Oxidation in apple juice. I.—Preliminary investigation of the relationship between the dissolved‐oxygen content and oxidation of apple juice during processing and shelf‐life in bottle

Abstract

Methods for estimating dissolved oxygen in beer and for measuring the reducing activity of beer have been applied to the study of oxidation in apple juice during processing and throughout its shelf‐life in bottle. Freshly pressed juice is highly oxidized but becomes less so after clarification and filtration. Juices differ in their ability to absorb additional oxygen during processing and there is a protracted time‐lag between absorption and increase in oxidation. In general, after bottling, oxidation increases unless the juice is pre‐heated before the bottles are sealed. After long storage in bottle, apple juice becomes strongly reducing, dissolved oxygen diminishes and a sediment is thrown. Hazes and deposits develop less rapidly in pasteurized juices than in those bottled by sterile filtration and are generally less intense if either air‐space in the bottle or excess oxygen in the juice is reduced.