Yesim Özogul

Chemical, microbiological and sensory evaluation of Atlantic herring (Clupea harengus) stored in ice, modified atmosphere and vacuum pack

The effects of modified atmosphere and vacuum packing on K values, microbial and sensory changes in herring (2 days in ice post capture) when stored at 2±2°C are investigated for up to 16 days. Although chemical and microbiological analyses indicated that CO2 and vacuum packing prolonged the shelf life of herring, compared with storage in ice, sensory analysis showed that the extension of shelf life was only with MAP (10 days) and VP (8 days). It was also found that 60% CO2 treatments showed lower K values compared to those observed for aerobically held fish. The results showed significant (P<0.05) differences between ice and MAP storage conditions. In addition, CO2 decreased the formation of Hx compared to aerobically and vacuum-held samples.

Marine Bioactive Compounds and Their Health Benefits: A Review

The significance of marine creatures as a source of unique bioactive compounds is expanding. Marine organisms constitue nearly half of the wordwide biodiversity; thus, oceans and sea present a vast resource for new substances and it is considered the largest remaining reservoir of beneficial natural molecules that maight be used as functional constituents in the food sector. This review is an update to the information about recent functional seafood compounds (proteins, peptides, amino acids, fatty acids, sterols, polysaccharides, oligosaccharides, phenolic compounds, photosynthetic pigments, vitamins, and minerals) focusing on their potential use and health benefits.

Fat content and fatty acid compositions of 34 marine water fish species from the Mediterranean Sea.

Fish is the best source of polyunsaturated fatty acids (PUFA), specifically n-3 fatty acids, especially eicosapentaenoic acid and docosahexaenoic acid. The objective of the present study was to determine the fat content and fatty acid compositions of 34 marine water fish species from the Mediterranean Sea. The fatty acid compositions of fish consisted of 30.10–46.88% saturated fatty acids, 11.83–38.17% monounsaturated fatty acids and 20.49–49.31% PUFA. In most species, the following fatty acids were identified: mystiric acid (C14:0, 0.72–8.09%), pentadecanoic acid (15:0, 0.05–2.35%), palmitic acid (C16:0, 15.97–31.04%), palmitoleic acid (C16:1, 1.48–19.61%), heptadecanoic acid (C17:0, 0.31–1.84%), cis-10-heptadecenoic acid (C17:1, 0.17–2.01%), stearic acid (C18:0, 2.79–11.20%), oleic acid (C18:1n9, 2.44–28.97%), linoleic acid (C18:2n-6, 0.06–3.48%), arachidonic acid (C20:4n-6, 0.12–10.72%), cis-5,8,11,14,17-eicosapentaenoic acid (C20:5n-3, 1.94–10%) and cis-4,7,10,13,16,19-docosahexaenoic acid (C22:6n-3, 3.31–31.03%). The proportions of n-3 PUFA ranged from 12.66% for annular seabream to 36.54% for European hake, whereas the proportions of PUFA n-6 were between 1.24% for oceanic puffer and 12.76% for flathead mullet. The results of this study show that these fish species were rich in n-3 PUFA, especially, eicosapentaenoic acid and docosahexaenoic acid.

Nucleotide degradation and biogenic amine formation of wild white grouper (Epinephelus aeneus) stored in ice and at chill temperature (4 °C)

Sensory (cooked and uncooked), chemical (proximate composition, TVB-N, nucleotide degradation products and biogenic amines) and microbiological quality (TVC and total coliform) changes were investigated during storage of ungutted white grouper kept in ice and at chill temperature (4°C). According to the sensory assessment, the shelf life of white grouper was 16 days in ice and 4 days for fish stored at chill temperature. TVB-N values increased with storage time. Amines found in white grouper stored in ice were TMA, putrescine, cadaverine, 2-phenylethylamine, dopamine, agmatine, tryptamine and serotonin. Histamine, spermine, spermidine were never detected with either storage condition. The acceptability limit in terms of microbial count was exceeded at 8 days in ice and at 4 days for fish stored at chill temperature. Total coliform count was 2.8log10cfu/ml at 1 day and reached 10(5)cfu/ml for both storage conditions.

