Electronic tongue, proton-transfer-reaction mass spectrometry, spectral analysis, and molecular docking characterization for determining the effect of α-amylase on flavor perception.

The effects of α-amylase on of flavor perception were investigated via spectrum analysis, electronic tongue, on-line mass spectrometry, and molecular docking. Aroma release results showed that α-amylase exhibited variable release patterns of different aroma compounds. Electronic tongue analysis showed that the perception of bitterness, sweetness, sour, and saltiness was subtly increased and that of umami was significantly increased (p < 0.01) along with the increasing enzyme activity of α-amylase. Ultraviolet absorption and fluorescence spectroscopy analyses showed that static quenching occurred between α-amylase and eight flavor compounds and their interaction effects were spontaneous. One binding pocket was confirmed between the α-amylase and flavor compounds, and molecular docking simulation results showed that the hydrogen, electrostatic, and hydrophobic bonds were the main force interactions. The TYP82, TRP83, LEU173, HIS80, HIS122, ASP297, ASP206, and ARG344 were the key α-amylase amino acid residues that interacted with the eight flavor compounds.

Nutritional Values and Bio-Functional Properties of Fungal Proteins: Applications in Foods as a Sustainable Source.

From the preparation of bread, cheese, beer, and condiments to vegetarian meat products, fungi play a leading role in the food fermentation industry. With the shortage of global protein resources and the decrease in cultivated land, fungal protein has received much attention for its sustainability. Fungi are high in protein, rich in amino acids, low in fat, and almost cholesterol-free. These properties mean they could be used as a promising supplement for animal and plant proteins. The selection of strains and the fermentation process dominate the flavor and quality of fungal-protein-based products. In terms of function, fungal proteins exhibit better digestive properties, can regulate blood lipid and cholesterol levels, improve immunity, and promote gut health. However, consumer acceptance of fungal proteins is low due to their flavor and safety. Thus, this review puts forward prospects in terms of these issues.

Molecular mechanisms of caramel-like odorant-olfactory receptor interactions based on a computational chemistry approach.

Molecular mechanisms of caramel-like odorant-olfactory receptor interactions were investigated based on molecular docking and molecular dynamics simulations. The transmembrane regions TM-3, TM-5 and TM-6 of receptors were main contributors of amino acid residues in the docking. Molecular docking results showed that hydrogen bonding and pi-pi stacking were the key forces for the stabilization of caramel-like odorants. The binding energies were positively correlated with the molecular weight of caramel-like odorants. Residues Asn155 (84%, OR2W1), Asn206 (86%, OR8D1), Ser155 (77%, OR8D1), Asp179 (87%, OR5M3), Val182 (84%, OR2J2) and Tyr260 (94%, OR2J2) with high frequencies played an important role in the complexes formation. Odorants 4-hydroxy-5-methylfuran-3(2H)-one (16#) and methylglyoxal (128#) were screened by molecular field-based similarity analysis, which tended to bind to the receptors OR1G1 and OR52H1 respectively, resulting a caramel-like aroma perception. The obtained results are useful for better understanding the perception of caramel-like odorants and their high-throughput screening.

Decoding the Effect of Age on the Taste Perception of Chicken Breast Soup Based on LC-QTOF-MS/MS Combined with a Chemometric Approach.

A nontargeted fingerprinting approach combined with the chemometrics method and sensory analysis was used to assess the differences in taste-chemical compositions of chicken breast soup with different ages and their sensory qualities. The sensory evaluation results showed that the overall taste as well as the sourness, saltiness, and umami scores of the soup were increased with the age of chicken. Fifty-nine compounds were identified from four soup samples by liquid chromatography-tandem quadrupole time-of-flight mass spectrometry (LC-QTOF-MS/MS), and their total content was the highest in the 90 wk soup samples. Six upregulated compounds (carnosine, hypoxanthine, inosine, inosine 5'-monophosphate (5'-IMP), adenosine 5'-monophosphate (5'-AMP), and lactic acid) were identified as potential contributors to the taste characteristics of the 90 wk soup samples by orthogonal projections to latent structures-discriminant analysis (OPLS-DA). Additional experiments showed that 5'-AMP particularly contributed to the sourness of the soup, while carnosine contributed to the saltiness and umami of the soup.

The Impact of Food Additives on the Abundance and Composition of Gut Microbiota.

