Biomonitoring of mercury and selenium in commercially important shellfish: Distribution pattern, health benefit assessment and consumption advisories.

This study aims to explore the concentrations of Se and Hg in shellfish along the Gulf of Mannar (GoM) coast (Southeast India) and to estimate related risks and risk-based consumption limits for children, pregnant women, and adults. Se concentrations in shrimp, crab, and cephalopods ranged from 0.256 to 0.275 mg kg-1, 0.182 to 0.553 mg kg-1, and 0.176 to 0.255 mg kg-1, respectively, whereas Hg concentrations differed from 0.009 to 0.014 mg kg-1, 0.022 to 0.042 mg kg-1 and 0.011 to 0.024 mg kg-1, respectively. Se and Hg content in bamboo shark (C. griseum) was 0.242 mg kg-1 and 0.082 mg kg-1, respectively. The lowest and highest Se concentrations were found in C. indicus (0.176 mg kg-1) and C. natator (0.553 mg kg-1), while Hg was found high in C. griseum (0.082 mg kg-1) and low in P. vannamei (0.009 mg kg-1). Se shellfishes were found in the following order: crabs > shrimp > shark > cephalopods, while that of Hg were shark > crabs > cephalopods > shrimp. Se in shellfish was negatively correlated with trophic level (TL) and size (length and weight), whereas Hg was positively correlated with TL and size. Hg concentrations in shellfish were below the maximum residual limits (MRL) of 0.5 mg kg-1 for crustaceans and cephalopods set by FSSAI, 0.5 mg kg-1 for crustaceans and 1.0 mg kg-1 for cephalopods and sharks prescribed by the European Commission (EC/1881/2006). Se risk-benefit analysis, the AI (actual intake):RDI (recommended daily intake) ratio was > 100%, and the AI:UL (upper limit) ratio was < 100%, indicating that all shellfish have sufficient level of Se to meet daily requirements without exceeding the upper limit (UL). The target hazard quotient (THQ < 1) and hazard index (HI < 1) imply that the consumption of shellfish has no non-carcinogenic health impacts for all age groups. However, despite variations among the examined shellfish, it was consistently observed that they all exhibited a Se:Hg molar ratio > 1. This finding implies that the consumption of shellfish is generally safe in terms of Hg content. The health benefit indexes, Se-HBV and HBVse, consistently showed high positive values across all shellfish, further supporting the protective influence of Se against Hg toxicity and reinforcing the overall safety of shellfish consumption. Enhancing comprehension of food safety analysis, it is crucial to recognize that the elevated Se:Hg ratio in shellfish may be attributed to regular selenoprotein synthesis and the mitigation of Hg toxicity by substituting Se bound to Hg.

A Generic LC-HRMS Screening Method for Marine and Freshwater Phycotoxins in Fish, Shellfish, Water, and Supplements.

Phycotoxins occur in various marine and freshwater environments, and can accumulate in edible species such as fish, crabs, and shellfish. Human exposure to these toxins can take place, for instance, through consumption of contaminated species or supplements and through the ingestion of contaminated water. Symptoms of phycotoxin intoxication include paralysis, diarrhea, and amnesia. When the cause of an intoxication cannot directly be found, a screening method is required to identify the causative toxin. In this work, such a screening method was developed and validated for marine and freshwater phycotoxins in different matrices: fish, shellfish, water, and food supplements. Two LC methods were developed: one for hydrophilic and one for lipophilic phycotoxins. Sample extracts were measured in full scan mode with an Orbitrap high resolution mass spectrometer. Additionally, a database was created to process the data. The method was successfully validated for most matrices, and in addition, regulated lipophilic phycotoxins, domoic acid, and some paralytic shellfish poisoning toxins could be quantified in shellfish. The method showed limitations for hydrophilic phycotoxins in sea water and for lipophilic phycotoxins in food supplements. The developed method is a screening method; in order to confirm suspected compounds, comparison with a standard or an additional analysis such as NMR is required.

An arithmetic correction for the effect of lipid on carbon stable isotope ratios in muscle and digestive glands of the American lobster (Homarus americanus).

