## 8 Nanotechnological Tools for Nutraceuticals and Functional Foods
### Protein-Based Nanocarriers  
[PERSON] et al. [261] discussed the state of the art in protein-based nanoencapsulation technologies and protein alteration methods to prolong their activity in nanocarriers to increase the encapsulation, retention, shielding and release of bioactive substances. [PERSON] et al. [262] published a literature review on the latest discoveries on nanoscale manifestations of denatured whey proteins and their agglomeration, which could help design protein nanostructures with new or significantly improved attributes for the implementation of nutraceuticals in food materials and their release. [PERSON] and [PERSON] [263] reported a spray freeze-drying-based microencapsulation approach as a viable strategy for improving the oral bioavailability of insufficiently water-soluble bioactive substances such as vitamin E, employing whey protein concentrate as an encapsulating reagent. Under gastric digestion circumstances, substantial incorporation and sedimentation of zein NPs comprising lutein (ZLNPs) with a hydrodynamic radius of approx. 75 nm were noticed, and ZLNPs that were not entirely metabolized by gastric enzymes conformed to lipid droplets; nevertheless, when salt (i.e., high ion concentration) was removed, the aggregation was lowered, and digestion was energized.  
On the other hand, lutein's digestive stability was improved once it was encapsulated in NPs [264]. The size of egg albumin (Alb)-FA nanocomplexes made by mixing egg Alb NPs with FA was not altered when the pH was changed from 3 to 4, but it increased significantly when the pH was adjusted to 5, 6 or 7. Notwithstanding this, the bioavailability of FA in the form of digestion process nanocomplexes for Lactobacillus rhamns was improved.  
Negatively charged (41 mV) sophorolipid-coated curcumin NPs with a particle size of 61 nm and high EE and loading capability for the amorphous form had 2.7-3.6-fold greater efficacy than curcumin in amorphous form-free curcumin crystals, which was primarily due to their higher nutrient digestibility [265]. In a system designed to simulate GI media, protein-lipid composite NPs with a three-layered structure and an inner aqueous compartment for loading the hydrophilic nutritional supplement vitamin B12 demonstrated controlled release actions. In in vivo tests, the NPs loaded with vitamin B12 led to excessive vitamin B12 levels in rats and lowered methylmalonic serum concentrations more effectively than in the control group. These NPs could be employed to improve vitamin B12 absorption when taken orally [266].  
[PERSON] et al. [267] showed improved physicochemical stability and in vitro bioavailability of vitamin D3 in maize protein hydrolysate-based vitamin D3 nanocomplexes with spherical structure and diameters of 102-121 nm. The nanocomplexation offered prominent safeguards and lowered vitamin D losses during pasteurization and also under many various sets of processing conditions in vitamin D-potato protein co-assemblies, implying that potato protein could be used as a protective barrier for carrying hydrophobic nutritional supplements adequate for the enhancement of clear beverages and other food or drink products with health-promoting properties [268].