Significance of Biogenic Amines in Foods and Their Reduction Methods

The term ＂biogenic amines＂ defines decarboxylation products such as histamine, putrescine, serotonin, tyramine, phenylethylamine, tryptamine and also aliphatic polyamines. They can be detected in both raw and processed foods. In the recent years, there is a great interest in biogenic amines as they are associated with quality, safety and freshness of some foods, particularly fermented foods. The presence of biogenic amines in foods can also be used as an indicator of hygienic quality. Biogenic amines also cause health hazards due to their toxic effects especially in sensitive individuals. It is therefore important to control and reduce the biogenic amines. The reduction can be brought about by the use of high pressure, irradiation, packaging, additives, starter cultures and by reduction of decarboxylase activity and temperature. This review summarizes the significance, function, occurrence and formation of biogenic amines in different foods and their reduction by different methods.     

Nonisothermal crystallization kinetics of poly(ethylene terephthalate)/clay nanocomposites prepared by melt processing

In this study, cold and melt crystallization behaviors of amorphous poly(ethylene terephthalate) (PET)/clay nanocomposites were investigated. Two nanocomposite samples with the same amount of inorganic content were prepared by melt processing using natural montmorillonite (Na‐MMT) and organo‐modified montmorillonite (org‐MMT). Depending on the clay structure, clay dispersion into PET and crystallization behavior of the samples were studied using X‐ray diffraction and differential scanning calorimetry methods, respectively. Effects of clay structure and organic groups between clay layers in org‐MMT on the melt crystallization kinetics of the samples were analyzed with various kinetic models, namely, the Ozawa, Avrami modified by Jeziorny, and Liu‐Mo. Crystallization activation energies of the samples were also determined by the Kissinger and Augis–Bennett models. Exfoliated structures were obtained in the nanocomposite samples prepared with both the Na‐MMT and org‐MMT. From the kinetics study, it was found that the melt‐crystallization rate of the sample prepared with the Na‐MMT was higher than that prepared with the org‐MMT at a given cooling rate. It can be concluded that organic ammonium groups in the org‐MMT decelerate the crystallization rate of PET chains possibly by affecting the chain diffusion and folding. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers     

Integrating manufacturing systems through knowledge exchange protocols within an agent-based Knowledge Network

Manufacturing enterprises need the ability to respond to rapid changes in the market more than ever before. Besides, they are forced to constantly modify their culture and internal organization structures because of change and intense competition in the market. This obviously requires industrial organizations to manage the different components of their organizations by integrating and coordinating them into a highly efficient, effective, and responsive system in order to maintain and improve their competitiveness. This paper presents a knowledge exchange procedure for creating an integrated intelligent manufacturing system. The basic features of the proposed scheme are introduced and the approach is supported through a case study.     

The effect of the use of hop additives and lactic acid bacteria starter in the preparation of dough on the properties of the resulting dough and bread

 In this research, the effects of lactic acid bacteria starter and hop additives, similar to yeast, on the quality of the resulting dough and bread, especially the development of staling, were investigated. In the experiments, a mixed culture containing Lactobacillus plantarum and L. fermentum was inoculated at the levels of 2% and 4% depending on the flour quantity. Hop additives were used at the levels of 0.025% and 0.05%. The effects of type-1, type-3 and type-5 flours were investigated with respect to their chemical composition, physical properties and bread experiment at three different periods, i. e. December 1993, March and June 1994. According to the results obtained, the best values for all three types of flours were found to occur in the second period, i. e. March 1994, whereas the lowest values were observed at the end of the third term. Almost all additives had an effect on dough and bread properties, pH and acidity development and, moreover, on the development of staling. The combined application of 0.05% hop and lactic acid bacteria starters at the levels of 2% and 4% was the most effective at delaying staling. Received: 10 December 1996     

Effect of added fat on plasma glucose and insulin response to ingested potato in individuals with NIDDM

