Numerous Compounds Orchestrate Coffee's Bitterness
Numerous Compounds Orchestrate Coffee's Bitterness
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DOI：
10.1021/acs.jafc.0c01373
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发表时间：
2020-06-17
影响因子：
6.1
通讯作者：
Behrens, Maik
中科院分区：
文献类型：
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作者：
Lang, Tatjana;Lang, Roman;Behrens, Maik
咖啡是世界上消费最多的热饮料之一，尽管有明显的苦味，但由于其刺激作用而受到高度重视。尽管已经鉴定出多种苦味成分，但除了咖啡因之外，咖啡苦味的详细分子基础尚不清楚，咖啡因可以激活五种人类苦味受体。我们通过使用表达人类苦味受体 cDNA 的哺乳动物细胞的功能性钙成像实验、感官实验和计算机建模方法，阐明了除咖啡因之外的其他苦咖啡成分的贡献。我们鉴定了两种人类苦味受体 TAS2R43 和 TAS2R46，它们对苦味物质莫桑比奥苷的反应比对咖啡因的敏感性高得多。此外，结构相关的苦味物质孟加拉醇、咖啡醇和咖啡醇也比典型的咖啡苦味物质咖啡因更有效地激活同一对苦味受体。然而，对于 kahweol（一种有效但较弱的 TAS2R43 和 TAS2R46 激活剂），我们观察到当与莫桑比苷同时应用于 TAS2R43 表达细胞时具有抑制作用。分子建模实验显示受体配体结合腔中存在重叠的结合位点，这表明部分激动剂 kahweol 可能有助于降低含咖啡饮料的整体苦味。综上所述，我们发现咖啡的苦味是由多种苦味化合物与几种人类苦味受体的复杂相互作用决定的。
Coffee is one of the most consumed hot beverages worldwide and is highly regarded because of its stimulating effect despite having a pronounced bitterness. Even though numerous bitter ingredients have been identified, the detailed molecular basis for coffee's bitterness is not well understood except for caffeine, which activates five human bitter taste receptors. We elucidated the contribution of other bitter coffee constituents in addition to caffeine with functional calcium imaging experiments using mammalian cells expressing the cDNAs of human bitter taste receptors, sensory experiments, and in silico modeling approaches. We identified two human bitter taste receptors, TAS2R43 and TAS2R46, that responded to the bitter substance mozambioside with much higher sensitivity than to caffeine. Further, the structurally related bitter substances bengalensol, cafestol, and kahweol also activated the same pair of bitter taste receptors much more potently than the prototypical coffee bitter substance caffeine. However, for kahweol, a potent but weak activator of TAS2R43 and TAS2R46, we observed an inhibitory effect when simultaneously applied together with mozambioside to TAS2R43 expressing cells. Molecular modeling experiments showed overlapping binding sites in the receptor's ligand binding cavity that suggest that the partial agonist kahweol might be useful to reduce the overall bitterness of coffe-econtaining beverages. Taken together, we found that the bitterness of coffee is determined by a complex interaction of multiple bitter compounds with several human bitter taste receptors.