Answer;
-Drying with sulfur dioxide
Step-by-step explanation;
-Thiamin also known as Vitamin B1 is one of the water-soluble B vitamins. Thiamin is naturally present in some foods, added to some food products, and available as a dietary supplement. This vitamin plays a critical role in energy metabolism and, therefore, in the growth, development, and function of cells.
-Heating foods containing thiamin can reduce their thiamin content. For example, bread has 20%–30% less thiamin than its raw ingredients, and pasteurization reduces thiamin content. Because Thiamin dissolves in water, a significant amount of the vitamin is lost when cooking water is thrown out. Processing also alters thiamin levels in foods.