Formation of Chain-like Structures in Apple Juice Haze

Red Delicious apple juice made by exclusion of oxygen (anaerobic juice) was stored in the presence of air at 21 °C for 67 d. During this period, a haze developed in the juice and partially sedimented at the bottom of the glass container. This haze/deposit contained 12 g/kg protein and the remainder was butanol–HCl and/or vanillin reactive material. Electron microscopic examination using negative staining with uranyl acetate showed that the haze/deposit preparations consisted of branched chain-like aggregates of globular particles of variable size. The particles had sufficient electron density to be examined in detail without staining. Their three-dimensional structure was confirmed by shadow casting. A mechanism of formation of these particles is proposed and discussed and a model for formation and aggregation suggested.