Investigation of bioactive compounds changes of two Lisbon (Citrus limon cv. Lisbon) and Cook eureka lemon (C. limon cv. Cook Eureka) varieties during ripening

In this study, some fruit physicochemical characteristics of two lemon varieties (Lisbon and Cook eureka) were investigated to determine the changes in bioactive compounds according to physicochemical properties during maturity until ripening stages. Fruits were evaluated every 10 days interval for one month (15 October to 15 November). The results showed that Cook eureka fruit with 131.04 g weight, 60.84 mm length, 115.12 mm3 volume and 39.22 percentage of juice was significantly larger than Lisbon. The highest amount of titratable acidity of varieties (13.51 and 10.95 percent in Lisbon and Cook eureka, respectively) observed at late October. Technological Index of varieties was the range of 3.40- 4.51 percent. The highest amount of pulp phenolics observed with 1.85 mg.g-1 at late October and 1.48 mg.g-1 at early November in Lisbon and Cook eureka, respectively. Ascorbic acid content of Lisbon lemon was high (57.05 mg.100g-1) at early November. Inversely, Cook eureka showed exceeding antioxidant activity with 65.33 % at mid November. In addition, the lowest amount of total chlorophyll in peel and pulp of Lisbon was 0.69 (early November) and 0.42 mg.g-1 (late October), respectively. The amount of total carotenoid (6.85 mg.g-1 at late October) in Lisbon was higher than other examined varieties. Therefore, it is better that fruits to be harvested before beginning of internal metabolism or at the full ripening stage to have higher bioactive compounds.