RATIONALE: Lipid correction models use elemental carbon-to-nitrogen ratios to estimate the effect of lipids on δ13 C values and provide a fast and inexpensive alternative to chemically removing lipids. However, the performance of these models varies, especially in whole-body invertebrate samples. The generation of tissue-specific lipid correction models for American lobsters, both an ecologically and an economically important species in eastern North America, will aid ecological research of this species and our understanding of the function of these models in invertebrates. METHOD: We determined the δ13 C and δ15 N values before and after lipid extraction in muscle and digestive glands of juvenile and adult lobster. We assessed the performance of four commonly used models (nonlinear, linear, natural logarithm (LN) and generalized linear model (GLM)) at estimating lipid-free δ13 C values based on the non-lipid-extracted δ13 C values and elemental C:N ratios. The accuracy of model predictions was tested using paired t-tests, and the performance of the different models was compared using the Akaike information criterion score. RESULTS: Lipid correction models accurately estimated post-lipid-extraction δ13 C values in both tissues. The nonlinear model was the least accurate for both tissues. In muscle, the three other models performed well, and in digestive glands, the LN model provided the most accurate estimates throughout the range of C:N values. In both tissues, the GLM estimates were not independent of the post-lipid-extraction δ13 C values, thus reducing their transferability to other datasets. CONCLUSIONS: Whereas previous work found that whole-body models poorly estimated the effect of lipids in invertebrates, we show that tissue-specific lipid correction models can generate accurate and precise estimates of lipid-free δ13 C values in lobster. We suggest that the tissue-specific logarithmic models presented here are the preferred models for accounting for the effect of lipid on lobster isotope ratios.

Environmental salinity and dietary lipid nutrition strategy: Effects on flesh quality of the marine euryhaline crab Scylla paramamosain.

The quality of crustaceans' flesh has direct impact on consumers' purchase choices, with water environment and dietary nutrition being effective ways to regulate flesh quality. The aim of present study was to investigate the impacts of water salinity (low, 4 and medium, 23) and dietary lipid source (fish oil and soybean oil) on nutritional values, texture, taste and odor of flesh of mud crab. While water salinity had no significant influence on nutritional values of crab flesh, crabs fed soybean oil displayed significantly lower contents of amino acids and n-3 PUFAs in muscle. However, crabs reared at low salinity showed reduced flesh hardness, chewiness and gumminess likely related to altered myofiber structure, that impacted muscle texture. Furthermore, low salinity and dietary soybean oil weakened umami taste and aroma characteristics of crab flesh associated with decreased contents of free amino acids, flavor nucleotides, inorganic ions and odor active compounds in flesh.

Lobster Supply Chains Are Not at Risk from Paralytic Shellfish Toxin Accumulation during Wet Storage.

Lobster species can accumulate paralytic shellfish toxins (PST) in their hepatopancreas following the consumption of toxic prey. The Southern Rock Lobster (SRL), Jasus edwardsii, industry in Tasmania, Australia, and New Zealand, collectively valued at AUD 365 M, actively manages PST risk based on toxin monitoring of lobsters in coastal waters. The SRL supply chain predominantly provides live lobsters, which includes wet holding in fishing vessels, sea-cages, or processing facilities for periods of up to several months. Survival, quality, and safety of this largely exported high-value product is a major consideration for the industry. In a controlled experiment, SRL were exposed to highly toxic cultures of Alexandrium catenella at field relevant concentrations (2 × 105 cells L-1) in an experimental aquaculture facility over a period of 21 days. While significant PST accumulation in the lobster hepatopancreas has been reported in parallel experiments feeding lobsters with toxic mussels, no PST toxin accumulated in this experiment from exposure to toxic algal cells, and no negative impact on lobster health was observed as assessed via a wide range of behavioural, immunological, and physiological measures. We conclude that there is no risk of PST accumulation, nor risk to survival or quality at the point of consumption through exposure to toxic algal cells.

Isolation and Characterization of Bioactive Proteoglycan-Lipid Nanoparticles from Freshwater Clam (Corbicula fluminea Muller) Soup.

