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This study aimed to investigate the effects of flavourzyme addition on protein degradation and flavor formation in grass carp during fermentation. The related results showed that the addition of flavourzyme reduced the moisture content and accelerated the hydrolysis of protein and generation of water‐soluble flavor substances (e.g., TCA‐soluble peptides, α‐amino nitrogen, and free amino acids), thereby contributing to fermented grass carp products with a better taste quality. Besides, radar map results of electronic tongue and electronic nose showed that flavourzyme addition gives fermented products a more intense umami taste and odor. Meanwhile, sensory evaluation results also further confirmed that the addition of flavourzyme significantly improved the sensory attributes of fermented grass carp products, especially the taste and odor attributes. Overall, flavourzyme addition may be an effective way to shorten fermentation time and improve the flavor quality of fermented grass carp products during fermentation. Practical Applications: In this study, to study the effects of flavourzyme addition on protein degradation and flavor formation in grass carp during fermentation, the related indicators include the moisture content, total nitrogen, non‐protein nitrogen, protein degradation index, TCA‐soluble peptides, α‐amino nitrogen, free amino acids, electronic tongue, electronic nose, and sensory attributes were analyzed. This study may provide some useful information for the improvement of fermentation methods and the production of high‐quality fermented grass carp products. [ABSTRACT FROM AUTHOR]

To investigate the effect of steaming time (0, 5, 10, 15, 20, and 25 min) on the protein degradation and non-volatile flavor substances of swimming crab (Portunus trituberculatus), the moisture content, total nitrogen (TN), non-protein nitrogen (NPN), free amino acids (FAAs), flavor nucleotides, electronic tongue analysis, and sensory evaluation were determined. The results showed that the contents of NPN and total FAAs were the highest after crabs steamed for 10 min. Meanwhile, the AMP (adenosine monophosphate) content reached the maximum value (332.83 mg/100 g) and the taste active value (TAV) reached 6.67, which indicated that AMP contributes the most to the taste of steamed crab at 10 min. The electronic tongue distinguished the taste difference well, and the sensory score was the highest at 15 min. Combined with equivalent umami concentration (EUC) and TAV value, swimming crab (weight = 200 ± 20 g) steamed for 10–15 min tasted best. [ABSTRACT FROM AUTHOR]

The study aims to obtain the information on taste and odor among different edible parts (white dorsal meat, white abdomen meat, white tail meat, and dark meat) of bighead carp. The results showed that the white dorsal meat and white abdomen meat had the higher content of total amino acids among all edible parts of bighead carp samples. The highest inosine monophosphate and adenosine monophosphate content presented in white abdomen meat, and the highest equivalent umami concentration value presented in dark meat. The principal component analysis result of electronic tongue and electronic nose showed significant differences in the overall taste and odor characteristics among four group samples. Additionally, 41, 30, 42, and 29 volatile compounds were identified by headspace solid‐phase microextraction/gas chromatography‐mass spectrometry among white dorsal meat, white abdomen meat, white tail meat, and dark meat of bighead carp, respectively. Based on the data of relative olfactory activity value (ROAV ≥ 1), 12 relative olfactory activity compounds may mainly contribute to the overall odor of bighead carp, including 2‐methylbutanal, hexanal, heptanal, (E)‐2‐octenal, nonanal, dodecanal, undecanal, decanal, 3‐methyl‐1‐pentanol, 1‐octen‐3‐ol, (Z)‐2‐octen‐1‐ol, and eucalyptol. Furthermore, according to the Partial Least Squares Discriminant Analysis profile derived from the ROAV of 12 characteristic volatile compounds, significant variations in the odor of different edible parts of bighead carp. Overall, there was a significant difference in taste and odor among different edible parts of bighead carp, and this study may provide useful information for unraveling the flavor characteristics of each edible part of raw bighead carp. Practical applications: The comprehensive information on taste and odor among different edible parts (white dorsal meat, white abdomen meat, white tail meat, and dark meat) of bighead carp were obtained using liquid chromatography‐mass spectrometry, automatic amino acid analyzer, electronic tongue (E‐tongue), headspace solid‐phase microextraction/gas chromatography‐mass spectrometry (HS‐SPME/GC‐MS), and electronic nose (E‐tongue), respectively. This study may provide useful information for unraveling the flavor characteristics of each edible part of raw bighead carp and improving the flavor of bighead carp products. [ABSTRACT FROM AUTHOR]

