Effect of some biopolymers on the rheological behavior of surimi gel

The objective of this study was to investigate the effect of selected biopolymers on the rheological properties of surimi. In our paper, we highlight the functional properties and rheological aspects of some starch mixtures used in surimi. However, the influence of some other ingredients, such as cryoprotectants, mannans, and hydroxylpropylmethylcellulose (HPMC), on the rheological properties of surimi is also described. The outcome reveals that storage modulus increased with the addition of higher levels of starch. Moreover, the increasing starch level increased the breaking force, deformation, and gel strength of surimi as a result of the absorption of water by starch granules in the mixture to make the surimi more rigid. On the other hand, the addition of cryoprotectants, mannans, and HPMC improved the rheological properties of surimi. The data obtained in this paper could be beneficial particularly to the scientists who deal with food processing field.     

Recent advances in starch–clay nanocomposites

Biological nanocomposites are a valuable addition to the existing nanocomposite materials and eventually can substitute petroleum-based composite materials in numerous applications due to their inherent advantages such as biodegradability, eco-friendliness, low cost, and easy availability to name a few. Recently, polymer–clay nanocomposites have achieved much more attention due to their enhanced properties such as size dispersion and significant enhancement in physicochemical and mechanical properties in comparison to the pure polymer systems. Among various biopolymers, starch is one of the most abundant natural polymers on the earth and is highly valuable due to its chemical and physical properties. Starch polymer has highly increased potential as an alternative to petroleum-based materials. However, starch cannot be used alone and starch–clay nanocomposite has emerged as a new potential green sustainable material. This article focuses on recent progress in starch-based nanocomposites with particular emphasis on starch–clay nanocomposite preparation, properties, and applications.     

Interaction between components of plant-based biopolymer systems

Proteins and polysaccharides are key elements in formulated foods, cosmetics, and pharmaceuticals. Their interaction behavior mainly determines the organoleptic, optical, textural, and rheological properties of foods. Traditionally, animal-based biopolymers have been widely used because of their excellent techno-functionality; however, plant-based alternatives gained enormous interest among scientists and manufacturers because of sustainable, religious, ethical, and nutritional reasons. The directed complexation of mixed biopolymers entirely originated from plants might be used to stabilize food colloids, modulate interfacial and bulk properties, control the release of bioactives, and mask bitter components. As such, this review highlights the general separation mechanism of mixed biopolymers systems entirely composed of plant-based biopolymers to be used as functional food ingredients. Particularly, ‘traditional’ and ‘novel’ proteins and polysaccharides obtained from different plant sources (e.g. soy, wheat, pea, potato, apple, citrus) are introduced to be assembled to modulate interfacial and bulk properties of food colloids.     

Chemical,technological, and rheological properties of hydrocolloids from sesame (Sesamum indicum) with potential food applications

BackgroundHydrocolloids are hydrophilic biopolymers which are widely used in the food industry due to their functional properties. In the present study, sesame hydrocolloids (Sesamum indicum) were obtained and, consequently, their physicochemical, proximal composition, functional, and rheological properties were evaluated to establish their potential applications in the food industry. Methods: Hydrocolloids were obtained from sesame seeds at 80 °C on evaluating the pH at 3, 7, and 10 and specific flour: water ratios during the solubilization process. Results: The hydrocolloids obtained had a good relationship between carbohydrates and proteins, which increased their potential use in the development of colloidal systems. The samples had high water holding capacity, solubility, and appropriate emulsifying and foaming properties. The hydrocolloids showed non-Newtonian shear-thinning behavior, adjusted to the Carreau-Yasuda model. Based on the dynamic viscoelastic rheological test, samples were characterized as a gel-like state when storage modulus values were higher than the loss modulus in the frequency and temperature ranges investigated. Conclusion: The findings revealed that sesame seeds can be considered appropriate raw material for extracting hydrocolloids as an alternative for obtaining natural food ingredients with interesting functional and rheological properties, with further applications in the development and formulation of micro-structured products.     

