UV-C treatments extend the shelf life of fresh-cut peppers by delaying pectin solubilization andinducing local accumulation o phenolics

RODONI L, ZARO MJ, HASPERUE J, CONCELLON A, VICENTE A

LEBENSMITTEL-WISSENSCHAFT UND-TECHNOLOGIE-FOOD SCIENCE AND TECHNOLOGY

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2015 vol. 63 p. 408 - 414

0023-6438

Fresh-cut red sweet pepper sticks (5x 1 cm) were irradiated with 3, 6, 10 or 20 kJ m-2 of UV-C in the internal I), outer (O) or both surfaces (I/O) and quality changes during storage were recorded. Treatments with 20 kJ m-2 I/O showed the lowest spoilage and visual deterioration and were selected for further analyses. UV-C treatment did not cause negative changes in sugars, color and acidity o or antioxidant capacity. In turn, fungal decay, soft rot, electrolyte leakage, weight loss and respiratory rate were significantly lower in treated pepper sticks during storage at 4 ºC. During the 12 day storage period control sticks lost 50% of their initial firmness, while remained unchanged in UV-C treated peppers. . In spite of the marked control of postharvest rots, the UV-C treatment caused only minor germicide effects in molds and moderate reductions of mesophylic aerobic bacteria. In turn indirect fruit-mediated responses to radiation were found; pectin solubilization was after 7 days of storage 3-fold higher in the controls than in UV treated sticks. Histochemical analysis of pepper sticks showed that the accumulation  of phenolic hydroxycinnamic acid-derivatives was induced by the selected UV-C treatment. Overall results suggest that UV-C treatments (20 kJ m-2 I/O) may be useful to complement low temperature storage and prevent deterioration of fresh-cut red peppers. Some of the benefits of UV-C exposure may be mediated by the induction of hydroxycinnamic acid phenolic-derivatives and by the reduced disassembly of cell wall polyuronides.