TY - JOUR
T1 - Classification of 'Granny Smith' apples with different levels of superficial scald severity based on targeted metabolites and discriminant analysis
AU - Mditshwa, Asanda
AU - Fawole, Olaniyi A.
AU - Vries, Filicity
AU - Van Der Merwe, Kobus
AU - Crouch, Elke
AU - Opara, Umezuruike Linus
N1 - Publisher Copyright:
© The Author(s) 2016.
PY - 2016
Y1 - 2016
N2 - To study the metabolic changes in 'Granny Smith' apples with different severities of superficial scald, fruit were stored in normal refrigerated air (0 °C, 95% RH) for 12 weeks followed by 7 d shelf-life under room conditions (20 °C, 65% RH). Fruit were graded to five groups based on scald severity and analysed for ethylene, α-farnesene and 6-methyl-5-hepten-2-one (MHO) levels. Reactive oxygen species (ROS) were measured by confocal laser-scanning microscopy on apple peel treated with fluorescent probe 2',7'-dichlorodihydrofluorescein diacetate. Ethylene production rate, α-farnesene and MHO contents and ROS intensity increased with increasing scald severity but declined in severely scalded fruit. Malondialdehyde (MDA) concentration in fruit peel, a measure of membrane damage, increased linearly (R = 0.891) with increase in scald severity. Discriminant analysis was used to classify fruit by scald severity on the basis of metabolites accumulated. The stepwise model indicated that three attributes (ROS, ethylene production and MDA) contributed significantly (R2 ≥ 0.5) to the separation of the five scald severity indexes, with ROS having the highest contri-bution (partial R2 = 0.961; p < 0.0001), followed by ethylene (R2 = 0.718; p < 0.0001) and MDA (R2 = 0.578; p < 0.0001).
AB - To study the metabolic changes in 'Granny Smith' apples with different severities of superficial scald, fruit were stored in normal refrigerated air (0 °C, 95% RH) for 12 weeks followed by 7 d shelf-life under room conditions (20 °C, 65% RH). Fruit were graded to five groups based on scald severity and analysed for ethylene, α-farnesene and 6-methyl-5-hepten-2-one (MHO) levels. Reactive oxygen species (ROS) were measured by confocal laser-scanning microscopy on apple peel treated with fluorescent probe 2',7'-dichlorodihydrofluorescein diacetate. Ethylene production rate, α-farnesene and MHO contents and ROS intensity increased with increasing scald severity but declined in severely scalded fruit. Malondialdehyde (MDA) concentration in fruit peel, a measure of membrane damage, increased linearly (R = 0.891) with increase in scald severity. Discriminant analysis was used to classify fruit by scald severity on the basis of metabolites accumulated. The stepwise model indicated that three attributes (ROS, ethylene production and MDA) contributed significantly (R2 ≥ 0.5) to the separation of the five scald severity indexes, with ROS having the highest contri-bution (partial R2 = 0.961; p < 0.0001), followed by ethylene (R2 = 0.718; p < 0.0001) and MDA (R2 = 0.578; p < 0.0001).
UR - http://www.scopus.com/inward/record.url?scp=84962109844&partnerID=8YFLogxK
U2 - 10.5073/JABFQ.2016.089.006
DO - 10.5073/JABFQ.2016.089.006
M3 - Article
AN - SCOPUS:84962109844
SN - 1613-9216
VL - 89
SP - 49
EP - 55
JO - Journal of Applied Botany and Food Quality
JF - Journal of Applied Botany and Food Quality
ER -