Enzymatic browning of apple and its control by chemical treatment: A review
A Rouf, HR Naik, MA Beigh, Varsha Kanojia, Shabeer Ahmad Mir, Syed Aafia, Qudsiya Ayaz, Uzma Altaf
This review paper is aimed at providing a comprehensive information of issues associated with minimally processed fresh cut apple slices and the quality changes associated with it. Physiological and biochemical changes in such products occur at a faster rate than in intact fruits. Mechanical injury sets oﬀ a complex series of events which result in loss of quality. Wounding stimulates respiration rate, induces ethylene synthesis, oxidation of phenols, enzymatic activity, and microbiological development, leading to an accelerated loss of quality, especially colour and ﬁrmness attributes. Appropriate steps must be taken during fruit processing against the development of this type of reaction. Browning damages the appearance, organoleptical properties, nutritional quality and, occasionally, safety of the commodities and apple is not an exception. Browning of cut surface of apple is on account of activity of polyphenol oxidase enzyme which during physical damage comes in contact with the phenolic substrates forming undesirable, brown colouring melanin pigment. Further this review paper elaborates the treatments employed for curbing such reactions with the help of anti-browning chemical treatments viz., anti-oxidant agents, acidifying agents, chelating agents and agents of firmness and also provides the comprehensive information of work being conducted globally for accessing the efficacy of browning inhibitors either alone or in combination, so as to provide an effective control of cut surface browning of the apple and thus maintain its quality.