A. Nussinovitch

Plant gum exudates of the world : sources, distribution, properties, and applications

Role and Sources of Exudate Gums Introduction Definitions Gum Yields Agricultural Issues Physical Properties of Gums Chemical Properties Commercial Assessments of Gums Industrial and Other Uses References Physiological Aspects of Polysaccharide Formation in Plants Introduction Stress Factors, Ethylene and Gummosis Borers and Gum Formation Gum Ducts Gummosis in Fruit Trees Induced Inoculation and Gum Yield References Major Plant Exudates of the World Introduction Gum Arabic and Other Acacia Gums Gum Tragacanth and Similar Gums Important Indian or Asiatic Gums and Their Botanical Sources Gums of the New World Miscellaneous Asiatic, African, and Australian Gums References Minor Plant Exudates of the World Introduction Adansonia Malvaceae (subfamily: Bombacoideae) Adenanthera Fabaceae (subfamily: Mimosoideae) Afzelia Fabaceae (subfamily: Caesalpinioideae) Albizia Fabaceae Anogeissus Combretaceae Atalaya Sapindaceae (subfamily: Sapindoideae) Balsamocitrus Rutaceae (subfamily: Aurantioideae) Bauhinia Fabaceae Julbernardia Fabaceae (subfamily: Caesalpinioideae) Bombax Malvaceae (subfamily: Bombacoideae) Borassus Arecaceae (subfamily: Coryphoideae) Bosistoa Rutaceae (subfamily: Toddalioideae) Brachystegia Fabaceae (subfamily: Caesalpinioideae) Burkea Fabaceae (subfamily: Caesalpinioideae) Capparis Capparaceae Careya Lecythidaceae (subfamily: Planchonioideae) Cassia Fabaceae (subfamily: Caesalpinioideae) Cedrela Meliaceae Ceiba Malvaceae (subfamily: Bombacoideae) Ceratopetalum Cunoniaceae Chukrasia Meliaceae Citrus Rutaceae Cocos Arecaceae (subfamily: Arecoideae) Cola Sterculiaceae Combretum Combretaceae Cordia Boraginaceae (subfamily: Cordioideae) Cordyla Fabaceae (subfamily: Faboideae) Corypha Arecaceae (subfamily: Coryphoideae) Crataeva Capparaceae Cussonia Araliaceae Cycas Cycadaceae Dichrostachys Fabaceae (subfamily: Mimosoideae) Echinocarpus Elaeocarpaceae Elaeocarpus Elaeocarpaceae Encephalartos Zamiaceae Entada Fabaceae (subfamily: Mimosoideae) Erythrophleum Fabaceae (subfamily: Caesalpinioideae) Flindersia Rutaceae Garuga Burseraceae Geijera Rutaceae Geodorum Orchidaceae Hakea Proteaceae Khaya Meliaceae Lagerstroemia Lythraceae Lannea Anacardiaceae Macrozamia Zamiaceae Melia Meliaceae Melicope Rutaceae Moringa Moringaceae Owenia Meliaceae Panax (Tieghemopanax) Araliaceae Saltera Penaeaceae Pentaceras Rutaceae Prunus Rosaceae Pseudocedrela Meliaceae Saccopetalum Annonaceae Sarcostemma Asclepiadaceae Schefflera Araliaceae Sclerocarya Anacardiaceae Semecarpus Anacardiaceae Sloanea Elaeocarpaceae Soymida Meliaceae Tamarindus Fabaceae (subfamily: Caesalpinioideae) Heritiera Malvaceae Terminalia Combretaceae Thevetia Apocynaceae Virgilia Fabaceae (subfamily: Faboideae) Food Applications of Plant Exudates Introduction Food Uses of Gum Exudates Gum Exudates in Animal Food Health-Related Aspects Gum Exudates in Water-Based Adhesives Introduction Gums as Adhesives Industrial Uses of Exudate Glues Biological Applications: A General Approach Hydrocolloid Adhesion Tests Exudates as Wet Glues Adhesion Mechanisms of Hydrogels Medical, Cosmetic and Biotechnological Uses of Gum Exudates Introduction Pharmacological Applications Folk Medicine Cosmetics and Other Products Biotechnological Applications Analysis and Identification of Gum Exudates Introduction Industrial Gums Group Analysis and Identification Schemes Additional Analytical Methods Miscellaneous Uses of Plant Exudates Introduction Paints, Pigments and Painting Inks Lithography Textiles Corrosion Inhibition Immersion Plating Drilling Fluids Oil-Well Cement Binders and Special Coatings Paper and E-Paper Explosives Ceramics Miscellaneous

Water-Soluble Polymer Applications in Foods

Preface. Acknowledgements. About the Author. Hydrocolloid adhesives. Hydrocolloid coatings. Dry Macro --and liquid --core hydrocolloid capsules. Multi--layered hydrocolloid products. Hydrocolloids in flavor encapsulation. Immobilization for food and biotechnological purposes. Texturization of vegetative materials. Hydrocolloid cellular solids. Hydroclloids in the production of special textures. Abbreviations. Index.

