycinnamic acids content. The crude enzyme of B. subtilis is useful to produce mixture of XOS and phenolic acids from biomass.     

Antioxidant Activity of Ethanol and Lipophilic Extracts of Common Fruity Vegetables in Bangladesh

The amount of phenolics, flavonoids, and anthocyanins in ethanol extracts and antioxidant activity of both ethanol and lipophilic extracts of common fruity vegetables in Bangladesh were studied. Among the ethanol extracts of 15 fruity vegetables, M. oleifera had the highest total polyphenol content (85.05 mg gallic acid equivalent/g extract) followed by L. acutangula (61.74 mg gallic acid equivalent/g extract) and A. esculentus (48.92 mg gallic acid equivalent/g extract). L. acutangula had high a content of flavonoids (14.46 mg (+)-catechin equivalent/g extract), which was almost similar to L. siceraria (13.67 mg catechin equivalent/g extract) followed by A. esculentus (11.95 mg catechin equivalent/g extract) and S. melongena (11.42 mg catechin equivalent/g extract). Highest anthocyanins content was in F. hispida (2.22 μmol/g extract) followed by S. melongena (1.04 μmol/g extract). Ethanol extracts of A. esculentus, F. hispida, L. acutangula, L. siceraria, and S. melongena exhibited high DPPH free radical scavenging activity with IC₅₀ of 70.4, 64.9, 70.4, 64.9, and 94.3 μg/mL respectively, whereas for the same lipophilic extracts of F. hispida and S. melongena showed lowest (37 μg/mL) IC₅₀ followed by M. oleifera (47.6 μg/mL), L. siceraria (57.5 μg/mL), and A. esculentus (63.3 μg/mL). These vegetables also showed high reducing powers, NO scavenging and total antioxidant capacity. Therefore, the top five potential fruity vegetables consist of both hydrophilic and lipophilic antioxidant(s), the order being F. hispida > M. oleifera > A. esculentus, L. acutangula > L. siceraria > and S. melongena.     

Predicted intake of trace elements and minerals via household drinking water by 6-year-old children from Krakow (Poland). Part 4: Copper

The aim of this study was to assess exposure of children to copper (Cu) from household drinking water (DW). DW samples were collected between 1997 and 2004 in ～650 households and pre-schools using a double-sampling method (morning – W1; evening – W2). The study group comprised ～300 children (5–7 years old) living in Krakow (urban, peripheral) and rural areas in southern Poland. Cu concentrations were determined by flame atomic absorption spectrometry. There was no significant relationship between the sampling period and Cu concentration, but statistically significant differences were found between urban and non-urban (rural, peripheral) sites and between morning and evening samples. Geometric means of Cu concentration in evening DW (95% confidence interval, in μg L^?1) were 8 (1–110), 20 (1–274) and 12 (0–364) in urban, peripheral and rural sites, respectively. DW contamination after overnight standing was comparable in all sites (average increase ～20 μg Cu L^?1). The adopted threshold of 100 μg Cu L^?1 was exceeded in evening DW by 3.6 and 15% in urban and non-urban households, respectively. Exceedance of the EC limit (2 mg L^?1) was not significant. The mean predicted contribution of evening DW to Cu intake by children were 18–37 μg day^?1 or 0.8–1.6 μg kg^?1 bw day^?1 but were 2–3-fold higher for morning DW. The Polish RDA (1 mg Cu day^?1) was exceeded for morning (evening) DW in 3.7 (0.2)% of children, with a mean intake of 159 (118)% of RDA. The observed copper levels and predicted intakes can be considered low and should not raise nutritional or toxicological concerns for the age group studied. Nevertheless, due to overnight contamination, the suggestion that the stagnant portion of drinking water should be discarded remains valid.     

