Investigating influence of aquaculture seawater with different salinities on non-volatile taste-active compounds in Pacific oyster (Crassostrea gigas)

Creating alternative seafood flavour from non-animal ingredients: A review of key flavour molecules relevant to seafood

This review summarises current knowledge of the molecular basis for flavour profiles of popular seafood types (crustacean (crab, lobster, prawn, etc.), mollusc (oyster, squid, etc.), oily fish (salmon, sardine, etc.) and white fish (barramundi, turbot, etc.)), and provides a foundation for formulating improved plant-based seafood alternative (PBSA) flavours. Key odour-active volatile molecules were identified from a systematic review of published olfactometry studies and taste-active compounds and macronutrient profiles of different seafood species and commercial PBSAs from nutrition databases were compared. Ingredients commonly used in commercial BPSAs and new potential sources of flavouring agents are evaluated. While significant challenges in replicating seafood flavour and texture remain, this review provides some insights into how plant-based ingredients could be applied to improve the acceptability of PBSAs.

The dynamic change of flavor characteristics in Pacific oyster (Crassostrea gigas) during depuration uncovered by mass spectrometry-based metabolomics combined with gas chromatography-ion mobility spectrometry (GC-IMS)

The flavor of Pacific oyster (Crassostrea gigas) significantly changed during the depuration process. This work aimed to explore the mechanism of flavor changes during the 72 h depuration by metabolomics combined with gas chromatography-ion mobility spectrometry (GC-IMS). The metabolomics analysis indicated that carbohydrate metabolism was more affected in the early stage of depuration, including the citrate cycle, glyoxylae and dicarboxylate metabolism, etc. After 72 h depuration, it affected mainly the metabolism of global and overview maps and nucleoside metabolism, etc. The equivalent umami concentration (EUC) value was calculated and exhibited a gradual increase following a 48 h depuration. The GC-MS results revealed that the content of furans was the highest, and the content of aldehydes, ketones, and alcohols was the lowest after 48 h depuration, while the content of aldehydes, ketones, and alcohols increased after 72 h depuration. All these results suggested the depuration period was recommended to be controlled within 48 h.

Interference mechanism of benzo[a]pyrene exposure on the taste substance metabolisms in Ruditapes philippinarum

Aquatic animals are popular for their unique umami and high-quality protein. However, under the realistic background of increasing marine pollution, whether it affects the aquatic animal tastes, and what the interference mechanism is still remains unknown. Benzo[a]pyrene (B[a]P) is a typical Polycyclic aromatic hydrocarbons (PAHs) with high toxicity. In this study, we investigated the effects of B[a]P (0, 0.8, 4 and 20 μg/L) on the content and taste evaluation of Ruditapes philippinarum taste substances, and clarified the interference mechanism of B[a]P on taste substance metabolisms with transcriptome analysis. The results demonstrated that B[a]P significantly altered the contents and taste activity values (TAVs) of free amino acids (FAAs), 5'-nucleotides, organic acids, flavor peptides, organic bases, sugars and inorganic ions, as well as the gene expressions within their synthesis and decomposition, indicating that B[a]P affected these taste substance contents by interfering with their metabolisms, thereby changing the clam tastes (decreases of umami and sweetness, and increase of bitter taste). This study provided scientific basis for quality assurance of bivalve cultivation and control of marine pollution.

Fitness and transcriptomic analysis of pathogenic Vibrio parahaemolyticus in seawater at different shellfish harvesting temperatures

IMPORTANCE

Given the involvement of Vibrio parahaemolyticus (Vp) in a wide range of seafood outbreaks, a systematical characterization of Vp fitness and transcriptomic changes at temperatures of critical importance for seafood production and storage is needed. In this study, one of each virulent Vp strain (tdh+ and trh+) was tested. While no difference in survival behavior of the two virulent strains was observed at 10°C, the tdh+ strain had a faster growth rate than the trh+ strain at 30°C. Transcriptomic analysis showed that a significantly higher number of genes were upregulated at 30°C than at 10°C. The majority of differentially expressed genes of Vp at 30°C were annotated to functional categories supporting cellular growth. At 10°C, the downregulation of the biofilm formation and histidine metabolism indicates that the current practice of storing seafood at low temperatures not only protects seafood quality but also ensures seafood safety.

