Physico-chemical and mechanical characterization of alkali-treated Agave americana L. fiber

This study investigates the effect of mercerization on the physico-chemical and mechanical properties of Agave americana L. fiber. The alkali concentration is a crucial parameter which affects the crystallinity and the tenacity of the fiber. Treatments with low alkali concentrations produce fibers that are stronger than the untreated fibers and at this level the crystallinity reaches high values. However, treatments with high concentrations (>2% wt/v) result in weaker fibers with low crystallinity index. The chemical composition of A. americana L. fibers is also altered by the mercerization process insofar as the cellulose content increased with the NaOH concentration while the hemicelluloses and lignin contents decreased.     

Study of the Mechanical Properties of Fibers Extracted from Tunisian Agave americana L.

Agave americana L. fibers, the most abundant variety in Tunisia, have a quite important textile potential. This potential is demonstrated by studying the extraction of these fibers from leaves, their physical properties such us fineness or density and their mechanical behavior in tensile tests. In this work, results of a mechanical behavior study of fibers extracted from the Agave americana L. plant are presented. These results deal with the principal and mechanical characteristics of these fibers which are the strain at break, the elasticity modulus and the rupture facture. These results permitted to situate these fibers, compared to the other textile fibers, as materials that can be used in technical applications such as reinforcing composites or geotextile. In order to understand the mechanical properties of these fibers, a correlation study between the properties already cited and the fine structure was done. The obtained results showed that the mechanical properties of Agave americana L. fibers are closely related to the individual fibers deformations and to the natural matrix (lignin and gums) that are linked to these elementary fibers.     

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.     

Chemical composition of alkaline-pretreated sugarcane bagasse and its effects on the physicochemical characteristics of fat-replaced sausage

The potential of cellulose from sugarcane bagasse used for pork sausage was investigated. The purity level of cellulose fibre from sugarcane bagasse and the functional characteristics in pork sausage were studied. The differences in the sugarcane fibre and sausage characteristics were strongly related to the cellulose/lignin content of the extracted cellulose under different amounts of bleaching. Bleached sugarcane fibres showed better water (3.55) and oil (2.34) holding capacity in comparison with untreated fibre (2.92 and 2.38, respectively). The sugarcane fibres in each treatment stage showed different effects on sausage properties. Sausages with 1% cellulose fibres added had an improved texture profile, but the addition of 3% cellulose fibres to sausages resulted in a higher cooking yield. Consumers considered the sensory characteristics of all sausages as acceptable. These results indicated that low levels of cellulose extracted from sugarcane bagasse could be added and maintain the inherent characteristics of meat products.     

Selection of dietary fibres for sucrose replacement in functional Chhana‐murki (Indian Cottage cheese‐based dessert) and their effect on sensory,physical and instrumental texture parameters

With a wide range of beneficial effects on human health, various dietary fibres such as microcrystalline cellulose (MCC), inulin, oat fibre and wheat fibre were screened based on their bulking ability in the functional Chhana‐murki (FCM) with respect to sensory and physical properties. Sensory scores were maximum for MCC at 7.5% having optimum moisture content and water activity and minimum hardness, whereas oat and wheat fibres increased the hardness of the product while decreasing the moisture content and water activity thus lowering the sensory scores. Further, replacement of MCC with inulin in 1:1 ratio improved the product characteristics.     

Characterization and analysis of ridge gourd (Luffa acutangula) fibres and its potential application in sound insulation

Ridge gourd, the fruit of Luffa acutangula, is extensively used throughout the world. Nevertheless, there is a dearth of scientific information related to the thermal, mechanical and chemical properties of these fibres to explore its potential application in textile industry. This research work is aimed to characterize the L. acutangula plant and investigate its potential application in sound insulation. The fibres are arranged in a cell like structure, when opened it gives a very lower fibre length of less than 10 mm. The chemical composition of fibres is as like other lignocellulosic fibres having around 64% cellulose, 21% hemicellulose and 10% lignin. The density is of fibre is around 1.46 g/cc and having the average linear density of 432 denier. The nonwovens were produced by blending the L. acutangula fibre with cotton as well polyester fibre webs using layering technique at three different blend proportions and their influence on bulk density, sound insulation, thermal resistivity and air permeability has been analysed. The ANOVA analysis showed that all the properties mentioned above was significantly influenced by the blend proportion of L. acutangula. The nonwoven sample produced from 50/50 blend proportion of cotton/luffa and polyester/luffa samples showed better sound reduction and thermal resistivity compared to other samples. The cell-like structure of luffa combined with low bulk density and higher thickness resulted in better results.     

