The Yangtze Coilia ectenes is a delicious fish known for its distinctive aroma, intense umami taste and high nutritional value. The analysis of Yangtze Coilia ectenes flesh extract using an e-Tongue indicated that saltiness and umami taste were the primary sensory attributes. The relationship between umami-related components and umami taste of this fish was studied by using an electronic tongue (e-Tongue) and sensory perception analysis. As free amino acids, nucleotides and inorganic ions are the main contributors for umami, their contents in Yangtze Coilia ectenes flesh extract were quantified instrumentally and a synthetic sample composed of similar contents of free amino acids, nucleotides and inorganic ions was prepared subsequently. No significant difference in umami taste between that of the synthetic sample and the flesh extract were observed by using the e-Tongue and sensory analysis (p < 0.05). Our further analysis using an omission test indicated nine components including Glu, Gly, AMP, IMP, GMP, K+, Na+, Cl− and PO43− are the key umami-related components with a proportion of 1:5:40 for amino acids, nucleotides and inorganic ions, respectively. Our results indicated that a simplified synthetic extract can replicate the umami taste of Yangtze Coilia ectenes flesh which provides solid evidence for the preparation of new flavor enhancers in the future.

Odorants were extracted from four Coilia ectenes (Yangtze River-Coilia, East China sea-Coilia, Chao Lake-Coilia and Yellow River-Coilia) by MonoTrap™ and analyzed by the headspace-monolithic material sorptive extraction technique combined with gas chromatography–mass spectrometry–olfactometry (GC–MS–O). A total of 63 volatile compounds were identified. The results of GC–MS–O analysis associated with odor intensity revealed that trimethylamine (fishy, ammonia-like), 1-penten-3-ol (mushroom, cabbage), N,N-diethyl-formamide (roasted meaty), hexanal (grassy, earthy), ethylbenzene (nutty, floral), (Z)-4-heptenal (fishy, boiled potato), benzaldehyde (almond, metallic), 1-octen-3-ol (mushroom, cabbage), nonanal (oily), and decanal (green, oily) were the important odorants in the four species of Coilia ectenes. Furthermore, trimethylamine and 1-penten-3-ol were common to four Coilia ectenes. TMA (fishy, ammonia-like), 1-penten-3-ol (mushroom, cabbage), N,N-diethyl-formamide (roasted meaty), hexanal (grassy, earthy), (Z)-4-heptenal (fishy, boiled potato), and benzaldehyde (almond, metallic) were included in Yangtze River-Coilia; TMA, 1-penten-3-ol, ethylbenzene (nutty, floral), (Z)-4-heptenal, 1-octen-3-ol (mushroom, earthy), and nonanal (oily) in East China sea-Coilia; TMA, 1-penten-3-ol, ethylbenzene, 1-octen-3-ol and nonanal in Chao Lake-Coilia; and TMA, 1-penten-3-ol, hexanal, (Z)-4-heptenal, 1-octen-3-ol and decanal (green, oily) in Yellow River-Coilia.

The profiles of the non-volatile taste-active compounds, including 5′-nucleotides, free amino acids and inorganic ions were first compared between the cooked meats of Yangtze Coilia ectenes, pre- and post-spawning. A total of nine 5′-nucleotides, 17 free amino acids and six inorganic ions were identified in the pre- and post-spawning cooked meats, and their taste effects were evaluated by taste-active values (TAVs) and equivalent umami concentration (EUC). Not only the total contents of the 5′-nucleotides, free amino acids and inorganic ions, but also the contents of flavor 5′-nucleotides and umami amino acids in pre-spawning cooked meat were significantly higher than those in post-spawning cooked meat. The main nucleotide was 5′-inosine monophosphate (IMP), and the TAV of IMP in pre-spawning cooked meat (3.31) was approximately twice that of post-spawning cooked meat. Glycine and alanine were major sweet amino acids, which did not differ significantly between pre- and post-spawning cooked meats. The main inorganic ions were potassium and phosphate, and these were higher in pre-spawning cooked meat than in post-spawning cooked meat. Compared with post-spawning cooked meat, pre-spawning cooked meat had characteristically higher contents of glutamate, IMP, potassium and phosphate. The EUC of pre- and post-spawning cooked meats were 0.99 and 0.33 g monosodium glutamate (MSG)/100 g, respectively, indicating that the umami taste in cooked meat of Yangtze Coilia ectenes was very intense. Sensory evaluation showed that pre-spawning cooked meat had a much stronger umami taste than that of post-spawning cooked meat.

