Composite films were prepared from pectin and fish skin gelatin (FSG) or pectin and soybean flour protein (SFP). The inclusion of protein promoted molecular interactions, resulting in a well-organized homogeneous structure, as revealed by scanning electron microscopy and fracture-acoustic emission analysis. The resultant composite films showed an increase in stiffness and strength and a decrease in water solubility and water vapor transmission rate, in comparison with films cast from pectin alone. The composite films inherited the elastic nature of proteins, thus being more flexible than the pure pectin films. Treating the composite films with glutaraldehyde/methanol induced chemical cross-linking with the proteins and reduced the interstitial spaces among the macromolecules and, consequently, improved their mechanical properties and water resistance. Treating the protein-free pectin films with glutaraldehyde/methanol also improved the Young's modulus and tensile strength, but showed little effect on the water resistance, because the treatment caused only dehydration of the pectin films and the dehydration is reversible. The composite films were biodegradable and possessed moderate mechanical properties and a low water vapor transmission rate. Therefore, the films are considered to have potential applications as packaging or coating materials for food or drug industries.

Crispness and crunchiness are important factors in the enjoyment of many foods, but they are defined differently among dictionaries, consumers, and researchers. Sensory, mechanical, and acoustic methods have been used to provide data on crispness and crunchiness. Sensory measurements include biting force and sound intensity. Mechanical techniques resemble mastication and include flex, shear, and compression. Acoustical techniques measure frequency, intensity, and number of sound events. Water and oil content contribute to crispness and crunchiness, which also have temporal aspects. Information in the literature is compared in this article to develop definitions of crispness and crunchiness.A dense-textured food which, when chewed with the molars, undergoes a series of fractures while emitting relatively loud, low-pitched sounds. CONCLUSIONSFurther work on differentiating and defining crispy and crunchy textures is needed so that universal standards can be obtained. Such definitions could be translated into any 960 TUNICK ET AL. language and would be applicable to fruits, vegetables, baked foods, extruded foods, etc. Research in our laboratory, described in a subsequent article, [74] represents a step in that direction.

An investigation of the diffusion competition between solvent and nonsolvent in a coagulation bath is presented for the formation of a new cellulosic fiber by wet‐spinning. The system consisted of the spinnable cellulose solution with a mixture of liquid ammonia/ammonia thiocynate as the solvent and low‐molecular‐weight alcohols as the nonsolvents. The diffusion competition between solvent and nonsolvent was quantitatively characterized in terms of their mass transfer rate differences. The measurements of this rate difference were performed on the model filament shaped from gelled cellulose solutions. Results revealed that an increase in molecular size of coagulant, bath temperature, and coagulant concentration in the bath enhanced preferential diffusion of solvent from cellulose solution. Fiber spinning experiments showed that a higher value of the initial modulus of the fiber was attained with a coagulation condition providing a lower value of mass transfer rate difference. The importance of mass transfer rate difference was also shown in the influence of the fiber cross‐sectional shapes.

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Sugar beet pulp and poly(lactic acid) (PLA) composites were prepared by compression-heating. The resultant thermoplastics had a lower density, but they had tensile strength similar to that of pure PLA specimens as well as the same geometric properties. Tensile properties depended on the initial water content of sugar beet pulp and the process by which composites were manufactured. In comparison with sugar beet pulp, the composite showed improved water resistance. This can be attributed to the hydrophobic character of PLA and pulp-matrix interactions. The composite thermoplastics showed suitable properties for potential use as lightweight construction materials.

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Totally biodegradable, double‐layered antimicrobial composite films were introduced for food packaging. The substrate layers of the sheets were prepared from poly(lactic acid) (PLA) and sugar beet pulp (SBP) or poly (butylene adipate‐co‐terephthalate (PBAT) and SBP by a twin‐screw extruder. The active layer consisting of antimicrobial in either PLA or chitosan was formed on the surfaces of the substrates by solution coating followed by solvent evaporation. Air‐coupled ultrasonic evaluation and microscopic examination showed a homogeneous structure for the composite sheets. Mechanical analysis and acoustic emission demonstrated the double‐layered composites possessing appropriate tensile strength and fracture characteristics for the use as light weight‐bearing materials. The release of Nisaplin® or allyl isothiocyanate (AIT) effectively suppressed the growth of Listeria monocytogenes and Salmonella cells, respectively; the co‐release of Nisaplin® and AIT played a synergistic effect on inhibition of L. monocytogenes. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

The U.S. sheep industry, more than 80,000 producers of 40 million pounds of raw wool per year, is an important component of the meat industry. New methods for the treatment of domestic wool with keratin isolated from the unmarketable fraction of wool, and functionalized for water, oil, or insect repellency are needed. As a first step in the process, we are evaluating the effectiveness of keratin solubilization via relatively benign methods that use thioglycolic acid, bisulfite or sulfide to reduce disulfide bonds, peracetic acid or percarbonate to oxidize disulfides, and urea/thiourea as hydrogen bond disrupters. The procedures are compared in terms of quality of soluble protein, cost effectiveness, potential for upscaling, environmental and operator safety. Successful completion of this project will provide the basis for commercial development of such methods, followed by functional modification of the soluble keratin, and its application to textiles.