Impact of plum processing on the quality and oxidative stability of cold-pressed kernel oil [Impacto del procesamiento de ciruelas en la calidad y la estabilidad oxidativa del aceite del hueso prensado en frío]

Abstract

Plum kernels of the “Čačanska rodna” variety, by-products from plum brandy production, were collected before and after fermentation and distillation, and used for cold-pressed oil production. Fatty acid and tocopherol contents were determined by capillary GC and HPLC, while the oxidation stability of the resulting cold-pressed oils was tested by the Rancimat method. The results showed that oleic fatty acid was dominant in the oil samples with a content of 56.6 to 61.8%, regardless of the plum kernels' origin. The fermentation and distillation processes had a pronounced effect on the tocopherol content and oxidative stability of the resulting kernel oils. Tocopherol contents were 61.8 mg·100g-1, 87.4 mg·100g-1, 79.6 mg·100g-1 of oil, while the induction periods were 38.7, 44.4 and 33.6 hours for samples before fermentation, after fermentation and distillation, respectively. Based on the results, it could be concluded that the fermentation process increased the content of tocopherols in kernel oil whereas the high temperature during the distillation process adversely affected the tocopherol content and oxidative stability of the obtained kernel oil.