Oyster Crassostrea gigas, a good model for correlating viral and chemical contamination in the marine environment.

To establish a relationship between viruses and chemicals, they were analysed in oyster Crassostrea gigas from an Italian experimental station. The chemicals concentrations were: Σ6 NDL-PCBs 0.82-7.12 ng g-1; BaP LOQ (<0.2 µg kg-1) to 1.2 µg kg-1; PAH4 LOQ (<0.2 µg kg-1) to 9.8 µg kg-1; Cd 0.073-0.365 mg kg-1; Pb 0.010-0.487 mg kg-1; and Hg < LOQ (0.089 mg kg-1). The viruses identified included: noroviruses (NoVGI/GII), astrovirus (AsV), rotavirus (RV), adenovirus (AdV), and sapovirus (SaV), while hepatitis A, hepatitis E, and Aichi viruses were not detected. Significant correlations were observed for NDL-PCBs with NoVGI, NoVGII, and AdV; BaP and PAH4 with NoVGI and AsV; Cd with RV; Pb with NoVGI and AsV; PAHs with Pb; AsV with NoVGI; and AdV with NoVGII. The study indicated as C. gigas is a model for correlating pollutants and foodborne viruses, whose co-presence may represent an additional food safety risk.

Quantitative Real-Time PCR and Digital PCR to Evaluate Residual Quantity of HAV in Experimentally Depurated Mussels.

Kinetics of hepatitis A virus (HAV) accumulation and depuration from mussels (Mytilus galloprovincialis) was studied in an experimental depuration system. Different parameters likely to influence the rate of virus accumulation and elimination were evaluated. Analyses were carried out by both real-time RT-qPCR and digital PCR. Results demonstrated that the animals start to concentrate the virus already after one hour and reach the maximum level of contamination in 6 h of experiment. With respect to depuration, HAV showed a rapid reduction of the concentration (89%) during the first 24-48 h of experiment and a very slow virus decrement in the following days with a 1% residual RNA at the ninth day of depuration. When process parameters likely to increase the depuration rate (presence of ozone, microalgal feeding, presence of lactic bacteria, pre-treatment with digestive enzymes) were tested, no significant differences in the kinetics were observed. Only treatment with pancreatin seemed to positively affect depuration in the first two days of the experiment.

Volatile compounds, physicochemical and sensory characteristics of Colatura di Alici, a traditional Italian fish sauce.

BACKGROUND: The present study reports for the first time the physical, chemical and sensory characterization of a traditional fish sauce from Italy, called 'Colatura di Alici', which is considered to be the direct descendant of the ancient roman sauce 'Garum'. RESULTS: Among the volatile compounds, carboxylic acids, aldehydes, sulphuric compounds and pyrazines were identified. The most abundant compounds identified were 3-methyl-butanoic acid, nonanal and 3-methyl-butanal. The sample A had the highest amount of volatile fatty acids (>250 µg kg-1 ) and sample B had the highest concentration of aldehydes (>80 µg kg-1 ). These volatile compounds arise from the long fermentation activity and oxidation of fatty acids of the fish flesh and are responsible for the strong cheesy and fishy aroma. The protein content ranged from 90 to 130 g kg-1 , and the soluble solids ranged from 30 to 38 °Brix, as a result of the high amount of NaCl used during processing. The sensory analysis showed a great intensity for the cheesy, fishy and umami attributes, and a medium intensity for the roasted and meaty attributes. CONCLUSION: For the first time, the volatile compounds and sensory characteristics of this traditional fish sauce are reported. The samples differ in terms of sensory and aromatic profiles. These differences are probably linked to the poorly standardized methods used in the production process. Overall, the results of the present study could be used by local fish sauce producers to monitor the quality of the product and to improve the production process. © 2020 Society of Chemical Industry.

Accumulation and Depuration Kinetics of Rotavirus in Mussels Experimentally Contaminated.

Bivalve mollusks as filter-feeders concentrate in their digestive tissue microorganisms likely present in the harvesting water, thus becoming risky food especially if consumed raw or poorly cooked. To eliminate bacteria and viruses eventually accumulated, they must undergo a depuration process which efficacy on viruses is on debate. To better clarify the worth of the depuration process on virus elimination from mussels, in this study we investigated rotavirus kinetics of accumulation and depuration in Mytilus galloprovincialis experimentally contaminated. Depuration process was monitored for 9 days and virus residual presence and infectivity were evaluated by real time quantitative polymerase chain reaction, cell culture and electron microscopy at days 1, 2, 3, 5, 7, 9 of depuration. Variables like presence of ozone and of microalgae feeding were also analyzed as possible depuration enhancers. Results showed a two-phase virus removal kinetic with a high decrease in the first 24 h of depuration and 5 days necessary to completely remove rotavirus.

Biochemical composition and in vitro digestibility of Galdieria sulphuraria grown on spent cherry-brine liquid.

The aim of this work was to valorise an industrial food by-product and to produce a microalgal biomass rich in phytochemicals at high added value for food and nutraceutical applications. The biochemical composition, in vitro digestibility and antioxidant activity of Galdieria sulphuraria biomass grown heterotrophically on standard medium (SM) and on spent Cherry-Brine Liquid (sCBL) were assessed and compared. The biomass produced in sCBL was characterized by a lower content of proteins and lipids, while showing an increase in carbohydrates and polyphenols (5.3 vs 1.6 mg g-1). The sCBL biomass lipid moiety had a lower palmitic and linoleic acid content and a higher oleic acid concentration than SM. The total protein digestibility of Galdieria grown in SM and sCBL was 79% and 63% respectively. The antioxidant activity (AA) of G. sulphuraria biomass grown in sCBL was significantly higher than that grown in SM. Studying the AA release for sCBL biomass during the digestion, the highest value was found in the intestinal phase. In conclusion, G. sulphuraria has a valuable nutritional profile and could become a valuable source of phytochemicals, depending on the cultivation media. Cultivation on sCBL would allow an environmentally and economically sustainable process, valorising the food by-product and producing a microalgal biomass rich in cherry anthocyanins with high AA released at the intestinal level.

