Storage quality of strawberry fruit treated by Pulsed Light: fungal decay, water loss and mechanical properties

DUARTE-MOLINA, FERNANDO; GÓMEZ, PAULA; CASTRO, MARIA AGUEDA; ALZAMORA, STELLA M.

INNOVATIVE FOOD SCIENCE & EMERGING TECHNOLOGIES

ELSEVIER SCI LTD

Año: 2016

1466-8564

The effect of different pulsed light (PL) doses (2.4- 47.8 J/cm2) on water loss, fungal spoilage, mechanical properties and structure of strawberries stored for up to 8 days at 6ºC was studied. Incidence of postharvest molds on strawberry fruits was reduced by over 16-42 % with PL application. There were not significant differences in maximal rupture force (FR), mechanical work (W) and deformability modulus (Ed) values between treated and untreated fruits immediately after treatments. After 8 days storage at 6 ºC, untreated strawberries showed a pronounced softening (≈ 48% reduction in FR),but stored strawberries exposed during 10 s and 40 s to PL presented slight or notsignificant changes in the mechanical parameters regarding day 0, while FR and Wvalues of 20 s-PL treated samples were increased by 35% and 88% compared to those at 0 day storage. Micro and ultrastructure changes evaluated by LM and TEM images demonstrated ITW cell wall strengthening and a major integrity of walls of hypodermis cells induced by PL stress, while cell wall disassembly and reduction of cell-to cell contact were detected in stored untreated fruit. There were not significant differences in weight loss among untreated and PL treated fruits after storage, excepting at the highest PL dose. PL technique would be able to simultaneously provide disinfection and delete softening of the tissues along cold storage. Present results make this non-thermal, residue-free alternative promising for extending shelf-life of traditional and organicstrawberry production.