In this study, the key odor-active compounds in the steamed meat of Coilia ectenes from Yangtze River were isolated by headspace monolithic material sorptive extraction and analyzed by gas chromatography–mass spectrometry–olfactometry (GC–MS–O). A total of 49 volatile compounds were identified and quantified in the extract. The results of gas chromatography–olfactometry analysis combined with odor activity value showed that trimethylamine (fishy, ammonia-like), 3-methylbutanal (dark chocolate), decanal (green, oily), hexanal (green), (Z)-4-heptenal (fishy, boiled potato) and benzaldehyde (bitter almond) were the key odor-active compounds contributing primarily to the overall aroma of steamed Coilia ectenes meat. Among them, trimethylamine and (Z)-4-heptenal were the most potent odor-active compounds on the basis of their detection frequency at high odor intensities.

The nutritional composition of muscles from three farmed pufferfish species, Fugu obscurus, Fugu flavidus and Fugu rubripes, was investigated. All three species had high crude protein contents ranging between 17.8 g/100 g and 18.9 g/100 g (with the highest for F. rubripes), and low crude fat contents, 0.73 g/100 g to 0.83 g/100 g for adults, and 0.21 g/100 g to 0.29 g/100 g for juveniles. Significant differences (P < 0.05) in macroelement contents and no significant differences (P > 0.05) in microelement contents were found among the three species. It was found that K was the most abundant macroelement, ranging from 287 mg/100 g to 402 mg/100 g, while Fe was the most abundant microelement, 1.52 mg/100 g to 2.11 mg/100 g. Total amino acid (TAA) contents of three species were between 51.7 g/100 g and 62.9 g/100 g dry weight. The ratios of total essential amino acids to TAA were between 0.43 and 0.50, and F. flavidus had the highest ratio. The ratios of total umami amino acids to TAA were between 0.36 and 0.45, with the highest for F. rubripes. In eight amino acid scores (AAS), six AAS of three adult pufferfish were close to 1.00, but two AAS of valine and sum of phenylalanine and tyrosine of juveniles were close to 1.00. This study shows that the three pufferfish species under investigation have high nutritional qualities and are good protein resources.Highlights► Nutritional composition of three farmed pufferfish muscles was investigated. ► Pufferfish had high crude protein and low crude fat contents. ► Significant differences (P < 0.05) in macroelement contents were found. ► No significant differences (P > 0.05) in microelement contents were found. ► High amino acid, essential amino acid and umami amino acid contents were also found.

The volatile and odor-active compounds in cooked meat of farmed obscure puffer (Takifugu obscurus) were analyzed by gas chromatography–mass spectrometry–olfactometry (GC–MS–O). The volatile compounds were extracted by the simultaneous distillation–extraction (SDE) method, then separated and identified by GC–MS. Odor-active compounds in the SDE extract were characterized by GC–MS–O. A total of 68 volatile compounds were found, including 23 aldehydes, 10 alcohols, nine ketones, 17 N- or S-containing compounds and aromatics, three acids, three alkanes, and three esters. Of these, 31 odor-active compounds were detected and identified. Trimethylamine (fishy), octanal (grassy, leafy, green), (E)-2-octenal (roast, fatty), 1-octen-3-ol (fishy, fatty, mushroom, grassy), 2-ethyl-1-hexanethiol (cooked fish), (E,E)-2,4-octadienal (cooked meat, sweet), 2-acetylthiazole (meaty, roast, nutty, sulfur), 2-acetylpyrrole (nutty, walnut, bread) were identified as the key odorants in the cooked meat of farmed obscure puffer based on posterior intensity and time-intensity methods.