Irregular textural features of dried alginate-filler beads

Abstract Freeze-dried hydrocolloid beads can be used as carriers for many food, non-food and biotechnological operations. Information on their shape and surface properties, how different features are produced on their outer surface as a result of technological procedures, and the influence of fillers and other ingredients on external and internal shape and texture have never been investigated in detail. These parameters are very important since the surface of the bead is the first part to come into contact with its fluid, solid or gaseous environment and together with its internal structure, will influence, if not determine, its suitability to a predetermined task. In our study, projections formed on the surface of the bead during freezing. Smaller-sized fillers (such as kaolin) gave a smoother surface; a rougher surface was achieved with a bigger-diameter filler, such as bentonite. The presence of filler and/or glycerol in the bead increased the number of mid-area ‘craters’ and reduced the number of the smaller ‘craters’ formed on the beads dried surface. Moreover, the inclusion of glycerol had a large influence on the distribution of pores within the beads. Filler inclusion in the dried product reduced its collapse and roundness distortion during the drying process. In conclusion, the components and the method by which the dried bead was formed completely determined its weight, volume, shape and surface features. Taking these parameters into consideration provides the researcher with a useful tool for creating tailor-made dried beads for a predetermined operation, thereby increasing the probability of success. This was proven by the improved antifungal activity of entrapped Pantoae agglomerans (biocontrol agent) within alginate–glycerol–chitin beads.

Modelling deformation and flow during vapor-induced puffing☆

Abstract An equation describing bubble expansion in pseudoplastic fluids was modified to provide a differential equation describing vapor-induced pore expansion in foams forming in ‘molten’ starch. Correlations for (1) the rheological properties of molten starches as functions of shear rate, water content, temperature and prior specific mechanical energy input; (2) equilibrium water partial pressures for such melts; (3) net latent heats; and (4) the diffusivity of water were used in conjunction with the pore expansion equation, mass and enthalpy balances, and equations describing diffusive transfer of water in shells surrounding pores, to model vaporinduced puffing of starch-based particles. Properties such as initial pore radius, popping temperature, surface tension and initial moisture contents and hypothetical correlations for the flow yield stress and wallrupture stress were used to permit the model to conform to known puffing characteristics of popcorn. The differential equations involved were solved by finite-difference procedures. Parameters in property correlations and unknown property values were adjusted to provide computed expansion times, expansion ratios, residual moisture contents and fractions of open pores that agreed with observed values for popcorn at different initial moisture contents.

Recombinant cellulose crosslinking protein: a novel paper-modification biomaterial

AbstractCellulose-binding domains have been isolated from various cellulases, and proteins, which lack hydrolytic activity. The hypothesis that a cellulose-binding domain can be used to alter surface and mechanical properties of paper was tested. Two cellulose-binding domains from Clostriium cellulovorans were fused to form a cellulose crosslinking protein (CCP). The recombinant bifunctional cellulose-binding protein was expressed in E. coli, appliedby immersion onto Whatman cellulose filter paper, and its mechanical properties were tested. The purified protein improved the treated papers mechanical properties (tensile strength, brittleness, Youngs modulus and energy to break). In addition, cellulose crosslinking protein treatment was shown to transform filter paper into a more water-repellent paper. The binding of cellulose-binding domains to cellulose under a wide range of envi-ronmentalconditions, without the need for chemical reactions, and its biodegradability make them attractive moieties for the design of a new class of paper-modification materials.p>

Gellan and alginate vegetable coatings

Gellan and alginate hydrocolloid coatings of garlic bulbs (Allium sativum) were studied. Coatings served as a barrier to moisture loss. Incorporation of ingredients that can be found naturally in garlic skin, or are chemically similar to these, into the gum solution before coating, improved adhesion of the film to the surface of the coated commodity. Adhesion strengths were about three times higher than those recorded for a film made of gum and crosslinking agent alone. Electron microscopy technique revealed the structure of the garlic skin and hydrocolloid coating. Distances between the film and the vegetable were measured using image processing, and they could sometimes be reduced by varying the film composition.

