烘焙好的咖啡中的酸主要有以下几种中国咖啡网

　　烘焙好的咖啡中的酸主要有以下几种 -郑伟(意利咖啡大学)

　　下面文字参照第一版the chemistry of quality 一书

　　烘焙好的的咖啡中的酸主要有以下几种：

　　甲酸在浅度烘焙时最多，随着深度烘焙的加深逐渐减少

　　醋酸在浅度烘焙时最多，随着深度烘焙的加深逐渐减少

　　丙酮酸和烘焙程度无关

　　乳酸和烘焙程度无关

　　苹果酸在浅度烘焙时最多，随着深度烘焙的加深逐渐减少

　　柠檬酸在浅度烘焙时最多，随着深度烘焙的加深逐渐减少

　　奎宁酸随着绿原酸的减少会增多

　　如果以ARABICA%或者ROBUSTA%测试，30秒萃取30ml ,他们的PH值都是5.2。

　　所以从严格意义的PH值来测定的话，咖啡是“酸”性的，但是酸性食物和碱性食物和我们普通意思喝到的酸又不是一回事。

　　含钾、钠、钙、镁等矿物质较多的食物，在体内的最终的代谢产物常呈碱性，如，蔬菜、水果、乳类、大豆和菌类食物等。与呈碱食物适当搭配，有助于维持体内酸碱平衡。食品的酸碱性与其本身的pH值无关(味道是酸的食品不一定是酸性食品)，主要是食品经过消化、吸收、代谢后，最后在人体内变成酸性或碱性的物质来界定。产生酸性物质的称为酸性食品，如动物的内脏、肌肉、植物种子(五谷类)。产生碱性物质的称为碱性食品，如蔬菜瓜豆类，茶类等。

　　下面的文章来自于：

　　http://www.alkaline-alkaline.com/acid_alkaline.html

　　NUTRITION AND ACID-ALKALINE BALANCE

　　Before World War II, there was considerable interest in how the food we eat affects the acid-alkaline balance of the body. While today the subject is not receiving much attention in orthodox circles, many alternative practitioners place considerable stress on the acid-base balance characteristics of various diets. In spite of a certain amount of ongoing debate, it is generally acknowledged that the food that is eaten is a major source of acid and alkali for the body (7).

　　Some confusion in terminology has resulted because of the way that the discussion evolved. In investigating how different foods might affect the acid-alkaline balance, various foods were burned to ash in the laboratory, and the pH of the resulting ash was measured. These foods were then classified as acid, alkaline or neutral ash foods as shown in Table 3 (8).

　　TABLE 3. Acid, Alkaline and Neutral Ash Foods (8)

　　Acid Ash FoodsAlkaline Ash FoodsNeutral Ash Foods

　　bread (grains)cheesearrowroot

　　cakecreambutter

　　cerealmost fruitcandy

　　mayonnaisejamcoffee

　　cranberriesmilkcornstarch

　　plumsalmondslard

　　pruneschestnutsmargarine

　　meatcoconutvegetable oil

　　Brazil nutsmolassespostum

　　walnutsmost vegetableswhite sugar