Food irradiation‐chemistry and applications∗

Abstract

Food irradiation is one of the most extensively and thoroughly studied methods of food preservation. Despite voluminous data on safety and wholesomeness of irradiated foods, food irradiation is still a “process in waiting.” Although some countries are allowing the use of irradiation technology on certain foods, its full potential is not recognized. Only 37 countries worldwide permit the use of this technology. If used to its full potential, food irradiation can save millions of human lives being lost annually due to food‐borne diseases or starvation and can add billions of dollars to the world economy. This paper briefly reviews the history and chemistry of food irradiation along with its main applications, impediments to its adoption, and its role in improving food availability and health situation, particularly in developing countries of the world.     

A cross‐cluster and cross‐region analysis of fashion brand extensions

To obtain sustainable growth in revenue and market share, many fashion brands deploy category extensions and line extensions. In this paper, we examine how different fashion brands in Europe, North America, and Asia execute their brand extension strategies over different periods. By classifying different fashion brands into four clusters according to different price points and fashion contents, we conduct a cross‐region and cross‐cluster analysis to examine how different fashion brands execute their brand extension strategies. Our analysis is based on publicly available data associated with 48 fashion brands over a 90‐year period. We discuss our findings along with managerial insights.     

The effect of low‐temperature plasma for improving wool and chitosan‐treated wool fabric properties

In this study, plasma treatment was used to modify the surface properties of wool fabrics by partial removal of the scales and the lipid layer. The effects of low‐pressure pseudo‐discharge in oxygen gas on the dyeing properties of untreated and pretreated wool fabrics are discussed. Three dyes were used, namely acid dye, 1:2 metal complex dye and reactive dye. Different exposure times (1–5 min) of oxygenated plasma treatment were effected to improve the hydrophilicity, wettabillity, dyeability and the washing and light fastness properties of the dyed wool fabrics (which were increased by increasing the plasma exposure time). Also, the washing and light fastness properties of the chitosan‐treated wool fabrics were investigated. In addition, the presence of chitosan before or after the plasma exposure had no effect on the washing and light fastness properties of the wool fabrics.     

A simple,effective and inhibitor‐free thermal treatment for enhancing mold‐proof property of bamboo scrimber

European Journal of Wood and Wood Products - The bamboo scrimber has been widely used in building materials and interior decoration. However, the bamboo scrimber is very vulnerable to mold due to...     

Stability and degradation of the high‐intensity sweeteners: Aspartame,Alitame, and Sucralose

Abstract

More than 170 million Americans consume low‐calorie foods and beverages. The interest of the consumer in low‐calorie foods that contain alternative sweeteners has grown. Currently, non‐nutritive high‐intensity sweeteners, aspartame and sucralose have been approved for use in the United States. Another sweetener, alitame, used in other countries such as Australia and China has not been granted approval for use in the States.

The paper reviews the stability and degradation products of high‐intensity sweeteners, aspartame, alitame, and sucralose.     

Changes in physico‐chemical and rheological properties of rice during flaking

Hydration, solubility, pasting and rheological properties of roasted‐parboiled rice and flakes were examined in comparison to raw rice. There was an increase in the hydration capacity, swelling power and solubility during roasting‐parboiling of rice as a result of gelatinization of its starch. Flaking caused further increase due to damage of starch by application of mechanical force. The changes were higher in flakes from roller‐flaker as compared to those from edge‐runner. Pasting characteristics of flour slurries in Rapid Visco Analyzer showed a typical profile for pregelatinized products viz. a higher initial viscosity but a lower peak viscosity for roasted‐parboiled rice and flaked rice than for raw rice. The viscosity curves and flow curves of the products over a wide range of shear rate indicated a non‐Newtonian, pseudoplastic behaviour for all the samples. All samples showed typical hysteresis loop in their viscosity curves indicating their thixotropic nature. Flakes from roller‐flaker exhibited lower viscosity but more thixotrophy indicating higher starch breakdown in them than in edge‐runner flakes, which seemed to have more of heat damaged starch.     