Pork organs as a potential source of flavour-related substances

The increase in world population has generated a higher demand for quality proteins, increasing the production in meat industry but also the generation of thousands of tons of by-products, with a negative economic and environmental impact. The valorisation of slaughterhouse by-products by giving by-products a new use as food ingredient is one of the best strategies to add value while reducing environmental damage. Flavour is one of the most influential parameters in the purchasing decision of consumers, and in meat products it is mostly influenced by the content in free amino acids and nucleotides. In this study, the potential of 4 pork organs (liver, kidney, lung, and brain) as a source of flavour-related substances was investigated. Liver proved to be the organ showing the highest content of free and total amino acids related to taste, while kidney was the organ with the highest content of umami nucleotides. The results of the Taste Activity Value indicated that umami, sweet, and bittersweet amino acids are main responsible for the taste of the organs. On the other hand, the synergy between amino acids and nucleotides in relation with umami taste was determined, showing liver and kidney the best values in Equivalent Umami Content. In addition, the antioxidant activity of the organs was determined, and liver and kidney showed the highest antioxidant activity in all assays (p < 0.05). In conclusion, pork organs, especially liver and kidney, may be good candidates to be used as raw materials to produce functional flavouring ingredients.

Metabolomic comparison of meat quality and metabolites of geese breast muscle at different ages

The purpose of this study was to distinguish the effect of age on the meat quality and chemical composition of Yangzhou goose breast meat. Nontargeted metabolomics analysis (UHPLC-MS/MS) was used to distinguish the metabolic composition of goose meat at different ages, and Pearson's correlations between differential metabolites and key meat parameters were assessed. Compared with goslings, adult geese had lighter, redder and chewier meat (p < 0.05). Metabolite analysis revealed significant differences in nucleosides, organic acids, amino acids and sugars. Levels of IMP, xanthosine, pretyrosine and l-threonine were significantly higher in older meat (p < 0.05) and positively correlated with meat freshness indicators. However, pyruvic acid, l-cysteine and glucose 6-phosphate were up-regulated in gosling meat (p < 0.05), which were important flavor compounds. These results facilitate the further investigation of changes in goose meat composition and provide biomarkers for determining goose meat quality at different ages.

Effects of Ammonia and Salinity Stress on Non-Volatile and Volatile Compounds of Ivory Shell (Babylonia areolata)

In this study, the flavor compounds of ivory shell (Babylonia areolata) and their changes caused by ammonia and salinity stresses were studied. Ammonia stress improved the contents of free amino acids (FAAs), 5'-adenosine monophosphate (AMP), citric acid, and some mineral ions such as Na+, PO43-, and Cl-. The FAA contents decreased with increasing salinity, while the opposite results were observed in most inorganic ions (e.g., K+, Na+, Mg2+, Mn2+, PO43-, and Cl-). Hyposaline and hypersaline stresses increased the AMP and citric acid contents compared to the control group. The equivalent umami concentration (EUC) values were 3.53-5.14 g monosodium glutamate (MSG)/100 g of wet weight, and the differences in EUC values among treatments were mainly caused by AMP. Hexanal, butanoic acid, and 4-(dimethylamino)-3-hydroxy- and (E, E)-3,5-octadien-2-one were the top three volatile compounds, and their profiles were significantly affected when ivory shells were cultured under different ammonia and salinity conditions.

