WOUND-INDUCED RESPIRATION AND ETHYLENE PRODUCTION IN FRESH CUT ROMAINE LETTUCE

A.I. Deltsidis, P. Tsouvaltzis, J.K. Brecht
Understanding of the physiological and biochemical processes induced by cutting can help in devising strategies to improve fresh-cut lettuce quality. We evaluated the response of Romaine lettuce to cutting temperature by cooling overnight and processing five, freshly harvested heads at 5 or 15°C. Undamaged, expanded leaves were immersed for 1 min in 5 or 15°C chlorinated water (1.34 mM NaOCl; pH 7), cut in half longitudinally then cut transversely into 2-cm wide pieces, the cut pieces were re-immersed in chlorine solution, and the excess liquid removed with a salad spinner. Cut pieces from each head (100 g) were measured in flow-through systems every 2 h for 24 h for O2, CO2, and C2H2 by gas chromatography. The CO2 evolution immediately after cutting was approximately 3.5-fold higher at 15°C than at 5°C, and O2 consumption was approximately 2.2-fold higher at 15°C. The CO2 evolution at 15°C increased during the first 4 h after cutting and thereafter remained steady; at 5°C, a small increase occurred during the first 8 h with a slight decline thereafter. The O2 consumption at 15°C increased during the first 3 h after cutting, decreased until hour 10, then remained steady or declined slowly. The O2 consumption at 5°C decreased by half during the first 12 h after cutting and changed little thereafter. The respiratory quotient (RQ) was <1.0 during the first 8-12 h after cutting, rose and remained steady at approximately 1 for 8-10 hours at 5°C and for about 8 h at 15°C, then finally increased to about 1.1 at 5°C and 1.7 at 15°C. Ethylene production was 6-fold higher at 15°C than at 5°C and did not change over time. These relative changes in CO2 production and O2 consumption suggest that non-respiratory oxidative reactions play a significant role in the post-cutting wound response of fresh-cut lettuce.
Deltsidis, A.I., Tsouvaltzis, P. and Brecht, J.K. (2012). WOUND-INDUCED RESPIRATION AND ETHYLENE PRODUCTION IN FRESH CUT ROMAINE LETTUCE. Acta Hortic. 934, 613-618
DOI: 10.17660/ActaHortic.2012.934.81
https://doi.org/10.17660/ActaHortic.2012.934.81
Lactuca sativa L., microbial quality, minimal processing, respiratory quotient
English

Acta Horticulturae