RESUMEN
PURPOSE: Various plants, herbal medicines, and marine foodstuffs have been used in kimchi preparation to improve its overall quality. Teff, which is rich in minerals and starches, facilitates stable blood glucose levels and is well-suited for use in gluten-free products; hence, it can be used to reinforce the mineral composition of kimchi. In this study, we probed the antioxidant activities of hydrolysates prepared by treatment of brown teff with three proteases under different conditions. METHODS: The mineral composition of brown teff was determined by inductively coupled plasma spectrophotometry-mass spectrometry, and we established optimal hydrolysis conditions by determining the total phenol and flavonoid contents of teff hydrolysates obtained using three different proteases (protamax, flavourzyme, and alcalase), two different protease concentrations (1 and 3 wt%), and three different incubation times (1, 2, and 4 h). The antioxidant activity of the hydrolysates was further investigated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity, total antioxidant capacity (TAC), and ferrous reducing antioxidant power (FRAP) assays. RESULTS: Brown teff was rich in I, K, Mg, and Ca, and the highest total phenol content (24.16 µg/mL), total flavonoid content (69.08 µg/mL), and TAC were obtained for 1 wt% protamax treatment. However, the highest DPPH scavenging activity and FRAP values were observed for hydrolysates produced by alcalase and flavourzyme treatments, respectively. CONCLUSION: Treatment of brown teff with proteases affords hydrolysates with significantly increased antioxidant activities and high total phenol and flavonoid contents, and these antioxidant activities of teff hydrolysates have the potential to enhance the quality and functionality of kimchi in future applications.
Asunto(s)
Glucemia , Eragrostis , Hidrólisis , Minerales , Mineros , Péptido Hidrolasas , Fenol , Plasma , Análisis Espectral , Almidón , SubtilisinasRESUMEN
Precisely controlling Au plasmonic coupling aggregates is of fundamental importance for tuning spectroscopic characters, and also is an effective way of access to practical devices. In our present study, we report a new type of amphiphilic gold nanoparticles (AuNPs) with the surfaces modified by thermo-responsive polymer brushes via sequential "grafting to" and "grafting from" reactions. This novel AuNPs can spontaneously self-assemble into AuNPs oligomers such as dimmers and trimmers by taking advantage of the molecular chain reorganization of polymer brushes. Interestingly, AuNPs oligomers can be reversibly disassembled into individually isolated AuNPs by changing temperature. These smart, temperature dependent reversible AuNPs oligomers have great potential applications of plasmonic coupling based sensors and optical imaging.