Assessment of crtRB1 Polymorphism Associated with Increased β-Carotene Content in Maize (Zea mays L.) Seeds

Breeding for increasing β-carotene levels in maize (Zea mays L.) kernel aims to address the dietary vitamin A deficiency. Due to 3’TE polymorphism, the crtRB1gene (that encodes β -carotene hydroxylase 1) exists in the three allelic forms, viz., 3’TE allele 1 (termed favorable allele, for it favors higher β-carotene accumulation in kernels), 3’TE allele 2 and 3’TE allele 3 (both termed unfavorable alleles, for they do not favor β-carotene accumulation). Here, we aimed to identify maize lines with favorable allele. First, 3’TE polymorphism assay in 210 inbreds revealed that only “UMI 176” had the favorable allele while the rest had the unfavorable alleles, confirming the previous finding that favorable allele is rare in frequency. Second, β-carotene content analysis in 24 inbreds revealed that it varied from 4.5 to 7.92 (μg/g), 0.23 to 2, and 0.42 to 4.22 for lines with allele 1, 2, and 3 respectively, corroborating the previous findings that the presence of favorable allele correlates with higher β-carotene content. In summary, UMI 176 has the favorable allele and had the highest amount of β-carotene content (7.92 μg/g), indicating that it is a promising donor line that can be utilized in β-carotene biofortification breeding.     

Influence of particle size on the physicochemical properties and stickiness of dairy powders

The compositional and physicochemical properties of different whey permeate (WPP), demineralised whey (DWP) and skim milk powder (SMP) size fractions were investigated. Bulk composition of WPP and DWP was significantly (P < 0.05) influenced by powder particle size; smaller particles had higher protein and lower lactose contents. Microscopic observations showed that WPP and DWP contained both larger lactose crystals and smaller amorphous particles. Bulk composition of SMP did not vary with particle size. Surface composition of the smallest SMP fraction (<75 μm) showed significantly lower protein (−9%) and higher fat (+5%) coverage compared with non-fractionated powders. For all powders, smaller particles were more susceptible to sticking. Hygroscopicity of SMP was not affected by particle size; hygroscopicity of semi-crystalline powders was inversely related to particle size. This study provides insights into differences between size fractions of dairy powders, which can potentially impact the sticking/caking behaviour of fine particles during processing.     

High-Efficient Expression and Pilot Scale Fermentation of Streptomyces Xylanase from a Constitutive Pichia pastoris Vector

To develop an efficient Streptomyces xylanase-expressing system necessary for large-scale industrial production, a DNA fragment encoding the endo-β-l,4-xylanase (XYL1) from Streptomyces sp. S38 was cloned into an expression vector pGAPZαA to generate a recombinant plasmid pGAPZαA-XYL1. The plasmid pGAPZαA-XYL1 was transformed into Pichia pastoris X-33. The secreted XYL1 protein was confirmed to be completely consistent to sequence as reported previously (GenBank accession number X98518.1). The secreted XYL1 protein was purified using the Q-Sepharose FF chromatography and Sephadex G-25 resin, with an estimated purity of greater than 90%. We also found that in a 50 L fermentor, the average level and enzymatic activity of secreted xylanases were up to 1.15 ± 0.09 mg/mL and 1528 ± 59 IU/mL, respectively. The pH and temperature for optimal XYL1 expression were 6.0 and 55°C, respectively. The Km and Vmax values of XYL1 were 2.0 mg/mL and 5000 μmol min^?1 mg^?1, respectively. In addition, the XYL1 was found to have good thermal stability and wide pH adaptability, suggesting that it may be a useful candidate for various commercial applications. The high-efficient expression and pilot scale fermentation of XYL1 in this study, together with enzymatic studies, provide a strong basis for future large-scale industrial production.     

