Enrichment of the umami‐taste‐active amino acids and peptides from crab sauce using ethanol precipitation and anion‐exchange resin

Recent advancements in the taste transduction mechanism, identification, and characterization of taste components

In the realm of human nutrition, the phenomenon known as taste refers to a distinctive sensation elicited by the consumption of food and various compounds within the oral cavity and on the tongue. Moreover, taste affects the overall comfort in the oral cavity, and is a fundamental attribute for the assessment of food items. Accordingly, clarifying the material basis of taste would be conducive to deepening the cognition of taste, investigating the mechanism of taste presentation, and accurately covering up unpleasant taste. In this paper, the basic biology and physiology of transduction of bitter, umami, sweet, sour, salty, astringent, as well as spicy tastes are reviewed. Furthermore, the detection process of taste components is summarized. Particularly, the applications, advantages, and distinctions of various isolation, identification, and evaluation methods are discussed in depth. In conclusion, the future of taste component detection is discussed.

Sensory-Guided Isolation, Identification, and Active Site Calculation of Novel Umami Peptides from Ethanol Precipitation Fractions of Fermented Grain Wine (Huangjiu)

Huangjiu is rich in low-molecular-weight peptides and has an umami taste. In order for its umami peptides to be discovered, huangjiu was subjected to ultrafiltration, ethanol precipitation, and macroporous resin purification processes. The target fractions were gathered according to sensory evaluation. Subsequently, we used peptidomics to identify the sum of 4158 peptides in most umami fractions. Finally, six novel umami peptides (DTYNPR, TYNPR, SYNPR, RFRQGD, NFHHGD, and FHHGD) and five umami-enhancing peptides (TYNPR, SYNPR, NFHHGD, FHHGD, and TVDGPSH) were filtered via virtual screening, molecular docking, and sensory verification. Moreover, the structure-activity relationship was discussed using computational approaches. Docking analysis showed that all umami peptides tend to bind with T1R1 through hydrogen bonds and hydrophobic forces, which involve key residues HIS71, ASP147, ARG151, TYR220, SER276, and ALA302. The active site calculation revealed that the positions of the key umami residues D and R in the terminal may cause taste differences in identified peptides.

Preparation of sunflower seed-derived umami protein hydrolysates and their synergistic effect with monosodium glutamate and disodium inosine-5'-monophosphate

Sunflower seeds are rich in protein and can be an excellent raw material for the production of umami peptides. In this study, sunflower seed meal, which was defatted at a low temperature, was taken as the raw material, and proteins were separated, followed by hydrolyzation for 4 h by flavourzyme^® to obtain hydrolysates with strong umami intensity. These hydrolysates were deamidated using glutaminase to increase the umami intensity. The highest umami value of 11.48 was recorded for hydrolysates deamidated for 6 h, and the umami intensity was determined. The umami hydrolysates mixed with 8.92 mmol IMP + 8.02 mmol MSG showed the highest umami value of 25.21. Different concentrations of ethanol were used for further separation of hydrolysates, and the highest umami value of 13.54 was observed for 20% ethanol fraction. The results of this study provide utilization method for sunflower seed meal protein and a theoretical basis for the preparation of umami peptides. PRACTICAL APPLICATION: A large number of sunflower seed meals after oil production are used as feed for livestock and poultry. Sunflower seed meal is rich in protein, and umami amino acid composition in sunflower seed meal is up to 25%-30%, which is potentially an excellent raw material for the production of umami peptides. The umami flavor and synergistic effect of obtained hydrolysates, with MSG and IMP, were analyzed in the present study. We intend to provide a novel way for utilization of protein from sunflower seed meal along with a theoretical basis for the preparation of umami peptides.

