Identification of optimum preprocessing storage conditions to maintain quality of black ripe 'Manzanillo' olives

Agar I., Hess-Pierce B., Sourour M., Kader A.

POSTHARVEST BIOLOGY AND TECHNOLOGY, vol.15, no.1, pp.53-64, 1999 (SCI-Expanded) identifier identifier


Black-ripe olives (Olea europaea cv. 'Manzanillo'), used for processing into canned olives or oil were stored at 0, 2.2 and 5 degrees C in air or 2 kPa O-2 (balance N-2). Olive samples were analyzed initially, and after 2, 4 and 6 weeks for fruit quality based on color, visual quality and fruit firmness, weight loss, water and oil content. Respiration rate, ethylene production and incidence of physiological disorders and decay were determined. Olive oil quality was evaluated based on titratable acidity, peroxide value, K-232 and K-270 coefficients, and fatty acid composition. Decay incidence increased with storage temperature and duration but it was lower in black-ripe olives kept in 2 kPa O-2 than in those kept in air. Fruit decay after 4 weeks storage in 2 kPa O-2 was 9.2, 8.2, and 7.7% in olives kept at 0, 2.2, and 5 degrees C, respectively. No visual chilling injury symptoms were observed in any of the storage treatments. Storage time and atmospheres had no significant effect on olive color but visual quality scores of olives stored in 2 kPa O-2 at 0 degrees C were generally higher than other treatments. Ethylene production and respiration rates were considerably higher at 5 degrees C than at 0 or 2.2 degrees C and in air than 2 kPa O-2. Fruit firmness declined markedly after 4 weeks storage in both the air and 2 kPa O-2 treatments, irrespective of storage temperature. There was no significant difference between the air and 2 kPa O-2 stored fruit. There were no significant differences in water and oil content among treatments. Oil obtained from olives stored at 0 degrees C, was within the limit of 'extra' virgin quality in terms of acidity, irrespective of storage atmosphere after 4 weeks storage, whereas oils extracted from olives stored at 2.2 degrees C in air and 2 kPa O-2 and olives stored at 5 degrees C in 2 kPa O-2 were qualified as 'fine' virgin quality. K-232 and K-270 values were not surpassed in any of the treatments except oil obtained from olives stored at 20 degrees C. Fatty acid composition was within the range required for 'extra' virgin olive oil, except for slightly higher linolenic acid. In conclusion, black-ripe 'Manzanillo' olives can be stored at 0-5 degrees C in air or in 2 kPa O-2 for up to 4 weeks between harvesting and processing while maintaining fruit and oil quality. (C) 1999 Elsevier Science B.V. All rights reserved.