Preference mapping of salmon–sauce combinations: The influence of temporal properties

Food–food combinations are complex stimuli where the dynamic nature of sensory interactions plays an important role for perception and acceptance. The aim of this study was to investigate if TDS provides additional insight about drivers of liking compared to DA in a preference mapping context. A trained sensory panel performed DA and TDS on six different samples (combinations of salmon and culinary sauces), and sixty-one consumers rated acceptance for the same samples. In addition to TDS SCORES, this study introduces the use of extracted parameters based on dominance information from TDS; the area of dominance based on the integrated area under the dominance curves and the number of dominant sensations and blends within a specified time period. Results from preference mappings showed that the TDS approaches generally provided similar but less detailed information regarding drivers of liking and disliking compared to DA. Moreover, with the use of the extracted TDS parameters, it was possible to identify the time of dominance of certain attributes and the number of perceived sensations and blends in specific time periods as potential drivers of liking and disliking. The results also showed that TDS has a potential to provide complementary information about the dynamic nature of sensory interactions in food–food combinations compared to DA.     

Enhanced water resistance of extruded wood–polypropylene composites based on alternative wood sources

Polypropylene wood flour composites made from short-rotation coppice (SRC) and low valued beech wood (Fagus sylvatica) were investigated with respect to their suitability for use in the production of wood–polymer composites (WPC). An industrial wood source consisting of spruce wood flour (Picea abies) was used as reference material. All composites were compounded on a co-rotating twin screw extruder containing either 60 or 70 wt% wood flour. Consolidation was done by profile extrusion. Mechanical and physical properties of the composites were investigated. The wood sources were characterized concerning their particle length and shape by the use of a dynamic optical particle analysis system. X-ray microtomography (µ-CT) was used to study the dispersion of wood particles and the internal composite structure. However, all composites based on alternative wood sources showed an equivalent performance regarding mechanical properties compared to the composite reference. Composites containing beech wood flour showed notably reduced water absorption rates, whereas the composites based on SRC wood flour revealed significantly reduced moisture content compared to reference composites. A different particle length distribution was depicted between the industrial wood source and three other investigated wood sources. Moreover, all wood flour sources were characterized by a mean aspect ratio up to 3:1. The X-ray microtomography illustrated morphological differences between composites. Based on the X-ray images, an alignment along the melt flow and a decent encapsulation by polypropylene were shown.     

The influence of temperature on residual deformation of Phenylon and Nomex yarns following the creep–recovery process

High-performance synthetic filaments and yarns are subjected to different loads and temperature during their practical and industrial applications, resulting in changes in their mechanical properties. Knowledge of the deformation and strength properties of these polymer materials at various temperatures and different levels of preliminary stretching is therefore very important. Semi-rigid chain polymers Phenylon and Nomex yarns are popular materials for use at high temperatures. Their mechanical properties can be changed significantly at high temperatures. It is also shown that preliminary stretching of Phenylon and Nomex yarns at more than 5% will change the nature of the stress–strain curves due to the rearrangement of the supermolecular structures which occur at this elongation. However, there is no change in the character of accumulation of residual deformation at elevated temperatures for Phenylon and Nomex yarns.     

Investigation of the fastness properties and color values of cotton fabrics knitted from ring spun and Sirospun® yarns

Sirospun yarn production is a new approach to produce two‐folded and twisted yarns. This method integrates the spinning and folding action in a single step. Therefore, it may have some important advantages such as simplicity of the process, lower production costs, lower investment, space saving, etc. The purpose of the study is to compare the color fastness and colorimetric properties of sirospun yarn, single and two‐folded ring spun yarns produced by same cotton fiber blend. Therefore, three reactive dyes were applied at 1% omf (on mass of fabric) depth of shade to the single jersey fabrics which are produced by sirospun yarn, single and two‐folded ring spun yarns at three different counts. The examination of color coordinates of undyed and dyed samples on CIELAB color space shows that undyed sirospun fabrics show slightly higher whiteness than both undyed single and two‐folded ring fabrics for all three yarn counts. Also, the color strength values of the samples are determined as slightly different for all three dyes. The experimental studies show that sirospun yarns have no disadvantages with respect to conventional folded and twisted yarns when their fastness properties were compared.     