BACKGROUND: Among various cooking methods, steaming is favored by many because it can cause less damage to nutrient components in muscle, retain the inherent food flavor, and reduce the generation of harmful substances. Steaming conditions are closely related to fish flavor, fat and protein oxidation, and digestibility. RESULTS: The black carp steamed for 4 to 14 min was studied in this article based on sensory assessment, electronic tongue, free amino acids, adenosine triphosphate (ATP)‐related compounds, total nitrogen and non‐protein nitrogen to explore the effect of steaming time on the taste substances and protein degradation of pickled black carp. The experimental result showed that the meat steamed within 8 min tasted better, showing high tastiness. The sensory assessment score increased significantly to the maximum value of 82.33 at 6 min. The content of umami and sweet amino acids increased significantly to the maximum value of 1.6801 g kg–1 at 6 min. In the meantime, the IMP (inosine monophosphate) content was 1.9128 g kg–1, with its taste activity value (TAV) reaching 7.65, which proved that IMP affected the taste most. Furthermore, the total nitrogen content was 30.77 g kg–1, which meant protein degraded a great deal. Based on equivalent umami concentration (EUC) and its TAV, the meat tasted best at 6–8 min. The longer the steaming time, the faster the protein degradation and the more the flavor precursors. CONCLUSION: The black carp pickled products (with a weight of 20 g, with the size of 3 cm × 3 cm × 2 cm) is suggested to be steamed for 6 to 8 min. This conclusion provides a theoretical basis for its better taste quality. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

This study was aimed at to investigate the quality changes of grass carp during short‐term starvation. The pH, lactic acid, free amino acid, and adenosine triphosphate‐related compounds of dorsal meat, belly meat and red meat in grass carp were measured during starvation for 6 days, and the quality of grass carp was evaluated by K value, equivalent umami concentration (EUC), taste activity value (TAV), and electronic tongue. The pH of three parts meat reached the maximum value on the fourth day, which was closely related to the lactic acid content. Concurrently, the contents of fresh sweet amino acids were higher on the fourth day in all parts. The K values in dorsal meat and belly meat were below 10% during starvation. Considering the overall results of electronic tongue, EUC, and TAV analysis, it is suggested that grass carp should be marketed and eaten with a starvation period of 2–4 days for best taste and quality. [ABSTRACT FROM AUTHOR]

The effect of heating medium (with water and steam) and initial temperature of heating medium (cold and boiling) on the taste quality and sensory properties of Portunus trituberculatus was investigated. Nonvolatile taste active components in the meat and gonad of crabs cooked under four different methods were detected and compared. Sensory evaluation and electronic tongue assessment were also conducted. Sensory evaluation and electronic tongue indicated that taste quality was different under four cooking methods. The results showed that steaming cooking preserved more water‐soluble substances as compared with boiling cooking, especially cooking began with boiling water. It is noteworthy that the umami intensity in gonad cooked from boiling water was stronger, either steaming or boiling. Therefore, this study can provide a theoretical basis and suggest the dynamic chemical changes of different organs during heating process need to be further studied. [ABSTRACT FROM AUTHOR]

In this study, adenosine triphosphate (ATP)‐related compounds and free amino acids were determined to study the changes of water‐soluble flavor substances in grass carp meat during steaming for 18 min. Sensory assessment, electronic tongue, equivalent umami concentration (EUC) value, and taste active value (TAV) were also performed to obtain the best quality of steamed grass carp meat. The results showed that the flavor presented by nucleotides in three parts meat was better within 9 min. The bitter amino acids in the dorsal meat and red meat significantly decreased at 6 min (101.33 mg/100 g and 44.64 mg/100 g, respectively). From the sensory analysis, EUC value, and TAV, it can be found that the quality of grass carp meat was the best when steamed for 6–9 min. The electronic tongue indicated that the taste differences were significantly between 6 and 9 min. Therefore, this study suggested that grass carp should be eaten during 6–9 min of steaming. Practical applications: As the main way of meat processing and eating, heating not only endows the product with good color, but also kill microorganisms and improve the product quality. The reasonable heating will make the protein denaturation of the food, so that the protein digestion and absorption rate can be improved, which is conducive to people to obtain more abundant nutrition. The quality changes of grass carp meat during 18 min of steaming were studied by measuring ATP‐related compounds and free amino acids, combining with sensory assessment, electronic tongue analysis, EUC value, and TAV. These results not only provide useful information for the quality control of grass carp in the heating process, but also provide theoretical reference for the improvement of the nutritional value of grass carp. In addition, the mechanism of flavor change in the heating process of grass carp will be further improved, and effective suggestions will be provided for consumers to reasonably eat grass carp. [ABSTRACT FROM AUTHOR]

