Giovani L. Zabot

Ultrasound-assisted encapsulation of annatto seed oil: Retention and release of a bioactive compound with functional activities

This paper brings forward the encapsulation of annatto seed oil (rich in geranylgeraniol) assisted by high intensity ultrasound using gum Arabic (GA) as stabilizing agent. We studied the effects of time (min) and ultrasonication power (W) over the emulsion characteristics. After forming microparticles from the best emulsion using freeze-drying (FD) and spray-drying (SD) techniques, we evaluated particle size distribution, moisture, water activity, surface oil, entrapment efficiency, encapsulation efficiency, geranylgeraniol retention, oxidative stability and kinetic release of geranylgeraniol, a biocompound with functional activities. The combined intensification of time and ultrasonication power reduced the superficial mean diameter (D32) and polydispersity (PDI) of emulsions. Drying the continuous phase of the optimized emulsion (smallest D32=0.69±0.03μm) using FD and SD formed microparticles with different morphological characteristics, Brouckere diameter (D43), particle size distribution, moisture and water activity. SD process led to microparticles with the highest oil encapsulation efficiency (85.1±0.1wt.%) as a consequence of their lowest surface oil (SO). However, GA-FD microparticles presented the highest oil entrapment efficiency (97±1wt.%). Geranylgeraniol retention (80-86wt.%) was similar for both drying techniques. GA-FD microparticles were more stable against oxidation through accelerated test Rancimat, even though presenting higher SO. This behavior is associated with the likely phase transition on the GA-SD matrix. The difference on the kinetic release of geranylgeraniol is linked to the difference on the particles morphology and particle size distribution.

Biopolymer-prebiotic carbohydrate blends and their effects on the retention of bioactive compounds and maintenance of antioxidant activity

The objective of this study was to evaluate the use of inulin (IN), a prebiotic carbohydrate without superficial activity, as an encapsulating matrix of lipophilic bioactive compounds. For achieving the encapsulation, IN was associated with biopolymers that present superficial activity: modified starch (HiCap), whey protein isolate (WPI) and gum acacia (GA). Encapsulation was performed through emulsification assisted by ultrasound followed by freeze-drying (FD) process to dry the emulsions. All blends retained geranylgeraniol. GA-IN blend yielded the highest geranylgeraniol retention (96±2wt.%) and entrapment efficiency (94±3wt.%), whilst WPI-IN blend yielded the highest encapsulation efficiency (88±2wt.%). After encapsulation, composition of geranylgeraniol in the annatto seed oil was maintained (23.0±0.5g/100g of oil). Such findings indicate that the method of encapsulation preserved the active compound. All blends were also effective for maintaining the antioxidant activity of the oil through ORAC and DPPH analyses.

Replacing modified starch by inulin as prebiotic encapsulant matrix of lipophilic bioactive compounds

The purpose of this work was to replace modified starch (SF) by inulin (IN), a prebiotic carbohydrate, during emulsification assisted by ultrasound. Oregano extract was encapsulated using five proportions of IN and SF as wall materials. The effect of such substitution on the microparticle characteristics was evaluated. Attempting to contribute with the increasing demand for prebiotic consumption, mixing one part of SF with three parts of IN (1:3, mass basis) yielded encapsulation efficiency equal to 66±1% and the largest thymol retention: 84±9%. Besides the entrapment of thymol, high amount of other compounds present in oregano extract could be entrapped in the polymeric matrix: 92±1%. Reduction of the microparticles sizes when increasing the proportion of inulin was also observed. Comprising such results and those presented for powder morphology, surface extract, particle size distribution, X-ray diffraction and thermal stability, the proportion 1:3 (SF:3IN) is a favorable prebiotic encapsulant matrix for encapsulating oregano extract and retaining target bioactive compounds.