The influence of main emulsion components on the physicochemical properties of soursop beverage emulsions: A mixture design approach

The physicochemical properties of soursop beverage emulsion were investigated using mixture design. Results indicated that the regression models were significantly fitted for all response variables studied, except creaming index at 10°C. Interactions between biopolymers and oil phase had the most significant effect on creaming stability; however, modified starch played a much prominent role in maintaining the cloudiness and average droplet size. Meanwhile, WPI contributed significantly to the conductivity of the emulsions. The optimum condition resulted in desirable physicochemical properties could be achieved using 8.70% (w/w) modified starch, 1.02% (w/w) WPI, 10.11% (w/w) flavor oil, and 76.57% (w/w) water.     

Food colloids under oral conditions

Recent studies have made clear that structural and rheological changes of soft foods when they are processed in the mouth play a crucial role in sensory perception. This applies to soft solid products (fracturing behaviour and exudation of fluid) as well as more liquid food systems (breakdown of starch by salivary amylase, saliva-induced droplet aggregation, deposition and retention of food material on the tongue surface).     

Foods As Dispersed Systems. Thermodynamic aspects of composition-property relationships in formulated food

Although most components contribute to structural and physical properties of food, the two main construction materials are proteins and polysaccharides in their molecular and colloidal dispersions. Native biopolymers in biological system interact specifically, whereas they are mainly denatured and interact non-specifically in formulated food. Most food components have limited miscibility on a molecular level and form multicomponent, heterophase and non-equilibrium dispersed systems. A thermodynamic approach is applicable for studying structure-property relationships in formulated foods since their structures are based on non-specific interactions between components. Thermodynamically-based operations, such as mixing of components, changing temperature and/or pH, underlie processing conditions. To simplify considerations, attention will focus only on the effects of thermodynamic incompatibility of biopolymers on food dispersion functionality. The excluded volume effect of the macromolecules is the main reason for their immiscibility. Molecular mimicry of globular proteins causes their more-than-ten-fold-higher miscibility compared to classical polymers. Biopolymer incompatibility results in phase-separated liquid and gel-like aqueous systems. In highly volume-occupied systems aggregation, crystallisation and gelation of biopolymers and their adsorption at oil/water interfaces favour an increase in the free volume, accessible for macromolecules. This revised version was published online in July 2006 with corrections to the Cover Date.     

In situ 13C solid-state polarization transfer NMR to follow starch transformations in food

Convenience food products tend to alter their quality and texture while stored. Texture-giving food components are often starch-rich ingredients, such as pasta or rice. Starch transforms depending on time, temperature and water content, which alters the properties of products. Monitoring these transformations, which are associated with a change in mobility of the starch chain segments, could optimize the quality of food products containing multiple ingredients. In order to do so, we applied a simple and efficient in situ ¹³C solid-state magic angle spinning (MAS) NMR approach, based on two different polarization transfer schemes, cross polarization (CP) and insensitive nuclei enhanced by polarization transfer (INEPT). The efficiency of the CP and INEPT transfer depends strongly on the mobility of chain segments—the time scale of reorientation of the CH-bond and the order parameter. Rigid crystalline or amorphous starch chains give rise to CP peaks, whereas mobile gelatinized starch chains appear as INEPT peaks. Comparing ¹³C solid-state MAS NMR experiments based on CP and INEPT allows insight into the progress of gelatinization, and other starch transformations, by reporting on both rigid and mobile starch chains simultaneously with atomic resolution by the ¹³C chemical shift. In conjunction with ¹H solid-state MAS NMR, complementary information about other food components present at low concentration, such as lipids and protein, can be obtained. We demonstrate our approach on starch-based products and commercial pasta as a function of temperature and storage.     

