Preparation of glucose by commerical method : When starch is boiled with dilute `H_(2)SO_(4)` at 393 K under pressure it undergoes hydrolysis to give glucose. Excess of `H_(2)SO_(4)` is neutralized by adding chalk powder. Colour impurities are removed by adding activated charcoal. The coloured impurities are absorbed on charcoal. On cooling crystals of glucose separate out which are removed by filtration.
`underset("(Starch)")((C_(6)H_(10)O_(5))_(n))+nH_(2)O overset("dil. "H_(2)SO_(4))underset("393 K, 2-3 atm")rarr underset("(Glucose)")(nC_(6)H_(12)O_(6))`
Formation of peptide linkage : Peptide bond or peptide linakge is an amide formed between `-COOH` and `NH_(2)` group by elinination of `H_(2)O.`