Influence and comparison of emerging techniques of yarn manufacturing on physical–mechanical properties of polyester-/cotton-blended yarns and their woven fabrics

Abstract

In this study, the physical–mechanical properties of ring spun, ring compact, rotor and air-vortex yarns were investigated. The study was carried with yarn having linear densities of 24.4 tex and 36.7 tex, which were then converted to woven fabrics. The ring spun yarns have higher values of strength but also with higher strength irregularities. Extra-ordinarily low hairiness was observed in air-vortex yarns due to its unique yarn formation technique. The deviation rate (DR) of yarns have correlation with the mass spectrogram of respective yarns obtained from USTER Tester 5. Rotor and air-vortex yarns exhibited higher coefficient of friction. The woven fabrics made from ring spun yarns exhibited higher tensile and tear strength with higher elongation at break. The fabrics made from air-vortex yarns have very good pilling grade due to less protruding fibres on their surface and good structural integrity.     

Antioxidant activity of phenolics–saponins rich fraction prepared from defatted kenaf seed meal

The current study is aimed to determine the antioxidant properties of crude ethanolic extract (CEE) of defatted kenaf seed meal (DKSM) and its derived n-butanol (BF) and aqueous (AqF) fractions. Spectrophotometric assays showed that BF contained the highest amount of phenolic compounds and saponins, followed by CEE and AqF (p < 0.05). Similarly, HPLC-DAD analysis revealed that level of all the detected predominant phenolic compounds was significantly higher in BF (p < 0.05). Through multiple antioxidant assays, BF exhibited higher antioxidant activity than CEE and AqF, except for iron chelating activity (p < 0.05). Antioxidant activity of CEE and fractions were strongly correlated to their phenolic and saponin contents. This study showed that phenolic compounds and saponins could be extracted and partially purified simultaneously from DKSM by employing a simple alcoholic extraction–fractionation procedure. High antioxidative phenolics–saponins rich fraction from DKSM is a potential active ingredient that could be applied in nutraceuticals, functional foods as well as natural food preservatives.     

Tensile behavior of staple fiber yarns,part IV: experimental verification of predicted stress–strain curves

In this paper, specific stress–strain curves were predicted for viscose, cotton, and polyester yarns spun by ring and rotor technologies. The average fiber-specific stress–strain curves were used to predict yarn-specific stress–strain curves. The predicted yarn-specific stress–strain curves captured the experimental yarn-specific stress–strain curves well both in shape and position for the three studied yarn types. However, higher prediction error was observed relatively in polyester yarns due to more slippage of fibers in these yarns. All rotor yarns exhibited higher difference between experimental and predicted results which might be the result of the nature of the twist in rotor yarn.     

Enrichment of chips with fibre from a tiger-nut (Cyperus esculentus) milk co-product at ‘source of fibre foods’ and ‘high fibre content foods’ levels: impact on processing,physico-chemical and sensory properties

The impact of integrating a tiger-nut milk co-product into the wheat chip production process for enriching fibre content to meet European recommendations for ‘source of fibre foods’ and ‘high fibre content foods’ was studied. Four different flours, based on their composition and particle size, were obtained from the co-product. Wheat flour was substituted at the 5%, 10% and 20% levels with the co-product, and the processing, physico-chemical and sensory properties of chip were studied. In the baking phase, mass loss was more marked for the substituted samples (42%) than the control (34%), but differences diminished after the tempering time (33%) by absorbing moisture from the environment. This effect was related to the increased chips surface (≈43%) in the forming phase because dough retraction decreased. The co-product as a fibre source produced alterations to chip processing and its physico-chemical properties should be taken into account. However, chips positively impacted consumer acceptability.     

