Influence of ripening index on the yield and quality of virgin olive

Abstract

Description of the subject: Algeria is considered one of the leading olive growing areas in the world. The maturity index is one of the most important factors contributing to oil quality. Objectives: This study was conducted to investigate the effect of olive maturity index on the physicochemical properties of oil using the chemlal cultivar in the region of Boumerdes. Methods: The study was conducted in a commercial chemlal olive planted in the village of chebat el Eumer. Seven samples were collected from 25 September 2018 to 03 February 2019. Each sample was tested for fruit characteristics including moisture maturity index, weight, length and width of fruits. Oil extracted by the mechanical method was tested for acidity, peroxide, UV light extinctions, oil fatty acid composition, pigments, polyphenols and functional analysis by FT-IR. Results: The oil content ratio increased significantly over the harvest dates, a clear correlation was observed between the colour index and each of the fruit weight ratios. Acidity and peroxide values increased during the harvest dates. K232, K272, ΔK were within the International Olive Oil Council specifications for extra virgin oil. Oleic acid and palmitic acid levels ranged from (64.04-70.63%) and (14.63-21.28%) respectively. Chlorophyll and carotenoids were all (31.07); (1.36) mg/kg respectively for the first ripening index. Total polyphenols show significant differences between harvest dates, the lowest value was observed at the last sampling date (259 mg/kg) and the highest at the date of 25/09/2018 (321 mg/kg). Conclusion: The results obtained could be useful in determining the optimal for picking olives, which is between the end of September and the end of October for the Chemelal variety.