IELTS Reading - Trí Đức English TRÍ ĐỨC ENGLISH Chuyên Mục IELTS Reading - Bài Tập & Phân Tích Chuyên Sâu (Passage 2: Bitterness & Taste) 1. Bài Đọc (Reading Passage) [Paragraph A] Have you ever wondered why grapefruit juice is often served in small glasses? It is because most people like to drink it only in small doses, as they find it somewhat bitter. Naringin, a natural chemical found in grapefruit, has a bitter taste. Although some people like that bitterness, there are other people who want nothing to do with it. So juice companies often decide to use grapefruit with lower naringin content, despite the fact that naringin has antioxidant properties that can help prevent cancer and arteriosclerosis. [Paragraph B] A New Jersey biotech company, the Linguagen Corporation, has found a way to eliminate the bitter taste in grapefruit juice. In a taste test, the company had participants drink grapefruit juice from two different sets of white paper cups, labeled 304 and 305. Each participant drank from one cup and then the other, cleansing their palates between tastings with water and a soda cracker. Even the smallest sip from the 304 cups was determined to have the bitter taste commonly associated with grapefruit. The 305 cups were found to be different, however. They still had the sour taste of citrus, but the bitter taste of naringin was gone. The 305 batch had been treated with adenosine monophosphate, also called AMP, a compound that blocks the bitter taste in foods without affecting the nutrition value of those foods. [Paragraph C] Taste research has become commonplace these days. Food biologists are researching all five basic tastes: sweet, bitter, sour, salty and umami, a Japanese term referring to savoriness. Food biologists are especially interested in bitterness, because there are thousands of bitter-tasting natural compounds that are not currently used as foods. Biologists view these bitter foods as an untapped potential food source for our future needs. Some bitter foods, such as grapefruit and cruciferous vegetables such as cabbage, kale, broccoli, and cauliflower are nutritious despite, and sometimes because of, their bitter-tasting components. Over time, many people have acquired a taste for bitter foods. [Paragraph D] It is important to note that people taste bitterness at different levels. These variances appear to be mostly genetic. About three-fourths of people are sensitive to the taste of the bitter compounds phenylthiocarbamide and 6-n-propylthiouracil. Those people who are sensitive to phenylthiocarbamide seem to be less likely than others to eat cruciferous vegetables, according to Stephen Wooding, a geneticist at the University of Utah. Some people, known as supertasters, are especially sensitive to 6-n-propylthiouracil because they have an unusually high number of taste buds. It is not unusual for supertasters to avoid all kinds of bitter-tasting foods and drinks, including some vegetables, coffee, and dark chocolate. Supert...