Nanoparticles can be prepared by several sophisticated processes but until now, it cannot be prepared by simple home cooking. Here, we report that two incidental food nanoparticles (iFNPs) consisting of proteoglycans and phytosterols were isolated from soup made from freshwater clam (Corbicula fluminea Muller), a renowned folk remedy for liver problems in China and other parts of East Asia. These two bioactive iFNPs were obtained and characterized by anionic exchange chromatography coupled with multi-angle laser light scattering measurement. Their hydrodynamic diameters and ζ-potentials were 50 ± 0.2 nm and -28.0 mV and 67 ± 0.4 nm and -9.96 mV, respectively. FT-IR revealed that the proteoglycans in the particles contained α-type heteropolysaccharides. Both iFNPs were resistant to pH changes and separation by mechanical force but responsive to temperature changes. They effectively inhibited cholesterol uptake in vitro, which resonates with the traditional belief that freshwater clam soup provides hepatoprotective benefits. This study suggests that these two proteoglycan-lipid iFNPs are the active moieties and offers a supramolecular structure-based approach to study the function of such complex matrices derived from food.

Physicochemical Properties and Consumer Acceptance of High-Pressure Processed, Sous Vide-Cooked Lobster Tails.

Sous vide (SV) and high-pressure processing (HPP) are promising techniques in the development of high-quality seafood products. The objectives of this study were to evaluate the impacts of HPP on the physicochemical quality and consumer acceptance of subsequently SV-cooked lobster tails. Raw shucked lobster tails were processed at 150 or 350 MPa for 5 or 10 min. Subsequently, half were SV cooked to a core temperature of 65 °C/10 min. Texture profile analysis, shear force, color, salt soluble protein content, water-holding capacity (WHC), moisture content, and weight loss were analyzed. Pressurization at 150 MPa/10 min decreased (P < 0.05) the hardness of raw lobsters compared to non-HPP-treated controls. However, 350 MPa for 5 or 10 min increased (P < 0.05) the shear force in raw and SV-cooked samples. HPP increased (P < 0.05) the L* values but did not affect moisture content, WHC, or weight loss of raw or SV-cooked lobsters. Lobsters were subjected to consumer acceptability testing using a 9-point hedonic scale. Although panelists rated the flavor, texture, and overall liking of the 350 MPa/10 min samples higher than the control and 150 MPa/10 min samples, there were no significant differences among treatment means, indicating that physicochemical changes induced by HPP did not affect consumer acceptance. In addition, approximately 84% of panelists reported that the 350 MPa product met their expectations compared to approximately 75% for the control and 150 MPa treatments. These results suggest that HPP has the potential to be applied in combination with SV cooking to produce consumer-acceptable, value-added lobster products. PRACTICAL APPLICATION: Lobsters are an expensive menu item in restaurants. However, they are susceptible to being overcooked using conventional methods, producing a tough and rubbery texture. Sous vide cooking is reported to provide evenly cooked lobsters with a succulent and juicy texture. In this study, lobsters were sous vide cooked to reach a core temperature of 65 °C, and then maintained at that temperature for 10 min. The application of moderate processing pressures to vacuum-packaged raw lobsters prior to SV cooking altered some physicochemical attributes but has the potential to increase the availability of high-quality, minimally processed seafood with good consumer acceptability.

Effects of dietary replacement of fish oil by vegetable oil on proximate composition and odor profile of hepatopancreas and gonad of Chinese mitten crab (Eriocheir sinensis).

Five different diets with different ratio of fish oil to vegetable oil were prepared. The biological index and proximate composition of Eriocheir sinensis fed with different diets were compared, and then sensory analysis, electronic nose (E-nose) and headspace-solid phase micro-extraction combined with gas chromatography-mass spectrometer (HS-SPME-GC-MS) analysis were applied to determine the odor profile of E. sinensis. The results showed that partial replacement (50%-75%) of fish oil by vegetable oil (FO/VO) was beneficial to the weight increment, nutrition accumulation, and odor-active compounds (OACs) formation of E. sinensis. A total of 7 and 11 OACs were detected in the hepatopancreas and gonad, respectively, these OACs contributed greatly to the overall odor profiles of E. sinensis when the dietary replacement levels were at 50% and 75%, respectively. The results could provide the guide for dietary fish oil replacement as well as improving the odor quality of E. sinensis. Practical application The objective of this research is to compare the effects of dietary replacement of fish oil by vegetable oil on proximate composition and odor profiles of E.sinensis. The results obtained from this study would not only chose an optimal dietary replacement level and serve as a useful database for the odor of female and crabs, but also provide some guide for the improvement of Chinese mitten crab aquaculture.

