Drying kinetics,colour, total phenolic content and antioxidant capacity properties of kiwi dried by different methods

This study analysed the convective (60, 70 and 80° C), microwave (120 and 350 W) and freeze drying methods in terms of their effects on the drying characteristics, colour, total phenolic content (TPC) and antioxidant capacity of kiwi slices. Nine different mathematical models were applied to experimental data to achieve the most accurate calculation for drying curves. The Midilli et al. and Wang and Singh models proved to be the most suitable at explaining the drying kinetics of kiwi samples as compared to other models according to the statistical tests. Each drying method was significantly affected by colour parameters (L*, a*, b*, C, α and ΔE). The dried samples exhibited respectively 5–49 % and 10–47 % less TPC and antioxidant capacity compared to the fresh sample. According to the correlation analysis conducted between TPC and antioxidant capacity for kiwi slices, there is a positive correlation (R ²  = 0.7796). Microwave dried samples at 120 W particularly had the lowest TPC and antioxidant capacity. Freeze drying method yielded the closest values with respect to colour values, total phenol content and antioxidant capacity to those of fresh samples when compared to the other methods.     

Diversity and functional characteristics of lactic acid bacteria from traditional kefir grains

Traditional kefir grains were collected from distinct parts of Turkey, and their microbial profile was determined. A wide bacterial biota was observed formed by distinct lactic acid bacteria (LAB) in which Lactococcus lactis strains appeared to be dominant. Yeast species were also identified in kefir grains. Significant levels of antifungal and antibacterial activities were monitored in kefir isolates. All tested LAB produced an exopolysaccharide (EPS) containing glucose and galactose, and some strains formed a fructan‐type EPS. Importantly, low levels of antibiotic resistance were observed among the kefir isolates.     

Synthesis and application of a new functionalized resin for use in an on-line,solid phase extraction system for the determination of trace elements in waters and reference cereal materials by flame atomic absorption spectrometry

The synthesis and characterization of the resin Amberlite XAD-4 functionalized with 2,6-pyridinedicarboxaldehyde and its application in an on-line system for the preconcentration of cadmium, cobalt, copper, lead and manganese prior to determination using flame atomic absorption spectrometry (FAAS) is proposed. Metal ions retained on the modified resin were eluted using 1.0 mol L⁻¹ HNO₃ solution and aspirated directly to the nebulizer–burner system of a FAAS instrument using a flow injection system. Detection limits (3σ) were determined to be 0.13 μg L⁻¹ for Cd, 0.29 μg L⁻¹ for Cu, 0.23 μg L⁻¹ for Mn, 0.58 μg L⁻¹ for Co and 2.19 μg L⁻¹ for Pb using a 10 mL of water sample loading volume. The limits of detection would be 100 times higher with units of μg kg⁻¹ for the solid samples in which their dilution ratios as (volume/weight) were 100. Enrichment factors ranged from 23.6 to 28.9 (for Co and Mn, respectively). The proposed method was successfully applied to determination of the analytes in natural water samples and certified reference materials.     

Uniform waveband assignment in optical mesh networks

The cost of an optical network in wavelength division multiplexing (WDM) networks can be reduced using optical reconfigurable optical add/drop multiplexers (ROADMs), which allow traffic to pass through without the need for an expensive optical-electro-optical (O-E-O) conversion. Waveband switching (WBS) is another technique to reduce the network cost by grouping consecutive wavelengths and switching them together using a single port per waveband. WBS has attracted the attention of researchers for its efficiency in reducing switching complexity and therefore cost in WDM optical networks. In this paper, we consider the problem of switching wavelengths as non-overlapping uniform wavebands, per link, for mesh networks using the minimum number of wavebands. Given a fixed band size b _s , we give integer linear programming formulations and present a heuristic solution to minimize the number of ROADMs (number of wavebands) in mesh networks that support a given traffic pattern. We show that the number of ROADMs (or number of ports in band-switching cross-connects) can be reduced significantly in mesh networks with WBS compared to wavelength switching using either the ILP or the heuristic algorithm. We also examine the performance of our band assignment algorithms under dynamic traffic.