Microencapsulation of lipophilic bioactive compounds using prebiotic carbohydrates: Effect of the degree of inulin polymerization

This paper presents novel outcomes about the effect of degree of inulin polymerization (DP) on the technological properties of annatto seed oil powder obtained by freeze-drying. Inulins with two DPs were evaluated: GR-inulin (DP≥10) and HP-inulin (DP≥23). Micrographs obtained by confocal microscopy were analyzed to confirm the encapsulation of bioactive compounds using both inulins, especially the encapsulation of the natural fluorescent substance δ-tocotrienol. Microparticles formed with both inulins presented the same capacity for geranylgeraniol retention (77%). Glass transitions of microparticles formed with GR-inulin and HP-inulin succeeded at 144°C and 169°C, respectively. Regarding water adsorption isotherms, microparticles formed with HP-inulin and GR-inulin presented behaviors of Types II (sigmoidal) and III (non-sigmoidal), respectively. Reduction of water adsorption capacity in the matrix at high relative moistures (>70%) was presented when HP-inulin was used. At low relative moistures (<30%), the opposite behavior was observed.

Mathematical modeling of Kluyveromyces marxianus growth in solid-state fermentation using a packed-bed bioreactor.

This work investigated the growth of Kluyveromyces marxianus NRRL Y-7571 in solid-state fermentation in a medium composed of sugarcane bagasse, molasses, corn steep liquor and soybean meal within a packed-bed bioreactor. Seven experimental runs were carried out to evaluate the effects of flow rate and inlet air temperature on the following microbial rates: cell mass production, total reducing sugar and oxygen consumption, carbon dioxide and ethanol production, metabolic heat and water generation. A mathematical model based on an artificial neural network was developed to predict the above-mentioned microbial rates as a function of the fermentation time, initial total reducing sugar concentration, inlet and outlet air temperatures. The results showed that the microbial rates were temperature dependent for the range 27–50°C. The proposed model efficiently predicted the microbial rates, indicating that the neural network approach could be used to simulate the microbial growth in SSF.

Fast analysis of phenolic terpenes by high-performance liquid chromatography using a fused-core column

A fused-core column was used to develop a fast and efficient analytical method for separating phenolic terpenes by high-performance liquid chromatography. The main chromatographic parameters, such as the composition of the mobile phase (mixtures of water and acetonitrile), the flow rate of the mobile phase (1.0–2.5 mL min−1), the column temperature (30–55 °C) and re-equilibration time after each injection (1–5 min) were studied and optimized during the development of the method. Using the current method, the major nonvolatile compounds from rosemary [rosmarinic acid (RA), rosmanol (RO), carnosol (CN), carnosic acid (CA) and methyl carnosate (MC)] could be separated in 4.7 min. The total time of analysis was 10 min, including the column cleanup and the re-equilibration period. The effect of the sample solvent was also studied. The combined influence of the injection volume and sample dilution on the performance of the chromatographic method was evaluated. The method was validated with several commercial samples, enabling the detection of low amounts (0.25 μg mL−1) of CA and RA. The chromatographic profile showed excellent repeatability (intraday) and reproducibility (interday). Furthermore, the peak separation was good when using ethanol for sample dilution with respect to resolution (2.1, 3.7, 6.4, 10.6 and 21.7 for RO, MC, RA, CA and CN, respectively), selectivity (1.0 for MC; 1.1 for RO and CA; 1.3 for CN; and 1.5 for RA) and peak symmetry (1.0 for RA, CN and MC; 1.1 for CA; and 1.2 for RO).

Hybrid modeling of xanthan gum bioproduction in batch bioreactor

This work is focused on hybrid modeling of xanthan gum bioproduction process by Xanthomonas campestris pv. mangiferaeindicae. Experiments were carried out to evaluate the effects of stirred speed and superficial gas velocity on the kinetics of cell growth, lactose consumption and xanthan gum production in a batch bioreactor using cheese whey as substrate. A hybrid model was employed to simulate the bio-process making use of an artificial neural network (ANN) as a kinetic parameter estimator for the phenomenological model. The hybrid modeling of the process provided a satisfactory fitting quality of the experimental data, since this approach makes possible the incorporation of the effects of operational variables on model parameters. The applicability of the validated model was investigated, using the model as a process simulator to evaluate the effects of initial cell and lactose concentration in the xanthan gum production.

