COMBINED EFFECT OF pH AND HEAT TREATMENT ON DEGRADATION OF AFLATOXINS IN DRIED FIGS

Dried figs are sensitive commodities to aflatoxin contamination. Although preventive methods are the logical solution to aflatoxin problems, once the product is contaminated, decontamination procedures are inevitable. In this study, the effectiveness of a procedure consisted of acidification/alkalization, and heat treatment in degradation of aflatoxins was evaluated. The pH of dried fig extracts was adjusted to 3.1, 3.5, 6, 8 or 10 by adding acid or base. Extracts were heated at 50, 75 or 98C for 1 or 2 h, and then the residual aflatoxin B₁, B₂, G₁ and G₂ were determined. The highest level of degradation for aflatoxin B₁ (97  ±  1%) and B₂ (87  ±  1%) were observed at pH 10 in samples heated at 98 and 50C, respectively. Some treatments resulted in 100% degradation of aflatoxin G₁ and G₂ so that they could not be detected.

PRACTICAL APPLICATIONS

Aflatoxin contamination is a serious problem for a number of processed and non-processed foods, including dried figs. This not only presents severe risks to human and animal health but also causes economic problems for countries such as Turkey, U.S.A., Greece and Spain, which produce and export dried figs. It is clear that detoxifying studies are unavoidable when the amount of crop contaminated by toxins is considered. Therefore, the food industry is in search of applications that are effective in mycotoxin detoxification and adaptable to food processes. This is the first report on degradation of aflatoxins in naturally contaminated dried figs by such a promising method.     

Physicochemical,mineral and sensory properties of set‐type yoghurts produced by addition of grape,mulberry and carob molasses (Pekmez) at different ratios

This study investigated the effects of adding grape, mulberry and carob molasses (Pekmez) at 6%, 10% or 14% on titratable acidity, pH, viscosity, whey separation, water holding capacity (WHC), gel firmness, acetaldehyde, volatile fatty acids, colour values, mineral profile and sensory properties of set‐type yoghurts. Increasing concentration of the molasses decreased whiteness value, viscosity and WHC, but increased redness/greenness and yellowness/blueness values, whey separation and mineral contents of the samples significantly (P < 0.05). Nevertheless, the yoghurts produced by adding grape molasses had the highest points in the sensory evaluation, followed by mulberry and carob molasses.     

The effect of inulin as a fat replacer on the quality of set-type low-fat yogurt manufacture

The influence of different levels of inulin on the quality of fat-free yogurt production was investigated. Inulin was added to milk containing 0.1% of milk fat to give inulin levels of 1, 2 and 3%. The experimental yogurts were compared with control yogurt produced from whole milk. The total solids content of milk was standardized to 14% by adding skim milk powder to the experimental yogurt. The chemical composition, pH, titratable acidity, whey separation, consistency, acetaldehyde and volatile fatty acidity contents were determined in the experimental yogurts after 1, 7 and 15 days. Sensory properties of the yogurts were evaluated during storage. The addition of inulin at more than 1% increased whey separation and consistency. Acetaldehyde, pH and titratable acidity were not influenced by addition of inulin. Tyrosine and volatile fatty acidity levels were negatively affected by inulin addition. With respect to the organoleptic quality of yogurt, inulin addition caused a decrease in organoleptic scores: the control yogurt had the highest score, and the lowest score was obtained in yogurt samples containing 3% of inulin. Overall, the yogurt containing 1% of inulin was similar in quality characteristics to control yogurt made with whole milk.     

On the harmonic distortion coefficients of active-loaded amplifiers

Starting from the modified Ebers-Moll model which represents the Early effect more accurately than conventional models with the Early voltage, new expressions to calculate the harmonic distortion coefficients of active-loaded BJT amplifiers are derived and applied to the determination of the optimum operating point, where the total harmonic distortion is at a minimum. The results are not obtainable with SPICE, therefore derived expressions provide the possibility of completing the simulation with manual calculations.     

