Light is another factor that affects the color stability of C3G. The effect of light on encapsulated and non-encapsulated C3G within maltodextrin and chitosan was investigated. The encapsulated powders were stored in dark and light conditions for 15 days, and then their light stability was assessed using UV and IR spectroscopic methods. Data showed that maltodextrin and chitosan can increase the light stability of C3G because the encapsulated polymeric matrices protect the C3G by inhibiting oxidation, which may explain why non-encapsulated C3G degraded more quickly than encapsulated C3G
. In comparison to non-encapsulated C3G samples, the half-life of all encapsulated C3G samples increased during storage
The pH is a significant additional factor that affects the stability of C3G. Anthocyanin nanoparticles are pH-sensitive in vitro, as demonstrated by Sun et al.’s research, which showed that, in comparison to pH 6.8 and pH 7.4, C3G encapsulated with chitosan nanoparticles at pH 5.3 demonstrated the greatest release ratio
[25]. According to the observation of a few in vitro studies, at a pH of around 3 or lower, the anthocyanin is orange or red and exists as a flavylium cation
[58]. The hydration process of the flavylium cation and the proton transfer reactions linked to the acidic hydroxyl groups of the aglycone compete kinetically and thermodynamically when the pH is raised. While the initial reaction produces an inert carbinol pseudo-base that can undergo ring opening to become a chalcone pseudo-base, the second reaction can produce quinonoidal bases at pH levels between 6 and 7 with the generation of purple, resonance-stabilized quinonoid anions
[58]. As a result of pH-dependent equilibrium forms, they may exhibit different colors in aqueous solutions: at very acidic pH, anthocyanin are primarily in their red cationic form (AH+), but as pH increases, the flavylium cation immediately undergoes deprotonation to give rise to quinoidal bases (A), and at the same time, but more slowly, it may hydrate to form colorless hemiketal species (B2), which then quickly tautomerize to yield cis-chalcone. The species in question might then isomerize into trans-chalcone
[61].
8. Uses of the Encapsulated Cyanidin 3-O-Glucoside
Numerous studies have demonstrated that C3G-encapsulated nanoparticles have strong encapsulation efficiency as well as the potential to further enhance and provide a framework for the investigation of C3G nanoparticle applications in functional foods
[55][62][63]. Converging research has recently shown that the natural pigment C3G has an impact on several physiological processes, including inflammation, cardiovascular disease, cancer, antioxidant activity, and antidiabetic effects
[64]. C3G is widely used as a food additive because of its appealing hue and advantageous bioactivity, which enhances both food color and health functions
[27]. C3G could possess the ability to scavenge free radicals, which might stop the oxidation of low-density lipoproteins and have a good impact on obesity, inflammation, and chronic gut inflammatory disorders
[65]. According to a number of studies, C3G prevents the negative effects of UV-B radiation, regulates important components of carcinogenesis, stops cancer cells from proliferating, and triggers the death of cancer cells, decreases oxidative stress, prevents oxidative stress brought on by H
2O
2 in human embryonic kidney (HEK 293) cells, triggers cell death, and prevents cell migration in TNF-α-challenged RASMCs in vitro
[65].
C3G was shown to inhibit UVB-induced apoptosis in human HaCaT keratinocytes
[29]. In vivo, C3G can guard against UVB-induced epidermal deterioration. However, the therapeutic use of C3G and its industrial applications as functional food components has been constrained by how quickly it degrades. Nowadays, polymeric nanoparticles are currently playing a crucial role in the advancement of therapeutic and calleidic systems in the new wave of the development of cosmetic or pharmaceutical dosage forms due to their capacity for regulating drug release and enhancing the stability of pharmaceuticals
[29]. The nano-C3G encapsulation within chitosan according to the animal experiment showed that nano-C3G could efficiently lower the levels of lipid peroxidation, malondialdehyde, and 8-hydroxy-2′-deoxyguanosine caused by UVB exposure, as well as downregulate the expression of p53, Bcl-2-associated X (Bax), caspase-3 and -9, and balance the B-cell lymphoma-2/leukemia-2 ratio
[29]. Liang et al. investigated the effect of C3G encapsulated with liposomes on normal GES-1 cells by evaluating cell viability and mitochondrial structure. The primary cell line in the human stomach is the human gastric epithelial cell line (GES-1 cells), and the health of the stomach is crucial for body health since it is the primary organ through which many biochemical interactions occur
[66].
9. Conclusions
Anthocyanin C3G is a secondary metabolite naturally present in herbal origin sources. It exerts tremendous health benefits, including regulation of cholesterol, antioxidant, anti-inflammatory, hepatoprotective, anticancer, anti-obesity, and antidiabetic effects. The recovery of C3G is influenced by many factors, such as extraction techniques, extraction conditions, and raw materials. Likewise, C3G is sensitive to many factors and its stability is affected by pH, light, temperature, and storage time. The nanoencapsulation improves the stability and bioavailability of C3G. Most nanocarriers used for its nanoencapsulation are proteins, polysaccharides, polymeric micelles, and phospholipid-based materials. Furthermore, the encapsulation techniques are also determinant factors that influence the production yield and availability of C3G. C3G is used as a food additive and colorant, as well as for therapeutic purposes.