Comparative analysis of photosynthetic and respiratory parameters in the psychrophilic unicellular green alga Koliella antarctica, cultured in indoor and outdoor photo-bioreactors.

Effect of temperatures and illumination of temperate winter on photosynthesis and respiration was studied in the psychrophilic microalgae, Koliella antarctica (Trebouxiophyceae). Outdoor and indoor algal cultures were compared. Photosynthetic as well as respiration rates increased as light and temperature increased, until 35 °C, more in outdoor than in indoor cells, in agreement with the calculated Q 10 values. K. antarctica showed important strategy mechanisms of adaption to the several temperature and light conditions. These significant photo-acclimation and thermo-acclimation abilities make it possible to cultivate Koliella for different uses, under less expensive outdoor conditions. Therefore, K. antarctica shows important strategy mechanisms of adaption to various temperature and light conditions; moreover, by varying the culture conditions, it is possible to modulate and optimize the growth and accordingly the biomass production. This is a very interesting point since it has been proved that this microalga is a promising potential source of functional ingredients, such as polyunsaturated fatty acids and carotenoids, suitable for industrial purposes.

Evaluation of anaerobic digestates from different feedstocks as growth media for Tetradesmus obliquus, Botryococcus braunii, Phaeodactylum tricornutum and Arthrospira maxima.

In this paper, two freshwater microalgae (Tetradesmus obliquus and Botryococcus braunii), a marine diatom (Phaeodactylum tricornutum) and a photosynthetic cyanobacterium (Arthrospira maxima) were investigated for their ability to grow on liquid digestates (LDs). Three LDs were obtained from anaerobic digestion of different organic wastes: zootechnical (ZW LD), vegetable biomass (VW LD) and the organic fraction of municipal solid wastes (MW LD). All the strains showed the same growth performance on VW LD as on the respective standard media (SM), while ZW LD was efficient only for growth of T. obliquus and B. braunii. MW LD was the poorest growth medium for all the strains. Data on nutrient removal efficiency showed that A. maxima and T. obliquus made the best use of NH4+-N with removal values ranging between 98.9-99.8%, while P. tricornutum and B. braunii showed values of 79.0 and 88.5% respectively. Applying repeated batch cultivation in photobioreactors, the biochemical composition of A. maxima and T. obliquus biomass grown on ZW LD and VW LD, showed an increase of lipid, carbohydrates and ash in both microalgae. Biomass biochemical profiles suggest possible applications in feed, chemicals and energy sectors.

Functional ingredients from microalgae.

A wide variety of natural sources are under investigation to evaluate their possible use for new functional ingredient formulation. Some records attested the traditional and ancient use of wild harvested microalgae as human food but their cultivation for different purposes started about 40 years ago. The most popular species are Arthrospira (traditional name, Spirulina), Chlorella spp., Dunaliella spp. and Haematococcus spp. Microalgae provide a bewildering array of opportunities to develop healthier food products using innovative approaches and a number of different strategies. Compared to other natural sources of bioactive ingredients, microalgae have many advantages such as their huge biodiversity, the possibility to grow in arid land and with limited fresh water consumption and the flexibility of their metabolism, which could be adapted to produce specific molecules. All these factors led to very sustainable production making microalgae eligible as one of the most promising foods for the future, particularly as source of proteins, lipids and phytochemicals. In this work, a revision of the knowledge about the use of microalgae as food and as a source of functional ingredients has been performed. The most interesting results in the field are presented and commented upon, focusing on the different species of microalgae and the activity of the nutritionally relevant compounds. A summary of the health effects obtained together with pros and cons in the adoption of this natural source as functional food ingredients is also proposed.

Biological activities of dermatological interest by the water extract of the microalga Botryococcus braunii.

The use of microalgae in the skin care market is already established although the scientific rationale for their benefit was not clearly defined. In this work, the biological activities of dermatologic interest of the water extract from the microalga Botryococcus braunii (BBWE) were evaluated by a battery of in vitro assays. At concentrations ranging from 0.1 to 0.001 % (w/v) BBWE promoted adipocytes differentiation by inhibiting hormone-sensitive lipase, thus promoting triglyceride accumulation in the cells. BBWE also induced gene expression of proteins involved in the maintenance of skin cells water balance such as aquaporin-3 (AQP3), filaggrin (FLG) and involucrin (INV). 0.1 % BBWE increased the gene expression of AQP3 of 2.6-folds, that of FLG and INV of 1.5- and 1.9-folds, respectively. Moreover, it induced the biosynthesis of collagen I and collagen III by 80 and 40 %, respectively, compared to the untreated control. BBWE antioxidant activity, evaluated by oxygen radical absorbance capacity (ORAC) assay, was of 43.5 µmol Trolox per gram of extract: a quite high value among those found for other microalgae extracts. BBWE inhibited the inducible nitric oxide synthase (iNOS) gene expression and the consequent nitrite oxide (NO) production under oxidative stress. At a concentration of 0.02 % BBWE reduced by 50 % the expression of iNOS and by about 75 % the NO production. Taken together, the results demonstrated that B. braunii water extract exerted an array of biological activities concurring with the skin health maintenance; therefore, it is a potential bioactive ingredient to be included in cosmetic products.