Polyphenol oxidase activity, phenolic acid composition and browning in cashew apple ( Anacardium occidentale, L.) after processing

• Published in: Food chemistry Vol. 125; no. 1; pp. 128 - 132
• Main Authors: Queiroz, Christiane, da Silva, Antonio Jorge Ribeiro, Lopes, Maria Lúcia Mendes, Fialho, Eliane, Valente-Mesquita, Vera Lúcia
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.03.2011; [Amsterdam]: Elsevier Science; Elsevier
• Subjects: Anacardium occidentale; ascorbic acid; Biological and medical sciences; Browning; Cashew apple; catechol oxidase; cinnamic acid; citric acid; enzymatic browning; enzyme activity; food composition; Food industries; food processing; food processing quality; food storage; Fruit and vegetable industries; fruit juices; fruits (food); Fundamental and applied biological sciences. Psychology; gallic acid; hydroxymethylfurfural; Injury; Maillard reaction; Phenolic acids; phytochemicals; plant damage; Polyphenol oxidase; protocatechuic acid; sodium chloride; sodium metabisulfite; sodium sulfate; storage quality; storage temperature; Browning; Cashew apple; Injury; Phenolic acids; Polyphenol oxidase; Fruit; Enzyme; Phenolic acid; Anacardium occidentale; Catechol oxidase; Apple; Dicotyledones; Angiospermae; Spermatophyta; Chemical composition; Oxidoreductases; Anacardiaceae
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2010.08.048

This study describes the extraction and characterisation of cashew apple polyphenol oxidase (PPO) and the effect of wounding on cashew apple phenolic acid composition, PPO activity and fruit browning. Purification factor was 59 at 95% (NH 4) 2SO 4 saturation. For PPO activity, the optimal substrate was catechol and the optimum pH was 6.5. PPO K m and V max values were 18.8 mM and 13.6 U min −1 ml −1, respectively. Ascorbic acid, citric acid, sodium sulphite and sodium metabisulphite decreased PPO activity, while sodium chloride increased PPO activity. Wounding at 2 °C and 27 °C for 24 h increased PPO activity but storage at 40 °C reduced PPO activity. Gallic acid, protocatechuic acid and cinnamic acid (free and conjugate) were identified in cashew apple juice. Cutting and subsequent storage at 40 °C hydrolysed cinnamic acid. 5-Hydroxymethylfurfural content in cashew apple juice increased after injury and storage at higher temperatures, indicating non-enzymatic browning.