Analysis of thermal and aqueous suspension stabilities of chitosan based nanoencapsulated vitamins

Abstract

publicado na web em 15/07/2016The food nutritional content is reduced as result of vitamins degradation. In order to minimize such losses, the encapsulation technique into polymeric nanoparticles (NPs) could offer an additional protection, extending the stability. The crosslinking formed by the ionic gelation process of chitosan and tripolyphosphate (Chi-TPP) has been widely used as an encapsulating matrix for several chemical compounds. In this way, Chi-TPP was used for encapsulation of C, B9 and B12 vitamins. The stability of the vitamins in NPs was evaluated in aqueous suspension by UV-Visible spectroscopy under different conditions: stored in dark, light exposure and effect of oxygen bubbling. The results indicated that encapsulation had a positive effect in preserving the vitamins, mainly vitamin C. The encapsulation preserved 47% of the initial concentration of vitamin C by the tenth day and around 28% after 17 days. Conversely, in non-encapsulated controls (neutral and acidic medium) the losses were higher, reaching 13% by the tenth day and almost 3% after 17 days of storage in both medium. When exposed to light and O 2 the protection provided by the encapsulation was even greater. By thermogravimetric analysis, the pure and the encapsulated vitamins showed distinct thermal behavior confirming Chi-TPP as a potential encapsulation material.

Vitamin B12 on Graphene for Highly Efficient CO2 Electroreduction

“…The atomic composition of VitB 12 shows the presence of C, O, N, Co, and P (Figure S1, Table 1). Considering the possible denaturation of VitB 12 at 60 °C overnight, 23 XPS analysis on VitB 12 before and after heat treatment was performed (Figure S2). The survey spectra and Co 2p, N 1s, and P 2p spectra remained nearly unchanged, indicating the stability of VitB 12 after drying.…”

Shelter for Biologically Relevant Molecules: Photoprotection and Enhanced Thermal Stability of Folic Acid Loaded in a ZIF-8 MOF Porous Host

“…Evidence of the enhancement of PteGlu thermal stability caused by confinement constitutes a desirable feature having in mind the requirements of potential applications, involving exposure to high temperatures ( e.g ., sterilization procedures or food processing). Although such a thermal protection effect was already observed for other edible biocompatible hosts, the use of ZIF-8 MOF allows enhanced maximum temperature limits and higher loadings (10% w/w). ,− Another interesting feature of the encapsulation of PteGlu on PteGlu@ZIF-8 is the photoprotection effect, which provokes a remarkable increase in stability toward irradiation with UV-A sources compared to free PteGlu (up to 80% increase). Although some radiation loss due to scattering must be considered; based on photosensitization experiments carried out with the addition of Fop, we hypothesize that the photoprotection mechanism involves a separation of PteGlu and whatever trace Fop amounts produced in the early stages of the irradiation process, which although difficult to detect can greatly accelerate the autocatalytic degradation process.…”