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.

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.

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 mu g kg(-1)) and sample B had the highest concentration of aldehydes (>80 mu g 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 degrees 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. (c) 2020 Society of Chemical Industry

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.

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.

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 Q10 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.

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.

The present work evaluated biomass productivity, carbon dioxide fixation rate, and biochemical composition of two microalgal species, Phaeodactylum tricornutum (Bacillariophyta) and Tetradesmus obliquus (Chlorophyta), cultivated indoors in high-technology photobioreactors (HT-PBR) and outdoors both in pilot ponds and low-technology photobioreactors in a greenhouse in southern Italy. Microalgae were grown in standard media, under nitrogen starvation, and in two liquid digestates obtained from anaerobic digestion of agro-zootechnical and vegetable biomass. P. tricornutum, cultivated in semi-continuous mode in indoor HT-PBRs with standard medium, showed a biomass productivity of 21.0 ± 2.3 g m−2 d−1. Applying nitrogen starvation, the lipid productivity increased from 2.3 up to 4.5 ± 0.5 g m−2 d−1, with a 24 % decrease of biomass productivity. For T. obliquus, a biomass productivity of 9.1 ± 0.9 g m−2 d−1 in indoor HT-PBR was obtained using standard medium. Applying liquid digestates as fertilizers in open ponds, T. obliquus gave a biomass productivity (10.8 ± 2.0 g m−2 d−1) not statistically different from complete medium such as P. tricornutum (6.5 ± 2.2 g m−2 d−1). The biochemical data showed that the fatty acid composition of the microalgal biomass was affected by the different cultivation conditions for both microalgae. In conclusion, it was found that the microalgal productivity in standard medium was about doubled in HT-PBR compared to open ponds for P. tricornutum and was about 20 % higher for T. obliquus.

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.

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.

Unicellular algae represent an interesting source of bioactive food ingredients. In this study, fatty acids and carotenoids of Koliella antarctica, a psychrophylic Antarctic unicellular alga, were investigated. K. antarctica was cultivated at different temperatures and harvested at the early exponential growth phase and at the late exponential growth phase. After 240h, at the end of the late exponential growth phase, the cell biomass concentration was 1.1gL−1 at 10°C while it was 2.2gL−1 at 15°C. The lipid profile of K. antarctica was rich in polyunsaturated fatty acids (PUFA) particularly at the early exponential phase (50.8% of total fatty acids). The comparison of data obtained from algae cultivated at 10°C and 15°C, showed at 15°C a strong increase in saturated lipids and a decrease in PUFA. At the same time the presence of EPA and DHA was marginally affected, with a percentage decrease around 15–20%. The productivity of EPA and DHA was similar at the two growth temperatures with maximum values of 0.6mgL−1day−1 and 1.3mgL−1day−1, at 10 and 15°C, respectively.

Chlorella vulgaris Beijerinck, strain 211/12, uses nitrate, nitrite and ammonium at pH 8.2 but not at pH 6.4 when kept under conditions of CO2‐deprivation, as observed in cell suspensions aerated with CO2‐free air during a 20–30. h period Most of the nitrate absorbed at pH 8.2, however, was not assimilated but was released into the external medium as nitrite and ammonium. Cells of Chlorella previously grown in phosphate‐limited continuous cultures were unable to absorb nitrate, nitrite or ammonium under conditions of phosphate starvation at either pH 6.4 or 8.2 in cell suspensions flushed with air containing 5% CO2, However, in cell suspensions flushed with CO2‐free air, the capacity of the alga to absorb and reduce nitrate and to excrete nitrite and ammonium at pH 8.2 was restored.It is hypothesized that in Chlorella the metabolism of nitrate, nitrite and ammonium is influenced by the availability of other nutrients and controlled by the cell's carbon status at the level of ion entry into the cell. With respect to nitrate this carbon‐dependent control is distinct and works independently of that triggered by the cell's nitrogen status.

Chemostat cultures of the unicellular alga Cyanidium caldarium have shown that under conditions of phosphate limitation nitrate reductase is completely derepressed even in cells growing in a large excess of ammonium, but that it occurs mainly in a catalytically inactive form. It is hypothesized that phosphate limitation contributes to maintaining intracellular level of glutamine suitable to stimulate inactivation but not repression of nitrate reductase. It is not excluded that in addition to variations in the intracellular level of glutamine, there are other metabolic events of the cell by which repression and inactivation of nitrate reductase could be differently influenced.

In the unicellular non-vacuolate red alga Cyanidium caldarium nitrate uptake occurs through two specific permease systems which, on the basis of kinetic constants can be defined as low affinity system and high affinity system. The high affinity system is saturated at very low nitrate concentrations (<1 μM), whereas the low affinity system is saturated only at high nitrate concentrations (Km=0.45±0.10 mM). The low affinity system is present in cells growing under conditions of nitrogen limitation as well as in cells growing in excess nitrate. In contrast, the high affinity system is present only in cells growing under conditions of nitrogen limitation. The high affinity system works only at acid pH and is inactive at neutral pH. The low affinity system is active both at acid and at neutral pH.