Band 9, Heft 2 -

Rosemary essential oil is used in pharmaceutical, cosmetic and food industries. Due to its constituents’ chemical activity, it is also used as antioxidant to preserve foods and as antibacterial and antifungal agents.The most abundant components of rosemary essential oil used in this work are α-pinene, myrcene, 1,8-cineole and camphor, which respond to 1,8-cineole chemotype. Two sets of molecular distillation experience were conducted. Antioxidant power of distillates and residues obtained was quantified, and the residues obtained from molecular distillation have more antioxidant power than distillates and rosemary essential oil.The results of this study show that it is feasible to use molecular distillation operation to obtain concentrates of rosemary essential oil. Residues collected present higher antioxidant power than rosemary essential oil, probably due to the presence of camphor, linalool, linalyl acetate and α-terpineol, which are present in higher proportion in the residues.

This study investigated the direct compression properties of Eurycoma longifolia Jack tablets using binary mixtures such as microcrystalline cellulose (mcc) and κ-carrageenan (carr). The mixtures were compacted to various compression pressures ranging from 7.5 to 74 MPa at a constant compression speed of 5 mm/min. The tensile strengths of the tablets were determined by a diametral compression test. A linear relationship between the tensile strength and the compression pressure was observed under the conditions of the test; hence, the slopes of the data were obtained by fitting linear trend lines. This paper shows that binary mixtures of 30% mcc and 70% Eurycoma longifolia Jack give the highest values for constant (a slope) compared with the other binary mixtures of both binders. Thus, this approach can be used to develop formulations for Eurycoma longifolia Jack tablets.

A multi-scale three-dimensional computational fluid dynamics (CFD) model was developed to predict airflow, heat and mass transfer in a typical full loaded cool storage. In order to reduce the computational costs, the porous media parameters of the bed of the apples inside the vented containers were extracted using a series of wind tunnel CFD simulations and then applied in the cool storage model. The model was validated against experiments by means of velocity, product temperature, and product weight loss measurements in cool storage. The errors of about 23.2 and 9.1% were achieved for velocity magnitude prediction in the cool storage and the product weight loss after 54 days of cooling in the loaded cool storage, respectively. The model over predicted the cooling rate of the products temperature; however, it showed a good trend of cooling rate. About 11°C difference was observed between the hottest and the coldest product temperatures at half cooling time by experiments that were in good agreement with the simulation results with about 10°C. This difference changes versus time of cooling and reached to about 4°C at the end of the cooling time. The product’s temperature heterogeneity was predicted 1.9°C between the 7 and 9 hours of cooling and reduced to 0.6°C at the end of the cooling. The multi-scale model was capable of predicting air velocity, product temperature, and weight loss with reasonable accuracy and was reliable enough for numerical studies on larger domain with high reduction in computational costs.

The dynamic weighing signal processing method in high-speed fruits sorting system directly affects the weighing accuracy. This paper describes a basic modeling method for time series, including modeling, order determining, applicability analysis, and prediction. Considering the structural characteristics of weighing system and the limit of PLC sampling speed, a modified auto-regressive (AR) model for stable value prediction of the high-speed weighing signals is presented. Meanwhile, a simulation base on Matlab platform and an implementation example are used to test the method performance. At last, the impacts of environmental changes, sorting speeds, fruits shapes, and sizes on the method performance are discussed. In experimental conditions, this method can be applied to fruits sorting system with sorting speed up to 18 per second for standard fruit (smooth round surface without defects) and an acceptable weighing accuracy can be obtained.

This work evaluated the effects of osmotic dehydration on convective drying kinetics of figs. It used the experimental design methodology to evaluate the influence of sucrose concentration, temperature and time on the amount of total soluble solids (TSS) and moisture content of the figs. After the osmotic dehydration, it evaluated the convective drying kinetics at temperatures from 55 to 75°C. A mathematical model was employed to fit the experimental data. From the experimental data of the osmotic dehydration, it was seen that the moisture content of the figs after the treatment was closely related to the amount of TSS of the figs. Low moisture content and high TSS content were obtained for a narrow range of independent variables comprised between 55–60°C, 55–63 wt% and 260–280 min for temperature, sucrose concentration and exposure time, respectively. In the convective drying kinetics of the figs, there were no verified significant differences in the final time of drying of non-treated and osmotically dehydrated figs. However, the shrinkage was considerably reduced in the osmotically treated figs. The use of osmotic treatment enables the obtainment of figs softer than the simple use of convective drying without changing the final time of drying.

