Water-soluble bioactives

This chapter considers the issues relating to the delivery of bioactives through foods. The choice of materials for encapsulation of bioactives, the formulation of the encapsulated delivery system and the processes used for their manufacture are discussed. Examples of materials and processes used for the manufacture of encapsulated fat-soluble and water-soluble bioactives and encapsulated probiotics are given. The effectiveness of various encapsulated delivery systems for protection of bioactive ingredients and new trends in encapsulation technology are covered. The... 

Spray drying is the most commonly used method in the food industry. Bioactive ingredients microencapsulated by this method include fats and oils, flavours, essential oils and other oil-soluble bioactives. Water-soluble bioactives can also be encapsulated by spray drying, where the encapsulant forms a matrix structure rather than a film surrounding the core. This process typically involves the dispersion of the core material into a solution of the encapsulant (e.g., protein, carbohydrate) and atomization of the mixture into the drying chamber. This leads to evaporation of the solvent... 

Encapsulated Delivery Systems for Water-Soluble Bioactives... 

Water-soluble bioaotives may also be protected from their environment by entrapment within a matrix (e.g., gel) or the use of lipid coats. Most research on delivery of water-soluble bioactives has been on systems for enriching foods with water-soluble vitamins and minerals and more recently on the use of bioactive peptides in food. The delivery of bioavailable iron has been of particular interest because of the widespread problem of iron deficiency. 

Hard fats are used to coat water-soluble bioactives. Release occurs by heating above the melting point of the fat or by mechanical rupture. Fat coatings have been used for protecting many water-soluble materials, which may otherwise be volatilized or damaged during thermal processing and to deliver materials such as ferrous sulfate, vitamins and other minerals. The peptides of casein hydrolysates encapsulated in lipospheres were shown to have reduced bitterness (Barbosa et al. 2004). 

Miller, E. and N. Peppas, Diffusional release of water-soluble bioactive agents from ethylene-vinyl acetate copolymers. Chemical Engineering Communication, 1983, 22, 303-315. 

Jiang H, Wang L, Zhu K (2014) Coaxial electrospinning for encapsulation and controlled release of fragile water-soluble bioactive agents. J Control Release 193 296-303... 

Finally, a new water-soluble polyphosphazene was recently synthesized that has the structure shown in 36 (46). This polymer has two attributes as a biomedical macromolecule. First, the pendent carboxylic acid groups are potential sites for condensation reactions with amines, alcohols, phenols, or other carboxylic acid units to generate amide, ester, or anhydride links to polypeptides or bioactive small molecules. Second, polymer forms ionic crosslinks when brought into contact with di- or trivalent cations such as Ca or Ai3+. The crosslinking process converts the water-soluble polymer to a hydrogel, a process that can be reversed when the system... 

In the past decade, general interest and research activities focusing on anthocyanins have considerably increased. This increased interest is not only based on the common knowledge that these water-soluble pigments can be used as possible alternatives to artificial food colorants, but also it relates to their bioactive properties. When search-... 

Possible Mechanism of Allelopathlc Action of Water-Insoluble Plant Lipids. Many non-polar natural products with germination and growth regulation activities In laboratory tests are In pure form not sufficiently water soluble to account for their allelopathlc activities observed In the field. For this reason the notion exists that sterols and other non-polar plant constituents are not likely to play a role In allelopathlc actions, and It Is generally concluded that the bioactivity data observed In the laboratory are therefore coincidental. 

This subject can be considered in terms of five different types of molecules or materials (a) biologically inert, water-insoluble polymers (b) water-insoluble polymers that bear biologically active surface groups (c) water-swellable polymeric gels, or amphiphilic polymers that function as membranes (d) water-insoluble but bioerodable polymers that erode in aqueous media with concurrent release of a linked or entrapped bioactive molecule and (e) water-soluble polymers that bear bioactive agents as side groups. 

Fig. 1.14 (A) Single-wall carbon nanotubes wrapped by glyco-conjugate polymer with bioactive sugars. (B) Modification of carboxyl-functionalized single-walled carbon nanotubes with biocompatible, water-soluble phosphorylcholine and sugar-based polymers. (A) adapted from [195] with permission from Elsevier, and (B) from [35] reproduced by permission of Wiley-VCH.

Another highly soluble bioactive compound, oxytetracycline HC1, loaded in halloysite gave 80 % release into water during 10 hours. The release rate was slowed... 

Similar structures were later employed to create original dendronized polymers 485 and 486, based on a chitosan backbone and using such sialodendrons as 484 (Fig. 50).328 Chitosan itself is nontoxic, biodegradable, and has widespread biological activities, but major intrinsic drawbacks such as low solubility in both organic solvents and water have hampered its development as a bioactive polymer. Thus, the synthesis of water-soluble... 

Flavonoids are a complex group of polyphenolic compounds with a basic C6-C3-C6 structure that can be divided in different groups flavonols, flavones, flavanols (or flavan-3-ols), flavanones, anthocyanidins, and isoflavones. More than 6,000 flavonoids are known the most widespread are flavonols, such as quercetin flavones, such as lu-teolin and flavanols (flavan-3-ols), such as catechin. Anthocyanidins are also bioactive flavonoids they are water-soluble vegetable pigments found especially in berries and other red-blue fruits and vegetables. 

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