The important physico-chemical properties of thiamin are as follows:
a) Thiamin hydrochloride is a white, needle-shaped crystalline substance.
b) It has a characteristic smell like that of yeast. In fact, the characteristic smell of yeast is because of its content of thiamin. Thiamin has a sulfurours odour and a bitter
c) The compound is readily soluble in water and slightly soluble in alcohol. This property makes it vulnerable, as thiamin in foods is easily lost during washinglsoaking and other cooking procedures. Moisture greatly accelerates destruction and thus it is much less stable to heat in fresh foods than in dry foods.
d) It is stable in acid medium at room temperature but destroyed, if heated at 120°C for 30 minutes.