Magnetic graphene oxide, a suitable support in ficin immobilization

In the present study, we aimed to develop a fast, non-toxic ultrasonic-assisted technique for the preparation of graphene oxide (GO) and GO that were accessorized with Fe3O4 (GO-Fe3O4) for enzyme immobilization. The structural properties of nanosheets were determined by FTIR, XRD, and SEM. Immobilized enzymes on the GO-Fe3O4 and GO were counted. Enzyme activity, reusability, and improvements in enzyme stability were studied. According to the results, the immobilization efficiency was 256.86 mg ficin/GO (g), and 253.63 mg ficin/GO-Fe3O4 (g). Furthermore, immobilized ficin was affected in terms of stability by variations in pH and temperature. The immobilized ficin on the GO-Fe3O4 could be easily recycled from the reaction medium by applying external magnetic separation, involving 10 cycles for 120 days. Over this period and with this number of cycles, the immobilized enzyme on the GO-Fe3O4 retained 74% of its original activity, whereas the immobilized enzyme on the GO was recycled from the reaction medium after centrifuging, thereby retaining 70% of its original activity. Thus, GO and GO-Fe3O4 nanosheets were obtained efficiently from the ultrasonic-assisted technique and can be regarded as excellent nanocarriers for enzyme immobilization

Refractance Window drying of pomegranate juice: Quality retention and energy efficiency

Refractance Window (RW) drying system utilizes circulating hot water as a means to carry thermal energy to materials to be dehydrated. Products are spread on a transparent plastic conveyer belt that moves over circulating water in a shallow trough. In this study the quality retention characteristics of pomegranate juice (PJ) concentrate dried in a continuous pilot scale RW drying system were evaluated against freeze drying and spray drying methods. Samples of PJ concentrate (Brix 64) mixed with Gum Arabic as a carrier (35%, dry basis) were dried by the RW drying, freeze drying and spray drying methods. Physicochemical properties including moisture content, solubility, bulk density and color parameters of samples dried using different methods were compared. Chemical analysis and color measurements of reconstituted samples showed that RW dryer can produce high-quality products with anthocyanins content, anthocyanins color and antioxidant activity equal or greater than those of the freeze dried and spray dried samples. Energy consumption of the RW dryer was about one third and 1/40 of those of spray drying and freeze drying systems, respectively

Effect of Heat Carrier Particles on Drying Characteristics and Germination Traits of Canola Seeds

Purpose Research into hybrid drying methods is generally aimed at increasing drying speed while maintaining seed quality. Heat Carrier Particles (HCPs) can be used in fluidized bed drying to accelerate the seed drying process. However, this requires qualitative analysis of seed characteristics.Methods In this study, canola seed was mixed with HCPs to accelerate the drying process while maintaining seed quality. The HCPs were steel or glass beads (2.7 mm diameter) mixed with canola seed in proportions of 0%, 25%, 50%, and 100% at different drying temperatures (40, 50, and 60 degrees C). A fluidized bed dryer was used to monitor the drying process and then the germination ability of the dried seeds was evaluated in the experimental conditions.Results The drying time was reduced when the HCP content was 50% of the sample weight. However, drying time increased when 100% HCP was added. Also, the germination ability of the seeds decreased as the drying temperature increased. A higher proportion of steel beads caused a decrease in germination, while the glass heat carrier (50% at 40 degrees C) was best for maintaining germination in canola seeds.Conclusions The germination rate, shoot length vigor index, root length vigor index, and germination energy were significantly affected by the amount of HCP and the drying temperature. The germination parameters were highest when glass HCP was used, and the drying time was also reduced to an acceptable level in this treatment. The most suitable temperature and percentage of HCP were 40 degrees C and 25% of glass HCP in sample weight, respectively

A New Study on the Steady Shear Flow, Thermal and Functional Properties of Beet Pulp Carboxymethyl Cellulose