Reaction Mixtures Rich in [γ-Glu](n≥1)-Arg Derived from Enzymatic Synthesis as Potential Salt and Umami Enhancers

Some arginyl dipeptides and γ-glutamyl peptides have been identified as salt and umami enhancers. These compounds provide an operable approach for reducing sodium uptake without losing the palatability of foods. γ-Glu-Arg was hinted to have a taste-enhancing effect in the past, but few research studies have focused on it. In the present study, a series of γ-glutamyl peptides containing Arg such as γ-Glu-Arg, [γ-Glu]_(n=2)-Arg, [γ-Glu]_(n=3)-Arg, [γ-Glu]_(n=4)-Arg, [γ-Glu]_(n=5)-Arg, [γ-Glu]_(n=6)-Arg, [γ-Glu]_(n=7)-Arg, and [γ-Glu]_(n=8)-Arg were synthesized using glutaminase from Bacillus amyloliquefaciens in the presence of Gln and Arg. A high solid concentration of 30% was found to increase the production of [γ-Glu]_(1≤n≤4)-Arg. Sensory evaluation revealed that individual [γ-Glu]_(n=1,2,3,4)-Arg has a slightly bitter and astringent taste. [γ-Glu]_(n=1,2)-Arg (1.0 mg/mL) significantly increased the umaminess in the mixture of salt and sodium glutamate but showed no significant effect on saltiness in the salt solution, whereas [γ-Glu]_(n=3,4)-Arg and postenzymatic reaction mixtures (1.0 mg/mL) significantly increased both saltiness and umaminess. [γ-Glu]_(n=3,4)-Arg and postenzymatic mixtures in the system with 30% solid concentrations showed a high and similar taste-enhancing effect. Moreover, umaminess and saltiness increased 1.9 and 2.4 times in the simulated broth, respectively, while saltiness increased 1.5 times in the salt solution by the addition of postenzymatic reaction mixtures in the system with 30% solid concentrations at 20.0 mg/mL. These results indicated that [γ-Glu]_(n=1,2,3,4)-Arg and postenzymatic reaction mixtures rich in [γ-Glu]_(n≥1)-Arg were potential salt or umami enhancers.

Research progress in the screening and evaluation of umami peptides

Umami is an important element affecting food taste, and the development of umami peptides is a topic of interest in food-flavoring research. The existing technology used for traditional screening of umami peptides is time-consuming and labor-intensive, making it difficult to meet the requirements of high-throughput screening, which limits the rapid development of umami peptides. The difficulty in performing a standard measurement of umami intensity is another problem that restricts the development of umami peptides. The existing methods are not sensitive and specific, making it difficult to achieve a standard evaluation of umami taste. This review summarizes the umami receptors and umami peptides, focusing on the problems restricting the development of umami peptides, high-throughput screening, and establishment of evaluation standards. The rapid screening of umami peptides was realized based on molecular docking technology and a machine learning method, and the standard evaluation of umami could be realized with a bionic taste sensor. The progress of rapid screening and evaluation methods significantly promotes the study of umami peptides and increases its application in the seasoning industry.

Compositional Features and Nutritional Value of Pig Brain: Potential and Challenges as a Sustainable Source of Nutrients

The goal of this study was to establish the nutritional value and compositional properties of the brains of crossbred pigs (Landrace-Large white-Duroc (LLD)), in order to realize the zero-waste concept and increase the use of by-products in the sustainable meat industry. Fat (9.25% fresh weight (fw)) and protein (7.25% fw) were the principal dry matters of pig brain, followed by carbohydrate and ash. Phospholipid and cholesterol had a 3:1 ratio. Pig brain had a red tone (L* = 63.88, a* = 5.60, and b* = 15.43) and a high iron content (66 mg/kg) due to a total heme protein concentration of 1.31 g/100 g fw. The most prevalent macro-element was phosphorus (14 g/kg), followed by potassium, sodium, calcium, and magnesium. Zinc, copper, and manganese were among the other trace elements discovered. The most prevalent nitrogenous constituents were alkali-soluble protein, followed by water-soluble protein, stromal protein, salt-soluble protein, and non-protein nitrogen. Essential amino acids were abundant in pig brain (44% of total amino acids), particularly leucine (28.57 mg/g protein), threonine, valine, and lysine. The total lipid, neutral, and polar lipid fractions of the pig brain had different fatty acid compositions. The largest amount was observed in saturated fatty acids (SFA), followed by monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA). Stearic acid and palmitic acid were the most common SFA. Oleic acid was the most prevalent MUFA, while docosahexaenoic acid was the most common PUFA. Thus, the pig brain can be used in food formulations as a source of nutrients.