Seasonal effects in the nutritional quality of the body structural tissue of cephalopods

The most commonly-consumed cephalopods around the world (the common cuttlefish, Sepia officinalis, European squid, Loligo vulgaris, common octopus, Octopus vulgaris and musky octopus, Eledone moschata) were evaluated in terms of seasonal variations in proximate and fatty acid compositions. The arms of the octopuses were used for this study, whereas the mantle of the other species (squids and cuttlefish) were used for the analyses. The lipid contents of species were found to be very low and considered as lean. The lowest lipid content was obtained from E. moschata (0.60-0.68%), whereas L. vulgaris gave the highest level of lipid (1.34-1.92%) throughout all seasons. Unlike lipid content, protein contents of cephalopods did not change across the seasons. The fatty acid compositions of each species ranged from 28.18% to 35.28% saturated (SFA), 4.36-9.47% monounsaturated (MUFAs) and 43.58-56.55% polyunsaturated acids (PUFAs). The highest proportions of fatty acids in cephalopods were myristic acid (C14:0, 0.96-2.96%), palmitic acid (C16:0, 15.53-25.20%), heptadecanoic acid (C17:0, 1.05-2.56%), stearic acid (C18:0, 4.32-9.96%), oleic acid (cis18:1 n-9, 1.80-4.29%), cis-11-eicosenoic acid (C20:1, 2.07-4.69%), linoleic acid (C18:2 n-6, 0.17-1.95%), arachidonic acid (C20:4 n-6, 1.48-11.65%), cis-5,8,11,14,17-eicosapentaenoic acid (EPA, C20:5 n-3, 7.86-16.97%) and cis-4,7,10,13,16,19-docosahexaenoic acid (DHA, C22:6 n-3, 20.99-39.00%). The results indicated that these cephalopod species are excellent protein sources and very rich in n-3 fatty acids.

Evaluation of fatty acid profiles and mineral content of grape seed oil of some grape genotypes

The grape seeds of seven grape cultivars (Alphonse Lavallée, Muscat of Hamburg, Alicante Bouschet, Razakı, Narince, Öküzgözü and Horoz karası) and two rootstocks (Salt creek and Cosmo 2) were evaluated in terms of quality properties including protein, oil, moisture, ash, fatty acid composition and mineral contents. The oil contents were found to be different for each cultivar, which ranged from 10.45% (Razakı) to 16.73% (Salt creek). Saturated fatty acid values were less than the values of monounsaturated fatty acids and polyunsaturated fatty acids in all genotypes. Among the identified fatty acids, linoleic acid (C18:2) was the predominant fatty acid and followed by oleic acid (C18:1) and palmitic acid (C16:0) in all varieties. The results of mineral analysis showed that all varieties contained considerable amount of macro and micro elements. These grape seeds could be used as a food supplement to improve the nutritive value of the human diet.

Technological Factors Affecting Biogenic Amine Content in Foods: A Review

Biogenic amines (BAs) are molecules, which can be present in foods and, due to their toxicity, can cause adverse effects on the consumers. BAs are generally produced by microbial decarboxylation of amino acids in food products. The most significant BAs occurring in foods are histamine, tyramine, putrescine, cadaverine, tryptamine, 2-phenylethylamine, spermine, spermidine, and agmatine. The importance of preventing the excessive accumulation of BAs in foods is related to their impact on human health and food quality. Quality criteria in connection with the presence of BAs in food and food products are necessary from a toxicological point of view. This is particularly important in fermented foods in which the massive microbial proliferation required for obtaining specific products is often relater with BAs accumulation. In this review, up-to-date information and recent discoveries about technological factors affecting BA content in foods are reviewed. Specifically, BA forming-microorganism and decarboxylation activity, genetic and metabolic organization of decarboxylases, risk associated to BAs (histamine, tyramine toxicity, and other BAs), environmental factors influencing BA formation (temperature, salt concentration, and pH). In addition, the technological factors for controlling BA production (use of starter culture, technological additives, effects of packaging, other non-thermal treatments, metabolizing BA by microorganisms, effects of pressure treatments on BA formation and antimicrobial substances) are addressed.

