Ripening and Postharvest Storage of ‘Soft Fruits’

VICENTE AR, SOZZI GO

Fruit, Vegetable and Cereal Science and Biotechnology

Global Science Books

Año: 2007 vol. 1 p. 95 - 103

Rubus. Most work in ‘soft fruit’ ripening regulation has been done on strawberry. Auxin has been shown to be a repressor of several ripening-associated genes which led to hypothesize that reduction in auxin levels in the receptacle could activate those genes. Despite that, some evidence suggest that that is only part of the story and that other factors are also involved in the regulation of ‘soft fruits’ ripening process. Softening is one of the most dramatic changes observed in ‘soft fruit’ ripening. Early reports on strawberry stated that the average molecular size of hemicelluloses greatly declines during ripening. In contrast, later work showed that pectin size is reduced while only slight depolymerization occurs in hemicellulosic polymers. Pectin metabolism has recently shown to be a major modification accompanying softening in species of the genus Rubus. Contrarywise, a reduction in glucan content and downshifts in hemicellulose molecular size are the main changes observed in blueberry. Extension of ‘soft fruit’ postharvest life has been an ongoing challenge. Strategies to reduce ‘soft fruit’ losses include selection of firmer genotypes and optimum postharvest handling procedures. A single postharvest technique is unlikely to fully control postharvest losses but new tools such as UV radiation, heat treatments or chitosan coatings may be added to the overall management plan (cooling conditions, modified atmospheres) to further delay softening and prevent decay losses. Biotechnology may be useful to address some of the concerns about bramble quality attributes (e.g. increased fruit firmness, improved flavor) and engineered resistance may be a sustainable method to control Botrytis cinerea.. Most work in ‘soft fruit’ ripening regulation has been done on strawberry. Auxin has been shown to be a repressor of several ripening-associated genes which led to hypothesize that reduction in auxin levels in the receptacle could activate those genes. Despite that, some evidence suggest that that is only part of the story and that other factors are also involved in the regulation of ‘soft fruits’ ripening process. Softening is one of the most dramatic changes observed in ‘soft fruit’ ripening. Early reports on strawberry stated that the average molecular size of hemicelluloses greatly declines during ripening. In contrast, later work showed that pectin size is reduced while only slight depolymerization occurs in hemicellulosic polymers. Pectin metabolism has recently shown to be a major modification accompanying softening in species of the genus Rubus. Contrarywise, a reduction in glucan content and downshifts in hemicellulose molecular size are the main changes observed in blueberry. Extension of ‘soft fruit’ postharvest life has been an ongoing challenge. Strategies to reduce ‘soft fruit’ losses include selection of firmer genotypes and optimum postharvest handling procedures. A single postharvest technique is unlikely to fully control postharvest losses but new tools such as UV radiation, heat treatments or chitosan coatings may be added to the overall management plan (cooling conditions, modified atmospheres) to further delay softening and prevent decay losses. Biotechnology may be useful to address some of the concerns about bramble quality attributes (e.g. increased fruit firmness, improved flavor) and engineered resistance may be a sustainable method to control Botrytis cinerea.