Effect of acid treatment on extraction yield and gel strength of gelatin from whiptail stingray (Dasyatis brevis) skin

Food Science and Biotechnology - Chemical properties of fish gelatins differ from those of conventional mammalian sources, representing an attractive technological alternative for the food...     

Evaluation of aeration and substrate concentration on the production of carotenoids by <Emphasis Type="Italic">Sporidiobolus salmonicolor</Emphasis> (CBS 2636) in bioreactor

This study aimed at optimising the cultivation conditions for the production of carotenoids by Sporidiobolus salmonicolor (CBS 2636) in a bioreactor. The maximum content of total carotenoids in the full factorial design 22 was 3131.3 μg/L in synthetic medium with 80 g/L of glucose, 15 g/L of peptone, 5 g/L of malt extract, aeration of 1.5 vvm, agitation of 180 rpm, initial pH of 4.0 at 25 °C. In the kinetic study, we could observe that the bioproduction of carotenoids is associated with cell growth in the exponential phase, and the average specific growth (μ) in bioreactor is 0.046 h⁻¹ with a maximum yield of 0.19 g cells/L h. The maximum yield of carotenoids (60.0 μg/Lh) is observed at 50-h bioproduction. The conversion factor for total organic carbon (TOC) in cells (Y_X/_SCOT) was 2.97 g/g (0–50 h) and 0.254 g/g (50–100 h), the conversion factor glucose into cells (Y_X/Sglicose) was 0.168 g/g (0–100 h). The specific production of carotenoids (Y_P/_X) was 390 μg of carotenoids per gram of cells, the conversion factor of carbon in the product (Y_P/SCOT) was 107.8 μg/g (0–50 h) and 34.4 μg/g (50–100 h), whereas the factor Y_P/_Sglicose was 69.59 μg/g. The agitation and aeration provided better homogeneity in the culture medium, and hence greater availability of nutrients and oxygen, leading to higher production of carotenoids.     

The Influence of Oxygen Volumetric Mass Transfer Rates on Cyclodextrin Glycosyltransferase Production by Alkaliphilic Bacillus circulans in Batch and Fed-Batch Cultivations

In this work, the influence of oxygen mass transfer rates on the production of cyclodextrin glycosyltransferase (CGTase) by the alkaliphilic bacterium Bacillus circulans ATCC 21783 was investigated. Experimental design and response surface methodology were applied to optimize agitation speed and air flow rate in batch cultivations, in order to identify their significant effects and interactions with the synthesis of CGTase. Results were expressed as the volumetric mass transfer rates of oxygen (k_la, [per hour]). The maximal CGTase productivity of 155 U mL⁻¹ h⁻¹ was achieved with k_la of 48 h⁻¹. CGTase production was also studied in fed-batch cultures using the optimized parameters obtained in the batch experiments. The maximal CGTase productivity on fed-batch cultivations was 137 U mL⁻¹ h⁻¹ with feeding rates of starch at 0.17 g L⁻¹ h⁻¹.     

Harmful dinoflagellate Ostreopsis cf. ovata Fukuyo: detection of ovatoxins in field samples and cell immunolocalization using antipalytoxin antibodies

Ostreopsis cf. ovata, a benthic dinoflagellate often blooming along the Mediterranean coasts, has been associated with toxic events ranging from dyspnea to mild dermatitis. In late September 2009, an Ostreopsis cf. ovata bloom occurred in the Gulf of Trieste (Northern Adriatic Sea; Italy), causing pruritus and mild dermatitis in beachgoers. An integrated study was initiated to characterize Ostreopsis cells by light and confocal microscopy, PCR techniques, immunocytochemistry, and high resolution liquid chromatography-mass spectrometry (HR LC-MS). The presence of Ostreopsis cf. ovata of the Atlantic/Mediterranean clade was unambiguously established by morphological and genetic analyses in field samples. Several palytoxin-like compounds (ovatoxin-a,-b,-c,-d,-e) were identified by HR LC-MS, ovatoxin-a being the most abundant (45-64 pg/cell). Surprisingly, no palytoxin was detected. For the first time, monoclonal and polyclonal antipalytoxin antibodies revealed the intracellular cytoplasmic localization of ovatoxins, suggesting their cross-reactivity with these antibodies. Since harmful dinoflagellates do not always produce toxins, the immunocytochemical localization of ovatoxins, although qualitative, can provide an early warning for toxic Ostreopsis cells before their massive diffusion and/or concentration in seafood.     

Distribution of T-2 and HT-2 toxins in milling fractions of durum wheat

The effect of processing on mycotoxin content in milling fractions has been investigated in 10 samples of durum wheat contaminated with T-2 and HT-2 toxins at levels ranging from 97 to 5,954 μg/kg (sum of T-2 and HT-2 toxins). Either naturally contaminated samples or samples artificially inoculated with Fusarium sporotrichioides under field conditions were used. A method based on liquid chromatography-tandem mass spectrometry coupled with immunoaffinity column cleanup was validated in-house for the simultaneous analysis of both toxins in a variety of matrices, including uncleaned wheat, cleaned wheat, screenings, bran, red dog, fine middlings, and semolina. Mean recoveries from samples spiked with T-2 and HT-2 toxins at levels of 100 μg/kg ranged from 85 to 107%, with relative standard deviations (RSDs) lower than 14%. The milling process led to an increase of T-2 and HT-2 toxin contents up to 13- and 5-fold in screenings and bran, respectively, compared with occurrence in the uncleaned wheat; however, an overall reduction of T-2 and HT-2 toxins by 54% (RSD, 20%) and 89% (RSD, 3%) was observed in cleaned wheat and in semolina, respectively.     

