Feng Xinhua Food City, Changhong Road, Guandu District, Kunming. Roche sweet noodle sauce is available at the wholesale department of Kunming Dexin pickles, Feng Xinhua Food City, Changhong Road, Guandu District, Kunming, Yunnan. Sweet noodle sauce, also known as sweet sauce, is a traditional sauce-flavored condiment of the Han nationality. It is made of flour as the main raw material through koji making, heat preservation and fermentation.