J. Cruz-Olivares

Establishing the Most Suitable Storage Conditions for Microencapsulated Allspice Essential Oil Entrapped in Blended Biopolymers Matrices

The adsorption isotherms of allspice essential oil microencapsulated in biopolymers blend (whey protein concentrate [WPC], mesquite gum [MG], and maltodextrin DE10 [MD]) in different proportions (WPC17%-MG17%-MD66% w/w and WPC66%-MG17%-MD17% w/w) with wall-to-core material ratios of 4:1 were determined at 25, 35, and 40°C. The isotherms were fitted using the Guggenheim-Anderson-de Boer (GAB) model and the enthalpies and entropies, both differential and integral, were estimated by the Clausius-Clapeyron method. The minimum integral entropy was considered as the point of maximum stability where strong bonds between the adsorbate and adsorbent occurred, and water would be less available and likely to participate in spoilage reactions. The point of maximum stability was found between 13.79 and 15.11 kg H2O/100 kg d.s. (corresponding to water activity, a W , of 0.444–0.551) for the microcapsules with WPC17%-MG17%-MD66% w/w as wall material and 18.71–19.63 kg H2O/100 kg d.s. (a W = 0.591–0.713) for the microcapsules with WPC66%-MG17%-MD17% w/w as wall material in the temperature range studied.

Inside the removal of lead(II) from aqueous solutions by De-Oiled Allspice Husk in batch and continuous processes

A new adsorbent material for removing lead ions from aqueous solutions has been investigated. The residue of the allspice extraction process (De-Oiled Allspice Husk) was used on the removal of Pb(II) from water solutions. The lead sorption capacity of De-Olied Allspice Husk (DOAH) was studied in batch and continuous processes. It was found that percentage removals of Pb(II) depend on the pH and the initial lead concentrations. The Pb(II) uptake process was maximum at pH 5 in a range concentrations of 5-25 mg L(-1). The overall sorption process was well described by the pseudo-second-order kinetic model under conditions of pH 5 (0.1 g adsorbent per 100 mL of contaminated solution) 0.001 mass/volume ratio and 25 degrees C. The sorption capacity of lead(II) onto DOAH in batch process was 5.00, 8.02, 11.59, 15.23 and 20.07 mg g(-1), when the concentration solutions were 5, 10, 15, 20 and 25 mg L(-1) respectively. These values are lower than obtained in continuous process, where lead was removed by 95% and the experimental results were appropriately fitted by the Yoon-Nelson model. X-ray photoelectron spectroscopy (XPS) provides information regarding the interactions between lead ions and the adsorbent surface indicating that the formation of 2 complexes depends on the functional groups associated.

Microencapsulation by spray drying of lemon essential oil: Evaluation of mixtures of mesquite gum–nopal mucilage as new wall materials

Abstract Mesquite gum (MG) and nopal mucilage (NM) mixtures were used for microencapsulation of lemon essential oil (LEO) by spray drying. Emulsions of MG, NM and MG–NM mixtures (25–75, 50–50, 75–25) were evaluated according to the droplet size (1.49–9.16 μm), viscosity and zeta potential (−16.07 to −20.13 mV), and microcapsules were characterised in particle size (11.9–44.4 μm), morphology, volatile oil retention (VOR) (45.9–74.4%), encapsulation efficiency (EE) (70.9–90.6%), oxidative stability and thermal analysis. The higher concentration of MG led to smaller droplet sizes and lower viscosity in the emulsions, and smaller particle sizes with the highest VOR in microcapsules. The higher concentration of NM induced to higher viscosity in the emulsions, and larger particle sizes with the highest values of EE and oxidative stability in microcapsules. This work shows evidence that MG–NM mixtures can have synergic effect in desirable characteristics such as retention and shelf life extension of LEO in microcapsules.

Ozonation of Indigo Carmine Enhanced by Fe/Pimenta dioica L. Merrill Particles

Green synthesis of metallic particles has become an economic way to improve and protect the environment by decreasing the use of toxic chemicals and eliminating dyes. The synthesis of metal particles is gaining more importance due to its simplicity, rapid rate of synthesis of particles, and environmentally friendly. The present work aims to report a novel and environmentally friendly method for the synthesis of iron particles using deoiled Pimenta dioica L. Merrill husk as support. The indigo carmine removal efficiency by ozonation and catalyzed ozonation is also presented. Synthesized materials were characterized by N2 physisorption and scanning electron microscopy (SEM/EDS). By UV-Vis spectrophotometry the removal efficiency of indigo carmine was found to be nearly 100% after only 20 minutes of treatment under pH 3 and with a catalyst loading of 1000 mgL−1. Analytical techniques such as determination of the total organic carbon content (TOC) and chemical oxygen demand (COD) showed that iron particles supported on deoiled Pimenta dioica L. Merrill husk can be efficiently employed to degrade indigo carmine and achieved a partial mineralization (conversion to CO2 and H2O) of the molecule. From the results can be inferred that the prepared biocomposite increases the hydroxyl radicals generation.

