Examination of freshness degradation of sourdough bread made with kefir through monitoring the aroma volatile composition during storage

The aroma volatile compositions of sourdough breads containing kefir grains were monitored by SPME GC–MS analysis during a 5-day storage. Breads were made with (A) 20% w/w and (B) 10% w/w (on flour basis) kefir sourdough, and were compared with breads made with 20% w/w commercial sourdough (C) and sourdough prepared in the laboratory (D) without addition of starter culture. A dramatic decrease of volatiles was observed during storage for all samples, but the kefir sourdough breads (A and B) exhibited more complex profiles of volatiles with lower loss rates during storage. Differences in the percentages of esters on total volatiles were also observed (6.2%, 5.0%, 2.8% and 2% in the case of breads A, B, C, and D, respectively). The customer oriented sensory evaluation revealed significant differences among the tested samples, with best results scored in the case of bread A in all days of storage, agreeing with the analytical data.     

Enrichment of table olives with polyphenols extracted from olive leaves

The possibility to increase the nutritional value of table olives using polyphenols extracted from olive leaves was studied. Leaves were subjected to extraction using water with proportions of 1%, 5% and 10% of leaves and various temperatures and times (room temperature/24 h, 40 °C/10 min and 70 °C/5 min). The antioxidant activity of extracts was determined using the Rancimat method and their content in oleuropein and hydroxytyrosol was determined by HPLC. The extract with the highest antioxidant activity and polyphenol content (10% ratio of olive leaves extracted at room temperature for 24 h) was used for the treatment of debittered table olives. The treated and untreated olives were subjected to determination of their α-tocopherol, oleuropein and hydroxytyrosol content. A 457% increase was observed for oleuropein and 109% for hydroxytyrosol content after treatment. Sensory evaluation of treated table olives showed an increase in bitterness. However, treated and untreated table olives showed equal overall acceptability and overall preference.     

Heating characteristics of western hemlock (Tsuga heterophylla) in a high frequency field

The research aimed to establish whether dielectric heating of wood at high frequency could be accomplished fast, without excessive temperature fluctuations and no wood degrade. The intention was to develop optimized dielectric heating schedules in order to effectively pasteurize green timbers and logs for export—an eco-friendly substitute to currently used toxic chemical method. Data analysis revealed that the electric field distribution within the specimen was a strong function of its dielectric properties. Specifically, homogeneous moisture contents generated constant electric field values while heterogeneous distributions generated sudden drops and raises of the electric field strength with heating uniformly dispersed due to a fast redistribution from hot to colder areas. Convection losses through air contact may reduce the average heating rate of the timber shell by about 50%.     

Comparison of Decontamination Efficacy of Antimicrobial Treatments for Beef Trimmings against Escherichia coli O157:H7 and 6 Non-O157 Shiga Toxin-Producing E. coli Serogroups

Abstract: The decontamination efficacy of 6 chemical treatments for beef trimmings were evaluated against Escherichia coli O157:H7 and 6 non‐O157 Shiga toxin‐producing E. coli (nSTEC) serogroups. Rifampicin‐resistant 4‐strain mixtures of E. coli O157:H7 and nSTEC serogroups O26, O45, O103, O111, O121, and O145 were separately inoculated (3 to 4 log CFU/cm²) onto trimmings (10 × 5 × 1 cm; approximately 100 g) fabricated from beef chuck rolls, and were immersed for 30 s in solutions of acidified sodium chlorite (0.1%, pH 2.5), peroxyacetic acid (0.02%, pH 3.8), sodium metasilicate (4%, pH 12.5), Bromitize^® Plus (0.0225% active bromine, pH 6.6), or AFTEC 3000 (pH 1.2), or for 5 s in SYNTRx 3300 (pH 1.0). Each antimicrobial was tested independently together with an untreated control. Results showed that all tested decontamination treatments were similarly effective against the 6 nSTEC serogroups as they were against E. coli O157:H7. Irrespective of pathogen inoculum, treatment of beef trimmings with acidified sodium chlorite, peroxyacetic acid, or sodium metasilicate effectively (P < 0.05) reduced initial pathogen counts (3.4 to 3.9 log CFU/cm²) by 0.7 to 1.0, 0.6 to 1.0, and 1.3 to 1.5 log CFU/cm², respectively. Reductions of pathogen counts (3.1 to 3.2 log CFU/cm²) by Bromitize Plus, AFTEC 3000, and SYNTRx 3300 were 0.1 to 0.4 log CFU/cm², depending on treatment. Findings of this study should be useful to regulatory authorities and the meat industry as they consider nSTEC contamination in beef trimmings. Practical Applications: Findings of this study should be useful to: (i) meat processors as they design and conduct studies to validate the efficacy of antimicrobial treatments to control pathogen contamination on fresh beef products; and (ii) regulatory agencies as they consider approaches for better control of the studied pathogens.     

