2. Because it has rotted, sweet noodle sauce, also known as sweet sauce, is a sauce-like condiment made of flour as the main raw material through koji making and heat preservation fermentation. Sweet noodle sauce has undergone a special fermentation process. If it expires, it will lead to abnormal fermentation, which is harmful to human health. The sweetness of sweet noodle sauce comes from maltose, glucose and other substances produced during fermentation. Umami taste comes from amino acids produced by protein decomposition, and salty taste is produced by adding salt. Sweet noodle sauce contains a variety of flavor substances and nutrients, which not only tastes delicious, but also enriches the nutrition of dishes, increases the edibility of dishes, and has the effect of appetizing and helping food.