Direct conversion of starch into glucose may be carried out by 
 

$\mathrm{Starch} \stackrel{\mathrm{HCl}/∆ }{\to } \mathrm{n} \mathrm{Glucose}$

(C₆H₁₀O₅)_n + nH₂O $\underset{393\mathrm{K},2-3 \mathrm{atm}}{\overset{{\mathrm{H}}^{+}}{\to }}$  nC₆H₁₂O₆

(Starch)                                                    (Glucose)