Impact of a Novel Cryoprotectant Blend on the Sensory Quality of Frozen Lobster (Homarus americanus).

Frozen storage of lobster meat (Homarus americanus) can result in undesirable quality changes that decrease consumer acceptability of these products. Current seafood industry methods use cryoprotective agents that contain phosphates including sodium tripolyphosphates (STPP). However, recent evidence suggests that cryoprotective mixtures that combine different carbohydrates and STPP can have equal or even greater cryoprotective properties compared to using STPP alone. The objective of this study was to compare the overall consumer acceptability of lobster meat stored for 6 months in different blends of these cryoprotective solutions. One hundred and seven panelists were recruited to score the acceptability of the lobster samples using nine-point hedonic scales. A check-all-that-apply (CATA) question containing 27 literature-informed, sensory descriptors was also used to identify terms frequently used to describe lobster meat. Analysis of variance analysis, indicated a significant increase for overall liking (22.1%, P < 0.0001), liking of flavor (23.6%, P < 0.0001) and texture (15.6%, P = 0.000) scores for samples stored in a novel carbohydrate blend plus sodium chloride (NaCl) and STPP compared to the water control. Subsequent penalty analysis revealed that overall liking scores were most positively associated with the attributes tender, sweet, moist and soft. Moreover, the attributes with the highest positive mean impact were more frequently used to describe lobster samples stored in solutions containing NaCl and the novel carbohydrate blend, as well as NaCl and STPP (Lobster-3 and Lobster-5 samples, respectively). PRACTICAL APPLICATION: The positive impact on the sensory quality of this novel blend of cryoprotective compounds (carbohydrates and NaCl) is proof of concept that this mixture is comparable, if not better than preservatives currently used by the seafood industry. Given the necessary regulatory approval and industry acceptance, lobster processors may consider this novel blend as a suitable alternative to freeze lobster products for up to 6 months.

Phosphorene-gold nanocomposite based microfluidic aptasensor for the detection of okadaic acid.

Okadaic acid (OA) is one of the most prevalent and largely distributed bio-toxin in the world. Consumption of OA results in a series of digestive ailments such as nausea and diarrhea. This study demonstrates the preparation and functioning of an electrochemical microfluidic biochip for the detection of OA. The screen-printed carbon electrode (SPCE) was modified by phosphorene-gold nanocomposite onto which an aptamer specific to OA was immobilized. BP-Au nanocomposites were synthesized by an in-situ, one-step method without the use of a reducing agent. Potassium ferro-ferri cyanide was used as a redox pair to quantify signal strength. To improve reaction time, increase sensitivity and portability, a microfluidic platform was designed and developed. This device comprised of channels identified for specific purposes such as sample mixing and incubation. Overall, the integrated system consisted of a polydimethylsiloxane microfluidic chip housing an aptamer modified SPCE, as a single detection module for Okadaic acid. The nanomaterials and the microfluidic channels prepared were spectroscopically and electrochemically analyzed. Differential pulse voltammograms revealed a detection limit of 8 pM, while a linear range was found between 10 nM-250 nM. Selectivity studies were also performed with spiked mussel samples and other interfering species. This point-of-care device can be deployed to perform on-farm assays in fishing units.

Simultaneous Detection of 13 Allergens in Thermally Processed Food Using Targeted LC-MS/MS Approach.

Food allergy is a major concern for public health and food industries. Because of the large numbers of food ingredients to be tested, MS is considered an alternative to existing techniques in terms of high selectivity, sensitivity, and capability to analyze multiple allergens simultaneously. In this study, we developed the method for monitoring significant peptides derived from 13 food allergens (milk, eggs, cod, shrimp, lobster, almonds, brazil nuts, cashew nuts, hazelnuts, walnuts, peanuts, wheat, and soybeans) and evaluated it in thermally processed foods (bread, cookie, fried fish, and frozen pasta). To select significant peptides to monitor, we used a bioinformatics-based approach and experimental confirmatory analysis. It was demonstrated that the developed method could detect target food ingredients from thermally processed foods successfully.