Study of stiffness and abrasion resistance of needle‐punched nonwoven blankets

The properties of needled fabrics depend on the nature of component fibers and the manner in which fibers are arranged in the structure. Fiber properties along with the various machine and web parameters contribute to the structure that emerges from the needling operation. In this paper, the effect of machine parameters such as depth of needle penetration and punch density on fabric stiffness and abrasion resistance of needled blankets has been studied. The effect of calendering and sandwiching hollow polyester fibers between two layers of fine polyester fibers on the abrasion resistance and fabric stiffness has also been studied. It was observed that fabric stiffness first increases and then decreases as the depth of needle penetration increases. Increase in punch density leads to a decrease in fabric stiffness only at higher levels of depth of penetration due to fiber rupture. Calendering improves the fabric abrasion resistance properties but fabric stiffness also increases. Sandwiching of hollow polyester fibers between the two layers of fine denier polyester fibers improves the abrasion resistance without increasing the fabric stiffness.     

Development of weft‐knitted and braided polypropylene stents for arterial implant

Textile biomedical materials have been used for various applications contributing considerably in improving quality of life. The current study aims at improving polypropylene fibre stents which may replace metallic ones. In order to produce the stents, weft‐knitting and braiding technologies were used. In the braiding technique, by varying the take‐up ratio (using gears with the appropriate number of teeth in the braiding machine), it was possible to manufacture regular braids with angles of 65°, 70° and 75° in order to obtain different covers. In the knitting technique, a circular machine was used and the tightness of the structure was adjusted by varying the loop length and thus the fabric loop density, resulting in variations of the sample diameter. The knitting machine had negative feed, and so loop length variations were achieved by varying the yarn input tension, the stitch cam settings and the fabric take‐down tension. The samples were heat set. Yarns were contracted by setting at 130°C and 140°C, and this led to increasing the loop density and the flexural rigidity of the samples. A high cover of the samples resulted in a greater stiffness of the structures. The stents were evaluated by undertaking the tests required for arterial support: rigidity to radial compression, resistance to tensile forces and bending rigidity. The best results were obtained with braided structures. Future work may concentrate in improving the stent design and using new biocompatible fibres.     

Study on needle‐punched nonwoven fabrics made from shrinkable and non‐shrinkable acrylic blends. Part III: filtration characteristics

This paper reports the filtration behaviours of needle‐punched bulked nonwoven fabrics made from shrinkable and non‐shrinkable acrylic blends. The basic idea of the present work is to explore the possibility of structural changes in needle‐punched nonwoven fabrics made from blends of shrinkable and non‐shrinkable acrylic fibres, as in the case of an acrylic bulked yarn, to improve the filtration behaviour. In Part I and Part II of this series, compressional and transmission characteristics of these fabrics were reported, respectively. The effects of variables, namely fabric areal density, needle punch density and the proportion of shrinkable acrylic fibre in the blend, on various filtration‐related properties of needle‐punched nonwoven fabrics have been studied by relaxing the shrinkable component of the fabric using hot steam treatment. A three‐variable factorial design technique proposed by Box and Behnken was used to investigate the combined interaction effect of the above variables on the filtration properties of these fabrics. The fabric areal density and needle punch density were found to have a significant effect on filtration efficiency as well as pressure drop. The proportion of shrinkable acrylic fibre has little effect on filtration efficiency, but the trends are dependent on the needle punch density.     

Citric acid production by Aspergillus foetidus in batch and fed‐batch cultures

Abstract

Sucrose and ammonium nitrate, respectively, were the preferred carbon and nitrogen sources for citric acid production by Aspergillis foetidus CCRC 30206. For a 7‐day fermentation, the maximal citric acid production of 7.2 ～ 28.4 g/l appeared at an initial sucrose concentration of 12 % under various initial levels of nitrogen and phosphorous sources. Citric acid production commenced and ceased earlier in either the nitrogen‐limited (NH₄NO₃, 0.5g/l) or the phosphorous‐limited (KH₂PO₄, 0.2 g/1) medium. The richer media delayed the onset of citric acid production. Nonetheless, 48.3 g/1 of citric acid was produced in the medium rich in nitrogen (NH₄NO₃, 2.0 g/1) and phosphorous (KH₂PO₄, 1.4 g/1) when the batch culture was extended to 16 days. The cultivation time of this rich medium was reduced to 12 days in a fed‐batch culture under dual limitation of both nitrogen and phosphorous.     