Rocha pear ( Pyrus communis L.) is the main cultivar produced in Portugal, usually consumed in fresh. However, the drying of the pear can be an opportunity for development and enables the provision of alternative products to consumers. This work evaluates the effect of drying on some chemical and physical properties of pears of the Rocha variety. Furthermore, the origin of the pears was also a variable studied. For the completion of this work, pears from five different locations were analysed in fresh and after convective air drying at two different temperatures, 40 and 60°C. The properties analysed were dimensions of pears in terms of height and diameter, total solids content, acidity, maturation index, processing yields, colour and textural attributes.The results showed that the peel had lower acidity and higher maturation index, when compared to the pulp and that drying greatly reduced acidity, either in the pulp or in the peel. However, this variation was not influenced by the drying temperature. With respect to colour, total colour differences between 25 and 50 were observed (for the dried pears in relation to the fresh) and in this case increasing the drying temperature caused evident variations in the peel but not in the pulp. As to the textural attributes, hardness and chewiness were the ones that showed the higher changes with drying, increasing considerably with drying temperature.

The production of coated foods using batters and breading is widespread in various meat, fish and vegetable products including poultry, i.e. chicken meat cuts. Thus, samples of coated and uncoated chicken meat cuts, i.e. leg and breast, fried or baked were applied in this study. Five batter samples as well as a breading coating sample were evaluated against non coated samples for physicochemical and sensory characteristics. The results indicated that batters enriched with protein produced coating systems with increased crispiness and adhesion while batters enriched with modified corn starches resulted in improved product yields. A combination of wheat flours with modified waxy corn starches resulted in products with excellent adhesive properties, desirable thickness, good crispness and appearance. The cooked meat pieces (coated and uncoated) were packaged after cooling in plastic bags and stored at ‒18C for further analysis, i.e. moisture, water activity, thiobarbituric acid (TBA) and pH values. The results showed reduction in moisture and water activity values and increase in pH and TBA values for the tested (coated and uncoated) products at 0, 1, 4, 8, 12, 16 and 24 weeks of testing periods. Sensory evaluation analysis showed a significant preference for the coated samples compared to the uncoated products.

Texture, appearance, and emulsion stability of soymilk are affected by the size and distribution of suspended particles. To produce soymilk which contains all solids in the soy, whole dehulled beans were used in the study. A microfluidizer with throttling valve attachment was used to study the influence of various pressure levels on the particle size distribution of soymilk. Soymilk was processed with a continuous flow high pressure throttling (CFHPT) system to study the effects of different pressures and flow rates in the temperature rise and particle size distribution of soymilk. The results showed that there existed a significant effect of flow rate through the CFHPT on the particle size suspended in soymilk. Temperature rise was proportional to increase in pressure of the CFHPT system. Significant decrease in particle size of soymilk was obtained by increasing pressure for both CFHPT and microfluidizer. Empirical models were established between the pressure applied, volume fraction of particle size, and particle size diameter obtained for soymilk in each system.

Volatiles are important flavor compounds of fruit juices and beverages. In this study, a headspace Solid-phase microextraction (SPME) gas chromatography-mass spectrometry (GC-MS) was used to analyze the volatile components in starfruit juices. Several experimental parameters (e.g. adsorption temperature, adsorption time, and sample volume) were optimized to improve sampling efficiency in two aspects; maximum adsorption and selective adsorption of volatile components onto SPME fiber. The following conditions were found to be optimal for selectivity and sensitivity: adsorption temperature of 50°C for 30 min, with a 65 μm divinylbenzene /polydimethylsiloxane (DVB/PDMS)-coated fiber with a sample volume of 15 g in a 30-ml vial. The proposed technique could be applied for the analysis of volatile compounds that contribute to starfruit juices flavor in different cultivars, and also their ripening stages.

The increasing interest in the antioxidant activity of lycopene has been to promote the consumption of tomato and tomato-based products. The aim of this work was to evaluate tomato ( Lycopersicon esculentum Mill) drying in thin layer through response surface methodology. The independent variables investigated in this study were drying air temperature (60, 70 and 80°C) and wet sample thickness (3, 5 and 7 mm). The drying condition with the lower colour value (Hue angle) and higher lycopene content was 60°C and sample thickness of 3 mm. In this condition, the responses for the colour (Hue angle) and lycopene content values were 47.7 0.2° and 301.9 3.1 μg g – 1 , respectively. The lycopene loss was similar to that reported in the literature (30–50%) using more expensive methods of tomato drying such as freeze-drying and lyophilization.