Studies on cotton–acrylic bulked yarns produced from different spinning technologies. Part I: yarn characteristics

The effects of different factors, namely spinning technologies (ring, rotor and DREF-II, i.e. Group A yarns), position of shrinkable acrylic feed sliver in DREF-II friction spinning system (Group B yarns) and proportion of shrinkable acrylic core fibre in core-sheath type DREF-III friction spun yarns (Group C yarns) on various properties of cotton-acrylic–blended bulked yarns have been studied. The bulk in the yarns was developed by relaxing shrinkable acrylic component of the yarns using boiling water treatment. All the above factors have a significant impact on various properties of cotton–acrylic blended bulked yarns. For all the yarns, after boiling treatment, there is lengthwise shrinkage of yarns and the specific volume also increases. Tenacity and breaking elongation of all the yarns of Group A and Group B increase after hot water treatment, whereas in case of core-sheath type DREF-III yarns (Group C yarns) there is drop in tenacity and breaking elongation after similar treatment. In general, for all the yarns the flexural rigidity of the yarns reduces and compressibility and compressional recovery of increases after bulking treatment.     

Structure and antioxidant activity of high molecular weight Maillard reaction products from casein–glucose

Maillard reaction products (MRPs) were prepared from a casein–glucose reaction and ultrafiltrated to provide six fractions. The high molecular weight glycated proteins (melanoprotein) were further purified with a Sephadex G-75 column. Two fractions were obtained and analysed for their reducing power and Fe²⁺ chelating activity. Results obtained from the first fraction, analysed by Fourier transform infrared spectroscopy (FT-IR) indicated that the amide I, II and III bands of casein were changed by the Maillard reaction. The obtained samples were also hydrolysed with pepsin and trypsin in vitro, and the proteolytic hydrolysates were evaluated for their antioxidant activities. Non-hydrolysed melanoproteins exhibited the highest reducing power, but peptic hydrolysates of different MRPs were more efficient in radical-scavenging activity.     

Antioxidant properties of resveratrol: A structure–activity insight

Resveratrol, a natural product, is known to affect a broad range of intracellular mediators. In the present study, we clarified the antioxidant activity of resveratrol by employing various in vitro antioxidant assays such as DPPH?, ABTS^?+, DMPD^?+, O₂^?? and H₂O₂ scavenging activities, total antioxidant activity, reducing abilities, and Fe²⁺ chelating activities. Resveratrol inhibited 89.1% of the lipid peroxidation of linoleic acid emulsion at 30 µg/mL concentration. On the other hand, BHA, BHT, α-tocopherol, and trolox exhibited inhibitions of 83.3, 82.1, 68.1, and 81.3% against peroxidation of linoleic acid emulsion at the same concentration, respectively. In addition, resveratrol had effective DPPH?, ABTS^?+, DMPD^?+, O₂^?? and H₂O₂ scavenging activities, reducing power, and Fe²⁺ chelating activities. The present study found that resveratrol had effective in vitro antioxidant and radical scavenging activity. It can be used in pharmacological and food industry due to its antioxidant properties.Industrial relevanceAntioxidants are often added to foods to prevent the radical chain reactions of oxidation and they act by inhibiting the initiation and propagation step leading to the termination of the reaction and delay the oxidation process. At the present time, the most commonly used antioxidants are BHA, BHT, propylgallate and tert-butyl hydroquinone. Besides that BHA and BHT are restricted by legislative rules because of doubts over their toxic and carcinogenic effects. Therefore, there is a growing interest on natural and safer antioxidants in food applications, and a growing trend in consumer preferences for natural antioxidants, all of which has given more impetus to explore natural sources of antioxidants. A variety of foods and beverages of vegetable origin contain several nonflavonoid classes of phenolic compounds synthesized by plants. Among them, resveratrol has been identified as the major active compound of stilbene phytoalexins and is presumed to be beneficial for human health. Resveratrol is naturally occurring in the fruits and leaves of edible plants, peanuts, mulberries, grapes and red wine. Resveratrol is currently in the limelight all over the world due to their beneficial effects on the human body. Resveratrol can be used for minimizing or preventing lipid oxidation in pharmaceutical products, retarding the formation of toxic oxidation products, maintaining nutritional quality and prolonging the shelf life of food products and pharmaceuticals instead of BHA and BHT and other antioxidant compounds because of their safer usage.     

