1. There are three kinds of leavening agents: baking soda, flour fertilizer (old flour) and dry yeast powder. They all work on the same principle: under the right conditions, the starter produces carbon dioxide gas in the dough, and then the dough becomes soft and delicious by heating and expanding.

2. The gas released by baking soda is not rich, so the softness of the finished product made of baking soda is not very good. Moreover, it is a weakly alkaline substance, which will destroy the vitamins in flour and reduce the nutritional value of pasta. It is not recommended to choose.

3, face fat Some places are also called old noodles. It's a piece of dough left after the last fermentation. After proper preservation, it began to ferment as a strain. Flour fertilizer must be used with alkali because it will make the dough sour. But alkali will destroy the nutrition of flour, and the dosage is difficult to master, and the finished product is easy to waste, hehe ~ so it is not recommended to use it.

4. Active dry yeast (yeast powder) is a natural yeast extract, which is not only rich in nutrition, but also rich in vitamins and minerals. It is not only rich in vitamins, but also has a protective effect on vitamins in flour. Not only that, yeast can also increase the B vitamins in dough during reproduction. Therefore, the nutritional value of pasta products fermented with it is several times higher than that of unfermented pasta such as cakes and noodles.