The amino-acids of apple juices and ciders

The free amino‐acids of apple juices and ciders have been examined by paper chromatography. Asparagine, aspartic and glutamic acids were the principal amino‐acids in most juices, together with small to medium amounts of serine, α‐alanine, γ‐aminobutyric acid, valine, isoleucine, and methylhydroxyproline. Ten other amino‐acids were sometimes present in trace amounts. The amino‐acid content of ciders was extremely small and consisted usually of aspartic and glutamic acids, methylhydroxyproline, an unidentified peptide and traces of several other amino‐acids and possible peptides. Yeast autolysis caused a marked increase in the amino‐acid content of a cider left on its lees. The presence of nucleotide material in juices and cider is indicated.