Rheological properties of rice–locust bean gum gels from different rice varieties

Pasting and gelatinization behavior of rice gels from Japonica (Ariete, Euro), Indica (Gladio, Suriname) and waxy (Glutinous) varieties were analyzed. These varieties differ widely in amylose contents and differential scanning calorimetry (DSC) gelatinization temperatures. Besides, the effect of locust bean gum (LBG) addition and the impact of successive viscoanalyser multiple-heating–cooling and freezing–thawing cycles on the gels pasting viscosities (peak-η_peak, trough-η_min, final-η_final), viscoelasticity by oscillatory rheometry and syneresis were evaluated.     

Genetic polymorphism of ovine milk proteins: its influence on technological properties of milk — a review

Current knowledge of the genetic polymorphism in ovine milk proteins including heterogeneity detected and their relationships with the technological properties of milk is reviewed. In the casein fraction a great heterogeneity has been determined either by the presence of genetic variants or other factors such as a discrete phosphorylation level and the coexistence of protein forms of different chain length. In the whey fractions, three genetic variants (A, B, and C) are described for β-lactoglobulin (β-LG), and two for α-lactalbumin (α-LA). The topics discussed include the rennetability of ovine milk, cheese yield and susceptibility of β-LG genetic variants to heat denaturation as well as the findings concerning the relationships between ovine milk protein polymorphism and milk production and composition. However, further investigation is needed in order to better outline the relevant features of polymorphism and technological properties of ovine milk.     

LC–DAD–ESIMS/MS characterization of antioxidant and anticholinesterase constituents present in the active fraction from Persicaria hydropiper

Persicaria hydropiper or ‘kesum’ is a herb used extensively as flavoring agent in food. The antioxidant activity was evaluated by measuring the hydroperoxide production resulting from linoleic acid oxidation using ferric thiocyanate (FTC) as well as the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging ability. Moreover, inhibition activity against cholinesterase, an enzyme that responsible in several physio-pathological processes, was also determined. Identification of phytochemical constituents in the bioactive fraction of P. hydropiper was carried out by LC–DAD–ESIMS/MS technique. Fifteen compounds were identified including flavonoids, flavonoid glycosides and phenylpropanoid glycosides. Six of the compounds were isolated and their structures were elucidated in order to confirm their identities. The antioxidant and antiacetylcholinesterase activities of the isolated compounds were also evaluated.     

Casein–whey protein interactions in heated milk: the influence of pH

Heat-treatment of milk causes denaturation of whey proteins, leading to a complex mixture of whey protein aggregates and whey protein coated casein micelles. In this paper we studied the effect of pH-adjustment of milk (6.9–6.35) prior to heat-treatment on the distribution of denatured whey proteins in aggregates and coating of casein micelles. Proteins were fractionated using an alternative fractionation technique based on renneting. Acid- and rennet-induced gelation of these milks were used to obtain more information on the characteristics of the milk. Acid-induced gelation appeared to be mainly influenced by the presence of whey protein aggregates. Rennet-induced gelation was determined by the whey protein coating of the casein micelles. Both the quantity of whey proteins present on the surface of the casein micelles and the homogeneity of the coating were determining the renneting properties. These results extend the current knowledge on pH dependent casein–whey protein interactions. In order to present a clear picture of the changes occuring during heat treatment of milk at various pH, the results are summarized in a model. In this model we propose that heating at a pH>6.6 lead to a partial coverage of the casein micelles and the formation of separate whey protein aggregates. Heating at a pH<6.6 lead to an attachment of all whey proteins to the casein micelles. At pH 6.55 the coverage is rather homogeneous but lowering the pH further lead to an inhomogeneus coverage of the casein micelles. Surprisingly small changes of the pH at which the milk was heated had considerable effects on the gelation behaviour both in renneting and in acid gelation.     