OBJECTIVE: In normal subjects, ingestion of butter with potato resulted in considerably lower blood glucose levels but similar or higher insulin concentrations compared with those observed in the same subjects after potato ingestion alone. We determined whether butter ingested with potato would result in a greater stimulation in insulin secretion than ingestion of potato alone in subjects with NIDDM. RESEARCH DESIGN AND METHODS: Seven male subjects with untreated NIDDM ingested 50 g CHO alone or 50 g CHO with 5, 15, 30, or 50 g fat as a breakfast meal. Fat was ingested in the form of butter, and CHO was given in the form of potato. Subjects received 50 g glucose on two separate occasions for comparative purposes. The subjects also were given only water and were studied over the same time period (water control). Plasma glucose, glucagon, alpha-amino nitrogen, nonesterified fatty acids, serum insulin, C-peptide, and triglyceride concentrations were determined over 5 h. The integrated area responses were quantified over the 5-h period using the water control as a baseline. RESULTS: The mean plasma glucose area response after ingestion of potato with or without the various amounts of butter were all similar and were 82% of that observed after ingestion of 50 g glucose. The mean insulin area response to potato alone was 532 pmol.h.L-1. The mean insulin area responses to potato plus 5,15,30, and 50 g of fat meals were 660,774,750, and 756 pmol.h.L-1, respectively. Thus, the mean insulin areas were all greater than for ingestion of potato alone, and a maximal response was observed with addition of 15 g fat (1.4-fold). The C-peptide data did not confirm an increase in insulin secretion. Overall the area responses after ingestion of meals containing fat were not different from the response to potato ingestion alone, although the responses were erratic. The glucagon area response was positive after ingestion of all fat containing meals except for that containing only 5 g fat, and there was a dose-response relationship. The plasma alpha-amino nitrogen and nonesterified fatty acid area responses were negative after potato ingestion and were not significantly different when fat was added. The serum triglyceride concentration increase was greater after the ingestion of butter with the potato as expected. CONCLUSIONS: In contrast to the results in normal subjects after ingestion of butter with potato, the glucose response was not smaller in subjects with NIDDM. The insulin response was greater. The insulin area response data indicated the presence of a dose-response relationship. Whether similar responses will be observed with other dietary fat and CHO sources remains to be determined.     

Time-varying ARMA stable process estimation using sequential Monte Carlo

Various time series data in applications ranging from telecommunications to financial analysis and from geophysical signals to biological signals exhibit non-stationary and non-Gaussian characteristics. α-Stable distributions have been popular models for data with impulsive and non-symmetric characteristics. In this work, we present time-varying autoregressive moving-average α-stable processes as a potential model for a wide range of data, and we propose a method for tracking the time-varying parameters of the process with α-stable distribution. The technique is based on sequential Monte Carlo, which has assumed a wide popularity in various applications where the data or the system is non-stationary and non-Gaussian.     

Antioxidant activity and phenolic compounds of ginger (<Emphasis Type="Italic">Zingiber officinale</Emphasis> Rosc.) determined by HPLC-MS/MS

Oxidative stress related diseases often arise from over production of free radicals and reactive oxygen/nitrogen species. The prevention of these diseases could be possible with the use of natural antioxidant plants that could be promising as therapeutic candidates. Since antioxidant properties of a species could be stem from phenolic compounds, it is, therefore, important to evaluate antioxidant and total/individual phenolic and flavonoid content. For this purpose, we evaluated antioxidant properties of ginger (Zingiber officinale Rosc.) based on three parameters: the antioxidant capacity, total phenolic and flavonoid content as well as identification of phenolic acids of water extract (WEG) and ethanol extract (EEG) of ginger. For antioxidant capacity, we performed FRAP, CUPRAC assay, Fe²⁺ chelating ability, DPPH and DMPD radical scavenging activities. Also, total phenolic and flavonoid contents in both extracts were also measured via Folin Ciocalteu’s method. For identification of phenolic acids, HPLC-MS/MS method was performed. The results showed that EEG had generally better antioxidant activity than WEG in all assays. HPLC-MS/MS analysis showed that there are at least eight different phenolic acids found in ginger, among which pyrogallol p-hydroxybenzoic acid, ferulic acid and p-coumaric acid were more abundant in both extracts. This study clearly showed that ginger extracts demonstrated effective antioxidant properties and their consumption may reduce or delay the progression of diseases that oxidative stress take place due to lack of antioxidant supplementation.