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bstract Batches of gutted Mediterranean hake ( Merluccius merluccius var. Mediterraneus) were stored, in different seasons of the year, for up to 20 d in ice. Changes in trimethylamine (TMA-N), total volatile bases (TVB-N), P-ratio and trimethylamine oxide (TMAO) were measured; sensory evaluation of raw and cooked hake samples was also carried out. Similar profiles were observed between the different trials for all the parameters studied. TVB-N was not correlated with the time of ice storage, and proved to be better as a spoilage index than a freshness one. In contrast, TMA-N appears to be a good index of hake quality, and the value of 5 mg/100g offish seems an appropriate limit of acceptability. P-ratio was a poorer index of freshness than was TMA-N. [ABSTRACT FROM AUTHOR]

Biogenic amines and polyamines were measured in unripened cheese and 4 types of ripened cheese. The study included cheeses produced from both pasteurized and raw milks. All amines were lower in unripened than in ripened cheeses. The amine contents varied among different types of ripened cheese, within the same type of cheese, and also within the parts of cheeses. The main amines in ripened cheeses were tyramine, cadaverine, and putrescine. The highest concentration of tyramine was found in hard-ripened raw-milk cheeses, while blue cheese had the highest level of cadaverine. Unripened cheeses could be considered as well-tolerated products for histamine- and tyramine-sensitive individuals, whereas the wide variability in biogenic amines makes it difficult to generalize this consideration for all ripened cheeses. [ABSTRACT FROM AUTHOR]

A Quality Index Method for the sensory assessment of freshness of Mediterranean hake was developed and validated by sensory, chemical, and microbiological parameters. The Quality Index was the ratio between the overall sensory score obtained and the total achievable sensory score of the scheme and ranging 0 (fresh) to 1 (spoiled). This index increased significantly along the time of ice storage, allowing prediction of the remaining shelf life of hake. A value of 0.60 to 0.65 was estimated by statistical treatment as the rejection value, being concordant with sensory score of cooked hake, trimethylamine content, pH, as well as with legal regulations for mesophylic and enterobacteria counts. [ABSTRACT FROM AUTHOR]

BSTRACT: The formation of biogenic amines in goat cheese can be prevented through ensuring hygiene in raw materials and during manufacture, thereby avoiding potential decarboxylating microorganisms. High-pressure treatment may be used to inactivate microorganisms and is a potential alternative to pasteurization. This treatment could provoke higher proteolysis than pasteurization, leading to a higher availability of biogenic amine precursors. We compared the biogenic amine profile throughout the ripening of goat cheese made from pressurized milk with that obtained from pasteurized milk. Results indicate that the profile of biogenic amines is very similar for both cheeses. Tyramine was the prevailing amine in both cheeses, followed by cadaverine, putrescine, and histamine. [ABSTRACT FROM AUTHOR]

BSTRACT: The main amines in frozen and fresh hake (Merluccius merluccius) are the natural polyamines, spermidine. The levels of volatile and nonvolatile amines during storage of hake were strogly dependent on temperature. In samples stored at -20° only changes in dimethylamine and agmatine were found, whereas major changes were observed in samples stored at higher temperatures. Cadaverine was the major amine formed followed by histamine, putrescine and tyramine. The maximum levels of biogenic amines were lower than those reported for other fish species. Trimethylamine and biogenic amines related to hake spollage showed levels higher in fresh than in frozen samples, whereas levels of natural polyamines were not statistically different. [ABSTRACT FROM AUTHOR]

Data were obtained on histamine and tyramine contents in 48 samples of preserved and semi-preserved Spanish fish products. Ranges of concentration for both amines were wide: from 1.35 to 219.20 mg/ kg for histamine, and from 0.5 to 66.40 mg/kg for tyramine. Higher concentrations were found in semi-preserved anchovies than in the rest of the samples studied: canned tuna, herring, mackerel and sardines. In semi-preserved anchovies stored at room temperature (18-22°), histamine production was observed after 6 months. The increase in histamine was not observed in the samples stored under refrigeration (4-6°). Tyramine did not increase at either temperature of storage. [ABSTRACT FROM AUTHOR]

The formation of biogenic amines (histamine and tyramine) during Engraulis encrasicholus storage and spoilage was studied and compared with changes of other fish spoilage indicators: trimethylamine nitrogen, volatile basic nitrogen, hypoxanthine and pH. Good correlations were observed between biogenic amines and the other indicators, at both refrigeration (4-6°C) and room temperature (18-22°C).Two trials were carried out at each temperature. Differences were observed in levels of biogenic amines as well as other indicators in experiments carried out under similar conditions. [ABSTRACT FROM AUTHOR]