Effects of cooling rates during depuration on the quality of Pacific oysters (Crassostrea gigas) at anhydrous preservation stage

The Pacific oyster could be affected by several pressure sources during cold chain logistics, which reduce the quality of oyster, and even improve its mortality. For improving the quality of oyster, the effects of depuration process at different cooling rates (1, 3, 7, 11 and 16 °C/h) on selected Pacific oyster were studied. The results indicated that extreme fluctuations in the depuration temperatures could affect the survival rates and qualities of oysters. The oysters exhibited low survival rates, glycogen contents and pH values at an increased cooling rate. Their contents in the 1 °C/h group after 3 d preservation were 100 %, 16.30 ± 1.64 mg/100 g and 6.72 ± 0.01, respectively, while there were 71 %, 7.72 ± 0.88 mg/100 g and 6.53 ± 0.01 in the 16 °C/h group after 3 d preservation, respectively. Furthermore, the ATP-related compounds were affected by the different cooling rates. AMP and IMP were the main ATP-related compounds, and their contents in the 1 °C/h group after 3 d preservation were 37.21 ± 1.10 mg/100 g and 29.47 ± 1.10 mg/100 g, respectively, while there were 32.07 ± 1.10 mg/100 g and 13.16 ± 1.60 mg/100 g in the 16 °C/h group after 3 d preservation, respectively. The proportions of the total umami, as well as the sweet amino acids also decreased, the proportions of the umami amino acids and sweet amino acids in the total amino acids, were 31.37%-38.80%, and their proportions in 1 °C/h group were higher than that in 16 °C/h group. Conversely, the fatty acid content of each group exhibited significant differences. Combined with the above results, the oyster maintained a high survival rate and higher quality at a cooling rate of 1 °C/h during depuration.

Cephalopods as Challenging and Promising Blue Foods: Structure, Taste, and Culinary Highlights and Applications

Foods are complex systems due to their biological origin. Biological materials are soft matter hierarchically structured on all scales from molecules to tissues. The structure reflects the biological constraints of the organism and the function of the tissue. The structural properties influence the texture and hence the mouthfeel of foods prepared from the tissue, and the presence of flavour compounds is similarly determined by biological function. Cephalopods, such as squid, cuttlefish, and octopuses, are notoriously known for having challenging texture due to their muscles being muscular hydrostats with highly cross-linked collagen. Similar with other marine animals such as fish and crustaceans, cephalopods are rich in certain compounds such as free amino acids and free 5′-ribonucleotides that together elicit umami taste. Scientific investigations of culinary applications of cephalopods as foods must therefore involve mechanical studies (texture analysis), physicochemical measurements of thermodynamic properties (protein denaturation), as well as chemical analysis (taste and aroma compounds). The combination of such basic science investigations of food as a soft material along with an exploration of the gastronomic potential has been termed gastrophysics. In this review paper, we reviewed available gastrophysical studies of cephalopod structure, texture, and taste both as raw, soft material and in certain preparations.

Molecular Basis of Taste and Micronutrient Content in Kumamoto Oysters (Crassostrea Sikamea) and Portuguese Oysters (Crassostrea Angulata) From Xiangshan Bay

Oysters are the most extensively cultivated bivalves globally. Kumamoto oysters, which are sympatric with Portuguese oysters in Xiangshan bay, China, are regarded as particularly tasty. However, the molecular basis of their characteristic taste has not been identified yet. In the present study, the taste and micronutrient content of the two oyster species were compared. Portuguese oysters were larger and had a greater proportion of proteins (48.2 ± 1.6%), but Kumamoto oysters contained significantly more glycogen (21.8 ± 2.1%; p < 0.05). Moisture and lipid content did not differ significantly between the two species (p > 0.05). Kumamoto oysters contained more Ca, Cu, and Zn (p < 0.05); whereas Mg and Fe levels were comparable (p > 0.05). Similarly, there was no significant difference between the two species with respect to total amount of free amino acids, umami and bitterness amino acids, succinic acid (SA), and most flavoring nucleotides (p > 0.05). In contrast, sweetness amino acids were significantly more abundant in Portuguese oysters. Volatile organic compounds profiles of the two species revealed a higher proportion of most aldehydes including (2E,4E)-hepta-2,4-dienal in Kumamoto oysters. Overall, Kumamoto oysters contain abundant glycogen, Ca, Zn, and Cu, as well as volatile organic compounds, especially aldehydes, which may contribute to their special taste. However, free amino acid and flavor nucleotides may not the source of special taste of Kumamoto oyster. These results provide the molecular basis for understanding the characteristic taste of Kumamoto oysters and for utilizing local oyster germplasm resources.