Improving the physical and mechanical properties of particleboards made from urea–glyoxal resin by addition of pMDI

The effect of pMDI on physical and mechanical properties of the particleboards made from urea–glyoxal resin was investigated. The nontoxic and ecofriendly urea–glyoxal (UG) resin was synthesized under weak acid conditions, and its different properties were measured. Then, pMDI at various contents (4, 6 and 8% on resin solids) was added to the UG resin prepared. The thermal and physicochemical properties of the resins prepared as well as their water absorption, flexural properties (flexural modulus and strength) and internal bond (IB) strength of the particleboard panels bonded with them were measured according to standard methods. According to the physicochemical results obtained, the addition of pMDI significantly accelerated the gel time and increased the viscosity and solids content of UG resins. Differential scanning calorimetry indicated that the addition of pMDI decreases the onset and curing temperatures of the UG resin. Physical analysis results of the panels indicated that the particleboards made from UG resins with isocyanate yielded lower water absorption when compared to those bonded with the control UG resins. Based on the findings of this research work, the mechanical properties of particleboard panels bonded with UG resins could be significantly enhanced by the addition of increasing percentages of pMDI. The panels having 8 wt% pMDI exhibited the highest flexural modulus, flexural strength and IB strength value and the lowest water absorption among all the panels prepared.     

Properties of an αs-casein-rich casein fraction: Influence of dialysis on surface properties,miscibility, and micelle formation

In this study, the surface tension, miscibility, and particle size distribution of a solution containing an α_s-casein (CN)-rich CN fraction (54 wt % α_s-CN, 32 wt % β-CN, and 15 wt % κ-CN) were determined at pH 6.6. The nondialyzed CN fraction was compared with a dialyzed one. In the nondialyzed sample, every charge on the protein was compensated by 0.3 charges coming from counterions, whereas in the dialyzed sample, only 0.2 charges could be assigned to each charge on the protein. This relation was determined by calculating the charges at the proteins, taking the measured mineral content into account. The surface tension was measured as a function of the protein concentration by the du Noüy ring method at room temperature. Results indicated alterations in the surface properties after reduction of counterions. The equilibrium surface tension above the critical micelle concentration increased from 40.1 × 10⁻³ to 45 × 10⁻³ N/m, the critical micelle concentration increased from 0.9 × 10⁻⁴ to 2 × 10⁻³ mol/L, and the minimal area occupied per molecule at the surface increased from 2.4 × 10⁻¹⁸ to 4.6 × 10⁻¹⁸ m². Cloud points were determined by measuring the absorbance of CN solutions as a function of the temperature. The cloud points were found to be concentration dependent and had a minimum at 0.2 wt % at 34°C for nondialyzed CN and at 0.25 wt % at 28°C for dialyzed CN, again demonstrating the influence of counterion reduction. Below the cloud point, a micellar phase was found to exist. The hydrodynamic diameter of the micelles were characterized by dynamic light scattering in both auto- and cross-correlation mode. However, no influence of reduction in counterions could be observed, possibly due to the fact that dynamic light scattering is not a suitable method for this type of system. The presence of self-assembled structures was verified by freeze-fracture electron microscopy. The observed differences between dialyzed and nondialyzed samples were explained by changes in the counterion cloud surrounding the proteins. Consequently, the electrostatic interactions between as well as within the CN are altered by dialysis, which, in turn, affects the behavior at the surface as well as the properties in the solution.