The Influence of Sawdust Handling Methods on the Quality of Table Grapes for Export

Abstract

The initial sawdust moisture content of 5-25% in packed export grape chests stored for 1-2 months was related inversely to the weight loss of the grapes (deterioration in fresh appearance), directly to decay, inversely to the relative humidity in the sawdust, directly to the weight gain of the container, and inversely to the weight gain of the sawdust—with a slight weight loss for sawdust initially at 25% moisture. The sawdust reached about 25% moisture after 2 months, irrespective of the initial water content. All the moisture increase came from the grapes, whereas that of the containers was derived from the room air as well. Cardinal grapes lost weight faster than Emperors. The dose of sodium bisulfite was related directly to bleaching injury and inversely to decay in sawdust of 15% moisture. There was a large difference in response between the 10- and 15-gram doses. Sawdust precooled very slowly, even with "forced air", unless moisturized so the moisture content was near equilibrium with the relative humidity of the precooling air. A commercial-scale system for moisturizing sawdust and pre-cooling it rapidly with forced air is described.