Freshwater clam extract reduces liver injury by lowering cholesterol accumulation, improving dysregulated cholesterol synthesis and alleviating inflammation in high-fat, high-cholesterol and cholic acid diet-induced steatohepatitis in mice.

Freshwater clam (Corbicula fluminea) is a traditional liver-protective food in Asia. Recent studies have renewed attention on high cholesterol accumulation and dysregulated cholesterol synthesis in the liver as a critical factor in the progression of nonalcoholic fatty liver disease (NAFLD) to nonalcoholic steatohepatitis (NASH). In this study, we investigated the protective effects of freshwater clam extract (FCE) and its fat fraction (FCE oil) on high-fat, high-cholesterol and cholic acid (HFHC) diet-induced lean steatohepatitis in mice. Mice were fed a HFHC diet containing FCE or FCE oil for 6 weeks. FCE, but not FCE oil, feeding reduced liver injury as indicated by decreased plasma alanine aminotransferase activity. Liver total cholesterol accumulation was reduced after FCE and FCE oil treatment. Accumulation of squalene and desmosterol, the precursors of cholesterol, in the liver was reduced by FCE but not by FCE oil. The caspase-1 (p10) and interleukin (IL)-1ß (p17) protein expressions in the liver were suppressed by both FCE and FCE oil. Therefore, FCE may act as functional food that can reduce steatohepatitis and liver injury by reducing cholesterol accumulation, improving dysregulated cholesterol synthesis and attenuating inflammation.

A baseline study of the metallothioneins content in digestive gland of the Norway lobster Nephrops norvegicus from Northern Adriatic Sea: Body size, season, gender and metal specific variability.

Metallothioneins content was investigated in digestive gland of two wild-caught Norway lobster Nephrops norvegicus populations from the Northern Adriatic Sea, in relation to body size, season and gender. Concomitant accumulation of cadmium, mercury, arsenic, lead, chromium and manganese, reactive oxygen species concentration and energy reserves in digestive gland were also assessed. While differences between genders were not recorded, metallothioneins content seasonal trends were affected by body size. Most of parameters displayed inconsistent trends across sampling sites. Significant correlation between metallothioneins content and cadmium, arsenic and mercury concentrations was recorded only for larger lobsters. A negative correlation of reactive oxygen species concentration and metallothioneins content was observed for small, but not large lobsters. Energy reserves, in particular lipids, could considerably influence biochemical and chemical parameters variations. The present results constitute the essential baseline for future studies aimed at evaluating the N. norvegicus health in relation to metal contamination of coastal sediments.

Total mercury levels in crustacean species from Italian fishery.

This study investigated mercury contamination levels in eight commercially valuable crustacean species caught off the Central Adriatic and Tyrrhenian coasts of Italy. Total mercury levels were measured by Thermal Decomposition-Amalgamation-Atomic Absorption Spectrophotometry. Results showed a high variability among species with values ranging from 0.070 to 1.24 (mg kg-1 wet weight). The lowest mercury levels were detected in caramote prawn (Penaeus kerathurus), warty crab (Eriphia verrucosa) and European spider crab (Maja squinado), decapods living in shallow waters. Levels exceeding the limits established by the European Commission were found in species living in close contact with bottom sediments: deepwater rose shrimp (Parapenaeus longirostris), blue and red shrimp (Aristeus antennatus) and Norway lobster (Nephrops norvegicus). For shrimps, the inter-individual variability observed was mostly related to the body size, indicating the accumulation of mercury with age. An estimation of the human intake of mercury associated to the consumption of the crustaceans sampled and its comparison with the Tolerable Weekly Intake are provided.

Trace elements in seafood from the Mediterranean sea: An exposure risk assessment.