Cardiovascular disease and nutrient antioxidants: Role of low‐density lipoprotein oxidation

Increasing evidence indicates that oxidative modification of low‐density lipoprotein (LDL) is causally related to atherosclerosis. Oxidatively modified LDL (oxLDL), in contrast to native LDL, is taken up avidly by macrophages, leading to formation of lipid‐laden foam cells. Foam cells are pathognomonic of the atherosclerotic fatty streak. Modified LDL may also promote atherosclerosis by many other mechanisms, such as recruitment and retention of monocyte‐macrophages, T‐lymphocytes, and smooth muscle cells in the arterial intima, and cytotoxicity toward endothelial cells and macrophage‐derived foam cells. The “oxidation hypothesis of atherosclerosis” is supported by a number of in vivo findings, such as the presence of oxLDL in atherosclerotic lesions, and increased titers of autoantibodies against modified LDL in patients with atherosclerosis.

As a corollary of the oxidation hypothesis of atherosclerosis, antioxidants that can inhibit LDL oxidation may act as antiatherogens. This conception is supported by animal studies showing that antioxidants such as probucol, butylated hydroxytoluene, and α‐tocopherol can slow the progression of atherosclerosis. Epidemiological and clinical data indicate a protective role of dietary antioxidants against cardiovascular disease, including vitamin E, β‐carotene, and vitamin C. Likewise, basic research studies on LDL oxidation have demonstrated a protective role for antioxidants, present either in the aqueous environment of LDL or associated with the lipoprotein itself. More studies are needed to establish the effectiveness and determine the required doses of specific antioxidants to prevent and possibly treat cardiovascular disease.     

Nanocellulose preparation via a dissolution and regeneration process and application to wood‐plastic composites as toughness enhancement

In this work, nanocellulose (NC) was prepared by a new route consisting of dissolution of cellulose in phosphoric acid followed by regeneration in water. To facilitate the dissolution, the cellulose was pre-treated with aqueous solution of urea. Although the regenerated cellulose from water had been in nanoscale, its size could be further reduced through ball milling. The composition, structure, and morphology of the materials from different preparation stages were studied by infrared spectroscopy (FTIR), X-ray diffraction (XRD) and transmission electron microscopy (TEM), respectively. NC was then incorporated into the HDPE based wood-plastic composites (WPCs) in a skillful way to guarantee its good dispersion. The influence of addition content of NC on the mechanical and thermal properties of WPCs was investigated comprehensively. WPCs incorporated with NC exhibited an obvious increase in impact strength compared with those without NC. In addition, the Rockwell hardness, Vicat softening temperature and thermal stability of WPCs incorporated with NC were also correspondingly improved. The effect of ball milling on the size of nanocellulose was also investigated. The application results showed that the NC prepared without ball milling was more efficient in enhancing the toughness of WPCs.

     

Eco‐friendly plasma treatment of linen‐containing fabrics

In the present work, linen‐containing fabrics were treated with atmospheric pressure plasmas of oxygen, air and nitrogen, and the impact of plasma treatment conditions on the surface chemistry and topography was evaluated. Plasma treatment is accompanied by a remarkable improvement in the hydrophilic properties: creation of new functional groups along with a noticeable increase in the affinity of treated substrates for subsequent H₂O₂‐bleaching. The extent of improvement in wettability as well as subsequent bleachability is governed by both the plasma gas, i.e. oxygen > air > nitrogen > none, and the discharge power, i.e. the higher the power supply, the shorter and greater was the modification extent. Oxygen or air plasma treatment significantly upgrades the hydrophilicity, enhances the subsequent bleachability, saves time, water and energy as well as prevents or decreases pollution at the source, i.e. an eco‐friendly substitute for conventional scouring of linen‐based textiles.     