Dietary fibre extracted from different types of whole grains and beans: a comparative study

Dietary fibre (DF) from different whole grains and beans (quinoa, buckwheat, highland barley, pea and mung bean) was extracted by enzymatic action. The components, crystallinity and properties were comparatively studied. Furthermore, we evaluated correlations between DF components and their crystallinity, thermal, physicochemical and functional properties. Results showed quinoa DF had highest polyphenol (25.58 mg GAE per 100 g), pectin (4.68%) and cellulose (52.34%) contents, crystallinity value (CV, 30.24%), ΔH (185.53 J g⁻¹), water-holding capacity (WHC, 5.35 g g⁻¹), α-amylase activity inhibition ratio (α-AAIR, 13.34%) and glucose absorption capacity (GAC), but lowest protein content (9.78%) and T_p (163.05 °C). Mung bean DF had highest lignin content (33.56%), fat adsorption capacity (4.73 g g⁻¹), and T_p (176.25 °C), but lowest CV (15.26%) and ΔH (132.15 J g⁻¹). Correlation analysis showed cellulose content had positive linear correlations with CV, ΔH, WHC, α-AAIR and GAC, but a negative correlation with T_p. The structure and properties of DF are largely attributed to cellulose content.     

Bran characteristics and wheat performance in whole wheat bread

The effect of the composition and physical properties of bran from four wheat samples from different cultivars was determined in whole wheat bread. High specific volume of whole wheat bread was correlated (r² = 0.8275) with strong mechanical properties (low friability) of the bran of wheat cultivars, as determined by sizing (over 425 μm) of bran particles after grinding with a rotor mill. Fibre content and composition of insoluble fibre (hemicellulose, cellulose and lignin) in the bran fraction had a non‐significant (P > 0.05) effect on the performance of wheat cultivars in whole wheat bread. Water absorption of bran was correlated (r² = 0.9532) with its insoluble fibre content. Based on data obtained with white flour, it was not possible to estimate the baking potential of wheat cultivars in whole wheat bread.     

Characterization of the conventional and organic cotton fibres

The characterization of the conventional and organic cotton fibres to understand the differences present between them is presented. The cotton fibres were characterized for their fibre properties such as the surface morphology, surface chemical composition, surface elemental composition and internal fibre structure. The results show that the surface morphology and surface chemical composition of both the cotton fibres are similar. The surface elemental composition of both the cotton fibres shows that organic cotton fibres have higher percentage of metals than the conventional cotton fibres. Based on the FTIR spectrum analysis, it is observed that the organic cotton fibres may have a higher proportion of representative groups compared to that of the conventional cotton fibres. The fraction of I _α and I _β cellulose shows that I _β cellulose dominates in both cotton fibres. The crystallinity of both the cotton fibres was determined using the wide angle X-ray diffraction data. The results show that crystallinity of both fibres is similar.     

Effects of psyllium and cellulose fibres on thermal,structural, and in vitro digestion behaviour of wheat starch

The study investigated the effects of adding different types of fibre (psyllium and cellulose) on in vitro digestion behaviour of wheat starch with its thermal and structural properties. Psyllium and cellulose fibres interfered with the wheat starch differently. Psyllium fibre hindered starch gelatinisation, restricted the loss of starch crystallinity, and decreased the accessibility of enzymes to starch. In contrast, cellulose fibre had no significant effect on gelatinisation and loss of crystallinity but limited the digestive enzyme mobility. The impact of psyllium was more pronounced than cellulose on reducing starch digestibility. Rapidly digestible starch fractions of the cooked starch reduced from between 57.90 ± 0.60–69.72 ± 0.46 (% in starch) to between 28.06 ± 0.36–46.34 ± 1.10 (% in starch) and 53.23 ± 0.36–66.71 ± 0.24 (% in starch) for psyllium and cellulose fibre, respectively. This information could be helpful to design foods containing starch with reduced digestibility for a healthy diet.     

