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.