Biochemical composition of some red and brown macro algae from the Northeastern Mediterranean Sea.

Proximate analysis and the fatty acid profile of brown algae (Stypopodium schimperii) and red algae (Spyridia filamentosa, Acanthophora nayadiformis and Halymenia floresii) were investigated. The highest protein content was obtained from H. floresii (3.05% on a dry weight basis) whereas the lowest protein content was obtained from S. schimperii (1.12% dry weight). The lipid content of macro algae ranged from 1.10% for S. filamentosa to 11.53% dry weight for S. schimperii. The ash content of all algae species were found to be high (17.98–27.15%) on a dry weight basis. The fatty acid compositions of macro algae species were in the range 29.92–68.93% saturated, 17.88–39.23% monounsaturated and 6.0–17.57% polyunsaturated acids. Among them, those occurring in the highest proportions were palmitic acid (C16:0, 28.36–64.67%), myristoleic acid (C14:1, 5.54–6.7%), palmitoleic acid (C16:1, 3.33–19.51%), oleic acid (C18:1n9 cis, 6.62–13.92%), linoleic acid (C18:2n6, 1.03–4.65%), arachidonic acid (C20:4n6, 1.2–6.9%), and cis-5,8,11,14,17-eicosapentaenoic acid (C20:5n3, 1.07–9.89%). According to results obtained from this study, these macro algae species can be regarded as a potential source for food or the neutraceutical industry.

Significance of antioxidants for seafood safety and human health.

The demand for high-quality seafood products is constantly growing worldwide. Nevertheless, seafood is susceptible to rapid rancidity mainly due to lipid oxidation and microbiological spoilage. Thus, treatment with antioxidants offers a preservation technique that can prolong the shelf life of seafood. However, because of food safety and health concerns about the use of synthetic antioxidants, there is growing interest in the application of natural antioxidants, mainly plant extracts and compounds, as an alternate means of confronting the problem of lipid oxidation. In this review, up-to-date information and recent discoveries about different naturally occurring antioxidants on the oxidation progress, synthetic antioxidants and their health concerns, health benefits of antioxidants, antioxidants used for seafood, and food safety concerns are addressed. The antibacterial effects of natural antioxidants are also reviewed. Finally, the most effective methods for analyzing a wide range of antioxidants in plants are described.

Determination of the quality parameters of pike perch Sander lucioperca caught by gillnet, longline and harpoon in Turkey

The effects of the different catching methods (gillnet, longline, harpoon) on sensory, chemical (pH, total volatile base nitrogen, K-value) and microbiological (total viable count [TVC]) changes in pike perch Sander lucioperca stored in ice were investigated. The same soaking time was used for both gillnet and longline fishing. The catching method had considerable influence on the freshness quality of pike perch. The acceptable shelf life was 15 days for pike perch caught by gillnet, and 22 days for longline and harpoon. The initial concentrations of inosine monophosphate (2.4 μmol/g) in pike perch caught by gillnet were significantly lower (P<0.05) than longline (4.1 μmol/g). and especially by harpoon (16.7 μmol/g). However, the initial K-values for fish caught by harpoon were significantly (P<0.05) lower (24.36%) than fish caught by longline and gillnet (57.69%, 64.41%, respectively). The average K, Ki, G and H-values at rejection day in terms of sensory assessment were approximately 90, 98, 156 and 40%, respectively, for all catching methods during ice storage. However, TVC reached 7.0 log cfu/g after approximately 11 days of storage for fish caught by gillnet, 19 days for fish caught by longline and 8 days for fish caught by harpoon. The result of this study suggests that the best catching method for preserving the freshness of pike perch is longline, based on the data obtained from the sensory and microbiological analysis.