RESUMEN
The coconut residual fiber (CRF) is the major byproduct obtained during production of virgin coconut oil. Its application as a biosorbent for adsorption of Congo red was investigated. The CRF was subjected to different pretreatments, namely, pressure cooking, hexane treatment, acid treatment and their combinations. The pretreatment of CRF with the combination of hexane, acid, and pressure cooking resulted in the highest degree of adsorption. The equilibrium data were analyzed and found to fit best to both Langmuir and Freundlich isotherms. Thermodynamic parameters such as standard free energy (ΔG0 kJ mol-1), standard enthalpy (ΔH0, kJ mol-1) and standard entropy (ΔS0, kJ mol-1 K-1) of the systems were calculated by using the Langmuir constant. The ΔG0, ΔH0 and ΔS0 were found to be 16.51 kJ mol-1, -19.39 kJ mol-1 and -0.12 kJ mol-1 K-1, respectively, at 300 K. These thermodynamic parameters suggest the present adsorption process to be non-spontaneous and exothermic. The adsorption process was observed to follow pseudo-second-order kinetics. The results suggest that CRF has potential to be a biosorbent for the removal of hazardous material (Congo red dye) with a maximum adsorption capacity of 128.94 mg g-1 at 300 K.
Asunto(s)
Cocos/química , Rojo Congo/química , Contaminantes Químicos del Agua/química , Purificación del Agua/economía , Purificación del Agua/métodos , Agua/química , Adsorción , Colorantes/química , Cinética , TermodinámicaRESUMEN
Reverse micellar extraction (RME) was used for the separation and purification of bromelain from pineapple core and efficacy of RME purified bromelain (RMEB) in tenderization of beef meat was compared with that of commercial stem bromelain (CSB). RME resulted in reasonably high bromelain activity recovery (85.0 %) and purification fold (4.0). Reduction in meat toughness was higher in RMEB treated meat (52.1 %) compared to raw (control) and CSB treated (26.7 %). Significant increase in water holding capacity (WHC) was observed in RMEB treated meat (91.1 %) as against CSB treated (55.6 %) and control (56.6 %). No change in cooking loss was observed in RMEB treated meat, whereas the loss increased by nearly 14.0 % in case of CSB treated. While the meat color was retained, trichloroacetic acid (TCA) soluble protein content increased due to hydrolysis of protein in RMEB treated meat. Scanning electron microscopy (SEM) analysis revealed that RMEB treatment completely ruptures myofibril tissues, indicating a higher degree of tenderization.
RESUMEN
In the current study, reverse micellar extraction (RME) for the purification of stem bromelain was successfully achieved using the sodium bis(2-ethylhexyl) sulfosuccinate (AOT)/isooctane system. A maximum forward extraction efficiency of 58.0% was obtained at 100 mM AOT concentration, aqueous phase pH of 8.0 and 0.2 M NaCl. Back extraction studies on altering stripping phase pH and KCl concentration, addition of counter-ion and iso-propyl alcohol (IPA) and mechanical agitation with glass beads indicated that IPA addition and agitation with glass beads have significant effects on extraction efficiency. The protein extraction was higher (51.9%) in case of the IPA (10% v/v) added system during back extraction as compared to a cetyltrimethylammonium bromide (100 mM) added system (9.42%). The central composite design technique was used to optimize the back extraction conditions further. Concentration of IPA, amount of glass beads, mixing time, and agitation speed (in rpm) were the variables selected. IPA concentration of 8.5% (v/v), glass bead concentration of 0.6 (w/v), and mixing time of 45 min at 400 rpm resulted in higher back extraction efficiency of 45.6% and activity recovery of 88.8% with purification of 3.04-fold. The study indicated that mechanical agitation using glass beads could be used for destabilizing the reverse micelles and release of bromelain back into the fresh aqueous phase.