Acid hydrolysis prior to automatic analysis for starch

Abstract The determination of starch in potatoes ( Solanum tuberosum L) by enzymic hydrolysis with amyloglucosidase (Hudson et al 1976), compared with the acid hydrolysis procedure suggested here, has several disadvantages. The extraction and hydrolysis stage is slower (21 h cf 5 h per batch of 30), activity of the enzyme may vary, reagents are more expensive, and complete hydrolysis is more difficult. Its main advantage is that it is more specific, not hydrolysing the non‐cellulosic polysaccharides of the cell walls. This communication examines whether an acid hydrolysis method is an acceptable, even preferable, method for determining starch in freeze dried potato samples. Effects of drying, hydrolysis and associated errors are quantified.