Discrete‐event simulation model of roll‐drafting process

This paper presents a model of the roll‐drafting process which is based on the concept of discrete‐event simulation (DES). This model is free of limitations and simplifications which are inherent in the known models of the roll‐drafting process and is able to trace each separated fiber within the roll‐drafting zone. Due to this feature DES model enables investigation of a wide range of roll‐drafting cases and representations. The influence of the parameters of the basic roll‐drafting model was studied. Models of the first and the second limit schemes, models with a randomly distributed velocity change point, and a model with a shifting velocity change point were elaborated and studied on the basis of the basic model of the roll‐drafting process. The effect of the feedback depth was simulated and analyzed in the frame of the model with the shifting velocity change point. The elaborated model and the obtained results will be useful for creating a neural network meta‐model of the roll‐drafting process.     

Kinematic analysis and synthesis of the beat‐up mechanism for handmade carpet looms

The beat‐up process has a great influence on the structure and appearance of the handmade carpet. Since all weaving processes of the handmade carpet are performed by the weaver, the production speed may be increased and the performance of the weaver may be improved by designing a suitable beat‐up mechanism. In this article, a crank‐rocker type of four‐bar mechanism has been studied for the handmade carpet loom beat‐up mechanism. First, the functional requirements of the beat‐up mechanism were established according to the problem statement. Later, a four‐bar crank‐rocker‐type mechanism was generated and developed from a slider‐crank‐type mechanism. Here, the dimensional synthesis of the mechanism was made as a solution to the slider‐crank‐type mechanism. Many alternative mechanisms were generated as a result of the dimensional synthesis. The slider‐crank‐type mechanisms were then translated into the crank‐rocker‐type mechanisms. These mechanisms were evaluated in terms of some mechanical criteria and the most suitable one was selected. Finally, a kinematic analysis of the beat‐up mechanism was performed.     

Utilization of sprout‐damaged wheat as raw material for sour dough pre‐ferments with mixed cultures of lactic and propionic acid bacteria

The utilization of sprout‐damaged wheat flour in pre‐fermentation for sour dough bread‐baking increased lactic acid formation and titratable acidity several fold in comparison to the use of baker's wheat flour, and also resulted in a lactic acid to acetic acid molar ratio acceptable for sour dough bread. Further, enzymic treatment of the sprout‐damaged wheat flour with malted grain flour appared to be necessary for a properly balanced acid formation although the α‐amylase activity of sprout‐damaged wheat flour was quite high. The accumulation of lactic acid in the pre‐ferment decreased in the presence of yeast, and thus the molar ratio of lactic to acetic acid could be adjusted suitable for sour bread‐baking even with homofermentative lactic acid bacteria. Finally, when using mixed culture pre‐ferments of Lactobacillus brevis and Propionibacterium jensenii, at least 0.1% of propionic acid (based on flour weight), sufficient to prevent mold growth in the final bread, was obtained.     

Tensile characteristics of Dref‐III friction core‐spun yarns

The tensile characteristics of Dref‐III friction spun yarns with jute as core and cotton as sheath components have been studied. Three yarns with different core–sheath proportions such as 55/45, 65/35 and 75/25 jute/cotton friction spun yarns were produced by using the Dref‐III friction spinning system. The influence of core and sheath components on the tensile properties at three different traverse rates at 150 mm/min, 750 mm/min and 1500 mm/min, respectively, have been reported. The work of rupture and specific work of rupture at break of these yarns were also analysed. From the test results, the maximum work of rupture was found in 55/45 core–sheath (jute/cotton) friction spun yarn when compared to 65/35 and 75/25 core–sheath (jute/cotton) friction spun yarns. It is due to the higher core–sheath interaction factor (CSI_T = 26.14) and better yarn‐packing density because of higher proportion of cotton fibres in the sheath component. The breaking tenacity and contribution factor of core and sheath component (CSI_T) of jute/cotton friction spun yarns were also analysed using multivariable ANOVA analysis.     

