Impact performance of two bamboo-based laminated composites

The present work aims to determine the impact performance of two bamboo-based laminated composites [bamboo/poplar laminated composite (BPLC) and bamboo/glass fiber laminated composite (BGFLC)] using low-velocity impact tests by a drop tower. In addition, fracture characteristics were evaluated using computed tomography (CT). Results showed that BPLC presented better impact properties in both directions than BGFLC. Three stages are noted in impact load–deflection curves. The load–deflection curve characteristics of two composites are different in different stages. Matrix cracking, fiber-matrix interface debonding and delamination, and fiber breakage are the three main fracture mechanisms of two composites. Structural characteristics of the components and bonding strength are the important factors for impact properties and fracture mechanism of both bamboo-based laminated composites.     

Proposal of visual strength grading rules for Uruguayan pine timber

A previous database with bending and density data of 261 structural size specimens of currently produced Uruguayan slash pine and loblolly pine timber was adjusted to meet testing and characterization requirements of European standards. Visual parameters and mechanical properties for each specimen were evaluated and their relationship was statistically analyzed. Results suggested that all specimens can be grouped in one visual grade with engineered properties similar to those of European C14 strength class. Modulus of elasticity and characteristic bending strength were the defining properties for class assignation.     

Investigating shrinkage and moisture diffusivity of melon seed in a microwave assisted thin layer fluidized bed dryer

This work aimed to investigate the drying behavior of melon seed during combined fluidized bed-microwave drying system. Three drying air temperatures (40, 55 and 70 °C), three microwave powers (270, 450 and 630 W) and three air velocities (0.8, 1.5 and 2.3 m/s) were tested. Five mathematical models were selected to fit the experimental data for drying kinetics, and the results revealed that the Aghbashloo et al. model exhibited, in all cases, the best performance in fitting the experimental data (R² varying from 0.99088 to 0.99998; χ² from 0.00000 to 0.00185 and RMSE from 0.02289 to 0.82316). Calculated values of moisture diffusivity for dried melon seed varied from a minimum of 6.51 × 10?10 to a maximum of 6.59 × 10?9 m²/s under the tested drying conditions. Moisture diffusivity values increased as air temperature and microwave power was increased. Shrinkage values were calculated and found to vary in the range from 46.99 to 15.09 %.     

Numerical simulation of transient heat transfer for tomato paste in semi rigid aluminum container

In this study, numerical model of heat transfer for tomato paste in semi-rigid aluminum container was developed by Fluent software 6.3.26. Grid independence was recognized. The impact of head space (air and water -vapor) and buoyancy force on heat transfer were investigated. Simulation results showed slowest heating zone (SHZ) located in (?11.676?<?X?<??10.738, 0.183?<?Y?<?1.269 and 4.417?<?Z?<?5.560) for model with air head space and in (?11.166?<?X?<??11.370, 0.762?<?Y?<?1.21 and 5.480?<?Z?<?5.506) for model with water–vapor head space in Cartesian system coordinate. A thermocouple was connected to container at (0, 0, 10 cartesian system coordinate) to get experimental data during process. Comparing temperatures of experimental model and predicted model (with head space) illustrated no significant difference (p?<?0.05).     

Qualitative improvement of catfish burger using <Emphasis Type="Italic">Zataria multiflora</Emphasis> Boiss. essential oil

This study investigates the effects of different concentrations of Zataria multiflora Boiss. essential oil on the quality of catfish burger during storage at 4?°C. For this purpose, fish burgers were produced with 0, 0.2 and 0.4?% ZMEO and the changes in their TBA, PV, FFA, TVB-N, microbiological loads and appeal to consumers during storage were evaluated. The obtained results indicated that the best sensory quality was attained at the highest ZMEO concentration (0.4?%) compared with control samples. The storage time significantly affected the TBA, PV, FFA, TVB-N values, as treated samples with ZMEO showed lower values of lipid oxidation products compared with the control samples. Regarding to microbial load, samples treated with 0.2 and 0.4?% of ZMEO revealed significant reduction at 9th day of storage as compared with the control samples.     

Color measurement: comparison of colorimeter vs. computer vision system

The aim of this work was to compare two food color measurement techniques, the traditional tristimulus colorimeter and an image analysis system. In this sense a computer vision system was developed, consisting of a digital camera, a controlled illumination environment, and a software package to process the images. The conversion between color spaces was performed employing empirical mathematical models; a standard color chart was used for its calibration. The color of 40 samples of raw and processed foods was measured in the CIELAB color space with the computer vision system and a colorimeter. The equivalence between both techniques, for individual L*, a* and b* values, was determined using appropriate hypothesis tests. For most samples both systems provide equivalent results, although the total color difference ?Ε was high enough to be noticeable. The average ?Ε was 5.88?±?3.32, with an average absolute ?L*?=?2.79?±?2.42, ?a*?=?3.02?±?2.94; ?b*?=?2.84?±?2.53. In addition, the color measured by the image analyses technique seemed to be more similar to the real ones.     

