Storage quality of chopped garlic as influenced by organic acids and high-pressure treatment

The storage quality of chopped garlic from bulbs in both dormant and dormancy-terminated states with or without citric and/or ascorbic acids was investigated. The chopped garlic plus acids was also treated under high hydrostatic pressure (600 MPa, 1 min). Quality attributes of processed garlic during storage at 10 °C were evaluated in terms of colour, pH, polyphenol oxidase (PPO) activity, glucose content and viable cell count. Overall, the combined treatments with organic acids and high pressure conferred the best storage stability of chopped garlic, but the results depended on the physiological state of the raw garlic bulbs. For garlic from dormant bulbs, addition of citric acid rather than ascorbic acid or a mixture of the two inhibited browning more effectively. However, garlic from dormancy-terminated bulbs, treated with organic acids or high pressure, turned green and then yellowish-brown or brown. While the PPO activities of chopped garlic treated with organic acids or high hydrostatic pressure were reduced nearly to zero, other possible factors may affect the discolouration of chopped garlic. Concerning microbiological stability, the total viable cells in chopped garlic decreased significantly during storage owing to its own antimicrobial activity and the synergistic effect of high pressure.