The effects of drying parameters and conditioning on mechanical properties of latex‐backed carpet

In this study, the effects of drying parameters and conditioning on the mechanical properties of latex‐backed carpet were investigated. Mechanical properties clearly correlated with the lowest moisture content (MC) experienced by samples in either drying or conditioning. Lowering MC was necessary to develop mechanical properties; however, the highest mechanical properties were achieved at the highest latex temperature, indicating that raising latex temperature can improve mechanical properties. The effect of conditioning on mechanical properties depended on the MC of the latex backing at the end of drying.     

Hard‐to‐cook phenomenon in common beans — A review

Legumes are one of the world's most important sources of food supply, especially in developing countries, in terms of food energy as well as nutrients. Common beans are a good source of proteins, vitamins (thiamine, riboflavin, niacin, vitamin B₆) and certain minerals (Ca, Fe, Cu, Zn, P, K, and Mg). They are an excellent source of complex carbohydrates and polyunsaturated free fatty acids (linoleic, linolenic). However, common beans have several undesirable attributes, such as long cooking times, being enzyme inhibitors, phytates, flatus factors, and phenolic compounds, having a “beany” flavor, and being lectins and allergens, which should be removed or eliminated for effective utilization.

Grain quality of common beans is determined by factors such as acceptability by the consumer, soaking characteristics, cooking quality, and nutritive value. Acceptability characteristics include a wide variety of attributes, such as grain size, shape, color, appearance, stability under storage conditions, cooking properties, quality of the product obtained, and flavor.

Storage of common beans under adverse conditions of high temperature and high humidity renders them susceptible to a hardening phenomenon, also known as the hard‐to‐cook (HTC) defect. Beans with this defect are characterized by extended cooking times for cotyledon softening, are less acceptable to the consumer, and are of lower nutritive value. Mechanisms involved in the HTC defect have not been elucidated satisfactorily. Attempts to provide a definitive explanation of this phenomenon have not been successful. The most important hypotheses that have been proposed to explain the cause of bean hardening are (1) lipid oxidation and/or polymerization, (2) formation of insoluble pectates, (3) lignification of middle lamella, and (4) multiple mechanisms. Most researchers have reported that the defect develops in the cotyledons. Recently, some authors have suggested that the seed coat plays a significant role in the process of common bean hardening. A better knowledge of cotyledon and seed coat microstructure may lead to a better understanding of the causes of seed hardness.

In order to prevent the development of the HTC defect several procedures have been proposed: (1) appropriate storage, (2) controlled atmospheres, and (3) pretreatments. Probably, the most workable solution to the hardening phenomenon may be the development of materials less prone to HTC phenomenon.

Decreasing cooking time, increasing nutritive value, and improving sensory properties of seeds with HTC defect would have great nutritional and economical impact. Furthermore, an understanding of the mechanisms leading to reversibility of this phenomenon would provide insight into the development of the defect itself and would aid in the search for appropriate methods to prevent it.

Efforts to develop technological processes are needed in order to transform the HTC beans into edible and useful products. Several economic alternatives to utilize HTC common beans have been proposed: (1) dehulling, (2) extrusion, (3) solid state fermentation, (4) quick‐cooking beans, and (5) production of protein concentrates and isolates and starch fractions.     

Comparison of the properties of Ring,Solo, and Siro core‐spun yarns

In this research, core‐spun yarns with an acrylic sheath fiber and a nylon flat core have been produced on the Ring, SIRO, and Solo spinning systems and the effects of some factors were investigated. The studied factors consist of filament pre‐tension (i.e. 1, 7/5, 10, 15, 50, and 100 g), spinning system (Ring, SIRO, and Solo), and feed position of the core filament in the strands of sheath fibers (six types of feed positions). Also, their physical and mechanical properties, including strength, elongation percentage, abrasion resistance, percentage of coefficient of variation (CV%), and hairiness, were all investigated. Finally, in each stage, the best case was determined. The results show that the quality of the core‐spun yarns produced by the SIRO spinning system is better than that of the Ring and Solo core‐spun yarns.