Liver paté enriched with dietary fibre extracted from potato fibre as fat substitutes

This experiment included studies of the functionality of three new enzymatically extracted fibres as ingredients in pig liver paté prepared using reduced amounts of pig fat with dry potato pulp and a commercial potato fibre (Potex) as references. The measured quality characteristics included colour, flavour, and texture profile analysis. Dry potato pulp, Potex and two of the new enzymically extracted fibre 1 and 2 with high contents of cellulose and lignin resulted in very hard patties with a high level of deformation energy, gumminess, and modulus that had a detrimental effect on paté texture and flavour. The enzymatically extracted fibre 3 with a low content of cellulose and lignin and a high content of soluble non-starch polysaccharides (SNSP) resulted in patties with a very delicious texture and flavour and values of the measured texture characteristics determined by texture profile analysis. The colour of the patties processed using the enzymatically extracted fibre 3 were darker, more red and less yellow compared to patties processed using Potex, dry potato pulp and new fibre 1 and 2. Baking loss that varied from 9.2 to 11.3 g/100 g was the lowest for patties processed using the new extracted fibre 3. The content of total dietary plant fibre in liver patties varied from 4.0 to 6.2 g/100 g paté.     

Effect of heating–cooling cycle on the opto‐structural properties of low‐density polyethylene fibres using two‐beam interference microscopy

A hot stage attached with a two‐beam interference (Pluta) microscope was used to apply a heating–cooling cycle (HCC) on low‐density polyethylene fibres (LDPE). The variation of the refractive indices (n ^∥ and n ^⊥) with the temperature was carried out during the heating and cooling of the LDPE fibres. The activation energy (E _a) and thermooptic coefficient (dn/dT) were calculated for the investigated LDPE fibres. The spectral dispersion curves, percent crystallinity and orientation function were determined for the treated LDPE fibres. It was found that the HCC for LDPE fibre implies: a reversible behaviour of both optical and structural properties against temperature and an improvement in the fibre crystallinity.     

Physicochemical properties of new cellulosic fiber extracted from Carica papaya bark

This article presents the characteristics of Carica papaya fibers (CPFs) extracted from the bark of the perennial papaya plant. Detailed chemical compositions of CPFs such as cellulose, lignin, ash, moisture, and wax contents were established and determined by using standard methods. Further, chemical groups, crystalline structure, surface roughness, and thermal stability of CPFs were examined using Fourier transform infrared analysis, X-ray diffraction, atomic force microscope, and thermogravimetric analysis, respectively. The physico-chemical properties of CPFs, crystallinity index (56.34%), cellulose content (38.71 wt. %), hemicellulose (11.8%), and density (943 kg/m³) were compared to those properties of other natural fibers. The results suggest that the biodegradable CPFs can be used as a potential reinforcemnet in the polymer matrix composite structure.     

Effect of Callosobruchus chinensis (L.) (Coleoptera: Bruchidae) on carbohydrate content of chickpea,green gram and pigeon pea

Effect of Callosobruchus chinensis (L.) infestation was seen on the carbohydrate and dietary fibre content of chickpea, green gram and pigeon pea at 10, 20, 30, 40, 50 and 60 per cent levels of infestation. With increase in level of infestation energy, starch, total sugars and non-reducing sugars decreased, whereas significant increase in the reducing sugars, crude fibre, neutral detergent fibre, acid detergent fibre, hemicellulose, cellulose and lignin was observed.     

Physico-chemical properties of commercial fibres from different sources: A comparative approach

The lower intake of fibre and fibre-containing foods has refocused the food industry on the benefits of incorporating different fibres in the foodstuff. Nowadays, a whole range of fibres are available in the market, but sometimes a good choice becomes complicated due to their varied physico-chemical properties. In order to give some light when selecting fibres, a comparative study regarding some physical properties of commercial fibres from different sources is presented, with a view to increasing their use in food products, namely bakery products. Commercial fibres included in this study were hydroxypropylmethylcellulose, cellulose, locust bean gum, guar gum, inulin, galactooligosaccharides, oat and wheat fibres, and fibres extracted from apple and bamboo. Particle size distribution (PSD) of the dry commercial fibres ranged from around 10 to 334 μm; moreover PSD in wet (water and ethanol) form was also determined to have precise information about their behaviour when processing. Cereal fibres (oat 600 and wheat) exhibited the highest values for hydration properties (swelling, water holding and water binding capacity). Only the hydrocolloids (HPMC, locust bean gum and guar gum), with the exception of cellulose, yielded highly viscous solutions during the heating-cooling cycle; moreover oat 600 and apple fibre developed viscous solutions after cooling. HPMC, locust bean gum and guar gum significantly augmented the four SRC values, thus those hydrocolloids affected the relative contributions to water absorption of proteins, carbohydrates, damaged starch and pentosans. Fibre sources and degree of replacement significantly affected the SRC values for the four solvents in all the fibre groups, with the exception of lactic acid SRC in the case of cereal fibres. Differences in fibres effect on wheat flour quality can be easily detected by assessing solvent retention capacity, which can give information on the end use functionality of the wheat flour.     

