Band 12, Heft 3 -

In this study, different concentrations and types of adsorbents (activated earth, chitin and chitosan) were tested for adsorption of carotenoids, chlorophylls and peroxides in the bleaching of rice bran oil (RBO). The bleaching kinetics showed that using 1 % (w/w) of activated earth for 20 min, there was a suitable reduction in peroxide and pigment contents. The bleaching with 2 % (w/w) of biopolymeric adsorbents promoted to a decrease of around 40 % in the peroxide value. The increased concentration of activated earth led to an increase in the adsorption rate constant, indicating more speed in the bleaching process. The pseudo-second-order model showed best fit to the experimental data in the oil bleaching onto activated earth; however, the pseudo-first-order model was more appropriate to describe the kinetic behavior of adsorption onto chitin and chitosan. The biopolymeric adsorbent has shown to be a potential source for adsorption of metal ions in RBO.

The Brabender Extensigraph is commonly used to measure dough strength by stretching a strand of dough until it tears. Data for extension and force are used to rate flours for strength, baking and processing qualities of doughs. The present study was carried out to examine how dough strength relates to dough sheetability. The latter was measured using an instrumented dough sheeter which provided data for dough thickness and roll-closing forces as a pad of dough was sheeted by passing back and forth through a set of rollers with reducing roll-gaps. Doughs were tested fresh and after 45 min of resting for a range of flours. The correlations between dough strength and dough sheetability were poor at all times. The roll forces were affected by dough thickness at each pass indicating dough elasticity affected dough stretchability. Doughs were found to become more elastic following resting.

Dough extension tests are used in industry to rate flours for dough processability. The results impact flour selection for product use. Previously, it was shown that dough extension data correlated poorly with dough sheetability irrespective of whether doughs were tested fresh or rested. It was noted that sample shapes varied between specimens of flours. To understand how sample shape affects extensigraph tests, a finite element (FE) simulation-based approach was taken. Real extensigraph samples were drawn on a computer equipped with the commercial FE package ABAQUS and using the anisotropic Bergstrom Boyce model with Mullins damage (ABBM) constitutive model to describe the dough’s rheology. Results show that the force–extension traces were affected by sample shape, and that thinning occurs more from the sides than the bulk for slumped samples. The FE predictions for sample shape effects on hook force were validated against real tests. Similar dependencies on sample shape are also predicted for the alveograph and Kieffer micro-extensigraph tests.

Koji preparation is the key step in soy sauce brewing. In this study, 21 medicinal herbs were tested for their abilities in enhancing the protease activities of soy sauce koji . Among these herbs Rhodiola rosea was found to be the most efficient in increasing protease activities. Kinetic analyses revealed that R. rosea addition not only promoted microbe growth and increase the activities of neutral and acid proteases (by 29.8% and 13.4%, respectively) but also elevated α-diphenyl-β-picrylhydrazyl (DPPH) radical scavenging activity and total phenolics and flavonoids (by 9.5%, 47.1% and 14.1%, respectively); the formations of proteases and antioxidant properties depend largely on microbe growth; and the promotion effects of R. rosea addition were mainly displayed in later stage of fermentation. Using the R. rosea koji for soy sauce production resulted in 8.9%, 19.1%, 6.6%, 23% and 102% higher of total and amino-type nitrogen contents, protein utilization, total phenolics and flavonoids, respectively.

Allicin nanocapsules were prepared via ionotropic pre-gelation. The wall materials were alginate-chitosan biopolymers. Nanocapsules were characterized using Fourier transform infrared spectroscopy (FT-IR) and field emission scanning electron microscopy (FE-SEM). We tried to simulate the effects of three different variables on particle size through artificial intelligence approaches. Feedforward neural networks (FFNN) and adaptive neuro-fuzzy inference system (ANFIS) were employed to model the size of allicin nanocapsules, and the latter was found to be relatively more successful in this regard. Finally, genetic algorithms were employed to determine the optimal values for the variables at which the smallest particles were formed.

