Agriculturae Conspectus Scientificus, Vol 82, No 4 (2017)

Inhibition of Polyphenol Oxidases and Peroxidase Activities in Green Table Olives by some Anti-browning Agents


Pages: 375-381


Almost, all table olive cultivars are susceptible to the formation of brown spots due to mechanical damage during harvesting and processing. Therefore, application of some anti-browning agents might be an effective strategy to minimize unfavourable effects of enzymatic browning in green table olives. The aim of this study was to assess the effect of ascorbic acid (AA), citric acid (CA), oxalic acid (OA), 4-hexylresorcinol (HR) and sodium hexametaphosphate (NaHMP) on reducing enzymatic browning of four green table olive cultivars ('Mari', 'Shengeh', 'Manzanilla' and 'Zard') fruit. The results showed that 'Mari' and ’Shengeh’ potentially had the highest browning index. AA could reduce peroxidase (POD) activity just in 'Mari', but NaHMP could beneficially suppress its activity in both cvs. 'Manzanilla' and 'Mari'. In general, the monophenolase activity of polyphenol oxidase (PPO) was significantly higher than its diphenolase activity in all studied cultivars. The highest inhibitory effect on monophenolase activity was found in 'Manzanilla' fruit by CA and OA, while HR and NaHMP could suppress monophenolase activity of 'Mari' fruits. Diphenolase activity of PPO with pyrocatechol and dopamine HCl substrates was also dependent on olive cultivars. The minimum diphenolase activity of PPO for both substrates was found in 'Zard' fruit with the lowest browning index. The inhibitory effect of anti-browning agents on reducing diphenolase activity of PPO with dopamine hydrocholoride (DPOA) substrates was cultivar-dependend. Total phenolic content of treated fruits was higher than control. Overall, this result confirms that the potency of anti-browning agents on suppressing POD and PPOs enzymes that are involved in fruits browning was completely cultivar-dependend.


anti-browning agents, enzymatic browning, peroxidase, polyphenol oxidase, table olive

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