Fish and shellfish belonging to five different species among pelagic, benthonic and molluscs, were collected from the Gulf of Catania in 2017 to evaluate arsenic (As), cadmium (Cd), chromium (Cr), lead (Pb), manganese (Mn), nickel (Ni), selenium (Se) vanadium (V) and zinc (Zn). Risk of developing chronic systemic effects derived from seafood consumption was evaluated with the Target Hazard Quotient (THQ) and compared with the results obtained from the same area and the species, collected in 2012. Hg, Cd and Pb concentrations were found below the limits set by European Community for human consumption in all the analysed species. The total risk is reduced from 1.1 to 0.49, and this result is strongly associated with the lower bioaccumulations levels found for Hg, Mn, Se and V. Others metals such as As, Pb, Ni and Zn bioaccumulation levels remain approximately the same, conversely, it is revealed a slight increase of Cd and Cr. Overall, the present study show a positive picture of the studied area, the Gulf of Catania, highlighting not only a decreased metal availability of the study area, but, above all, a decreased risk to develop chronic systemic effects derived from consumption of local seafood.

Development and single-laboratory validation of a UHPLC-MS/MS method for quantitation of microcystins and nodularin in natural water, cyanobacteria, shellfish and algal supplement tablet powders.

A simple, rapid UHPLC-MS/MS method has been developed and optimised for the quantitation of microcystins and nodularin in wide variety of sample matrices. Microcystin analogues targeted were MC-LR, MC-RR, MC-LA, MC-LY, MC-LF, LC-LW, MC-YR, MC-WR, [Asp3] MC-LR, [Dha7] MC-LR, MC-HilR and MC-HtyR. Optimisation studies were conducted to develop a simple, quick and efficient extraction protocol without the need for complex pre-analysis concentration procedures, together with a rapid sub 5min chromatographic separation of toxins in shellfish and algal supplement tablet powders, as well as water and cyanobacterial bloom samples. Validation studies were undertaken on each matrix-analyte combination to the full method performance characteristics following international guidelines. The method was found to be specific and linear over the full calibration range. Method sensitivity in terms of limits of detection, quantitation and reporting were found to be significantly improved in comparison to LC-UV methods and applicable to the analysis of each of the four matrices. Overall, acceptable recoveries were determined for each of the matrices studied, with associated precision and within-laboratory reproducibility well within expected guidance limits. Results from the formalised ruggedness analysis of all available cyanotoxins, showed that the method was robust for all parameters investigated. The results presented here show that the optimised LC-MS/MS method for cyanotoxins is fit for the purpose of detection and quantitation of a range of microcystins and nodularin in shellfish, algal supplement tablet powder, water and cyanobacteria. The method provides a valuable early warning tool for the rapid, routine extraction and analysis of natural waters, cyanobacterial blooms, algal powders, food supplements and shellfish tissues, enabling monitoring labs to supplement traditional microscopy techniques and report toxicity results within a short timeframe of sample receipt. The new method, now accredited to ISO17025 standard, is simple, quick, applicable to multiple matrices and is highly suitable for use as a routine, high-throughout, fast turnaround regulatory monitoring tool.

Therapeutic potential of abalone and status of bioactive molecules: A comprehensive review.

Marine organisms are increasingly being investigated as sources of bioactive molecules with therapeutic applications as nutraceuticals and pharmaceuticals. In particular, nutraceuticals are gaining popularity worldwide owing to their therapeutic potential and incorporation in functional foods and dietary supplements. Abalone, a marine gastropod, contains a variety of bioactive compounds with anti-oxidant, anti-thrombotic, anti-inflammatory, anti-microbial, and anti-cancer activities. For thousands of years different cultures have used abalone as a traditional functional food believing consumption provides health benefits. Abalone meat is one of the most precious commodities in Asian markets where it is considered a culinary delicacy. Recent research has revealed that abalone is composed of many vital moieties like polysaccharides, proteins, and fatty acids that provide health benefits beyond basic nutrition. A review of past and present research is presented with relevance to the therapeutic potential of bioactive molecules from abalone.

Quantitative determination of the neurotoxin ß-N-methylamino-L-alanine (BMAA) by capillary electrophoresis-tandem mass spectrometry.