Characterization of cellulosic fibers from Morus alba L. stem

The chemical microstructural, physical, and thermal properties of the Morus alba L. stem fibers (MAFs) are described for the first time in this work. By analyzing the results of chemical composition, it was observed that the cellulose content of the stem of MAFs is an acceptable value when compared with other fibers and showed better results. Due to their lightweight (1316 kg/m³) and the presence of high cellulose content (58.65%) with very little amount of wax (0.56%), they provide good bonding properties. In addition, analyzing the results of X-ray diffraction and Fourier transform infrared spectroscopy, we observe a degree of crystallinity of 62.06%, which is closely associated with the presence of crystalline cellulose, while the other components are amorphous. The diameter of the extracted cellulosic fibers was in the range 6–20 µm. Moreover, it was possible to identify the degradation step of each primary component of lignocellulosic fiber and to observe that it is thermally stable up to 216°C. The characterization results show that the MAF is a better replacement material for synthetic fibers because of its significant physical, chemical, and thermal properties.     

Structural characteristics,physicochemical properties and prebiotic potential of modified dietary fibre from the basal part of bamboo shoot

The basal part of bamboo shoot is a novel resource to produce dietary fibre (BDF). However, its insolubility in water, stiff texture and low degradability limit its applicability in foods. This study explored the feasibility of improving the structural and functional properties of BDF by enzymatic hydrolysis and dynamic high-pressure micro-fluidisation (DHPM). Both methods are efficient to reduce the fibre particle size and caused significantly increased roughness on the fibre surface, especially for the porous structure after DHPM treatment. Crystallinity of DHPM-modified fibres was increased from 23.01% to 33.53%, due to the disruption of lignin and hemicellulose, which was further confirmed by the FT-IR spectra. The modified fibres exhibited significantly enhanced swelling capacity and holding water/oil capacities. Moreover, the modified fibres exhibited improved in vitro prebiotic property, which could constantly supply the carbon source and stimulate the growth of Lactobacillus acidophilus ATCC 4356 and Bifidobacterium longum ATCC 15707.     

Chemical Composition of Pea Fibre Isolates and their Effect on the Endogenous Amino Acid Flow at the Ileum of the Pig

Pea starch, hulls and cotyledon inner fibres, isolated from pea seeds, were incorporated in N-free diets, on a NDF-content basis, in order to study their effect on the ileal endogenous amino acid (AA) excretion in the growing pig. Maize starch and wood cellulose were selected as references. The inner fibre-containing diet was also supplemented with enzymatically hydrolysed casein (EHC) in order to test the peptide alimentation method on a diet containing a fibre source with a high water-holding capacity (WHC=10·9 g water g⁻¹ DM). The fibres were also analysed by different methods (crude fibre, NDF, ADF, enzymatic–gravimetric method, Englyst method). The fibre content of the inner fibre fraction varied widely from one method to another and ranged from 109 g crude fibre to 480 g AOAC fibre kg⁻¹ DM. Compared to the ‘maize starch+wood cellulose’ diet (11·0 g AA excreted kg⁻¹ DM intake), pea starch had no effect on ileal AA losses (9·6 g), whereas pea hulls slightly increased them (14·2 g). The AA excretion dramatically increased with the incorporation of inner fibres (28·0 g), because of their very high WHC. The addition of EHC increased the output (48·0 g) further, at a level that can hardly be explained only by an increase of the endogenous secretions. The results suggest that the NDF content of grain legume products is not indicative of their effect on the ileal endogenous AA losses in pigs and that the physiological effects of fibres along the gastrointestinal tract are due to both their chemical and physical properties.     

By-products from different citrus processes as a source of customized functional fibres

Dietary fibre encompasses a huge variety of macromolecules, exhibiting a wide range of physicochemical properties. Citrus fibre can be obtained from different industrial sources and different kinds of citrus. The chemical components of fibre (pectin, lignin, cellulose and hemicellulose), together with other compounds, such as flavonoids, were analysed in nine different industrial sources. Final fibre composition was more dependent on the industrial process than on the type of citrus. The chemical changes gone by citrus fibre showed losses of functional values; i.e. soluble dietary fibre and ascorbic acid content decreased when waste products were transformed into fibres. The water-holding and lipid-holding capacities of analysed citrus fibres suggested a non-linear behaviour of these properties for the analysed citrus fibres.