Ramirez I
Monell Chemical Senses Center, Philadelphia, PA 19104-3308.
Physiol Behav. 1994 Sep;56(3):549-54. doi: 10.1016/0031-9384(94)90300-x.
Previous studies suggest that rats might be able to discriminate between sucrose and fructose, but no previous study has examined this possibility in much detail. Rats were conditioned to avoid either sucrose or fructose by injecting them with lithium chloride when they drank these substances. Control rats were given the same injections but were not exposed to either sugar during training. After training, the rats were given a choice of fructose vs. sucrose. Data from control rats provided information about the relative taste intensity of the sugars. If the sugars possess only a single gustatory quality, control rats should prefer the sweeter sugar; under this assumption, sucrose appears to be two-four times sweeter than fructose. The two sugars share a common taste because rats trained to avoid sucrose avoided fructose when the fructose concentration was much greater than the sucrose concentration. Nevertheless, the two sugars are discriminable because, when the apparent sweetness of the sugars was matched, rats showed a greater aversion to the sugar they were trained to avoid. Aversions to sucrose and fructose also generalized to maltodextrins, but sucrose may have a somewhat greater maltodextrin flavor than does fructose. It is proposed that the biological function of maltodextrin taste is to allow animals to sense the ratio of glucose to fructose in foods.
先前的研究表明，大鼠或许能够区分蔗糖和果糖，但之前尚无研究对此可能性进行过详细探究。通过在大鼠饮用蔗糖或果糖时注射氯化锂，使其形成避免饮用这两种物质的条件反射。对照大鼠接受相同注射，但在训练期间未接触任何一种糖。训练后，让大鼠在果糖和蔗糖之间进行选择。对照大鼠的数据提供了有关这两种糖相对味觉强度的信息。如果这两种糖仅具有单一味觉特性，对照大鼠应偏好更甜的糖；在此假设下，蔗糖的甜度似乎是果糖的两到四倍。这两种糖具有共同的味道，因为当果糖浓度远高于蔗糖浓度时，训练成避免蔗糖的大鼠也会避免果糖。然而，这两种糖是可区分的，因为当两种糖的表观甜度相匹配时，大鼠对它们被训练避免的那种糖表现出更强的厌恶。对蔗糖和果糖的厌恶也会泛化到麦芽糊精，但蔗糖的麦芽糊精风味可能比果糖略强。有人提出，麦芽糊精味觉的生物学功能是使动物能够感知食物中葡萄糖与果糖的比例。