The gut microbiota has been confirmed as an important part in human health, and is even take as an 'organ'. The interaction between the gut microbiota and host intestinal environment plays a key role in digestion, metabolism, immunity, inflammation, and diseases. The dietary component is a major factor that affects the composition and function of gut microbiota. Food additives have been widely used to improve the color, taste, aroma, texture, and nutritional quality of processed food. The increasing variety and quantity of processed food in diets lead to increased frequency and dose of food additives exposure, especially artificial food additives, which has become a concern of consumers. There are studies focusing on the impact of food additives on the gut microbiota, as long-term exposure to food additives could induce changes in the microbes, and the gut microbiota is related to human health and disease. Therefore, the aim of this review is to summarize the interaction between the gut microbiota and food additives.

Development of an Effective Protocol for Evaluating the Saltiness Intensity Enhancement of Umami Compounds.

Reducing sodium intake without decreasing saltiness perception remains an important target in the food industry. This study developed an effective protocol for evaluating the saltiness perception enhanced by umami compounds. Two sodium chloride solutions (2.00 and 6.00 g/L) were the preferred concentrations for consumers. Two-alternative forced-choice evaluation results confirmed that at a concentration of 2.00 g/L (sodium concentration), the highest replacement ratios of monosodium glutamate and l-alanine (Ala) were 10 and 20% in sodium chloride solution without saltiness intensity decrease, respectively. The highest replacement ratios of l-glycine (Gly) and Ala were 10 and 20% compared to 6.00 g/L, respectively. Temporal dominance of sensations analysis figured out that gum Arabic (GA) could compensate for the decrease of the retention time and increase the overall saltiness perception in the sodium-reduced sample. Quartz crystal microbalance with dissipation results showed that Ala and Gly could inhibit the binding of Na+ to mucin, thereby increasing the saltiness perception. GA exhibited the best saltiness enhancement effect in sodium-reduced solution by producing the nanoparticles from GA, decreasing the stability of the solution system, enhancing the loading effect of mucin on Na+, and prolonging the saltiness perception.

Optimization of beef broth processing technology and isolation and identification of flavor peptides by consecutive chromatography and LC-QTOF-MS/MS.

To investigate the flavor peptides of beef broth obtained under optimized stewing conditions, separation procedures such as ultrafiltration, Sephadex G-15 column chromatography, and reversed-phase high-performance liquid chromatography were employed to isolate the umami taste peptides. Sensory evaluation was combined with liquid chromatography-mass spectrometry to detect the flavor peptides. The optimization of the stewing process conditions was studied using the orthogonal method, which indicated that time had the most significant effect on the taste efficiency of sensory evaluation, followed by the mixed spices, sucrose, and salt. The optimized cooking conditions included 3.5 hr of cooking time, 1.800 g of sucrose, 2.125 g of salt, and 1.500 g of mixed spices. The results showed that six peptides, including SDEEVEH, AEVPEVH, GVDNPGHP, GSDGSVGPVGP, SDGSVGPVGP, and DEAGPSIVH, were detected in sample X1M1; and seven peptides, including VAPEEHPT, VVSNPVDIL, VGGNVDYK, PFGNTHN, EAGPSIVHR, VDFDDIQK, and DEAGPSIVH, were detected in sample X2M2. This study compared the flavor peptides in stewed beef before and after the optimization, and thus provided a basis for the improvement of beef processing technology.

Comparison of taste components in stewed beef broth under different conditions by means of chemical analyzed.

The aims of this study were to investigate the effect of stewing process on the content of taste compounds in stewing beef broth. The amino acids, 5'-nucleotides, and organic acids in stewing beef broth were determined by HPLC. The results showed that the contents of four 5'-nucleotides in raw beef were significantly lower than that in stewed beef broth. The addition of spices, salt, and sucrose was beneficial to promote the release of amino acid in beef broth. The highest contents of umami, sweet amino acid, and total amino acid were 907.67, 2930.11, and 5088.76 µg/g in stewed beef broth with salt addition, and 1085.10, 3367.48, and 5595.20 µg/g with sucrose addition. The contents of those in the stewed beef optimal group (s-b-o) were 7008.53, 34007.67, and 49282.82 µg/g, respectively, which was far higher than that with salt addition and sucrose addition. The content of total amino acid and total organic acid was significantly higher in s-b-o-o than in s-b-o. The proper amount of blend oil was beneficial to the release of flavor substances in stewed beef broth. The EUC value of the stewed beef blank group (s-b-b) was 3.50 g MSG/100 g. The addition of spices could significantly increase the EUC of stewed beef broth. The TAVs of 8 compounds were more than 1 in the sample of s-b-o-o, including Asp, Glu, Pro, Ala, Val, Met, Arg, and tartaric acid. These 8 compounds contribute more to the taste of stewed beef broth.