Permeability and roughness determinations of wax-hydrocolloid coatings, and their limitations in determining citrus fruit overall quality

Abstract Water vapor, O 2 and CO 2 permeability of wax-hydrocolloid (xanthan, locust bean gum or guar) coatings were determined in custom-made apparatuses. Because the formulations do not have a ‘body’ of their own, they were uniformly smeared on cellulose and low-density polyethylene for WVP and gases permeability determinations, respectively, by speedball hard-rubber brayer. The permeances were calculated and used to estimate the permeabilities of the coatings. No statistical differences were observed between water vapor permeabilities of xanthan-, guar- and locust bean gum-containing coatings and a commercial coating for citrus fruit. For O 2 and CO 2 , all coatings were less permeable than the commercial one. These results could lead to the assumption that wax-hydrocolloid-coated citrus fruits suffer from considerable ethanol and acetaldehyde buildup, as well as that of off-flavors. However, the wax-hydrocolloid-coated fruits were, in fact, tasty due to disturbances in the smooth coating and less blockage of stomata. The average roughness of the wax-hydrocolloid coatings was slightly (but not statistically) higher than that of the commercial one. The added hydrocolloids caused the structure of the coating to be less ordered. Although no visible difference in wax-flake appearance was detected, their size as a result of gum addition was much smaller: thus, the hydrocolloid either coats the wax flakes and eliminates their continuous layer structure or helps limit their growing process from a grain or small flake to a uniform, undisturbed coating layer.

Influence of immobilization of bacteria, yeasts and fungal spores on the mechanical properties of agar and alginate gels

Abstract Lactococcocus lactis bacteria, Saccharomyces cerevisiae yeasts and Trichoderma viride fungal spores were immobilized in agar and alginate gels. The mechanical properties of these gels were tested by compression using a Universal Testing Machine. Data was collected as volts versus time, and later converted to stress versus strain. Both gel systems exhibited similar behavior after incorporation of the microorganisms. In most cases addition of microorganisms up to 105 CFU/ml of gel, did not change gel strength (stress at failure) and affect its deformability modulus or Henckys strain at failure. Different behavior was observed for lactic acid bacteria in an alginate gel where no changes were detected, even after adding 106 microorganisms/ml of gel. Major changes in the gel properties occurred when 107–109 microorganisms were immobilized per ml of gel matrix. Both agar and alginate gels suffered weakened textures (even though their mechanical properties, gelation mechanisms and immobilization methods were very different). Gel strengths and deformability moduli decreased by a factor of 1.2–4.4 depending on the type of gel, the number of microorganisms per ml and the diameter of the embedded microorganisms. Following immobilization gels became more brittle, as demonstrated by a decrease in their Henckys strain at failure. Results are also presented in this paper as the ratio between mechanical properties of gels with or without microorganisms versus the occupied volume of the tested gel.

The behavior of hydrocolloid coatings on vegetative materials

Coating vegetative materials by gelling agents is a process characterized by four different time scales. After wetting and penetration of the vegetative skin by the gum solution, adhesion of the viscous solution to the outer layer (skin) of the coated material is possible. The gelled film (coating) collapses during further drying and adheres to the vegetative tissue. Critical surface tensions of the solid object to be coated, its apparent and real roughness, wettability of the surfaces by the gum solution, the composition and polarity of the films designed to coat the solid, and the surface tension of gum coating solutions are among the critical properties that need to be explored and changed for a successful coating process. The critical surface tensions of garlic peel and gellan and alginate films (coatings) were evaluated by Zisman plots. Garlic skin has a low surface tension compared with those of synthetic films such as polystyrene and polyethylene. A spreading technique was used to determine the surface tension of the dry film and the solid garlic skin. Surface tension was divided into dispersive and polar components. The similarity between the coating solution and the object to be coated in values of dispersive and polar components influences the spreadability of the coating gum solutions. Better compatibility between the coated object and the coating films can be achieved by incorporating surface‐active agents within the coating gum solution. From the compatibility requirements detailed above, it can be concluded that tailor‐made hydrocolloid coatings for different vegetative materials can only be achieved by further exploring the chemical and physical properties of the coating solutions and the coated objects.

Plasticizers in the manufacture of novel skin-bioadhesive patches

The effects of plasticizer inclusion (10%, w/w) on roughness, mechanical and adhesive properties of novel skin-bioadhesive patches produced from polyvinyl alcohol and polyvinyl pyrrolidone were studied. Dry, non-adhesive patches became adhesive upon wetting. Roughness profiles of the patches and a skin model were studied, by measuring average values of Ra (recognized as average roughness in practice) and Rz (average of the vertical distances from the highest peak to the lowest valley within five equal sampling lengths). These values ranged from 2.4 to 3.8microm and from 10.9 to 12.5microm, respectively. Plasticizers had no significant effect on them. The average Ra obtained for the skin model was six- to eightfold higher than that obtained for the patches. Plasticizer inclusion caused a reduction in patch tensile strength and an increase in its strain at failure-the lower the plasticizers molecular weight, the greater its effect. Plasticizer inclusion also caused a significant reduction in peeling force: 1.5+/-0.11 and 2.8+/-0.13g force/cm for patches with and without glycerol, respectively. Patch adhesion to the skin also depended on the time elapsed between application and removal. In summary, plasticizer inclusion widened the range of mechanical and adhesive properties of the patches.