A cross-layer fault tolerance management module for wireless sensor networks

It is a well-established fact that wireless sensor networks (WSNs) are very power constraint networks, but besides this, they are inherently more fault-prone than any other type of wireless network and their protocol design is very application specific. Major reasons for the faults are the unpredictable wireless communication channel, battery depletion, as well as fragility and mobility of the nodes. Furthermore, as traditional protocol design methods have proved inadequate, the cross-layer design (CLD) approach, which allows for interactions between different layers, providing more flexible and energy-efficient functionality, has emerged as a viable solution for WSNs. In this study we define a fault tolerance management module suitable to the requirements, limitations, and specifics of WSNs, encompassing methods for fault detection, fault prevention, fault management, and recovery. The suggested solution is in line with the CLD approach, which is an important factor in increasing the network performance. Through simulations the functionality of the network is evaluated, based on packet loss, delay, and energy consumption, and is compared with a similar solution not including fault management. The results achieved support the idea that the introduction of a unified approach to fault management improves the network performance as a whole.     

The functional, rheological and sensory characteristics of ice creams with various fat replacers

The effects of fat replacers (Simplesse® D-100, N-Lite D, and inulin) on the melting characteristics, overruns, hardness, rheological parameters and sensory attributes of reduced (RF, 60.0 g/kg), low (LF, 40.0 g/kg), and nonfat (NF, 1.0 g/kg) ice creams were investigated. The magnitudes of the melting rates were in the order RF>LF>NF for samples that contained Simplesse® D-100 or inulin, but the reverse order was found for samples with N-Lite D. The nonfat ice creams had lowest overrun values of around 10%. Inulin-containing ice creams possessed higher overrun values than others ( P  > 0.05). The use of fat replacer decreased the hardness of ice creams. All ice cream samples showed pseudoplastic (shear-thinning) behavior. The addition of N-Lite D and inulin decreased the flow behaviour index of ice cream samples. The reduced and low fat ice cream samples were rated as similar to the control by a sensory panel. On the other hand, no correlations ( P  > 0.05) were observed between rheological parameters and sensory texture and mouthfeel.     

双壁碳纳米管的电子显微学研究

本文分析研究了甲酸镍二水合物作为催化剂前驱体,多壁管为原料,采用氢电弧放电法制得的双壁碳纳米管样品中不同管壁数目碳纳米管的分布及双壁碳管直径分布,发现样品中单壁和双壁碳管占主要地位,双壁管的内径主要分布在1.67 nm～3.67 nm之间,外径主要分布在2.33 nm～4.33 nm之间.此外,精确测定了三个双壁碳纳米管的螺旋指数,分别为[(28,3)(29,17)],[(19,8)(29,6)]及[(23,15)(28,22)],其电学性能分别为[半导体性,金属性],[半导体性,半导体性]及[半导体性,金属性].同时,观察了在不同条件下的电子辐照效应.结果表明,经辐照碳管的最内层管壁先发生断裂,其形变速度逐渐变慢,单根碳管易依附于大块物质.在相同的辐照条件下,管壁数目越多碳管越稳定.当管壁数目相同时,直径小的管比直径大的管稳定.高加速电压能够加速碳管的变形.     

ANTIMICROBIAL ACTIVITY AND PROTEIN PROFILES OF PEDIOCOCCUS SPP. ISOLATED FROM TURKISH "SUCUK"

In this study, a total of 206 lactic acid bacteria were isolated on De Man–Rogosa–Sharpe agar from 20 fermented Turkish “sucuk” samples. Twenty‐five isolates were identified as Pediococcus spp. and were tested for their antibacterial activity against Staphylococcus aureus, Micrococcus luteus, Listeria monocytogenes, Bacillus cereus, Salmonella Typhimurium and two strains of Escherichia coli. Only eight strains (32%) of pediococci showed a significant degree of antibacterial activity against L. monocytogenes and S. aureus. According to sodium dodecyl sulfate‐polyacrylamide gel electrophoresis results, among eight isolates, two showed different protein profiles. The size of proteins that made the difference was calculated from 60 to 80 kDa. After partial purification, the highest degree of inhibition against L. monocytogenes was caused by the protein fractions collected after 40% ammonium sulfate precipitation. Therefore, these isolates, which produce antimicrobial substances, have a potential especially to control L. monocytogenes in fermented meat products.