Membrane structural lipid changes in fresh-cut carrots: revisiting the "wounding and aging" phenomenon.
Picchioni, G. A.; Watada, A. E.;
Acta Horticulturae Year: 1998 Issue: No. 464 Pages: 237-242 Ref: 17 ref.
1998
บทคัดย่อ
Changes in membrane sterols and glycerolipids in shredded carrots as a result of the rupture of cell membranes and activation of membrane lipid catabolic processes was studied. Apache and Caropak carrots were shredded and stored under conditions similar to those used in retail markets (10 deg C and 95% RH). Some samples of Caropak shreds where immersed in 1% CaCl2 rather than distilled water before storage. Between 0 and 10 days of storage, membrane lipid concentrations in the shredded tissue were determined using HPLC/evaporative light scattering detection. Total phospholipid and acylated sterol glycoside concentrations increase by as much as 31% and 135%, respectively, following 10 days of storage. These increases are indicative of membrane restructuring ("repair") processes, were accentuated by Ca2+ pretreatment, and appeared to be cultivar-dependent. During storage, Ca2+ pretreatment also delayed the onset of increases in the ratios of free sterols to phospholipids and of free stigmasterol t
o free sitosterol (both senescence-driven processes), and as expected, Ca2+ pretreatment reduced cell permeability. However, Ca2+ pretreatment did not curb the rate of accumulation of phosphatidic acid, a membrane degradation product. Coexistence of membrane degradation and "repair" processes appeared to be a characteristic feature of wounding and long-term storage of carrots. It is suggested that Ca2+ pretreatment may prove to be a valuable approach for maintaining quality of fresh-cut carrots and possibly other fresh-cut products, owing to its stabilizing influence on cell membrane systems.