Pino Catalina, Sepúlveda Betsabet, Tapia Francisco, Saavedra Jorge, García-González Diego L, Romero Nalda
Departamento de Ciencia de los Alimentos y Tecnología Química, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago 8380000, Chile.
Centro Para el Desarrollo de la Química-CEPEDEQ, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago 8380000, Chile.
Antioxidants (Basel). 2022 Apr 27;11(5):852. doi: 10.3390/antiox11050852.
The organoleptic characteristics of virgin olive oil (VOO), together with its nutritional and health properties, have led the olive tree to be cultivated beyond the Mediterranean basin, reaching latitudes with colder climates, with minimum temperatures below 0 °C and with a higher probability of early frosts. The freezing of olives generates destruction within the tissues and promotes degradation reactions. In this study, the impact of mild frost occurring at different harvesting times on the composition of volatiles and phenolic compounds in VOO were investigated. Arbequina variety olives were harvested at different stages of ripening. Half of the olives were subjected to oil extraction and the other half were frozen at -3 ± 1 °C for 12 h prior to oil extraction. A significant decrease of phenolic compounds with harvesting time was observed in both types of oils (fresh and frozen olives). Oils from frozen olives presented a slightly higher content of total phenols, except in the advanced ripening stage (September), and a slightly lower content of volatile compounds at all harvesting times. In addition, a higher content of 3,4-DHPEA-EDA was observed in oils from frozen olives, which is attributed to an early action of the endogenous β-glucosidase enzyme on oleuropein in freeze-damaged olive fruits. Principal component analysis and Discriminant Partial Least Square Regression allowed the oils to be classified according to the type of fruit (fresh and frozen) and the month of harvest. This study would indicate that mild frost would have a low impact on the chemical composition of virgin olive oil, although, this depends on the ripening stage.
初榨橄榄油（VOO）的感官特性，连同其营养和健康特性，使得橄榄树的种植范围超出了地中海盆地，延伸至气候更寒冷的纬度地区，这些地区的最低温度低于0°C，且早霜发生的可能性更高。橄榄受冻会导致组织内部遭到破坏，并促进降解反应。在本研究中，调查了在不同收获时间发生的轻微霜冻对初榨橄榄油中挥发性化合物和酚类化合物组成的影响。对Arbequina品种的橄榄在不同成熟阶段进行收获。将一半的橄榄用于榨油，另一半在榨油前于-3±1°C冷冻12小时。在两种类型的油（新鲜橄榄和冷冻橄榄榨出的油）中均观察到酚类化合物的含量随收获时间显著降低。冷冻橄榄榨出的油除在成熟后期（9月）外，总酚含量略高，且在所有收获时间挥发性化合物含量略低。此外，在冷冻橄榄榨出的油中观察到3,4-DHPEA-EDA的含量较高，这归因于内源性β-葡萄糖苷酶在受冻害橄榄果实中对橄榄苦苷的早期作用。主成分分析和判别偏最小二乘回归能够根据果实类型（新鲜和冷冻）以及收获月份对这些油进行分类。本研究表明，轻微霜冻对初榨橄榄油的化学成分影响较小，不过，这取决于成熟阶段。