Inclusion of poultry based food ingredients in the formulation of noodles and their effects on noodle quality characteristics

Incorporating exogenous proteins into food products is a better practice for improving nutritional attributes of food commodities. In the search for a way to improve the product and nutritional quality of noodles, this study was aimed to evaluate the impact of the incorporation of poultry based ingredients egg yolk powder (EYP) and chicken mincemeat (CMM) in noodles at different levels (5, 10 and 15%, w/w). The incorporated noodles were subjected to evaluation of the cooking, texture, colour, sensory and microstructure properties. The results showed that the incorporation of poultry based food ingredient types and amount influence the nutritional content of noodles. Simultaneously, poultry based ingredients incorporated noodles showed the acceptable firmness and colour charatertistics. Scanning electron micrograph of the incorporated noodles showed the gelatinized starch granules enveloped by protein matrix, and also indicating a better structure as compared to the control. The sensory profile of incorporated noodles was showed significant (p?≤?0.05) high overall quality. The result of this study showed that 10% (w/w) EYP and 15% (w/w) CMM incorporated noodles showed a better overall noodles quality attributes (texture, colour, sensory and microstructure). The results also provide ideas about the inclusion of the appropriate levels of poultry based ingredients (EYP and CMM) with a better sensory and nutritional profile. Therefore, this study may be useful in the food industry for the production of poultry based ingredients noodles with enhanced quality characteristics.     

Influence of bleached palm oil on the physicochemical and sensory properties of beef patty

The effect of palm oil on the physico-chemical and sensory properties of beef liver patty were studied. Seven batches (3units per batch) of beef liver patty with different palm oil content (5, 10, 20, 30, 40 and 50%) and a control with pork fat (30%) were manufactured by component mix at 1500 rpm for 1 min and cooked in an oven at 90?°C. Physico-chemical analysis of raw and cooked samples showed improvement of emulsion stability, water binding capacity, technological yield and hardness of patties substituted with lower proportions of deodorized bleached palm oil. No significant difference (P?>?0.05) was found between physico-chemical properties of liver patty formulated with 20% palm oil and the control (formulated with 30% pork fat). Sensory attributes generated by a semi-trained panel based mainly on texture, homogeneity (colour and aspect), odour and meltiness of the patties confirmed this tendency.     

Pasting,thermal, gel texture,resistant starch and colour properties of unripe banana flour from 10 desert banana varieties cultivated in South Africa

Unripe banana flour is a potential commercial ingredient in various food products for increased resistant starch and reduced gluten contents. In the present study, the pasting (rapid visco-analysis), gel texture (penetration test), thermal (differential scanning calorimetry), colour (tri-stimulus colour indices) and the resistant starch properties of unripe banana flour produced from different dessert banana varieties (n?=?10) cultivated in South Africa, were analysed and juxtaposed to wheat and maize flour. The functional properties varied significantly (p?≤?0.05) between banana varieties, and from wheat and maize flours, to various extents. Selected functional property ranges of unripe banana, wheat and maize flours, respectively included; flour colour index (63.16–76.42, 77.34 and 80.96), paste viscosity (405.5–556.6, 124.7 and 115.6 RVU), gelatinization temperature (64.67–71.21, 71.11 and 69.95?°C), gel firmness (7.24–11.44?×?10^??2 N, 3.49?×?10^??2 N and 6.56?×?10^??2 N) and resistant starch content (19.9–47.4, 2.8 and 2.2% w/w). Multivariate analysis (principle component analysis) showed that the unripe banana flours from different varieties were distinguished from each other based on the pasting temperature. The unripe banana flours were distinguished from both wheat and maize flour based on breakdown and peak paste viscosities. The breakdown viscosity was the most positively related measure to the resistant starch content with a linear regression R-squared value of 0.898, indicating a significant role played by granule structure in resistance to enzymatic hydrolysis. The present research demonstrates that selection of appropriate dessert banana variety is important when replacing staple flours (wheat and maize) with unripe dessert banana flour as a functional ingredient.     

Effect of thermosonication on peroxidase,pectin methylesterase activities and on bioactive compounds in custard apple juice

Custard apple juice faces long term storage challenges such as pink discoloration and bitterness due to peroxidase activity. Therefore, inactivation of peroxidase becomes a necessity for longer shelf life of custard apple and its application in food preparations. Heat processing has certain pitfalls such as loss in nutritional contents of custard apple juice, thereby adversely affecting the sensory quality. In the present study, thermosonication of custard apple juice at a constant temperature of 30?±?1?°C (20 kHz, 67.84 W/cm²) from 0 to 40 min has been studied with respect to peroxidase and pectin methylesterase inactivation. Effect of thermosonication has also been studied on bioactive components such as total phenolics and flavonoids along with enzyme inactivation. Complete inactivation of peroxidase and pectin methylesterase with 0% residual activity was achieved within 40 min and 50 s, respectively. Total phenolics were found to increase from 70.9?±?1.6 to 81.7?±?2.5 mg GAE/g. Sonication was found to have no significant effect (P?>?0.05) on pH, °Brix, titratable acidity. Ascorbic acid content remained relatively unaffected during sonication. Hence, thermosonication may be employed as food processing technique where retention of bioactive components have been achieved along with safety and quality attributes.