The volatiles of off‐flavoured unblanched green peas (<i>Pisum sativum</i>)

Abstract

Abstract Volatile extracts of moderately off‐flavoured frozen peas, prepared by vacuum sublimation followed by concentration of the sublimate by low temperature vacuum distillation, were examined by gas chromatography, silica gel chromatography and combined gas chromatography–mass spectrometry. The constituents identified included alcohols (29), carbonyls (31), esters (12), hydrocarbons (19), terpenes (6) and 3‐alkyl‐2‐methoxypyrazines (3). Olfactory monitoring of the gas chromatographic column effluent indicated that most of the strong odours were associated with alkanals, alk‐2‐enals, alka‐2,4‐ and 2,6‐dienals, octa‐3,5‐dien‐2‐ones, 3‐alkyl‐2‐methoxypyrazines and hexanol. However, no compound which, by itself, could account for the “hay‐like” off‐flavour of peas was evident. The off‐flavour is considered to be complex and composed largely of the more odorous unsaturated carbonyls derived from the enzymic breakdown of the unsaturated pea lipids. The volatiles of pea shells similarly examined were found to contain many of the compounds present in peas.