Polygalacturonase and Pectate Lyase Activity During Ripening of Kluay Hom Thong Fruit

Abstract

The research focused on the change of enzymes associated with the maturation of Kluay Hom Thong bananas [Musa acuminate (AAA group) ‘Gros Michel’]. Polygalacturonase (PG) and pectate lyase (PL) enzymes from the Kluay Hom Thong (ripening Stages 2-8) were extracted and partially purified by ammonium sulfate fractionation. The results showed an increase in PG activity from 3.0 ±0.11unit/g fresh banana in the 2^nd Stage to 4.89 ± 0.39 unit/g fresh banana in the 6th Stage . Furthermore, the PG activity decreased slightly to approximately 4.33± 0.49 unit/g fresh banana as the ripening stage increased (the 8^th Stage). PL enzyme activity also depended on the ripening stage of the banana. When the banana was riper, the PL activity gradually increased from 8.73 ± 0.23 unit/g fresh banana in the 2^nd Stage to 35.37 ± 1.05 unit/g fresh banana in the 8^th Stage. When compared to the commercial pectinase enzyme from Aspergillus aculentus (Pectinex Ultra SP-L, Novozymes A/S, Denmark), the enzymes obtained from the banana demonstrated much lower activity. The PG and PL activities from the commercial pectinase were 7966.46 and 1709 unit/ml, respectively.