Institute of Chemistry and The Fritz Haber Research Center, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
Institute of Chemistry and The Fritz Haber Research Center, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
Food Chem. 2017 Dec 15;237:1209-1215. doi: 10.1016/j.foodchem.2017.06.047. Epub 2017 Jun 10.
Trehalose is revered for its multiple unique impacts on solution properties, including the ability to modulate the salty and bitter tastes of sodium and potassium salts. However, the molecular mechanisms underlying trehalose's effect on taste perception are unknown. Here we focus on the physico-chemical effect of trehalose to alter the activity of monovalent salts in aqueous solution. Using a modified isopiestic methodology that relies on contemporary vapor pressure osmometry, we elucidate how trehalose modifies the thermodynamic chemical activity of sodium and potassium chloride, as well as the effect of the salts on the sugar's activity. We find that trehalose has a specific impact on potassium chloride that is unlike that of other sugars or polyols. Remarkably, especially at low salt concentrations, trehalose considerably elevates the activity (or chemical potential) of KCl, raising the salt activity coefficient as high as ∼1.5 its value in the absence of the sugar. Moreover, in contrast to their action on other known carbohydrates, both KCl and NaCl act as salting-out agents towards trehalose, as seen in the elevated activity coefficient compared with its value in pure water (up to ∼1.5 higher at low sugar and salt concentrations). We discuss the possible relevance of our findings to the mechanism of trehalose taste perception modification, and point to necessary future directed sensory experiments needed to resolve the possible link between our findings and the emerging biochemical or physiological mechanisms involved.
海藻糖因其对溶液性质的多种独特影响而备受推崇，包括调节钠和钾盐的咸和苦味道的能力。然而，海藻糖对味觉感知影响的分子机制尚不清楚。在这里，我们专注于海藻糖改变单价盐在水溶液中活性的物理化学效应。我们使用一种依赖于现代蒸汽压渗透压计的改良等压法，阐明了海藻糖如何改变氯化钠和氯化钾的热力学化学活性，以及盐对糖活性的影响。我们发现海藻糖对氯化钾具有独特的影响，这与其他糖或多元醇不同。值得注意的是，尤其是在低盐浓度下，海藻糖大大提高了 KCl 的活性（或化学势），使盐的活度系数高达其在没有糖时的约 1.5 倍。此外，与它们对其他已知碳水化合物的作用相反，KCl 和 NaCl 都对海藻糖起到盐析作用，这从与纯水中的值相比，活度系数升高（在低糖和低盐浓度下，最高可达约 1.5 倍）。我们讨论了我们的发现对海藻糖味觉感知修饰机制的可能相关性，并指出需要进行未来的定向感官实验，以解决我们的发现与涉及的新兴生化或生理机制之间可能存在的联系。
