Edible polysaccharide-protein

Edible films from polysaccharides, proteins, and/or lipid compounds are used in various food products to control gas transfer (15-17). 

Polysaccharide-protein complexes isolated from the edible mushroom Himematsutake show marked antitumour activity, notably a (1-6)-/3-D-glucan compound xyloglucans and glucoxylans were also... 

Biodegradable films made from edible biopolymers from renewable sources could become an important factor in reducing the environmental impact of plastic waste. Proteins, lipids, and polysaccharides are the main biopolymers employed to make edible films and coatings. Which of these components are present in different proportions and determine the properties of the material, as a barrier to water vapor, oxygen, carbon dioxide, and lipid transfer in food systems (Gomez-Guillen et al. 2002 and 2009). 

The materials used in these type of films include lipids, polysaccharides, and proteins. Starch (Maizura and others 2007), methylcellulose (Olivas and others 2003), hydroxypropyl cellulose (Brindle and Krochta 2008), chitosan (No and others 2007), xanthan gum (Mei and others 2002), alginate or zein (Zapata and others 2008), and soy protein (Park and others 2001) have been used for edible coatings. 

The term food colloids can be applied to all edible multi-phase systems such as foams, gels, dispersions and emulsions. Therefore, most manufactured foodstuffs can be classified as food colloids, and some natural ones also (notably milk). One of the key features of such systems is that they require the addition of a combination of surface-active molecules and thickeners for control of their texture and shelf-life. To achieve the requirements of consumers and food technologists, various combinations of proteins and polysaccharides are routinely used. The structures formed by these biopolymers in the bulk aqueous phase and at the surface of droplets and bubbles determine the long-term stability and rheological properties of food colloids. These structures are determined by the nature of the various kinds of biopolymer-biopolymer interactions, as well as by the interactions of the biopolymers with other food ingredients such as low-molecular-weight surfactants (emulsifiers). 

Edible moisture barriers usually include hpids. Because of their apolar nature, these hydrophobic substances are capable of forming a water-impervious structure and reduce efficiently the water transfer. However, lipid-based materials are most of the time brittle so they are frequently combined with proteins and/or polysaccharides to improve their mechanical and structural properties (Wu et al. 2002). Several reviews focussing specifically on edible moisture barriers (Debeaufort et al. 2000 Koelsch 1994) and/or lipid-based edible films have been published (Baldwin et al. 1997 Callegarin et al. 1997 Greener and Fennema 1992 Hernandez 1994 Quezada-Gallo et al. 2000). The most recent review on lipid-based moisture barriers is that of Morillon et al. (2002). 

Several studies reviewed formulations, barrier properties and possible application of edible protein-based films (Table 23.3) (Gennadios et al. 1994 Krochta and Me Hugh 1997 Torres 1994). Overall, similarly to polysaccharide films, proteins exhibit relatively low moisture barrier properties, two to four times lower than conventional polymeric packaging materials (McHugh and Krochta 1994d). The limited resistance of protein films to water vapour transmission is attributed to their substantial hydro-philicity and to the amounts of plasticizers, such as glycerol and sorbitol, incorpo-... 

Ketones (e.g., acetone) and alcohols (e.g., ethanol) are strongly bound to whole milk powder (24.3% lipids, 25.4% protein) and skimmed milk powder (0.6% lipids, 31.6% protein), fairly strongly to potato flakes (72.2% polysaccharide, 8% protein), but only weakly to instant coffee powder and strawberry powder. The interactions of the acetone with whole milk, skimmed milk and edible oil have already been shown in Fig. 

Tamarind seed is a by-product of the tamarind pulp industry. Presence of tannins and other dyeing matters in the seed testa make the whole seed unsuitable for consumption, but they become edible after soaking and boiling in water. Tamarind seed is also used as raw material in the manufacture of polysaccharide (jellose), adhesive and tannin. Seeds and kernels are high in protein content, while the seed coat is rich in fiber and tannins (anti-nutritional factors). Seeds are gaining importance as an alternative source of proteins, and are besides a good source of fatty acids and rich in some essential minerals, such as Ca, P, Mg and K. 

Edible films and coatings are thin materials made from biological macromolecules (biopolymers).1 The main biopolymers used in preparing biofilms are polysaccharides2 and proteins.3,4 Among the most studied polysaccharides are pectin, cellulose and derivatives, alginates, carrageenan, chitosan and starch.1 5... 

It is well established that the extrusion of proteins is a potential for obtaining edible films on a large scale [41]. For these authors, the incorporation of polysaccharides and inclusion of nanoparticles in these films tend to improve their mechanical properties. Park et al. [42] studied bioplastics made from extruded gelatin plasticized with glycerol, sorbitol or a mixture of both. In this study, they discard sorbitol as a plasticizer because of low flow in the extrusion of the material. 

The main natural biomaterials for bioplastics are proteins, cellulose derivatives, alginates, pectins, starch and other polysaccharides. The solubility in water of the polysaccharide film is advantageous in situations where the film is consumed with the product, resulting in little change in the food s sensory properties. " Edible films based on proteins, polysaccharides or lipids minimize special care with the final package and increase food quality. ... 

Proteins and polysaccharides produced on an annual kiloton scale in the world have attracted extensive research attention as potentially the most significant eco-materials as well as edible and biodegradable films and coatings (Thakur and Thakur 2014a, b, c). Edible films made from polysaccharides and proteins act as excellent barriers to nonpolar substances such as O2, CO2, and lipid, particularly at low relative humidities. In contrast to synthetic polymers having a simpler and more random structure, biopolymers are complex molecular assemblies with precise and... 

---