As one of the five basic tastes, umami signals the intake of nitrogenous nutrients such as protein or/and L-amino acids. It also assumes a dual role in flavoring and physiological function regulation, providing a pleasant taste experience and psychological enjoyment. Although the science of umami has been developed for over a century, controversies about the taste of umami (umami peptides) and the safety of umami still exist among the public. Therefore, this review summarizes the recent progress in research on the sensory descriptions of umami and umami peptides, the safety of monosodium glutamate as a representative of umami substances, and the function of umami. Moreover, this review describes the broad and narrow definitions of umami, the taste multiplicity of umami peptides and its influential factors, and affirms the role of umami taste in daily intake safety and appetite regulation. We expect this review to provide a reference for research on the umami taste of food.

Food flavor is an important attribute of high-quality foods. The consumers’ preference for foods is largely determined by taste and smell perception. The traditional food flavor evaluation methods include sensory evaluation, smart devices and instrumental analysis methods. Sensory evaluation is reliable but prone to taste fatigue and individual subjectivity. The structure of smart devices is complex, and there are some differences between the working principle and the actual taste transmission, resulting in limited applications. The cell-based biosensor is a new method to detect and evaluate food flavor that integrates living cells as sensitive elements, transducers and signal processing devices. They show the advantages of high sensitivity, good selectivity and fast response and have become a hotspot in the field of biosensors. Based on a review of recent research achievements, this paper briefly introduces the concept and basic structure of cellbased biosensors, and focuses on the results of research in the field of taste and smell evaluation and their application. The perception and transmission mechanisms in practical application are elucidated, and the flavor perception information for foods that has been obtained by researchers is summarized. Finally, the problems existing in the development of cell-based biosensors are discussed, and possible future trends are projected in food flavor evaluation.

The decline in meat freshness can result in resource waste and even pose high risks to human health. Therefore, development of effective evaluation technologies for meat freshness is crucial for ensuring food safety. Nanozymes, as a new generation of artificial enzymes, offer several advantages, including convenient preparation, low cost, high stability, and robust catalytic performance. Consequently, various nanozymes have been extensively applied in sensors for evaluating meat freshness. This paper first systematically summarizes five representative nanozymes and the signal generation mechanisms of different types of sensors (e.g. colorimetric, fluorescent, electrochemical, and surface-enhanced Raman spectroscopy (SERS) sensors) from the perspective of signal transduction in nanozyme-based freshness sensors. Furthermore, it focuses on the application of various nanozyme-based sensors in evaluating meat freshness. Finally, the challenges facing the application of nanozymes in detecting meat freshness are discussed. Our aim is to provide new ideas for advancing the development of nanozyme-based sensing technology for the detection of meat freshness.

SARS-CoV-2, particularly the Omicron variant, often leads to flavor perception dysfunction in infected individuals, making a comprehensive understanding of its duration and recovery patterns a critical part of disease management. This study surveyed a cohort of 199 mildly-to-moderately affected SARS-CoV-2 Omicron-infected patients, focusing on the alterations in their olfaction, taste, and chemesthesis perception. Further, a subset of 36 participants (18 healthy and 18 infected) underwent sensory evaluations to check the variation of umami taste sensitivity. The results demonstrated that most of the infected cohort experienced chemosensory disorders, with the recovery period varying between one week and over a month. Intriguingly, the severity of flavor perception changes during infection significantly correlated with the length of the recovery period. Furthermore, this study explored the specific manifestations of flavor perception dysfunction, potential contributing factors, and potential mechanistic explanations for chemosensory disorders. These include local damage, inflammatory responses, and virus-induced neural damage. However, this study revealed no significant change (P > 0.05) in umami taste sensitivity among infected patients 55 days post-infection. While this research faces limitations related to its self-reported, cross-sectional design, and regional focus, it offers valuable insights into the multifaceted impact of COVID-19, particularly the Omicron variant, on chemosensory perception.

The study of ligand-receptor interactions is of great significance in food flavor perception. In this study, a computer simulation method was used to investigate the mechanism of interaction between umami peptides and T1R1/T1R3-Venus-flytrap domain (VFT) receptor. The binding site, conformational changes, and binding free energy between umami peptides and T1R1/T1R3-VFT were analyzed through molecular modeling, molecular docking, and molecular dynamics simulations. The receptor model constructed using AlphaFold2 has the best rationality. The molecular docking results showed that umami peptides primarily bound to T1R1-VFT through hydrogen bonding, with key binding residues such as Thr149, Arg151, and Asp108. The binding of umami peptides led to a more stable complex system, and the positively charged amino acids contributed positively to the overall binding free energy. This study provides theoretical support for the development of a better understanding of the interaction between umami substances and the umami receptor.

