Taste psychophysics of bitter phytochemicals

描述（申请人提供）：富含蔬菜和水果的饮食可以降低患癌症和其他全身性疾病的风险。植物化学物质如酚类、类黄酮、异黄酮、萜烯和硫代葡萄糖苷具有抗氧化和抗癌特性，并显示出广泛的肿瘤阻断活性。这些植物化学物质中的许多都有苦味，这可能导致人们避免食用含有它们的食物。口味也是选择食物时最重要的因素；它比营养价值、成本、便利性和体重控制更重要。然而，感知某些苦味物质的能力是由基因介导的；大约25%的人无法感知6-n-丙基硫脲嘧啶（PROP）的苦味，50%的人可以品尝它，25%的人被认为是超级味觉者。研究表明，PROP品尝者对苦味蔬菜和沙拉蔬菜的接受度较低。因此，PROP品尝者可能不太可能采用强调食用苦味蔬菜的癌症预防饮食。对植物化学物质柚皮素、柠檬苦素、槲皮素、紫荆素和染料木素的阈值和超阈值苦味感知知之甚少。本研究的目的是确定这些苦味植物化学物质是如何被（超级）品酒者和非品酒者感知的。通过提出的实验所获得的知识将深入了解遗传味觉敏感性在食物偏好和食物选择中的作用。五种植物化学物质、氯化钠和PROP的检测阈值将通过最大似然自适应阶梯法确定。所有七种物质的心理物理功能将用标记量值量表进行测量。受试者还将对七种物质的五种浓度中的每一种的喜爱程度进行评分。此外，还将收集食物偏好数据。预计这项研究将为每种植物化学物质提供安全和可用的刺激范围，以便将来可以获得儿童的数据。

DESCRIPTION (provided by applicant): Diets rich in vegetables and fruit lower the risk of cancer and other systemic diseases. Phytochemicals such as phenols, flavonoids, isoflavones, terpenes and glucosinolates have anti-oxidant and anti-carcinogenic properties and demonstrate a wide spectrum of tumor-blocking activities. Many of these phytochemicals have a bitter taste, which could lead to avoidance of the foods containing them. Taste also is the most important factor in food choice; it is more important than nutritional value, cost, convenience and weight control. The ability, however, to perceive some bitter substances is genetically mediated; about 25% of the population is unable to perceive the bitterness of 6-n-propylthiouracil (PROP), 50% can taste it, and 25% are considered supertasters. It has been shown that PROP tasters have a lower acceptance of bitter vegetables and salad greens. PROP tasters might therefore be less likely to adopt a diet for cancer prevention that emphasizes consumption of bitter vegetables. Very little is known about threshold and suprathreshold bitter perception of the phytochemicals naringin, limonin, quercetin, sinigrin and genistein. The purpose of this study is to determine how these bitter phytochemicals are perceived by (super) tasters and non-tasters of PROP. The knowledge gained through the proposed experiments will provide insight into the role genetic taste sensitivity plays in food preference and food choice. Detection thresholds for the five phytochemicals and sodium chloride and PROP will be determined with a maximum likelihood adaptive staircase method. Psychophysical functions for all seven substances will be measured with the Labeled Magnitude Scale. Subjects will also rate how much they like each of five concentrations of the seven substances. Furthermore, food preference data will be gathered. It is anticipated that this study will result in safe and usable ranges of stimulation for each of the phytochemicals, so that in the future data from children can be obtained.