The effects of modified atmosphere gas composition on microbiological criteria, color and oxidation values of minced beef meat

This paper reports the effects of modified atmosphere gas compositions with different concentrations of CO(2)/O(2)/N(2) on color properties (L*, a* and b* values), oxidation stability (TBARS value) and microbiological properties of minced beef meat stored at +4 °C. Sampling was carried out on the 1st, 3rd, 5th, 7th, 9th, 11th and 14th day of storage. The gas mixtures used were as follows: (i) %30O(2) + %70CO(2) (MAP1), (ii) %50O(2) + %50CO(2) (MAP2), (iii) %70O(2) + %30CO(2) (MAP3), (iv) %50O(2) + %30CO(2) + %20N(2) (MAP4), and (v) %30O(2) + %30CO(2) + %40N(2) (MAP5). Control samples (AP) were packaged under atmospheric air. Pseudomonas, lactic acid bacteria, Brochothrix thermosphacta, and Enterobacteriaceae members were monitored. Among these five modified atmosphere gas compositions, the best preservation for minced beef meat was in MAP4 gas combination maintaining acceptable color together with oxidation stability and acceptable microbial loads until the end of storage period of fourteen days.     

Acetaldehyde migration from polyethylene terephthalate bottles into carbonated beverages in Türkiye

Polyethylene terephthalate (PET) is one of the packaging materials that is widely used for packaging of soft drinks. PET may contain acetaldehyde which is a thermal degradation product, and hence acetaldehyde may migrate into the product in the package. In this study, the migration of acetaldehyde from PET bottles into soft drinks containing carbonic acid was determined by gas chromatography without headspace instrument. Carbonated beverage samples obtained from four different firms following the filling process were stored at 5, 20 and 40 °C for 6 months and analysed periodically at 0 day, 2, 4 and 6 months. As a result, it was seen that the acetaldehyde concentrations of all samples were quite different from each other and also related to the storage temperature, and an increase in storage time raised acetaldehyde concentrations in beverages. Especially, storages at 40 °C had very serious effect on acetaldehyde concentrations in the beverages.     

Performance Analysis of OFDM Repeater Networks with Spatial Fading Correlation

This paper analyzes the performance of the OFDM diversity systems with the spatial fading correlation when the network includes an RF repeater. In case of OFDM transmission, since the combining scheme is usually employed in the frequency domain, the correlation between different subchannels should be considered. In a multipath channel, correlation varies over subchannels depending on the channel delay profile and the spatial correlation between each individual delayed paths. In this study, a multipath channel is constructed by the repeated signal instead of natural multipath due to cluttered environments and the system performance with spatial correlation per subcarrier is evaluated. Previously, it is reported that the effect of correlation can be reduced by the Time Shifted Sampling (TSS) technique which relies on the multipath diversity. Numerical results indicate that the TSS technique is also effective in reducing the effect of correlation for the multipath channels constructed by the repeaters.     

A Novel Underlay Cognitive Radio Based on Direct Sequence Complementary Coded CDMA

In this study, we propose a spectrum sharing scheme where secondary-users (SUs) can co-exist at the same frequency band with the primary-users simultaneously. Both primary (PN) and secondary networks (SN) are considered as CDMA based networks with the same set of orthogonal complementary codes. An orthogonal complementary code set possesses both ideal auto-correlation function (ACF) of any code and ideal cross-correlation function for any two codes in the same set. In the proposed scheme, a delay is applied to the transmission of the SN which exploits ideal ACF properties of complementary codes and will not interfere the transmission of the primary user. Numerical results show that the proposed scheme enables SUs to efficiently utilize the PN’s licensed spectrum without any harmful interference.     

GPU Accelerated Successive Interference Cancellation for NOMA Uplink with User Clustering

Wireless Personal Communications - Non-orthogonal multiple access (NOMA) can achieve high throughput by using the same time and frequency resources for multiple users. NOMA distinguishes multiple...     

Correction to: GPU Accelerated Successive Interference Cancellation for NOMA Uplink with User Clustering

Wireless Personal Communications - There was a typo in the second author’s name in the initial online publication. The original article has been corrected.