According to its elemental composition, foods can be divided into three categories: alkaline foods, neutral foods and acidic foods. Foods containing phosphorus, chlorine, sulfur, sulfur and other elements are generally acidic foods, such as flour, meat, grains, oils and fats, alcohol and sugar.

1, rice, is a finished product made of rice after cleaning, husking, milling and finishing. The cleaning process is to remove all kinds of impurities mixed into rice by using appropriate equipment, proper technological process and proper operation methods, so as to improve the quality of finished rice products, and at the same time, remove nails and iron chips from rice by using magnets to ensure production safety. The husking process is to remove the glume of rice with rubber roller husker or emery husker and separate the glume from brown rice. In the rice milling process, the brown rice is milled and rubbed by a rice mill to separate the cortex from the endosperm, and then the rice is brushed, chaff removed, broken and dried, so that the rice with the required grade can be obtained. Modern new rice also uses processing technologies such as color selection, air separation, sterilization and dust removal, sterilization and insect elimination, antibacterial, oxygen-blocking, enzyme-inhibiting, bionic packaging, etc. to make rice more hygienic and safe, delicious and nutritious, and less loss.

2. Flour is a kind of powder ground from wheat. According to the content of protein in flour, it can be divided into high gluten flour, medium gluten flour, low gluten flour and gluten-free flour. Flour (wheat flour) is the staple food in most parts of northern China. There are many kinds of food made of flour, with various patterns and different flavors.