Investigation of a tunnel pasteurizer for “Nocellara del Belice” table olives processed according to the “Castelvetrano method”

Abstract

SUMMARY:The influence of pasteurization temperature and time of treatment on the flesh firmness and the evolution of microbial communities was studied for table olives Cv. Nocellara del Belice, packed in glass jars and processed with a tunnel pasteurizer. The experiment was first carried out on the laboratory level in order to select the optimal combination of pasteurization time/temperature so as to obtain the proper balance between the consistency of the pulp and the microbiological quality of the final product. Pasteurization at industrial scale was then carried out in a tunnel pasteurizer applying the treatment at 75 °C for 8 min in the thermal center of the jars. Besides flesh firmness and microbial evolutions, the pH, total titratable acidity (TTA) and color were evaluated for the table olives during storage at 6, 12 and 15 months from packing. The table olives showed a high stability and acceptable flesh firmness for the entire period under observation. Specifically, olive pulp texture decreased during the storage period, but the softening was most evident in the deeper layers of the pulp. The results indicated that the storage period should not exceed 6 months. Although the hygiene is preserved, after this period the firmness might not be acceptable to consumers. KEYWORDS: Compression force; Dynamometer; Microbiological analysis; RESUMEN:Investigación sobre un pasteurizador de túnel para las aceitunas de mesa "Nocellara del Belice" procesadas mediante el "Método Castelvetrano". En el presente trabajo se estudió la influencia de la temperatura y del tiempo de pasteurización en la firmeza de la pulpa y la evolución de las comunidades microbianas para la aceituna de mesa "Nocellara del Belice" procesadas con un pasteurizador de túnel. El experimento se llevó a cabo preliminarmente a nivel de laboratorio con el fin de seleccionar la combinación óptima de tiempo/temperatura de pasteurización para obtener el compromiso adecuado entre la consistencia de la pulpa y la calidad microbiológica del producto final. A continuación se llevó a cabo la pasteurización en escala industrial dentro de un pasteurizador de túnel aplicando el tratamiento a 75 ° C durante 8 minutos. Fueron evaluados pH, acidez total titulable (ATT) y el color para las aceitunas de mesa durante el almacenamiento a los 6, 12 y 15 meses de envasado. Las aceitunas de mesa mostraron una alta estabilidad y una firmeza de pulpa aceptable para todo el período de observación; en particular, la textura de pulpa disminuyó durante el período de almacenamiento, pero el ablandamiento fue más evidente en las capas más profundas de la pulpa. Los resultados indicaron que el período de almacenamiento no debe ser superior a 6 meses.

Effect of O2 control and monitoring on the nutraceutical properties of extra virgin olive oils

“…The study was performed on a typical Sicilian olive cultivar "Nocellara del Belice" in 2013 (Catania et al, 2014), manually harvested and processed within 24 h from harvesting using an Alfa Laval oil mill plant. The oil mill plant was equipped with an olive washing machine, a disk crusher, a single-stage malaxation machine, a horizontal decanter, and a vertical centrifuge.…”

Heat treatment effect on tocopherols, total phenolics and fatty acids in table olives (Olea europaea L.)

“…In the food industry, after harvesting, olives are treated with sodium hydroxide solution to eliminate the bitterness. In order to prolong the shelf time and maintain quality of table olives, one of the preserving methods that can be applied is pasteurization (Aponte et al, 2010;Catania et al, 2014). However, the heat treatment can negatively affect the quality of table olives in terms of decreasing the content of polyphenols, lipids, proteins and vitamins, changing the colour and texture (Campus et al, 2018).…”

Changes in the volatile composition of Spanish‐style green table olives induced by pasteurisation treatment

“…"cooked" defect) is detected (Casado et al, 2007). Although the effect of pasteurisation treatment on quality parameters such as colour and texture has been previously determined in table olives (Sánchez et al, 1991;Catania et al, 2014), its impact on the composition of volatile compounds has hardly been investigated. Navarro et al (2004) studied the effect of several pasteurisation conditions (60 °C or 80 °C each for 5 or 9 min) on the volatile compounds of "Campo Real" unfermented table olives and did not find significant changes in the main volatile compounds evaluated, with the exception of 2-butanol which decreased by treatment at 80 ºC.…”