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Bitter compounds widely exist in foods and have an important impact on food flavor. The major bitter compounds in foods include amino acids, peptides, polyphenols, alkaloids, and inorganic salts. Bitterness is perceived through binding between bitter compounds and the specific sites of the 25 human bitter taste receptors (hTAS2Rs), which further activates the downstream signal pathway mediated by G protein, converting chemical signals into electrical signals and transmitting them to the brain. Some foods with strong bitterness taste are not well accepted by consumers, so appropriately reducing bitterness in foods can improve consumers’ preference. At present, there are two main methods to reduce the perception of food bitterness: 1) masking bitterness by polymerization/complexation or flavor interaction, and 2) removing bitterness by reducing the content of bitter compounds or changing their structure. In this paper, the bitter compounds in foods, the analytical methods for them, the mechanism of bitterness perception and the methods used to reduce bitterness perception are reviewed in an effort to provide theoretical guidance for food bitterness regulation.

An online survey was conducted to show that most respondents preferred sports drinks with sweet and fruity characteristics. Eleven sports drinks with higher consumers' preferences were further selected for aroma and taste evaluation. Temporal dominance of sensations analysis showed that fruity and fresh attributes were dominant, while sour and fruity sweet were dominant tastes during consumption. β-Damascenone, β-ionone, and linalool contributing to floral perception, γ-decalactone, ethyl cinnamate, and isoamyl acetate contributing to fruity perception, and menthol contributing to fresh perception were confirmed by odor activity value analysis. Running affected the nasal air flow and the saliva secretion, resulting in the flavor perception changing from fruity sweet, sweet, and fruity to sour because the recognition threshold decreased for sweet, fruity, floral, and fresh flavors and increased for saltiness, astringency, and sour tastes. [ABSTRACT FROM AUTHOR]

Spherical gamma‐alumina (γ‐Al2O3) has a wide range of applications in the field of adsorption due to its low bulk density, larger pore size, higher strength and thermal stability. In this study, spherical γ‐Al2O3 with macro‐mesopores was prepared with isopropanol aluminium as the aluminium source via a sol–gel process. Spherical γ‐Al2O3 was characterised by means of nitrogen adsorption and desorption curve, scanning electron microscope, transmission electron microscope, X‐ray diffraction and so on. The adsorption performance of the prepared spherical γ‐Al2O3 was studied by probe experiment of adsorption of acid fuchsin (AF) solution. The results showed that the spherical γ‐Al2O3, which was prepared under the condition of hydrolysis time of 1 h, hydrolysis temperature of 85°C, ageing temperature of 95°C and ageing time of 7 h, had the strongest adsorption capacity for AF, and the adsorption efficiency could reach 96.24% in 40 mg/l AF solution. In addition, after six cycles of use, the spherical γ‐Al2O3 had no damage and the adsorption efficiency still could reach 88.40%. This work provides a feasible method for the preparation of spherical γ‐Al2O3, and could also help to understand the connection between its textural properties and adsorption performance. [ABSTRACT FROM AUTHOR]