Curcumin, a natural yellow-orange polyphenol with low molecular weight is extracted from the rhizome of the herb Curcuma longa (turmeric). In addition to food consumption such as stabilizer in jellies and a natural colorant, this compound has been attracted a lot of attention in the pharmaceutical industry, due to its wide pharmacological application including antioxidant, anti-inflammatory, anti-cancer, anti-microbial, anti-parasitic, anti-mutagenic and anti immunodeficiency (Mangolim et al., 2014). However, the application of curcumin in the food has been restricted due to its low solubility in aqueous media. Other environmental factors like heating, alkaline condition, enzymes, oxygen, UV irradiation and metallic ions can also affect its decomposition (Li, Shin, Lee, Chen, & Park, 2016; Paramera, Konteles, & Karathanos, 2011). To resolve the mentioned restrictions, we have to use methods like encapsulation to increases solubility and protecting of curcumin.
Encapsulation according to the proposed definition, refers to a process in which specific component is entrapped within a different kind of matrix that this matrix can be made up one or multiple components. The most common matrixes are proteins, polysaccharides, surfactant, lipids, water and/or minerals (Garti & McClements, 2012). Whey protein, one of two milk protein fractions are used widely because of high nutritional value and different functional properties like the binding of water and flavor, gelation, emulsification, and foaming. Β-lactoglobulin (BLG) and α-lactalbumin (ALA) are the major fractions of whey proteins with globular structure. Recently, whey has been considered as a tool for the delivery of bioactive and pharmaceuticals due to the presence of α-helix and β-sheet in BLG and ALA. The secondary and triple structure make this biopolymer a suitable vehicle for encapsulation (Li et al., 2016; Sullivan, Tang, Kennedy, Talwar, & Khan, 2014).
The other common matrix is beta cyclodextrin (β-CD) that is formed by the enzymatic modification of starch. β-CD is cyclic glucose oligomer with seven glucose units (α-1,4-glucose). The cavity of this oligomer is able to form inclusion complex with hydrophobic compound due to its hydrophobicity. Past researches showed, encapulation in β-CD can improved solubility and stability of insolube compounds. The cavity of this oligomer fits hydrophobic compound with molecular weights in the range of 200 – 800 g/mol (Mangolim et al., 2014; Paramera et al., 2011).
Various approaches are obtained to fabricate biopolymer-based encapsulated bioactive compound like coacervation, liposome, nanoemulsion, nanostructure lipid carrier, spray drying, electrospinning, electrospray, supercritical fluid, emulsion-diffusion, reverse micelle, ultrasonication, emulsification/solvent evaporation, high pressure homogenization (Fathi, Martín, & McClements, 2014; Fathi, Mozafari, & Mohebbi, 2012). In recent years, the use of electrospray or electrospinning has been broadly developed as a new method for encapsulation of bioactive compound.
Electrospraying is a versatile and cost-effective method to produce capsules in micro, sub-micro or nano range. Organic solvents and temperature used in other methods that make the destruction of sensitive encapsulated bioactive are able to be removed and it doesn’t have toxicity problems associated with residual organic agents (López-Rubio & Lagaron, 2012; López-Rubio, Sanchez, Wilkanowicz, Sanz, & Lagaron, 2012).
In the past, several types of researches have been done for increasing solubility, stability and bioavailability of curcumin by use of whey protein with spray drying and antisolvent precipitation method (Aditya, Yang, Kim, & Ko, 2015; Liu, Chen, Cheng, & Selomulya, 2016). Also, complex inclusion with β-CD and loading with biopolymers like zein from the corn, casein, and amaranth-pullulan are other examples of a delivery system of curcumin (Li et al., 2016). In this research, whey protein isolate and β-CD were used as a protein-based and carbohydrate based delivery system for encapsulation of curcumin by electrospraying method.