Abstract: The influence of two manufacturing processes on biogenic amine formation during the manufacture of Spanish dry fermented sausages of different diameters (fuet and llonganissa) was evaluated to elucidate which conditions allow better control of the aminogenic activity of spontaneous microbiota. Technological conditions affected both the amounts and the qualitative profile of biogenic amine accumulated. The higher processing temperature and relative humidity in process A (simulating those applied in industrial manufacture) favoured aminogenesis, since biogenic amine accumulation was faster and higher than in sausages manufactured under the process B (close to those used in traditional practices). The major amine differed depending on the diameter of the sausages, tyramine being the major amine in fuet (2.5cm diameter sausage), and putrescine in llonganissa (4.5cm). Moreover, sausages of higher diameter (llonganissa) had higher biogenic amine contents compared with the thinnest sausages (fuet). Conditions would modulate biogenic amine accumulation not only due to its influence on development of the bacterial population but also on its aminogenic activity. From the biogenic amine point of view, when sausages are spontaneously fermented, traditional lower temperatures and relative humidities are more appropriate than those usually applied in industrial processes. [Copyright &y& Elsevier]

Biologically active amines were determined in commercial soybean products. The antioxidant polyamines were found in both non-fermented and fermented soybean products. Natto and tempeh showed the highest content of polyamines (75–124 and 11–24 mg/kg of spermidine and spermine, respectively). On the other hand, the bacterial-related biogenic amines, tyramine, histamine, tryptamine and β-phenylethylamine, were detected in practically all fermented products with a high variability. The highest contents were found in sufu, tamari and soybean paste. Extremely high tyramine and histamine contents, 1700 and 700 mg/kg, respectively, found in some sufu samples could be unhealthy. However, biogenic amines observed in the other soybean products should not be a risk for healthy consumers. However, individuals who take monoamine and diamine oxidase inhibitors drugs should be strongly recommended to avoid this kind of products in order to suffer no adverse health effects. These biogenic amines were not detected in non-fermented soybean products. [ABSTRACT FROM AUTHOR]

The application of ultra high pressure homogenisation (UHPH) treatments is useful to obtain fine and stable soymilk emulsions. Changes of isoflavones, protein digestibility and lysine availability during 4 months of storage at 20 ± 2 °C in soymilk treated by UHPH (300 MPa and 75 °C of inlet temperature) were studied in comparison to UHT-sterilised soymilk (142 °C, 6 s). Results indicated that although there was a significantly higher extractability of isoflavones in UHT (about 38%) than in UHPH-treated samples (about 15%), similar total contents were found at the end of storage. The interconversion of isoflavones into β-glucosides was faster in UHT than in UHPH-treated soymilk. Similar evolution of protein digestibility in both UHPH and UHT-treated soymilks was found, being slightly higher in the initial UHT (88.4%) than in UHPH-treated samples (83.3%). No great differences were observed in the % of blocked lysine among samples after treatments, neither in their evolution throughout storage. [ABSTRACT FROM AUTHOR]

Highlights: [•] Changes of isoflavones in ultra-high-pressure homogenised (UHPH) soymilks under refrigerated storage. [•] Aglycone formation was lower in UHPH than in heat-processed samples. [•] In-vitro protein digestibility was similar during storage in heat-pasteurised and UHPH soymilks. [•] Blocked lysine was higher during storage in heat-pasteurised than in UHPH soymilks. [Copyright &y& Elsevier]

Highlights: [•] The effect of UHPH on the bioactive compounds of soymilk was studied. [•] Phytosterol and isoflavone extractability increased with the UHPH treatments. [•] Tocopherols were affected by the effect of UHPH treatment. [•] Polyamines were stable with the combinations of pressure and temperature applied. [Copyright &y& Elsevier]

Abstract: Ultra high pressure liquid chromatography (UHPLC) has become a widely used technique in separation science as it can shorten analysis time while maintaining resolution and increasing sensitivity. Here we developed a UHPLC method with UV detection for the simultaneous determination of isoflavone aglycones (daidzein, glycitein and genistein), their corresponding glycoside forms (daidzin, glycitin and genistin), and acetyl and malonyl conjugate forms of glycosides (malonyldaidzin, malonylglycitin, malonylgenistin, acetyldaidzin, acetylglycitin, acetylgenistin) in soy milk. The method allowed reliable determinations of 12 isoflavones in less than 8min of chromatographic elution. It provided a satisfactory linearity ranging from 0.1 to 5mg/L, except for daidzin and genistin, for which it ranged from 0.1 to 10mg/L. In addition, it showed acceptable chromatographic sensitivity, with a detection limit lower than 0.05mg/L and a determination limit below 0.2mg/L. The precision, in terms of relative standard deviation, was lower than 5% and the accuracy, as mean recovery, was greater than 95%. Total isoflavone content in commercial soy milk samples (n =8) ranged from 1805.22 to 3195.59mg/kg dw. Genistin and Daidzin were the major isoflavones in all samples. The proportion of aglycones, ß-glucosides, and acetyl and malonyl glucosides differed among the samples. ß-Glucosides were identified as the predominant forms. [Copyright &y& Elsevier]