Recent reports of the widespread occurrence of the neurotoxin ß-N-methylamino-L-alanine (BMAA) in cyanobacteria and particularly seafood have raised concerns for public health. LC-MS/MS is currently the analytical method of choice for BMAA determinations but incomplete separation of isomeric and isobaric compounds, matrix suppression and conjugated forms are plausible limitations. In this study, capillary electrophoresis (CE) coupled with MS/MS has been developed as an alternative method for the quantitative determination of free BMAA. Using a bare fused silica capillary, a phosphate buffer (250 mM, pH 3.0) and UV detection, it was possible to separate BMAA from four isomers, but the limit of detection (LOD) of 0.25 µg mL-1 proved insufficient for analysis of typical samples. Coupling the CE to a triple quadrupole MS was accomplished using a custom sheath-flow interface. The best separation was achieved with a 5 M formic acid in water/acetonitrile (9:1) background electrolyte. Strong acid hydrolysis of lyophilized samples was used to release BMAA from conjugated forms. Field-amplified stacking after injection was achieved by lowering sample ionic strength with a cation-exchange cleanup procedure. Quantitation was accomplished using isotope dilution with deuterium-labelled BMAA as internal standard. An LOD for BMAA in solution of 0.8 ng mL-1 was attained, which was equivalent to 16 ng g-1 dry mass in samples using the specified extraction procedure. This was comparable with LC-MS/MS methods. The method displayed excellent resolution of amino acid isomers and had no interference from matrix components. The presence of BMAA in cycad, mussel and lobster samples was confirmed by CE-MS/MS, but not in an in-house cyanobacterial reference material, with quantitative results agreeing with those from LC-MS/MS. Graphical Abstract CE-MS separation and detection of BMAA, its isomers and the internal standard BMAA-d3.

Characterization of Key Aroma Compounds in Raw and Thermally Processed Prawns and Thermally Processed Lobsters by Application of Aroma Extract Dilution Analysis.

Application of aroma extract dilution analysis (AEDA) to an aroma distillate of blanched prawn meat (Litopenaeus vannamei) (BPM) revealed 40 odorants in the flavor dilution (FD) factor range from 4 to 1024. The highest FD factors were assigned to 2-acetyl-1-pyrroline, 3-(methylthio)propanal, (Z)-1,5-octadien-3-one, trans-4,5-epoxy-(E)-2-decenal, (E)-3-heptenoic acid, and 2-aminoacetophenone. To understand the influence of different processing conditions on odorant formation, fried prawn meat was investigated by means of AEDA in the same way, revealing 31 odorants with FD factors between 4 and 2048. Also, the highest FD factors were determined for 2-acetyl-1-pyrroline, 3-(methylthio)propanal, and (Z)-1,5-octadien-3-one, followed by 4-hydroxy-2,5-dimethyl-3(2H)-furanone, (E)-3-heptenoic acid, and 2-aminoacetophenone. As a source of the typical marine, sea breeze-like odor attribute of the seafood, 2,4,6-tribromoanisole was identified in raw prawn meat as one of the contributors. Additionally, the aroma of blanched prawn meat was compared to that of blanched Norway and American lobster meat, respectively (Nephrops norvegicus and Homarus americanus). Identification experiments revealed the same set of odorants, however, with differing FD factors. In particular, 3-hydroxy-4,5-dimethyl-2(5H)-furanone was found as the key aroma compound in blanched Norway lobster, whereas American lobster contained 3-methylindole with a high FD factor.

New High-Performance Liquid Chromatography Coupled Mass Spectrometry Method for the Detection of Lobster and Shrimp Allergens in Food Samples via Multiple Reaction Monitoring and Multiple Reaction Monitoring Cubed.

Crustacean shellfish allergy ranks among the most frequent and severe food allergies for adults, demanding rugged and sensitive analytical routine methods. The objective of this study was therefore to develop a mass spectrometric approach for the detection of contamination with shrimp and lobster, two economically important types of crustaceans, in complex food matrices. Following a biomarker approach, we identified proteotypic peptides and developed a multiple reaction monitoring (MRM) method allowing for the identification and differentiation of shrimp and lobster in the food matrix at concentrations down to 0.1%. To further enhance sensitivity, we employed the MRM-cubed (MRM(3)) mode, which allowed us to detect crustaceans down to concentrations of 25 µg/g (crustacean/food, 0.0025%). We hereby present the first mass spectrometric method for the detection of shrimp and lobster in food matrices.