Ju et al. (1995) found that ethephon application (250 ppm) at 20 days before harvest increased anthocyanin accumulation and UDPGal:flavonoid-3-o-glycosyltransferase (UFGalT) activity during maturation, but had no effect on flavonoid concentrations and chalcone synthase (CHS) activity in both ‘Delicious’ and ‘Ralls’ apples. However, ethephon applied during 60 days before harvest induced high UFGalT activity and increased the accumulation of flavonoids, but did not induce anthocyanin formation when the fruits were picked 40 days before the harvest time. Application of the ethylene inhibitor aminoethoxyvinylglycine (AVG) (500 ppm) alone did not affect activity of CHS and UFGalT or the accumulation of anthocyanin and flavonoids, but when applied with ethephon, AVG partially counteracted the effect of ethephon. Prohexadione Ca, an inhibitor of gibberellins metabolism and possible growth retardant in apple favoured the accumulation of eriodictyol and luteoliflavan, which do not normally occure in apple tissue (Roemmelt et al., 1999) Also cycocel (CCC) is known to inhibit gibberellins (Saure,1990) and thus might stimulate formation of anthocyanin and other flavonoids.
Thus, using these materials, the objectives of our study were to (1) examine the relation between maturity/ripening and anthocyanin and red colour formation in fruit skin and (2) study the concomitant changes in flavonoid and chlorogenic acid concentrations.