Curcumin is a fat soluble yellow pigment present in turmeric. The water soluble form of curcumin has been applied onto expanded extruded balls, made from corn and defatted soybean flours. The stability of this natural turmeric colourant has been examined and compared with that of the permitted synthetic colour like tartrazine. The products are packed in polypropylene pouches and subjected to storage studies at ambient (27 degrees C, 65% relative humidity), and are tested for moisture content, and colour and pigment retention. Brightness of the sample reduces markedly up to 30% during storage. After 10 weeks of storage, the retention of curcumin is about 77%, and the effective shelf life of the product is 6 weeks at ambient condition with 83 and 93% retention of curcumin and tartrazine, respectively. The retention of both colours follows first order kinetics (0.86 less than or equal to r less than or equal to 0.98, p less than or equal to 0.01) while curcumin showing a faster rate of degradation compared to tartrazine. Turmeric colourant may be a viable alternative for tartrazine for using it onto extruded products.

Among oral delivery systems, oil in water nano-emulsions (O/W NEs) are of particular interest to improve pharmacokinetics of lipophilic compounds. Recently, we have implemented a successful strategy to improve O/W NEs stability, based on a polymeric coating on an oil core, namely secondary O/W NEs, through the use of pharma grade formulations. However, in the field of food supplements, food grade materials are the top choice since they combine safety and cost effectiveness. Here, we have replaced pharma grade (PG) with food grade (FG) materials in the preparation of the polymer coated O/W NEs, and performed a comparative study between the two formulations to assess the FG one. At the same time, in order to provide formulations with enhanced mucus-adhesion to the intestinal barrier, secondary O/W NEs were prepared by adding thiol groups to chitosan (Ct) via a simple non-covalent procedure based on N-acetyl-cysteine (NAC) salification, thus easily implementable to a food supplement formulation. PG and FG formulations, in different materials combinations, were prepared and physico-chemically characterized (DLS, ¹H NMR, ITC, CRYO-TEM) showing similar behaviour. FG formulations (NEs, Ct-NEs and Ct-NAC-NEs) loaded with curcumin were prepared and compared with the free drug in terms of drug bioaccessibility through the INFOGEST protocol confirming improved bioaccessibility. Very interestingly, by comparing mucus-adhesion properties of the two polymeric coatings (Ct and Ct-NAC) within an intestine on chip device able to mimic the complex intestinal functions, a significant enhancement in the mucus-adhesive properties of the proposed novel Ct-NAC-NE formulation was observed with respect to Ct due to the presence of thiol groups. Nonetheless, in-vivo assays are required as a final assessment of the proposed system.

Curcumin was extracted from Curcuma Longa employing a green, bio-based, and food-agreed surfactant-free microemulsion (SFME) consisting of water, ethanol, and triacetin. Concerning the high solubility of curcumin in the examined ternary mixtures, it was attempted to produce highly concentrated tinctures of up to a total of ~130 mg/mL curcuminoids in the solvent by repeatedly extracting fresh rhizomes in the same extraction mixture. The amount of water had a significant influence on the number of cycles that could be performed as well as on the extraction of the different curcuminoids. In addition, the purity of single extracts was enhanced to 94% by investigating several purification steps, e.g. vacuum distillation and lyophilization. Through purification before extraction, the water insoluble curcumin extract could be solubilized indefinitely in an aqueous environment. Additional stability tests showed that solutions of curcumin can be stable up to five months when concealed from natural light.

Food and beverages enrichment with water-insoluble health-promoting nutraceuticals is important, but technologically challenging. Sugar beet pectin (SBP) is a natural dietary fiber with high emulsifying capacity. However, its potential as a natural encapsulator of hydrophobic nutraceuticals for beverage enrichment, has hardly been explored. Curcumin is a potent antioxidant with numerous attributed health benefits, but very low aqueous-solubility. We herein explored SBP as a carrier for solubilization and protection of curcumin (CUR). Using spectrofluorimetry, the CUR-SBP binding constant determined was (6.74 ± 0.5) ∙ 10⁵M⁻¹. As CUR:SBP molar ratio increased from 14:1 to 140:1, CUR encapsulation capacity increased from 14.5 ± 0.8 to 127.4 ± 0.4 mg CUR/gSBP, and encapsulation efficiency moderately decreased from ~100% to 86 ± 7%. The encapsulation in SBP dramatically decreased CUR particle size, from >17 μm to <0.5 μm, in average, and conferred substantial protection to CUR during simulated shelf-life, decreasing the decay rate constant ~7 fold. Therefore, SBP is a potent natural encapsulator for hydrophobic nutraceuticals for food and even clear beverage enrichment.

International audience | Use of nanonized curcumin-whey protein (CWP) composite particles as Pickering stabilizers are an attractive strategy due to their edibility and natural origin. This study aimed to examine the effect of physico-chemical conditions (pH, ionic strength, protein form) during the formation of CWP composite nanoparticles on their physico-chemical characteristics (size, surface charge, morphology) and further their Pickering ability by influencing their aptitude to stabilize oil/water interfaces. Our study demonstrated that, to favor the protein-curcumin interactions and to improve the particle characteristics (smaller size, monodispersity), one should increase the accessibility of hydrophobic moiety of proteins (denaturation) and control ionic strength. Increasing the concentration of the CWP composite nanoparticles decreased size and polydispersity enhancing emulsion stability. Use of these CWP composite nanoparticles in food products with high ionic strength will tend to flocculation and thereby emulsions destabilization. This work allows for a better understanding of the role of physico-chemical conditions on the formation of CWP composite nanoparticles and thereof their oil/water interfacial activity.

A simple and efficient determination of curcumin in water and food samples based on the combination of dispersive liquid–liquid microextraction (DLLME) and spectrophotometric estimation has been described. The effects of DLLME effective parameters [extraction solvent (CHCl₃), disperser solvent (ethanol), pH, centrifugation time, and KCl concentration] were optimized via central composite design (CCD) and response surface methodology (RSM) and desirability function (DF) using STATISTICA. At optimum condition specified as 150 μL of chloroform, 900 μL of ethanol, pH = 4.0, and 4 min of centrifugation time in the absence of any salt, a linear calibration graph in the range of 10–2000 ng mL⁻¹ of curcumin with R ² = 0.99942 (n = 6) confirms good applicability of the method for quantification of analytes over a wide range of analytes. The reasonable limit of detection (LOD) and quantification (LOQ) (0. 23 and 0.78 ng mL⁻¹, respectively) makes it suitable for trace analysis. Good relative standard deviation [1.16–2.3 % (n = 12)] and high enrichment factor (EF) 2182.04 are a good remark of the present method. Curcumin with relative standard deviation (RSD) less than 3 % (n = 4) and recoveries in the range 91.76–100 % can be successfully quantified in different real samples.