The flavor of gonad and meat of female Portunus Trituberculatus cultured in indoor and outdoor were studied by tested free amino acid, taste nucleotide, volatile compounds, and analyzed combined with sensory, electronic nose, and electronic tongue results. The results of electronic nose, electronic tongue, and sensory showed that the flavor were slightly different under two conditions. For taste substance, indoor culture can significantly increase the contribution of AMP, glutamate, alanine, proline to the taste and the content of TAA and EAA of gonad. Also, it could significantly increase the contribution of AMP, lysine, and histidine and the content of EAA of meat, while the TAA and FAA were adverse (p < 0.05). The equivalent umami concentration value of gonad and meat were higher than outdoor cultured. For volatile compounds, the content of aldehydes, ketones, and furans in gonad and meat were decreased by indoor culture, but others were increased. Practical applications: At present, many scholars have studied the effects of culture methods and conditions, including temperature, region, salinity, feed, etc. On the growth and development of Portunus Trituberculatus, some studies have studied the effects of free amino acids on their flavors, but few have reported the influences of culture methods and conditions on the overall flavor of the Portunus Trituberculatus. In this study, we explored the overall flavor of indoor and outdoor breeding of the gonads and crab meat of the Portunus Trituberculatus by the sensory evaluation analysis, volatile substance analysis, free amino acid, and taste nucleotide analysis, combined with electronic tongue and electronic nose analysis, provides a certain theoretical reference to the swimming crab pond aquaculture industry. [ABSTRACT FROM AUTHOR]

Chinese mitten crab (Eriocheir sinensis) is widely distributed along the eastern coast of China and is considered one of the most economically important crabs in China. Evaluating its taste substances can help to develop new varieties of Eriocheir sinensis with distinctive flavours to meet the diversified needs of the market. In the current research work, we compared the meat yield and flavour of wild adult male Eriocheir sinensis muscle from five rivers. The results showed that crabs from the Min River had the highest meat yield (32.94 ± 2.93%). The electronic tongue showed that the taste profiles of Min River and Ou River crabs were similar. The Min River crabs had the highest total amino acid content of 1404.01 ± 2.83 mg/100 g, of which sweet amino acids accounted for 64.9%, the highest 5′-inosine phosphate of 14.49 ± 2.11 mg/100 g, and the highest equivalent umami concentration (3.82 gMSG/100 g). Taste activity value analysis showed that crabs in Min River, Ou River, and Yangtze River were more influenced by alanine, arginine, and 5′-guanosine phosphate. Overall, wild male Eriocheir sinensis from Min River enriched the flavour substance, making it a potentially valuable resource for the Eriocheir sinensis industry. • Compared flavour and taste substances of wild Eriocheir sinensis from five rivers. • Significant flavour differences between different geographic populations. • The results help to develop germplasm resources of wild Eriocheir sinensis. [ABSTRACT FROM AUTHOR]

Grass carp is an important freshwater fish but little is known about its quality postmortem. We tracked changes in the pH, texture, lactic acid, ATP‐related compounds, K value, free amino acids (FAA) contents in grass carp stored at 4°C for 192 hr. Sensory and electronic tongue assessment were also performed. The results showed a consistent trend in the hardness and chewiness. pH were closely correlated with the lactic acid content and hardness. The fresh sweet amino acids gradually decreased with time while the opposite occurred with the bitter amino acids. The content of Hx and HxR increased gradually. The K value remained increased throughout the storage. Sensory assessment followed the opposite trend. The electronic tongue indicated that the differences were distributed in various areas between the first 2 days and the last 6 days. Overall, we recommend that grass carp should be consumed within 6 days when stored at 4°C. Practical applications: In fish, the process of quality change after death can normally be divided into four stages: the early biochemical change, rigidity and dissolving, self‐dissolution and finally, corruption. Rigidity can delay the process of corruption somewhat as fish in the rigid period are almost as fresh as newly caught fish. Preservation may thus be described as an extension of the period of rigor mortis. Postmortem changes in grass carp meat were studied over a period of 192 hr by measuring its pH, texture properties, lactic acid, ATP‐related compounds, K values, and FAA content. Sensory assessment and electronic tongue measurements were also conducted. In addition to establishing a theoretical basis for the quality control and processing of grass carp, these results provide useful information for manufacturers and product developers seeking to improve the quality of their grass carp products and will also provide farmers with valuable insights into quality retention. [ABSTRACT FROM AUTHOR]