Statistical Properties for the Envelope and Phase of the α ? η ? μ Generalized Fading Channels

In this paper, a study on the statistical properties for the envelope and phase of both formats of the ?? ? ?? ? ?? generalized fading channels is provided by deriving novel closed-form expressions. Specifically, a simple and closed-form expression for the phase crossing rate of the ?? ? ?? ? ?? generalized fading channels is obtained. Moreover, exact analytical expressions for the level crossing rate and the average duration of fades, as well as the PDF of random FM noise are presented. Confirmation of the provided analytical formulations is attained by reducing the general model to some widely known special cases (Nakagami-m, Hoyt, and Rayleigh). Extra validation is performed by means of a sample of numerical results obtained by Monte Carlo simulation.     

Prediction of high-risk asymptomatic carotid plaques based on ultrasonic image features

Carotid plaques have been associated with ipsilateral neurological symptoms. High-resolution ultrasound can provide information not only on the degree of carotid artery stenosis but also on the characteristics of the arterial wall including the size and consistency of atherosclerotic plaques. The aim of this study is to determine whether the addition of ultrasonic plaque texture features to clinical features in patients with asymptomatic internal carotid artery stenosis (ACS) improves the ability to identify plaques that will produce stroke. 1121 patients with ACS have been scanned with ultrasound and followed for a mean of 4 years. It is shown that the combination of texture features based on second-order statistics spatial gray level dependence matrices (SGLDM) and clinical factors improves stroke prediction (by correctly predicting 89 out of the 108 cases that were symptomatic). Here, the best classification results of 77 ±1.8% were obtained from the use of the SGLDM texture features with support vector machine classifiers. The combination of morphological features with clinical features gave slightly worse classification results of 76 ±2.6% . These findings need to be further validated in additional prospective studies.     

Transmission medium and full fiber-optic setup for quantum key distribution applications

A fiber-optic-based coupled waveguide transmission medium is proposed to distribute secret keys in a single-photon polarization-based quantum cryptography setup. Polarization maintenance properties and coupling phenomena of the transmission medium are exploited to achieve accuracy and security of the transferred key. Elliptic fibers and fiber couplers are used to prepare the transmitted photons at the sender as well as analyze them at the receiver. The uniqueness of the setup stands on the exclusive use of fiber-optic components, enabling its construction on a single fiber line.     

Einfluß der lokalen Geologie von Köln auf die Form von Freifeldantwortspektren

Influence of the local Geology of Cologne on the shape of response spectra. In the course of a microzonation, the area of Cologne has been divided into 8 subregions based on the thickness of the local sedimentary cover. Using the focal parameters of the standard events of the draft of the national earthquake code E‐DIN 4149, synthetic seismograms were generated and subsequently applied to investigate the influence of the local sediments on the shape of transfer functions and acceleration response spectra. The results of 3 well known modelling techniques (2‐layer model, multi‐layer model in SHAKE 91, Haskell‐algorithm in SIMUL) were compared and discussed among themselves and with the elastic acceleration response spectra of the E‐DIN 4149.