Validating allergen coding genes (Cor a 1, Cor a 8, Cor a 14) as target sequences for hazelnut detection via Real-Time PCR

Hazelnuts have been shown to contain different allergenic proteins. Amongst these, major allergens Cor a 1 and Cor a 8 and the 2S albumin Cor a 14 were selected as targets to comparatively validate three Real-Time PCR protocols. We investigated both on the choice of the amplification target, and on the matrix effect on different sample foods. Applying statistics on the validation parameters obtained from the three protocols, we showed a significant difference in Ct values. This could turn critical when a high sensitivity method is required for the detection of hazelnut traces, confirming how fundamental the choice of the template during primer design phase is. Concluding, statistical approach represents a useful tool for the identification of the best performing primer pairs in Real-Time PCR. Cor a 8 gene permitted the identification of hazelnut based ingredients in complex foods, providing a significantly higher sensitivity in the PCR amplification, when compared to Cor a 1 and Cor a 14.     

Determination of carnosine,anserine, homocarnosine,pentosidine and thiobarbituric acid reactive substances contents in meat from different animal species

The aim of this research was to determine the content of the histidinic antioxidants, advanced glycation end products (pentosidine) and thiobarbituric acid reactive substance (TBARS) in the meat from different animal species. Carnosine, anserine, homocarnosine and pentosidine were quantified by HPLC/MS, while TBARS was determined by photometric measurements. The total CRCs (carnosine + anserine + homocarnosine) content was in the increasing order: beef < rabbit < pork < horse < chicken < turkey. The analysis showed traces of pentosidine above the instrumental determination limits in all the meat samples, while the susceptibility of these meat to lipid oxidation decreased from beef to chicken, with the exception of turkey meat, which presented a high TBARS content towards even though its total CRCs was the highest. The structure of homocarnosine was elucidated by high resolving power multistage mass spectrometry.     

Antifungal activity of sourdough fermented wheat germ used as an ingredient for bread making

This study aimed at investigating the antifungal activity of sourdough fermented (Lactobacillus plantarum LB1 and Lactobacillus rossiae LB5) wheat germ (SFWG). Preliminarily, methanol and water/salt-soluble extracts from SFWG were assayed by agar diffusion towards Penicillium roqueforti DPPMAF1. As shown by hyphal radial growth rate, the water/salt-soluble extract showed the inhibition of various fungi isolated from bakeries. The antifungal activity was attributed to a mixture of organic acids and peptides which were synthesized during fermentation. Formic (24.7 mM) acid showed the highest antifungal activity. Four peptides, having similarities with well known antifungal sequences, were identified and chemically synthesized. The minimal inhibitory concentration was 2.5–15.2 mg/ml. Slices of bread made by addition of 4% (wt/wt) of freeze dried SFWG were packed in polyethylene bags and stored at room temperature. Slices did not show contamination by fungi until at least 28 days of storage and behaved as the calcium propionate (0.3%, wt/wt).     

Effect of water/fuel emulsions and a cerium-based combustion improver additive on HD and LD diesel exhaust emissions

One of the major technological challenges for the transport sector is to cut emissions of particulate matter (PM) and nitrogen oxides (NOx) simultaneously from diesel vehicles to meet future emission standards and to reduce their contribution to the pollution of ambient air. Installation of particle filters in all existing diesel vehicles (for new vehicles, the feasibility is proven) is an efficient but expensive and complicated solution; thus other short-term alternatives have been proposed. It is well known that water/diesel (W/ D) emulsions with up to 20% water can reduce PM and NOx emissions in heavy-duty (HD) engines. The amount of water that can be used in emulsions for the technically more susceptible light-duty (LD) vehicles is much lower, due to risks of impairing engine performance and durability. The present study investigates the potential emission reductions of an experimental 6% W/D emulsion with EURO-3 LD diesel vehicles in comparison to a commercial 12% W/D emulsion with a EURO-3 HD engine and to a Cerium-based combustion improver additive. For PM, the emulsions reduced the emissions with -32% for LD vehicles (mass/km) and -59% for the HD engine (mass/ kWh). However, NOx emissions remained unchanged, and emissions of other pollutants were actually increased forthe LD vehicles with +26% for hydrocarbons (HC), +18% for CO, and +25% for PM-associated benzo[a]pyrene toxicity equivalents (TEQ). In contrast, CO (-32%), TEQ (-14%), and NOx (-6%) were reduced by the emulsion for the HD engine, and only hydrocarbons were slightly increased (+16%). Whereas the Cerium-based additive was inefficient in the HD engine for all emissions except for TEQ (-39%), it markedly reduced all emissions for the LD vehicles (PM -13%, CO -18%, HC -26%, TEQ -25%) except for NOx, which remained unchanged. The presented data indicate a strong potential for reductions in PM emissions from current diesel engines by optimizing the fuel composition.