The current work presents a study of rheological, thermal and functional properties of carboxymethyl cellulose (CMC) produced from beet pulp compared with commercial CMC primarily at low-solid concentrations. Differential scanning calorimetry (DSC) results demonstrated two endothermic peaks around 104, 173C and two exothermic peaks at 307 and 361C. The flow properties of produced CMC were performed under steady shear at different pH and salt (NaCl) contents using Power law equation. Changes in the viscosity were observed depending on the type and concentration of hydrocolloid. Apparent viscosity of CMC samples decreased at acidic and alkaline pH solutions and at the presence of salt, because of the reduction in carboxylate repulsion of the CMC backbone. Furthermore, the effect of produced CMC on rheological and serum loss of ketchup was investigated. The data showed promising outcomes for the addition of beet pulp CMC in ketchup formulation with a decrease in serum separation during storage time

Drying of green bell pepper slices using an IR-assisted Spouted Bed Dryer: An assessment of drying kinetics and energy consumption

In the current investigation, an IR-assisted spouted bed dryer containing inert aluminum particles was employed for drying of Green Bell Pepper Slices (GBPS). In order to evaluate the dryer's performance, a completely randomized factorial design with three independent factors including drying temperature (50, 60, and 70 °C), mass percentage of inert particles to GBPS (0, 25, and 50%), and surface area of GBPS (1.44, 3.24, and 7.84 cm2) were used. According to findings, by using the inert particles with mass percentage of 25%, a reduction of around 25% in drying time was realized. However, increasing in the ratio to 50%, an increasing the drying time (56%) was noted. An optimum drying condition in terms of specific energy consumption (SEC) was achieved at an air temperature of 70 °C, 25% inert material and GBPS with a surface area of 1.44 cm2. Moreover, a dimensionless model for describing the drying kinetics of GBPS was established and evaluated60sem informaçãosem informaçã

Production and properties of tragacanthin-conjugated lysozyme as a new multifunctional biopolymer

In this communication we describe preparation and characterization of an enzyme-biopolymer conjugate composed of water-soluble part of gum tragacanth and chicken egg white lysozyme (LZM) under mild Maillard reaction conditions. SDS-PAGE together with FT-IR spectroscopy revealed that Maillard reactions occurred between LZM and tragacanthin (TRG). Under optimum conditions (pH = 8.5, 60 degrees C, RH = 79%, 8 days), approximately 2 TRG molecules were attached to one LZM molecule. DSC analysis showed that conjugation with TRG increased denaturation temperature by 6.35 degrees C. The resulting conjugates were characterized using scanning electron microscopy. The modified enzyme activity retained 77% of the original enzymatic activity after 8 days. TRG-conjugated LZM exhibited improved solubility and emulsion properties as compared with the native LZM. In addition, a significant increase in foam capacity and stability of LZM-TRG conjugate was detected. Conjugate with TRG significantly improved the inhibitory effect of LZM on the growth of Staphylococcus aureus, Bacillus cereus, Escherichia coli and Salmonella typhi in a dose dependent manner such that at 4000 mu g/ml, LZM-TRG conjugate inhibited S. aureus, Bacillus cereus, Escherichia coli and Salmonella typhi by 90%, 80%, 50% and 40%, respectively. Taken together these results suggest that the functional properties and antimicrobial activities of LZM can be improved by conjugation with TRG. The conjugation might expand the applications of LZM as a multifunctional ingredient in food and pharmaceutical industries

Effect of different processing stages of commercial fruit leather on patulin reduction

Fruit leather (Lavashak) is a high consumption food product especially among children in Iran. This product is being manufactured by low quality fruits that usually are contaminated with molds and patulin mycotoxin.  The objective of this study was to determine the effect of industrial processing stages of leather production (including pre-heating, filtration, evaporation, formulation and final heat boiling and drying) on reduction of patulin level. Samples were taken for analysis prior and following each processing steps and patulin level was determined using HPLC technique. The results indicated that the maximum reduction of patulin level was ooccurred during formulation and evaporation steps which was estimated at 24.60 and 18.20%, respectively. Meanwhilewhile after drying, filtration, and pre-heating processes, the main loss of patulin was 8.58, 3.82 and 2.48%, respectively. It was concluded that the amount of residual patulin in final product was higher than 40% of its primary concentration. Besides, various processing stages were found insufficient to eliminate all of patulin or to reduce its level to lower than the maximum acceptable limit