POTATO WASTE MEAL. I. COMPOSITIONAL ANALYSES

Abstract

Potato waste meal (PW), produced by drying and grinding whole potatoes, potato pulp and peelings, and off-color french fries and potato chips, contained slightly less crude protein (76 g/kg) but more lipid (70 g/kg), crude fiber (40 g/kg) and ash (40 g/kg) compared with corn. Although PW is not devoid of any of the essential or nonessential amino acids, it contained considerably less of each amino acid than corn and appears limiting with respect to methionine and cystine, arginine and the aromatic amino acids. The results suggest that this potato by-product might be considered a substitute ingredient for a proportion of the ground corn in practical diets for poultry and other livestock. Both PW and corn contain up to 0.46 and 0.34 g/kg 4-hydroxyproline, respectively. This discovery indicates that an amino acid previously thought to be confined almost exclusively to the collagens and elastins of vertebrates and invertebrates is in error. Thus, this hydroxyamino acid should no longer be used as an accurate index for assessing connective tissue content or the quality of composite protein supplements containing bone, meat or fish meals. Key words: Potato waste, composition, amino acids