There is some controversy regarding the respiratory pattern of loquat (
Eriobotrya japonica
[Thunb.] Lindl.). Thus in order
to provide information on this aspect of loquat, fruit of 50-70 g, from cv. Golden Nugget were harvested in four stages of
maturity: green (BBCH 709), color break (BBCH 801), yellow (BBCH 807), and orange (BBCH 809). The parameters
evaluated in each stage were: soluble solids, titratable acidity, respiration, ethylene generation, and activity of the enzymes
pectin methyl esterase (PME), peroxidase, polyphenoloxidase (PPO), polygalacturonase (PG), and cellulose, and the soluble
solids:acidity ratio was calculated. The results show that ethylene concentration increased at the time of color break, which
was not the case for the change in the respiratory rate. The activity of the peroxidase enzyme increased from the green
stage to color break, while the enzymes PME, cellulase, and PG showed a constant reduction from the green to the orange
stage, and PPO showed no change over the four stages studied. With regards to quality, from color break onwards soluble
solids increased to 11.8 °Brix and titratable acidity dropped from 0.67 to 0.28 g L
-1 malic acid. Based on these results, the
conclusion is that towards the end of its development loquat cv. Golden Nugget evidence enzymatic and ethylene behavior
similar to that of climacteric fruits.