Effect of superfine grinding on physicochemical and antioxidant properties of pomegranate peel

Pomegranate peel powders were prepared by superfine grinding, whose effects were investigated on the composition, functional and antioxidant properties of the pomegranate peel products. Fluidised bed jet milling technology was used to process superfine pomegranate peel powder. The physical–chemical properties of coarse powder A (D50 = 413.4 μm) and B (D50 = 197.1 μm), fine powder C (D50 = 142.6 μm) and D (D50 = 41.2 μm), superfine powder E (D50 = 7.68 μm) and raw material powder (RMP) (D50 = 352.2 μm) were investigated in this study. SEM images revealed the shape and surface morphology of six pomegranate peel powders. The physical determinations showed that the smaller the powder particle size was, the greater the surface area (from 0.214 to 1.597 m² g^?1) and bulk density (from 0.653 to 0.751 g mL^?1) were, the smaller the angles of repose (from 51.69° to 38.74°) and slide (from 48.32° to 34.18°) were. The water holding capacity (WHC), water‐solubility index (WSI), polyphenols and flavonoids release were significantly improved as the size of pomegranate peel particle decreased. The results of FTIR and UV indicated that grinding process would not influence chemical composition of pomegranate peel. Vitamin C (VC) and butylated hydroxytoluene (BHT) were used in DPPH scavenging activity determination, and DPPH scavenging activity was A < RMP < BHT < B < C < D < E < VC.     

Turbidimetric Behavior of Colloidal Particles in Beer Before Filtration Process

The effect of colloidal particles and yeast on turbidity of Pilsen beer before the filtration process was studied in this work. The colloidal particles are mainly composed of polysaccharides, representing 96.89 %, in second place proteins with a concentration close to 2 %, and polyphenols less than 0.3 %. There is also a very low concentration of yeast (<0.25 %). The presence of different types of particles in the sample caused multimodal histogram in the particle size distribution and four distinct zones were identified: (1) very small individual particles ( $ \overline D = 0.0{\text{6}}\mu {\text{m}} $ ), (2) yeast ( $ \overline D = {\text{3}}\mu {\text{m}} $ ), (3) colloidal aggregates ( $ \overline D = {\text{17}}\mu {\text{m}} $ ), and (4) a zone with a high dispersion of size, with two $ \overline D $ values (101 and 200 μm). Particles size counts well correlate with both the scanning electron microscopy (SEM) digital image analysis, and the turbidity determination. The fractal dimension (D _f) of the aggregates was determined by analyzing the SEM images with the Variogram method, obtaining D _f?>?2.4 values. Those values are typical of aggregates formed by rapid flocculation or diffusion limited aggregation. Results of this study support the formulation of a model valid for the prediction of colloidal particles concentration in beer.     

Production of silver carp bone powder using superfine grinding technology: Suitable production parameters and its properties

Superfine grinding technology is a new type of food processing that is employed to produce powders with outstanding properties such as high solubility, dispersion, adsorption, chemical reactivity and fluidity. The objective of this work was to study the superfine grinding technology on the silver carp bone and to optimize the operational parameters. The optimum processing conditions of superfine grinding were: feeding pressure of 0.85 MPa, grinding pressure of 1.0 MPa, feeding rate of 0.0325 g/s, feeding particle size of 150-300 μm and one pass through the grinder. Silver carp bone powder with average particle size (D₅₀) of 7.65 μm was produced at these conditions. It was found that the smaller particle size of the powder, the higher its fluidity, solubility, solubility of protein, electric conductivity and water holding capacity of the powder were. So the quality of the products produced by the superfine grinding technology was said to be improved.     

Total phenolic content,antioxidant activity,shelf-life and reconstitutability of okra seeds powder: influence of milling and sieving processes

This study aimed at relating phytochemical properties (total phenolic content and antioxidant activity), reconstitutability (water absorption capacity and water solubility index) and preservation ability (water activity) of okra seed powders to physicochemical properties (particle size distribution and moisture content). Okra seed powders were produced at three different milling frequencies, and then, each obtained sample was sieved with 180, 315 and 500 μm sieves. An increased milling frequency resulted in lower median particle size, water activity and moisture content. The maximal water activity and moisture content were 0.583 ± 0.010 and 12.07 ± 0.05% (w/w), respectively, showing the good preservation ability of okra seed powders. Total phenolic content and antioxidant activity were raised at higher milling frequency. Reconstitutability was significantly enhanced at higher milling frequency and/or for smaller median particle size. Thus, the successive milling and sieving process was successful in improving physicochemical and functional properties of okra seed powders, especially for smaller particles.