Expolysaccharides from lactic acid bacteria: Technological bottlenecks and practical solutions

Microbial exopolysaccharides are added to or occur in a wide variety of food products, where they serve as viscosifying or gelling agents. Exopolysaccharides with different composition, size and structure are synthesized by several strains of lactic acid bacteria. Structural analyses combined with rheological studies reveal that there is considerable variation among the different exopolysaccharides; some of them exhibit remarkable thickening and shear-thinning properties and display high intrinsic viscosities. Hence, several slime-producing lactic acid bacterium strains and their biopolymers have interesting functional and technological properties, which may be exploited towards different products. However, the production of exopolysaccharides from lactic acid bacteria is low and often unstable, and their downstream processing is difficult. Strain improvement, enhanced productivities and advanced modification and production processes (both enzyme and fermentation technology) may contribute to their economic soundness.     

Polysaccharide functionality through extrusion processing

Extrusion processing is a technology applied in the food and pharmaceutical industry for affecting product microstructure, product chemistry or the macroscopic shape of products. Starch based products are often extruded to break down the starch granule to render it digestible and to produce a shaped product. Encapsulation of flavors, nutrients and drugs is another frequent application of extrusion processing. This short review article is concerned with the use of extrusion processes to modify polysaccharide functionality. Extrusion processes are applied to polysaccharides for specific purposes such as physical modification or chemical modification (reactive extrusion), manufacture of confectionary gels and encapsulation of flavors or drugs. Non-starch polysaccharides and confectionary gels have also been extruded. Another application area is in the field of dietary fibers, obtained through extrusion processing of by- or waste-products of the food industry. The focus of this article is on extruding starch and other polysaccharides as an ingredient rather than as part of a final food product obtained by extrusion processing. It concludes with a discussion on extrusion as microstructure generating process and the relevance of this application to taste perception in semi-liquid foods.     

Biopolymer-based nanoparticles and microparticles: Fabrication,characterization, and application

Tailor-made microparticles and nanoparticles are finding increasing use in food products to alter their nutritional characteristics, flavor profile, appearance, rheology, stability, and processability. These particles are often fabricated from food-grade biopolymers, such as proteins and polysaccharides. Food biopolymers display a diverse range of molecular and physicochemical properties (e.g. molecular weight, charge, branching, flexibility, polarity, and solubility) which enables the assembly of colloidal particles that exhibit a broad range of functional attributes. By careful selection of appropriate biopolymers and assembly methods, biopolymer particles can be fabricated with tailored behaviors or features. In this article, we review recent developments in the design and fabrication of functional biopolymer nanoparticles and microparticles, and highlight some of the challenges that will be the focus of future research.     

Thermoplastic Starch

The thermoplastics processing of native starch in the presence of water is a recent development with very wide possible applications. Eventually, oil-based polymer materials have to be replaced in many applications by sustainable, inexpensive, natural materials from renewable resources. The present contribution focuses on the injection moulding of starch. The bases of the processing and the thermal and molecular changes occurring are described. In addition, the rheological behaviour of starch-water melts during processing is analysed quantitatively to give apparent melt viscosities. The dimensional, thermal and mechanical properties of moulded thermoplastic starch polymer (TSP) materials and the products presently being produced from them are discussed.     

A rheological study of cationic micro- and nanofibrillated cellulose: quaternization reaction optimization and fibril characteristic effects

Driven by the demand for various cationic biopolymers in recent years, the quaternization of cellulose nanofibers was carefully investigated to have tight control over their final characteristics. The addition of sodium hydroxide (NaOH) to the reaction mixture is crucial as it catalyzes the conversion of alcohol groups of cellulose into more reactive alcoholate groups. On the other hand, excessive concentration proves to inhibit the reactivity of hydroxyl groups. The addition of glycidyltrimethylammonium chloride (GTMAC) increases the yield of the trimethylammonium chloride content (TMAC) reaction, while in excess it affects the rheological properties of the quaternizated cellulose nanofibers. The effects of NaOH and GTMAC on the TMAC content and rheological properties have been investigated in detail and mathematically evaluated. Furthermore, a comparison of the viscoelastic behavior and shear thinning character of commercial cationic micro- and nanofibrillated cellulose is presented. The research allows to extend the possibility of using cellulose in many applications of cationic biopolymers.