Abstract: The influence of technological factors (temperature and relative humidity of the manufacturing process and the diameter of the sausage) on the aminogenic activity of the strain Lactobacillus curvatus CTC273 was evaluated. Inoculation of sausages with L. curvatus CTC273 resulted in the accumulation of large amounts of biogenic amines (higher than 1000 mg/kg dry matter in some samples) during the manufacture of fuet and llonganissa sausages. Sausages produced via process ‘A’ (3 days at 20–23 °C and 90–95% RH followed by 20 days at 12–14 °C and 70% RH) contained significantly higher amounts (p < 0.05) of biogenic amines than those manufactured via process ‘B’ (23 days at 12–13 °C and 70–90% RH), specifically tyramine, cadaverine and phenylethylamine in llonganissa and phenylethylamine in fuet. The higher fermentation temperature and relative humidity during the fermentation stage in process ‘A’ promoted decarboxylase activity in L. curvatus CTC273 and thus favoured amine accumulation. The diameter of the sausages also influenced biogenic amine production. Higher amine levels were found (p < 0.05) in llonganissa than in fuet, regardless of the manufacturing conditions. The effect of the factors considered on the modulation of aminogenic activity is not necessarily linked to the effect of strain growth, but chiefly favouring proteolytic and decarboxylase reactions. [Copyright &y& Elsevier]

Abstract: The screening TLC method described enables the simultaneous identification and semi-quantification of eight biogenic amines with a large number of samples handled in a short period of time. The dansylation process time was drastically reduced from 80 to 18min by increasing the reaction temperature to 100°C. Bacteria could be classified as no, low, moderate or powerful amine producers when no spots were noticeable in TLC plates, less than 50mg/L, from 50 to 500mg/L, or more than 500mg/L of amines were present in the decarboxylase broth medium, respectively. This TLC method is a simpler, faster and less expensive alternative to other methods, such as differential culture media, HPLC and even more sensitive than other TLC procedures. [Copyright &y& Elsevier]

Abstract: Aminogenesis in traditional fermented sausages produced in Europe was studied during manufacturing process taking into account technological, physico-chemical and microbial factors. Tyramine was the major amine, followed by putrescine and cadaverine, although the occurrence of di-amines was much more variable. By principal component analysis, relationships between aminogenesis and the country of origin, physico-chemical parameters, processing conditions and microbial counts, were not found, probably due to the high dispersion observed in those variables. Therefore, biogenic amines occurred irrespectively of physico-chemical changes and technological conditions applied for sausage manufacture. By cluster analysis, five groups of fermented sausages were identified on the basis of their quantitative and qualitative profile of total biogenic amine content. Group A included products from very low to low total amine content (from not detected to 150mg/kg); group B, products with moderate levels (from 150 to 350mg/kg) tyramine being the major amine; group C, also with moderate amine contents but cadaverine being the major amine; and groups D and E, comprising products with high (from 350 to 550mg/kg) and very high (higher than 550mg/kg) amine content, respectively. Samples with moderate, high or very high levels of biogenic amines could be considered as products of less quality, and their consumption could be unhealthy for sensitive individuals or for those under classical monoamine oxidase inhibitor drug therapy. [Copyright &y& Elsevier]

Abstract: Naturally fermented sausages produced in nine traditional French processing units and their environmental surfaces were characterised by microbial and physico-chemical analyses. Salmonella and Staphylococcus aureus were not detected in the environment whereas Listeria monocytogenes was detected in four samples. Staphylococcus/Kocuria, lactic acid bacteria (LAB), Enterobacteriaceae, Pseudomonas, yeasts/moulds and enterococci contaminated the surfaces of two processing units, indicating insufficient cleaning and disinfection procedures. The final sausages did not present any health risk in seven of the processing units. In two of the processing units, the final sausages were contaminated with S. aureus and L. monocytogenes, respectively, at levels exceeding the maximum tolerable limit. Staphylococcus/Kocuria and LAB grew well in the products. Biogenic amines were found in the majority of the final products. Their occurrence was associated with high numbers of lactic acid bacteria and enterococci. The study outlined the processing and microbial diversities of French naturally fermented sausages. [Copyright &y& Elsevier]

Abstract: The application of high hydrostatic pressure (200MPa) to meat batter just before sausage fermentation and the inoculation of starter culture were studied to improve the safety and quality of traditional Spanish fermented sausages (fuet and chorizo). Higher amounts of biogenic amines were formed in chorizo than in fuet. Without interfering with the ripening performance in terms of acidification, drying and proteolysis, hydrostatic pressure prevented enterobacteria growth but did not affect Gram-positive bacteria significantly. Subsequently, a strong inhibition of diamine (putrescine and cadaverine) accumulation was observed, but that of tyramine was not affected. The inoculated decarboxylase-negative strains, selected from indigenous bacteria of traditional sausages, were resistant to the HHP treatment, being able to lead the fermentation process, prevent enterococci development and significantly reduce enterobacteria counts. In sausages manufactured with either non-pressurized or pressurized meat batter, starter culture was the most protective measure against the accumulation of tyramine and both diamines. [Copyright &y& Elsevier]