In this study, umami taste intensity (UTI) and umami taste components in chicken breast (CB) and chickenspices blends were characterized using sensory and instrumental analysis. Our main objective was to assess the aroma-umami taste interactions in different food matrices and reconcile the aroma-taste perception to assist future product development. The impact of key aroma, including vegetable-note “2-pentylfuran”, meaty “methional”, green “hexanal”, and spicy-note “estragole and caryophyllene” on UTI was evaluated in monosodium glutamate and chicken extract. We found that spices signif icantly decreased UTI and umami taste components in CB. Interestingly, the perceptually similar odorants and tastants exhibited the potential to enhance UTI in food matrices. Methional was able to increase the UTI, whereas spicy and green-note components could reduce the UTI signif icantly. This information would be valuable to food engineers and formulators in aroma selection to control the UTI perceived by consumers, thus, improving the quality and acceptability of the chicken products.

Inosine monophosphate (IMP), as a critical umami substance, is one of the most important indicators for evaluating the quality of meat products. Here, a sensitive electrochemiluminescence (ECL) biosensor based on graphdiyne (GDY)/AuNPs/luminol nanocomposites was constructed to detect IMP. The GDY/AuNPs/luminol nanocomposites were synthesized by using simple one-pot method. GDY utilized its 2D framework to disperse and fix gold nanoparticles, which inhibited the agglomeration of gold nanoparticles and greatly improved its stability and catalytic properties. Importantly, GDY/AuNPs/luminol nanocomposites showed excellent catalytic ability and superior ECL activity towards luminol-H₂O₂ systems due to the synergistic effect of GDY and AuNPs. Under optimal conditions, the prepared biosensor exhibited a wide linear range from 0.01 g/L to 20 g/L, a satisfactory limit detection of 0.0013 g/L, as well as an excellent specificity. Moreover, we carried out the precise analysis of IMP in actual meat samples with acceptable results compared to the liquid chromatography. We believe that this work could offer an efficient ECL platform for accurate and reliable report of IMP levels, which is significant for maintaining food quality and safety.

Pufferfish is prone to deterioration due to abundant nutrients and high moisture content. Drying technology can extend the shelf life and enhance the flavor quality of aquatic products. The study investigated the effect of hot air drying (HAD), microwave vacuum drying (MVD) and hot air assisted radio frequency drying (HARFD) on the taste and volatile profiles of Takifugu obscurus. Different drying methods had significant influence on the color, rehydration, 5’-nucleotides, free amino acids and volatile components (P < 0.05). The results showed that HAD and HARFD could promote the flavor of T. obscurus by producing higher equivalent umami concentration (EUC) values, which were about two times of MVD group, and more pronounced pleasant odor according to sensory analysis. HAD is more appropriate for industrial application than HARFD and MVD considering the economic benefits. This study could provide a reference for the industrial application of drying T. obscurus.

Sanhuang chicken is a popular native breed in China and well-known for delicious flavour. Spices could enhance the chicken meat flavour and work well in preservation. Chinese 5-spice blend (CS) and garam masala (GM) are routinely using spices in China and Pakistan, respectively. The flavour profiles of Sanhuang chicken breast (CB) and its blends with CS and GM were obtained by electronic nose (E-nose), solid-phase microextraction gas chromatography-mass spectrometry (SPME GC-MS) and GC-ion mobility spectrometry (GC-IMS). Principal component analysis (PCA) efficiently discriminated the aroma profiles of three chicken formulations. The GC-chromatographs revealed the significant aroma alterations of chicken breast meat after marination with spices. Aldehydes were the major contributors of chicken aroma, while most of the aromatic hydrocarbons were generated by spices. Almost all chicken key-compounds produced by oxidation reaction were either reduced or eliminated by marination, showing the antioxidation capacity of spices leading to meat preservation. GC-IMS is not only a rapid and comprehensive detection method, but also proved to be more sensitive than GC-MS. The substantial role of both traditional spices in enhancing flavour quality of chicken meat, and their exposure as functional ingredients in Chinese and Pakistan cuisines could lead to the cross-cultural meat trade opportunities.

Tilapia is a freshwater fish group with a sustainable prospect but suffers off-notes appearing during cooking processes. To promote pleasant odorants by thermal cooking processes, tilapia fillets were cooked in different ways (roasting, microwave-heating, boiling and steaming). Their aroma profiles were analysed with special focus on off-notes and umami-enhancing odorants by principal component analysis, and correlated with the heating time, colour, moisture and water activity by partial least squares regression analysis. Results showed that the “green” and “earthy” off-notes were highly correlated with the boiling process (excess of water, short heating time), while most of the umami-enhancing odorants had a high association with the roasting process (low water content, long heating time, better Maillard reaction). This study indicated that roasting is the most adapted cooking process promoting Maillard-derived aromas, umami-enhancing aromas and meanwhile, reducing off-notes. This research helps in understanding the off-note generation in tilapia and promoting desirable umami-enhancing odorants.