Rheological properties of tamarind (Tamarindus indica L.) seed mucilage obtained by spray-drying as a novel source of hydrocolloid

Tamarind seed mucilage (TSM) was extracted and obtained by spray drying. The power law model well described the rheological behavior of the TSM dispersions with determination coefficients R2 higher than 0.93. According to power law model, non-Newtonian shear thinning behavior was observed at all concentrations (0.5%, 1%, 1.5% and 2%) and temperatures (25, 30, 40, and 60°C) studied. Increasing temperature decreased the viscosity and increased the flow behavior index, opposite effect was observed when increasing the concentration. The temperature effect was more pronounced at 2.0% TSM concentration with an activation energy of 20.25kJ/mol. A clear dependence of viscosity on pH was observed, as pH increased from acidic to alkaline conditions, the viscosity increased. It was found that the rheological properties of TSM were affected by the sucrose and salts and their concentrations as well due to the addition of ions (or sucrose) decreases repulsion and allows molecule expansion promoting a significant reduction in viscosity. These results suggest that TMS could be applied in the production of foods that require additives with thickening capacity.

Pb(II) Removal Process in a Packed Column System with Xanthation-Modified Deoiled Allspice Husk

The present research dealt with lead removal using modified Pimenta dioica L. Merrill as biosorbent in a batch and in continuous flow column systems, respectively. The allspice husk residues were modified first with a treatment through the xanthation reaction. For the adsorption tests, the atomic adsorption spectrophotometry method was used to determine the lead concentrations in the liquid samples. In the kinetic batch study (10 mg of sorbent in 10 mL of 25 mg L−1 lead solution), the removal efficiency was 99% (adsorption capacity of 25.8 mg g−1). The kinetic data followed the pseudo-second-order model. The adsorption isotherm was fitted to the Freundlich model, where constants were and (8.06 mg  g−1 L and 0.52), corresponding to adsorption capacities of 8 and 62 mg g−1, at liquid equilibrium concentration of 1 and 50 mg L−1, respectively. In the continuous flow systems where lead solution of 50 mg L−1 was treated in 2 columns of 5 cm (4.45 g) and 10 cm (9.07 g) bed heights, the dynamic adsorption capacity obtained by fitting the Thomas model was 29.114 mg g−1 and 45.322 mg g−1, respectively.

Supercritical Extraction Process of Allspice Essential Oil

Allspice essential oil was extracted with supercritical carbon dioxide (SC-CO2) in a static process at three different temperatures (308.15, 313.15, and 318.15 K) and four levels of pressure (100, 200, 300, and 360 bar). The amount of oil extracted was measured at intervals of 1, 2, 3, 4, 5, and 6 h; the most extraction yield reached was of 68.47% at 318.15 K, 360 bar, and 6 h of contact time. In this supercritical extraction process, the distribution coefficient ( ), the mean effective diffusion coefficient ( ), the energy of activation ( ), the thermodynamic properties ( , , and ), and the apparent solubility ( ) expressed as mass fraction (w/w) were evaluated for the first time. At the equilibrium the experimental apparent solubility data were successfully correlated with the modified Chrastil equation.

Adsorption of Lead Ions from Aqueous Solutions Using Gamma Irradiated Minerals

For the first time, an irradiated mineral was used as a novel modified adsorbent for lead removal of aqueous solutions. The effects of gamma radiation doses and temperature on the lead adsorption capacity of an unknown mineral were evaluated. The results show that, in the chemisorption process, the highest adsorption capacity (9.91 mg/g) and the maximum percentage of lead removal (99.1%) were reached at 40°C when using an irradiated mineral at 150 kGy. The improvement on the lead adsorption speed was the most important feature of the irradiated mineral. The experimental results were successfully correlated with the pseudo second-order kinetic model. For all results, the average absolute relative deviations (AARD) were less than 13.20%, and the correlation factor ( ) was higher than 0.998. Moreover, the average values of the thermodynamic parameters (  J/mol,  J/mol, and  J/mol K) suggest the feasibility of the proposed process, in terms of the endothermic and irreversible chemisorption results; moreover, ion exchange was evaluated through the EDS results. The X-ray diffraction analysis showed that the unknown irradiated mineral is mainly composed of quartz (SiO2), calcite (CaCO3), and calcium magnesium silicate (Ca0.15Mg0.85) Mg (SiO6).