     

Structural and mechanical properties of edible films from composite mixtures of starch,dextrin and different types of chemically modified starch

Abstract

Recent regulations restricting the use of one-use-plastics open the possibility to develop starch-based edible packaging material. The objective of this work was to determine the effect of three different modified starches on starch and dextrin composite edible films by a mixture design approach on edible films’ mechanical properties. The amylose content of chemically modified starches influenced their swelling capacities, where higher amylose content was inversely related to water-power uptake and directly related to film thickness. CMS3 Nifrastarch-TS edible films, with higher amylose content, presented higher puncture force and tensile strength, but lower puncture deformation and elongation, related to a less smooth surface, according to atomic force micrographs. The use of CMS1 Gelamil-100, with lower amylose content, decreased stiffness but increased films’ stretching, presenting higher surface smoothness film topography. The use of commercial chemical modified starches in combination with starch and dextrin will allow to control of edible film thickness and hence, mechanical properties, depending on food covering necessities.     

Structural and functional alterations in major peanut allergens caused by thermal processing

The majority of foods that we eat are subjected to some type of processing either at home or by the manufacturer. The biochemical reactions that occur in foods as a result of thermal processing can be both beneficial and harmful. Here, we briefly review the effects of thermal processing and some of the effects of the Maillard reaction on the allergenicity of food proteins. Specifically, we focus on the known effects of roasting on the allergenic properties of peanut proteins and the contribution of Maillard reaction products or advanced glycation end products to these observed effects. The most thorough understanding of the effects of thermal processing on allergenicity involves the peanut proteins. Thermal processing alters specific biophysical and immunological properties of peanut proteins, such as structure, function, solubility, digestibility, immunoglobulin E (IgE) binding, and T-cell responses. A better understanding of the effects of thermal processing-induced biochemical and immunological alterations is of utmost importance for proper risk assessment of existing and newly introduced proteins in the food source, as well as development of effective diagnostic tools and therapeutic treatments for food allergy.     

Thermal analysis,state transitions and food quality

Thermal properties of food systems are important in understanding relationships between food properties and changes in food quality. Concentrated food systems (low-moisture and frozen foods) are seldom in an equilibrium state and they tend to form amorphous, non-crystalline structures. Several glass transition-related changes in such foods affect stability, e.g., stickiness and caking of powders, crispness of snack foods and breakfast cereals, crystallisation of amorphous sugars, recrystallisation of gelatinised starch, ice formation and recrystallisation in frozen foods and rates of non-enzymatic browning and enzymatic reactions. Relationships between glass transition, water plasticisation and relaxation times can be shown in state diagrams. State diagrams are useful as stability or quality maps and in the control of rates of changes in food processing and storage.This revised version was published online in November 2005 with corrections to the Cover Date.     

Correlation between mechanical adhesion and interfacial properties of starch/biodegradable polyester blends

Biopolymers are preferred ingredients for the manufacture of materials because they are based on abundantly available and renewable raw materials that have benign environmental problems associated with their production, fabrication, use, and disposal; however, the wide use of biopolymers in engineering applications has not been achieved, mainly because of the inferior quality of many biopolymer‐based products. To overcome this limitation, studies have been initiated on blends of biopolymers and biodegradable synthetic polymers. We used the contact angle of probe liquids to measure the surface energy of polystyrene, the biodegradable polyesters polycaprolactone, poly(hydroxybutyrate‐co‐hydroxyvalerate), polylactic acid, polybutylene adipate terephthalate, and adipic poly(hydroxy ester ether), and normal starch. The surface energies were used to estimate the starch/polymer interfacial energy and work of adhesion. The calculated starch/polyester work of adhesion showed mixed correlation with published starch/polyester mechanical properties, indicating that factors other than interfacial properties might be dominant in determining the mechanical properties of some starch/polyester blends. © 2001 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 39: 920–930, 2001     

Effects of pectin and xanthan gum on induced-flocculation phenomenon in an acidic model emulsion system

