Effects of modified atmosphere packaging on microbiological load and physico-chemical properties of barramundi (Lates calcarifer Bloch) fillets at 8°C

Different modified atmosphere conditions with various CO2 concentrations on microbial load (psychrophile, mesophile aerobic and anaerobic bacteria) and physico-chemical properties of barramundi (Lates calcarifer Bloch) fillets stored at 8°C were compared to determine the best packaging conditions. The gas conditions evaluated were 100% CO2 (M1), 75% CO2/25% N2 (M2), 50% CO2/50% N2 (M3), 25% CO2/75% N2 (M4) and 100% N2 (control). High CO2 concentration (M1 and M2) of fish fillets delayed the psychrophilic bacteria growth compared to low CO2 concentration (50% and 25% CO2) as well as the mesophilic, anaerobic and histamine forming bacteria. We concluded that the atmosphere with 75:25% and 100:0 (CO2:N2) had the most appropriate gas composition to inhibit the microbial growth and prolong the shelf life of barramundi fillets (p<0.05)

Use of Spectroscopic Techniques to Monitor Changes in Food Quality during Application of Natural Preservatives: A Review

Consumer demand for food of high quality has driven research for alternative methods of food preservation on the one hand, and the development of new and rapid quality assessment techniques on the other hand. Recently, there has been a growing need and interest in healthier food products, which has led to an increased interest in natural preservatives, such as essential oils, plant extracts, and edible films and coatings. Several studies have shown the potential of using biopreservation, natural antimicrobials, and antioxidant agents in place of other processing and preservation techniques (e.g., thermal and non-thermal treatments, freezing, or synthetic chemicals). Changes in food quality induced by the application of natural preservatives have been commonly evaluated using a range of traditional methods, including microbiology, sensory, and physicochemical measurements. Several spectroscopic techniques have been proposed as promising alternatives to the traditional time- consuming and destructive methods. This review will provide an overview of recent studies and highlight the potential of spectroscopic techniques to evaluate quality changes in food products following the application of natural preservatives

A Pilot Randomized Controlled Trial to Explore Cognitive and Emotional Effects of Probiotics in Fibromyalgia

It has recently been found that microbes in the gut may regulate brain processes through the gut microbiota–brain axis, which modulates affection, motivation and higher cognitive functions. According to this finding, the use of probiotics may be a potential treatment to improve physical, psychological and cognitive status in clinical populations with altered microbiota balance such as those with fibromyalgia (FMS). Thus, the aim of the present pilot study with a double-blind, placebo-controlled, randomised design was to test whether a multispecies probiotic may improve cognition, emotional symptoms and functional state in a sample of patients diagnosed with FMS. Pain, impact of FMS, quality of life, anxiety and depressive symptoms were measured during the pre- and post-intervention phases; participants also completed two computerised cognitive tasks to assess impulsive choice and decision-making. Finally, urinary cortisol concentration was determined. To our knowledge, this is the first study that explore the effect of a multispecies probiotic in FMS patients. Our results indicated that probiotics improved impulsivity and decision-making in these patients. However, more research is needed to further explore the potential effects of probiotics on other cognitive functions affected in FMS as well as in other clinical populations

Approaches in biotechnological applications of natural polymers

Natural polymers, such as gums and mucilage, are biocompatible, cheap, easily available and non-toxic materials of native origin. These polymers are increasingly preferred over synthetic materials for industrial applications due to their intrinsic properties, as well as they are considered alternative sources of raw materials since they present characteristics of sustainability, biodegradability and biosafety. As definition, gums and mucilages are polysaccharides or complex carbohydrates consisting of one or more monosaccharides or their derivatives linked in bewildering variety of linkages and structures. Natural gums are considered polysaccharides naturally occurring in varieties of plant seeds and exudates, tree or shrub exudates, seaweed extracts, fungi, bacteria, and animal sources. Water-soluble gums, also known as hydrocolloids, are considered exudates and are pathological products; therefore, they do not form a part of cell wall. On the other hand, mucilages are part of cell and physiological products. It is important to highlight that gums represent the largest amounts of polymer materials derived from plants. Gums have enormously large and broad applications in both food and non-food industries, being commonly used as thickening, binding, emulsifying, suspending, stabilizing agents and matrices for drug release in pharmaceutical and cosmetic industries. In the food industry, their gelling properties and the ability to mold edible films and coatings are extensively studied. The use of gums depends on the intrinsic properties that they provide, often at costs below those of synthetic polymers. For upgrading the value of gums, they are being processed into various forms, including the most recent nanomaterials, for various biotechnological applications. Thus, the main natural polymers including galactomannans, cellulose, chitin, agar, carrageenan, alginate, cashew gum, pectin and starch, in addition to the current researches about them are reviewed in this article.. }To the Conselho Nacional de Desenvolvimento Cientfíico e Tecnológico (CNPq) for fellowships (LCBBC and MGCC) and the Coordenação de Aperfeiçoamento de Pessoal de Nvíel Superior (CAPES) (PBSA). This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit, the Project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER-027462) and COMPETE 2020 (POCI-01-0145-FEDER-006684) (JAT)

