Bk. Dadzie et al., REDUCED GREASINESS OF GRANNY-SMITH APPLES WASHED IN TWEEN-20 SOLUTION, New Zealand journal of crop and horticultural science, 23(2), 1995, pp. 219-222
'Granny Smith' apples (Malus domestica Borkh.) tend to develop greasy
skins after extended storage which makes them slippery to touch and re
duces their aesthetic appeal. Washing fruit in 0.15% (w/w) Tween 20 su
rfactant solution reduced greasiness, loss of greenness, and firmness
after 22 days at 20 degrees C. These effects were associated with decr
eased skin permeance to gases, depressed internal oxygen (O-2) partial
pressure and respiration, and increased internal partial pressure of
ethylene, in washed compared to control fruit. Washing depressed the s
um of O-2 and carbon dioxide partial pressures, suggesting that this t
reatment enhanced differential permeability characteristics of the fru
it skin. Pre-treatment by wiping without using Tween 20 solution had n
one of these effects but stimulated weight loss. The potential for usi
ng a surface coating to delay the development of greasiness in stored
apples should be re-examined.