THICK JUICE DEGRADATION DURING STORAGE

A study of the changes occurring in thick juice during storage in larg e tanks for periods of up to 200 days is reported. Additional laborato ry work to investigate the effect of storage parameters such as pH val ue, dry substance content and temperature is described. The work focus es on the occasional rapid fall in pH value which can occur after a lo ng period of satisfactory storage. The cause of the pH fall was found to be the production of L-lactic acid, formed from sucrose as a result of bacterial activity. High juice pH value: high dry substance conten t and low initial bacterial count were found to allow longer storage w ithout juice degradation but did not eliminate the possibility of bact erial growth. Temperatures below 10 degrees C prevented bacterial grow th over a storage period of one year even when bacteria were initially present.