The proximate composition of three marine pelagic fish: blue whiting (Micromesistius poutassou), boarfish (Capros aper) and Atlantic herring (Clupea harengus)

peer reviewedThis study presents data from an in-depth proximate compositional analysis of three marine fish species: blue whiting (Micromesistius poutassou), boarfish (Capros aper) and Atlantic herring (Clupea harengus). These fish contained significant amounts of protein (16–17%), lipids (4–11%) and minerals (2–6% ash). The proteins, particularly from boarfish, had close to optimum amino acid profiles for human and fish nutrition. They compared favourably with other fish species in terms of total lipids and relative concentration of the omega-3 fatty acids docosahexaenoic acid and eicosapentaenoic acid (11.8–13.3% and 5.9–8.1% in triacylglycerols [TG] and 24.6–35.4% and 5.8–12.0% in phospholipids [PL]). Atlantic herring had the highest lipid content among the three fish and was found to contain high levels of PL poly-unsaturated fatty acids, including omega-3 fatty acids. Minerals detected in the fish included calcium (272–1,520 mg/100 g), phosphorus (363–789 mg/100 g), iron (1.07–2.83 mg/100 g), magnesium (40.70–62.10 mg/100 g), potassium (112.00–267.00 mg/100 g), selenium (0.04–0.06 mg/100 g), sodium (218.00–282.00 mg/100 g) and zinc (1.29–5.57 mg/100 g). Boarfish had the highest ash fraction and also the highest levels of all the minerals, except potassium. Atlantic herring had considerably lower mineral content compared with the other two species and, levels detected were also lower than those reported in previously published studies. Heavy metals contents were quantified, and levels were significantly below the maximum allowable limits for all elements except arsenic, which ranged from 1.34 to 2.44 mg/kg in the three fish species. Data outlined here will be useful for guiding product development. Future studies would benefit from considering catch season, sex and developmental stage of the fish

Formation of biogenic amines by Gram-negative rods isolated from fresh, spoiled, VP-packed and MAP-packed herring (Clupea harengus)

Bacterial strains (120) were isolated from fresh, spoiled, VP-packed and MAP-packed herring. Identified bacterial strains were investigated for their abilities to produce biogenic amines in histidine, lysine and ornithine decarboxylase broth by a rapid high-performance liquid chromatography (HPLC) method. The microflora of fresh herring was dominantly Pseudomonas (30%), Enterobacteriaceae (23.2%), Vibrio (13.3%) and Moraxella (13.3%) but, the microflora of herring stored in VP and MAP was dominated by species belonging to Vibrio (23.3%) and Moraxella (20%), which indicates that these packaging systems prevented the growth of Pseudomonas and Enterobacteriaceae. In a laboratory medium containing amino acid (histidine, ornithine and lysine), most of bacterial strains produced histamine, putrescine and cadaverine. The highest histidine decarboxylase activities were observed in Klebsiella oxytoca, Hafnia alvei and Proteus vulgaris which produced 396, 232 and 54 mg histamine/L, respectively in histidine-enriched broth. The accumulation of cadaverine by Klebsiella oxytoca and Hafnia alvei was 325 and 208 mg/l, respectively. All strains isolated produced putrescine in an ornithine-enriched broth, ranging from 3 to 249 mg/l. The production of putrescine by Klebsiella oxytoca and Hafnia alvei was 249 and 195 mg/l, respectively. Moraxella spp and Acinetobacter spp did not produce histamine which indicates they did not have histidine decarboxylase activity. © Springer-Verlag 2005

The ability of biogenic amines and ammonia production by single bacterial cultures

The amino acid decarboxylating activity and production of biogenic amines, trimethylamine and ammonia by Morganella morganii (two strains), Klebsiella pneumoniae (three strains), Hafnia alvei (two strains), Enterococcus faecalis, Photobacterium phosphoreum, Micrococcus sp., Psychrobacter immobilis, Corynebacterium sp., Vibrio fischeri, Vibrio harveyi and Pseudomonas putida were investigated using a rapid HPLC method. In a laboratory medium containing amino acid (histidine, ornithine, lysine, tyrosine and arginine), not all bacterial strains produced the biogenic amines but most of them produced histamine, putrescine, cadaverine and ammonia. Cadaverine production by Klebsiella pneumoniae (8152), Klebsiella pneumoniae (673), Klebsiella pneumoniae (2122), Hafnia alvei (6578), Hafnia alvei (11999), Vibrio fischeri (25) Vibrio harveyi (42) and Pseudomonas putida (10936) was 531, 422, 532, 485, 472, 343, 547 and 343 mg/l, respectively in lysine decarboxylase broth. Tyramine was produced in highest concentration (526 mg/l) by Enterococcus faecalis (775). Agmatine was not produced apart from Psychrobacter immobilis (100) in an arginine decarboxylase broth. © Springer-Verlag 2007