Superficial scald, a functional disorder of stored apples. V.—Oxidation of α‐farnesene and its inhibition by diphenylamine

Abstract

a-Farnesene was oxidised to conjugated trienes with an absorbance maximum at 269 nm and the oxidation was inhibited by diphenylamine both in hexane solution and in the natural coating of stored apples. The results suggest that superficial scald is caused by the oxidation of a-famesene and that the control of scald by diphenylamine is due to its antioxidant action. The mechanism of scald induction is discussed.

Expression of anti-oxidant enzyme genes in scald-resistant ‘Belfort’ and scald-susceptible ‘Granny Smith’ apples during cold storage

“…In addition to a number of environmental factors, susceptibility to scald is dependent on apple cultivar, indicating a genetic basis for this disorder (DeLong and Prange, 2003). It is generally accepted that scald develops when the sesquiterpene compound, ␣-farnesene, present in apple peel, is oxidised to a number of compounds known as conjugated trienes (CTs), and that this oxidative event causes browning of the hypodermal cell layer and leads to cell death (Huelin and Coggiola, 1968;1970;Anet, 1972). However the molecular mechanisms leading to oxidation of ␣-farnesene are still unknown.…”

Pome fruits

“…Traces of farnesene are present on the surface of preclimacteric fruits and it increases rapidly on ripening. Damage to cell membranes probably occurs through free radical chain reactions during the spontaneous oxidation of farnesene to 'conjugated trienes' (Huelin and Coggiola, 1970). The initiation of these reactions may be influenced by the levels of 'natural antioxidants' which are also present in the surface wax (Sal'kova and Zvyagintseva, 1981;Meir and Bramlage, 1988).…”

Evolución del daño por insolación de manzanas 'Granny Smith' durante el almacenaje refrigerado

“…La concentración de α-farneseno se cuantifi có a 232 nm, utilizándose el coefi ciente de extinción (E) = 27.700 (Huelin y Coggiola, 1970). Los tres valores de los trienos conjugados (CTs) se registraron como CT 259 = OD 259-290nm , CT 269 = OD 269-290nm y CT 281 = OD 281-290nm (Du y Bramlage, 1993).…”

“…El escaldado superfi cial se inició a los 3 meses de almacenaje a 0°C, más un periodo de 15 d a 20°C, y se caracterizó por manchas pardas intensas, con bordes defi nidos en la zona de las mejillas de la manzana. El daño según la literatura se relaciona con la acumulación de trienos conjugados, compuestos asociados a la oxidación del α-farneseno, presente en la piel de manzanas y peras (Huelin y Coggiola, 1970).…”