Mayonnaise is one of the most well-known dressings in the world and has properly found its impossibility to apply thermal processing, the high level of cholesterol and some consumers’ allergy to egg. In this study, the production of egg- free mayonnaise in model system has been investigated with the emphasis on flocculation enhancement in the system. Flocculation of emulsion droplets can have beneficial or harmful effect on food quality depending on product nature. In this study, influence of flocculation inducing on the stability, microscopic structure, zeta potential, droplet size and rheological properties of egg-free mayonnaise system were evaluated. Xanthan (XG), pectin (PE) and modified starch (MS) biopolymers mixed at different concentrations were used as flocculation inducer in emulsion system. XG-MS and PE-MS mixed polymers created depletion flocculation and reduced the speed of the oil droplets movement in the product and thus increased emulsion stability. In addition, an increase of all gum concentration caused an increment in the stability, consistency coefficient and heat stability values. Depending on the desirable level of xanthan gum and pectin gum for creating depletion flocculation, production of egg-free mayonnaise with properties closely matching those of commercial ones with egg is possible.     

Protein-Polysaccharide Interactions for Stabilization of Food Emulsions

Proteins, polysaccharides and their blends, as examples of natural biopolymers, are surface active materials. Biopolymers may be considered as amphiphilic macromolecules that play an essential role in stabilizing food formulations (foams, emulsions and dispersions). Under specific conditions (such as protein-to-polysaccharide ratio, pH, ionic strength, temperature, mixing processing), it has been stated that proteins and polysaccharides form hybrids (complexes) with enhanced functional properties in comparison to the proteins and polysaccharides alone. Different protein-polysaccharide pairs are reviewed with particular attention to the emulsification capability of their mixtures. In the case of uncomplexed blends of biopolymers, competitive adsorption onto hydrophobic surfaces is generally reported. Conversely, electrostatic complexation between oppositely charged proteins and polysaccharides allows better anchoring of the new-formed macro-molecular amphiphile onto oil-water interfaces. Moreover, improved thermal stability and increased resistance to external treatment (high pressure) involved in food processing are obtained. This review presents basic and applied knowledge on protein-polysaccharide interactions in aqueous medium and at the oil-water interface in food emulsion systems. Electrostatic interactions and thermodynamic incompatibility in mixed biopolymer solutions are correlated to the functional properties (rheology, surface hydrophobiciry, emulsification power) of these interesting blends. Basic and industrial selected systems of different families of hydrocolloids (as gum Arabic, galactomannans, pectins) and protein (caseins, whey, soya, gelatin) mixtures are reviewed.     

Development and Characterization of Functional Starch-Based Films Incorporating Free or Microencapsulated Spent Black Tea Extract

Antioxidant polyphenols in black tea residue are an underused source of bioactive compounds. Microencapsulation can turn them into a valuable functional ingredient for different food applications. This study investigated the potential of using spent black tea extract (SBT) as an active ingredient in food packaging. Free or microencapsulated forms of SBT, using a pectin–sodium caseinate mixture as a wall material, were incorporated in a cassava starch matrix and films developed by casting. The effect of incorporating SBT at different polyphenol contents (0.17% and 0.34%) on the structural, physical, and antioxidant properties of the films, the migration of active compounds into different food simulants and their performance at preventing lipid oxidation were evaluated. The results showed that adding free SBT modified the film structure by forming hydrogen bonds with starch, creating a less elastic film with antioxidant activity (173 and 587 µg(GAE)/g film). Incorporating microencapsulated SBT improved the mechanical properties of active films and preserved their antioxidant activity (276 and 627 µg(GAE)/g film). Encapsulates significantly enhanced the release of antioxidant polyphenols into both aqueous and fatty food simulants. Both types of active film exhibited better barrier properties against UV light and water vapour than the control starch film and delayed lipid oxidation up to 35 d. This study revealed that starch film incorporating microencapsulated SBT can be used as a functional food packaging to protect fatty foods from oxidation.