This study is designed to investigate drying kinetics, heating characteristics and energy consumption of heat pipe-impingement drying (HID) kiwifruit slices. Subsequently, color and rehydration characteristics of dried kiwifruit slices were also studied. The results showed that Modified Page model and trinomial regression equation provided appropriate fit for drying and heating curves of kiwifruit slices, respectively. In addition, the treatment for increasing drying temperatures and air velocities, and decreasing the distance between jet nozzles and material steel wire mesh box (DJM) was shown to enhance drying productivity. It was also found that low temperature, high air velocity and low DJM contributed to the processing of high-quality dried kiwifruit and the reduction of energy consumption. These results suggest that kiwifruit slices can be dried effectively with HID, and the predictive equations of heat and mass transfer could be applied to industrial design and operational guide for the HID of kiwifruit.

In this study, the overall quality characteristics of ice cream powders (drying yield, moisture content, water activity, bulk density, solubility and glass transition temperature) and ice creams made from their corresponding reconstituted powders (overrun, melting behavior) were analyzed. The effect of spray drying conditions such as inlet air temperature (120, 140 and 160 °C) and feed flow rate (1.5, 3 and 4.5 mL/min) and black mulberry juice addition (15, 30 and 45 %) were included in the design. The results showed that, by increasing inlet air temperature water activity, bulk density and overrun were decreased, while solubility and melting rate of reconstituted powders were increased. Generally, mass recovery percentage of ice cream powders was decreased with increase of feed flow rate and juice concentration at the same air inlet temperature due to the stickiness problem and the low glass transition temperature of components. The following optimum process conditions with the desirability of 0.86 were determined: inlet air temperature of 140 °C, feed flow rate of 1.5 mL/min and juice concentration of 30 %.

Egg is a complete food package. Importance and quality of this sealed food package rely on its invulnerability to external contaminants. Therefore, eggshell with no cracks and high resistance against loads during transportation, packaging, and so on is recommended. There are two methods for measurement of shell resistance: destructive and nondestructive methods. Modeling and simulation of eggshell by computer and finite element software (FEM) is one of the nondestructive methods which was used in this study to measure eggshell resistance. ANSYS 10 software was utilized to perform finite element analysis. In destructive testing of 90 hen eggs, the average eggshell rupture force was determined to be 22.7 N at 0.144 mm displacement when applying parallel plate force. Results of the finite element analysis showed that for 0.144 mm displacement, the estimated rupture force was 21.7 N. Results of FE analysis showed that maximum stress and displacement occurred at the point of application of the force interface with the supports and at the equator. Stress value at failure point was 14.307 MPa for the first principal stress, 8.75 MPa for the second and –0.028 MPa for the third principal stress by finite element method.

Chlorella pyrenoidosa is one of the best candidates for biofuel production. The yield and chemical composition of decomposed products of Chlorella pyrenoidosa were determined using thermogravimetric analyzer (TGA), differential scanning calorimeter (DSC), and pyrolysis-gas chromatographic mass spectrometry (Py-GC/MS) by varying the temperature ranges. The results indicated that the main decomposition temperature of Chlorella pyrenoidosa was 294.53°C and up to 46.7% of the mass was lost. A complete decomposition of Chlorella pyrenoidosa was detected until 642.64°C. The pyrolysis of Chlorella pyrenoidosa at 800°C produced 63.58% (the maximum yield) of pyrolysis products compared to 40.22% at 300°C. It is suggested that the generation of pollutants during microalgae pyrolysis can be avoided by controlling the temperature at a relatively low stage (approximately 300°C).

The aim of the present study was to evaluate antioxidative activities of the encapsulated and unencapsulated bitter orange peel extract on the shelf-life of the common carp fillets during 16 days of refrigerated storage. Common carp fillets were treated with bitter orange peel extract (0.5 and 1% w/w), liposomal encapsulated bitter orange peel extract (0.5 and 1% w/w) and beta-hydroxytoluene (BHT, 100 and 200 ppm); their quality changes in terms of total volatile basic nitrogen (TVB-N), free fatty acid (FFA) peroxide value (PV), thiobarbituric acid (TBA) and sensory characteristics were investigated. Results showed that the encapsulated and pure extract and BHT could reduce chemical deterioration and lipid oxidation in the fillets compared to the control, as reflected with lower TVBN, FFA, PV and TBA values. Furthermore, common carp fillets treated with high concentration (1%) of the encapsulated bitter orange peel extract showed the lowest amount of lipid oxidation during the storage period compared with the others without any undesirable changes in sensorial attributes.