Changes in free amino acids and biogenic amines of Egyptian salted-fermented fish (Feseekh) during ripening and storage Rabie Mohamed a , Simon-Sarkadi Livia a, * , Siliha Hassan b , El-seedy Soher b , El Badawy Ahmed-Adel b a Department of Applied Biotechnology and Food Science, Budapest University of Technology and Economics, P.O. Box 91, H-1521 Budapest, Hungary b Department of Food Science, Faculty of Agriculture, Zagazig University, Egypt article info Article history: Received 14 October 2008 Received in revised form 27 October 2008 Accepted 19 December 2008 Keywords: Feseekh fish Biogenic amines Free amino acids Ripening Storage abstract The aim of this study was to investigate changes in the formation of amino acids and biogenic amines in Egyptian salted-fermented fish (Feseekh) during ripening (20 days) and storage (40–60 days). The total concentration of free amino acids increased from 8 (dry weight; DW) to 72 g/kg (DW) after 60 days of storage. The predominant free amino acids were leucine, glutamic acid, lysine, alanine, valine, aspartic acid, isoleucine and citrulline. Their concentrations accounted for 68% of the total concentration of amino acids after 60 days. The total contents of biogenic amines ranged from 84 to 1633 mg/kg (DW) during the investigated period. Cadaverine was the major amine detected in Feseekh at all sampling stages and its concentration varied between 21 and 997 mg/kg (DW). The histamine content (211 mg/kg DW) only exceeded the maximum tolerance level (200 mg/kg) after 60 days. It could be concluded that Feseekh can be consumed without any health risks between 20 and 40 days but it can be hazardous after 60 days due to the biogenic amine content. Ó 2008 Elsevier Ltd. All rights reserved. 1. Introduction Feseekh is the traditional name for the salted-fermented Bouri fish (Mugil cephlus) produced in Egypt. It is popular not only as an appetiser, but also as the main dish at some feasts in Egypt (El-Sebaiy & Metwalli, 1989). There are two types of Feseekh on the Egyptian market, the first type having a low salt content and being suitable for consumption after 15–20 days of maturing, whilst the second has a high salt content and can be eaten after 2–3 months of storage. From the nutritional point of view, Feseekh is a rich source of high quality protein, essential amino acids, vita- mins, and minerals. Fish is known to have an excellent essential amino acid compo- sition, which is why it is recommended for a balanced, healthy diet. The amino acid composition of foodstuffs does not vary greatly; however, the free amino acid composition changes considerably after processing and storage. The concentration of amino acids depends on the harvesting season and manner of feeding prior to capture. For example, large quantities of lysine and arginine can be found in fish harvested in the summer season (Aksnes & Brekken, 1988). Biogenic amines are naturally occurring, low molecular weight organic bases, ubiquitous in animals and plants. Putrescine, cadav- erine, spermidine and spermine have an aliphatic structure, hista- mine and tryptamine have a heterocyclic structure and tyramine and phenylethylamine have an aromatic structure. The formation of high levels of biogenic amines, especially his- tamine, in fish products may be rapid, and their development de- pends on the number of microorganisms present. Several genera are involved in toxicity, such as Bacillus, Citrobac- ter, Clostridium, Klebsiella, Escherichia, Proteus, Pseudomonas, Shi- gella, Photobacterium and the lactic acid bacteria (Lactobacillus, Pediococcus, and Streptococcus). These bacteria are capable of pro- ducing hazardous amounts of histamine in a very short period of time when the fish are kept at elevated temperatures (Omura, Price, & Olcott, 1978). From the toxicological point of view, the consumption of an excessive amount of biogenic amines can represent a health risk for sensitive individuals. The typical symptoms are nausea, hot flushes, cold sweat, palpitations, headaches, red rash and high or low blood pressure. It is thus important to monitor the levels of biogenic amines in foodstuffs and beverages from food safety aspects. Mietz and Karmas (1977) found that the histamine content var- ied extensively with the fish species and they created a biogenic amine index, calculated using the formula BAI = (mg/kg putres- cine + mg/kg cadaverine + mg/kg histamine)/(1 + mg/kg spermi- dine + mg/kg spermine). They found that BAI values exceeding 10 can be considered as an indication of the extent of quality loss. This opinion was confirmed by Mendes (1999), who examined the his- tamine formation in sardines and mackerel. 0308-8146/$ - see front matter Ó 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.foodchem.2008.12.077 * Corresponding author. Fax: +36 1 463 3855. E-mail address: sarkadi@mail.bme.hu (L. Simon-Sarkadi). Food Chemistry 115 (2009) 635–638 Contents lists available at ScienceDirect Food Chemistry journal homepage: www.elsevier.com/locate/foodchem