Nanotechnology is an enable technology that has the potential to revolutionize agriculture and food systems. Driven by increasing consumer demand for healthy food products, researchers have been applying tools and knowledge in nanotechnology to address the issues relevant to food and nutrition. This concise review is mainly focused on nanoemulsions and polymer micelles-based delivery systems which have shown enhanced oral bioavailability and biological efficacies (that is, antiinflammation, anti-cancer, and so on) of different phytochemicals. Nanoemulsions are a class of extremely small droplets that appear to be transparent or translucent with a bluish coloration. They are usually in the range 50 to 200 nm but much smaller than the range (from 1 to 100 μm) for conventional emulsions. Nanoemulsion preparation, characterization, and bioavailability have been discussed. Curcumin nanoemulsions show 85% inhibition of TPA-induced mouse ear inflammation as well as the inhibition of cyclin D1 expression, while dibenzoylmethane (DBM) nanoemulsion shows about 3-fold increase in oral bioavailability compared to the conventional DBM emulsion. Biopolymer micelles show significantly improved water solubility/dispersibility and in vitro anti-cancer activity of phytochemicals. More research efforts are still needed for the understanding of the potential impacts of nanoencapsulated phytochemicals on the human body and environment to address the public concerns.

Turbidity, dynamic light scattering, and electrophoretic mobility were used to study the effects of added salt on coacervation in the system composed of the strong cationic polymer poly(diallyldimethylammonium chloride) (PDADMAC) and oppositely charged mixed micelles of Triton X-100 (TX100) and sodium dodecyl sulfate (SDS). The phase behavior in the range of ionic strengths from 0.05 to 0.60 M includes regimes of soluble complex formation, coacervation, and precipitation. The corresponding phase boundaries are determined from differential turbidity curves. The shift of the phase boundaries to higher ratios of SDS:TX100 with increase in salt concentration is explained on the basis of electrostatic screening. The width of the coacervation region is found to increase with ionic strength. These observations are consistent with previous reports of the “salt suppression” and “salt enhancement” of coacervation. In the coacervation region, the electrophoretic mobility is found to be close to zero. At higher and lower ionic strengths, soluble complexes are positively or negatively charged, respectively. It is suggested that the principal factor governing coacervation in this system is electroneutrality of the polyion−micelle complex which in turn depends on the charge and number of bound micelles.

FT-IR, in combination with residual amino group determination using a fluorescence technique, has been used to investigate the chemical functional groups involved in the cross-linking reaction between glutaraldehyde and gelatin molecules. The results suggest that, at high pH values (i.e., close to the pK(a) of lysine), the cross-linking reaction is mainly governed by the well-known Schiff base formation, whereas at low pH (i.e., when the amino groups of lysine are protonated), the reaction may also involve the -OH groups of hydroxyproline and hydroxylysine, leading to the formation of hemiacetals.

Curcumin is a natural bioactive compound with many health-promoting benefits. Its low oral bioavailability limits its application in functional foods. In the present study, novel organogel-based nanoemulsions have been developed for oral delivery of curcumin and improvement of its bioavailability. Recently developed curcumin organogel was used as the oil phase in the curcumin nanoemulsion formulation. Tween 20 was selected as the emulsifier on the basis of maximum in vitro bioaccessibility of curcumin in the nanoemulsion. In vitro lipolysis profile revealed that the digestion of nanoemulsion was significantly faster and more complete than the organogel. Permeation experiments on Caco-2 cell monolayers suggested that digestion-diffusion was the major absorption mechanism for curcumin in the nanoemulsion. Furthermore, in vivo pharmacokinetics analysis on mice confirmed that the oral bioavailability of curcumin in the nanoemulsion was increased by 9-fold compared with unformulated curcumin. This novel formulation approach may also be used for oral delivery of other poorly soluble nutraceuticals with high loading capacity, which has significant impact in functional foods, dietary supplements and pharmaceutical industries.

Background Colloidal particles assembled from food grade materials with proper fabrication and/or modification can function as Pickering emulsion stabilizers. Scope and Approach This paper summarized recent research practices in developing food-grade particles stabilized Pickering emulsions. Recent advances in methods for their fabrication and characterization were reviewed. Research progresses in clarifying their stabilization mechanisms based on interfacial microstructure observation as well as promising research trends in basic research and fields of applications were highlighted.

The mixture of peppermint oil (PO) with medium-chain triacylglycerol was emulsified in water and stabilized with a food-grade biopolymer, modified starch, to form PO nanoemulsions. The effects of emulsifying conditions including homogenization pressure, the number of processing cycles, and oil loading on the mean diameters and viscosities of nanoemulsions were characterized by dynamic light scattering, optical microscopy, and rheological measurements. The formulated PO nanoemulsions with mean diameters normally <200 nm showed high stability over at least 30 days of storage time. Their antimicrobial properties related to those of PO have also been evaluated by two assays, the minimum inhibitory concentration (MIC) and time-kill dynamic processes, against two Gram-positive bacterial strains of Listeria monocytogenes Scott A and Staphylococcus aureus ATCC 25923. Compared with bulk PO, the PO nanoemulsions showed prolonged antibacterial activities. The results suggest that the nanoemulsion technology can provide novel applications of essential oils in extending the shelf life of aqueous food products.

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