Coating and modified atmosphere effects on potato tuber greening

Abstract

Coating and modified atmosphere treatments reduced light-induced greening of King Edward potatoes. Although ' Pro-long' coating and 5 % O 2 treatments gave more complete inhibition of greening in some tubers, the variability of response was greater and the mean response less than for treatment with 15 % CO 2 , 21 % O 2 . The pattern of greening in the different treatments suggested the presence of O 2 gradients within the tuber flesh. Coating caused small internal atmosphere changes, with CO 2 content being negatively correlated with chlorophyll content. Larger changes achieved by modifying the external atmosphere of such tubers increased greening suppression. However, the magnitude of response to coating and to the low O 2 treatment varied with maturity and growing conditions. The success of coating for inhibition of greening in potatoes will depend upon the physiological variability of the tubers to which it is applied.

Measuring Internal Gases and Lenticel Resistance to Gas Diffusion in Potato Tubers

“…If the tubers' flesh had had no significant resistance to gas diffusion, the 0 2 contents of the two chambers initially should have been the same and then have fallen by the same amount as the radius of the covered area around one of them was increased. The gradients between the two chambers induced in this experiment clearly demonstrate the existence of significant flesh resistance to 0 2 diffusion in potato tubers, confirming the indirect evidence for this resistance obtained in previous studies (3,4). The possibility that these effects were due to a progressive reduction in gas leakage between the chamber base and the tuber surface had been eliminated through conducting a similar experiment on tubers harvested in 1984, in which a gap had been left between the base of the chamber and the inner edge of the covered area.…”

“…Internal atmosphere studies on potatoes are of great potential importance in developing modified atmosphere treatments for extended shelf life (3,11) and improving the understanding of the low -02-induced disorder blackheart (14). However, potato tubers are particularly difficult organs from which to obtain accurate estimates of internal atmosphere composition because of the low proportion of intercellular volume in the tissue [1% to 2%, compared with *25% in apples (8)].…”

“…One of these methods (7) relied on extrapolation of a curve and provided information on the combined cellular and intercellular 0 2 contents, rather than the composition of the atmosphere in the intercellular spaces. In another study (3), samples were taken by syringe from a surgically created sealed cavity in the tuber. Although several days were allowed for wound respiration to subside, the possibilities of residual wound respiration and gradients of gas concentration between the cavity and the tuber flesh could not be eliminated.…”

“…Calculations by Burton (8) suggested that the gradients in 0 2 concentration within potato tubers would be so small as to have no physiological significance. However, recent work (3,4,9) has provided indirect evidence for significant flesh resistance to gas diffusion in potatoes.…”

Skin Color Retention in Red Potatoes during Long-Term Storage with Edible Coatings

“…Chitosan-based coating were applied for different applications on potato tubers for reducing weight loss and maintaining firmness [ 27 ], resistance to fusarium dry rot [ 28 ], and also applied to reduce greening [ 29 ]. Chiabrando and Giacalone [ 30 ] reported that the application of a chitosan coating on blueberry delayed changes in anthocyanin content and antioxidant activity compared to the control.…”