Immobilization of inulinase obtained by solid-state fermentation using spray-drying technology

Abstract This work focuses on the immobilization of a crude inulinase extract obtained by solid-state fermentation using spray-drying technology. Maltodextrin and arabic gum were used as immobilizing agents. The effects of inlet air temperature, maltodextrin/arabic gum ratio and mass fraction of crude enzyme extract on the activity of immobilized inulinase were assessed using a central composite rotatable design (CCRD) (23). The optimum operational conditions for the immobilization of inulinase by spray-drying was obtained at an inlet air temperature of 200°C, mass fraction of crude enzyme extract of 0.5 wt% and using only arabic gum as immobilizing agent. The immobilized enzyme had good thermostability, comparable with other inulinases obtained from different microorganisms. The method used gave good enzyme activity after immobilization and could be applied to other enzymes which have good thermal stability.

Desolventizing of Jatropha curcas oil from azeotropes of solvents using ceramic membranes

ABSTRACT The separation of Jatropha curcas oil from azeotropes of ethyl alcohol–n-hexane and isopropyl alcohol–n-hexane using ceramic membranes with different cutoffs (5, 10 and 20 kDa) is presented. The mass ratios of oil:azeotropes (O:S) studied were 1:3 for feeding pressures of 0.1, 0.2 and 0.3 MPa, and 1:1 for the feeding pressure of 0.1 MPa. Isopropyl alcohol was the best solvent for the membranes conditioning to permeate n-hexane (240 kg/m2 h). In the separation of J. curcas oil and azeotropes of solvents, both membranes showed oil retention and total flux decreases with time. Overall, the lowest decrease in the retentions was reached in the 5 kDa membrane, while the lowest decrease in the total flux was reached in the 20 kDa. In the separation of oil and ethyl alcohol–n-hexane azeotrope, the best retention at 60 min of the process was equal to 17.3 wt% in the 20 kDa membrane at 0.3 MPa and O:S ratio equalled to 1:3. In this condition, the total permeate flux was 17.5 kg/m2 h. Different retentions and permeabilities are provided when changing the O:S ratio, the feeding pressure and the molecular weight cutoff of membranes. GRAPHICAL ABSTRACT

Concentration of metabolites from Phoma sp. using microfiltration membrane for increasing bioherbicidal activity

ABSTRACT This study is focused on the concentration of fermented broth from Phoma sp. to increase its herbicidal activity. For this purpose, biomolecules produced by submerged fermentation using Phoma sp. were concentrated by hollow fiber microfiltration membranes. The membrane feed was separated into two streams (retentate and permeate) and the crude broth was concentrated to 10, 30, 50, 70 and 90% (relative to the initial volume). The retentate samples were submitted to bioassays (triplicate) for evaluating their phytotoxic effects on five young leaves of species of Cucumis sativus and also on pre-emergence of weeds as Bidens pilosa and Amaranthus retroflexus. The highest herbicidal activity was 80.7% obtained for a concentration of 30% in the retentate fraction. At this condition, the bioherbicide presented severe damage symptoms on the detached leaves of Cucumis sativus if compared to the crude fermented broth. In the pre-emergence of B. pilosa and A. retroflexus, 100% control was obtained for assays performed in a germination chamber. For greenhouse assays using the substrate, the control rate of A. retroflexus was dependent of concentration of bioherbicide. The promising results achieved in the research with membrane separation process allow us to propose and develop further studies for evaluating this technology in the concentration of other metabolites produced by fermentation which also have bioherbicidal activity. GRAPHICAL ABSTRACT