Impact of plum processing on the quality and oxidative stability of cold-pressed kernel oil

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.

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

“…Quantification of tocopherols was carried out using high performance liquid chromatography (Waters M600E, Milfold, USA) on a reversed phase column Nucleosil 50-5 C18 (Machery-Nagel, Germany) with fluorescence detection. The samples were prepared according to the procedure described in Rabrenović et al (2021).…”

Antioxidant potential, anti-nutritional factors, volatile compounds and phenolic composition of microwave heat-treated plum (Prunus domestica. L.) kernels: an analytical approach

“…, 2018). Plum pits represent 9–11% of the total weight of the fruit, while the kernels located inside the pit represent 17–20% of the weight of pit (Rabrenović et al. , 2021).…”

“…The greater part of plum production is processed into foodstuffs such as juice, jams, nectars, beverages, dry fruits, etc., during which a significant amount of plum pits are generated that are mostly underused and undervalued (Xue et al, 2018). Plum pits represent 9-11% of the total weight of the fruit, while the kernels located inside the pit represent 17-20% of the weight of pit (Rabrenovi c et al, 2021). These underused kernels are usually incinerated or sent to landfills (Sheikh et al, 2021b), but they have huge industrial significance not only in the pharmaceutical industry but also in the food sector (Gonz alez-Garc ıa, 2014;Nati c et al, 2020).…”

“…, 2020). The high oleic fatty acid content (56.6–61.8%) makes plum kernels an excellent raw material for the production of oil with all nutritionally valuable components as described by codex standard (Rabrenović et al. , 2021).…”

“…They are the natural source of phytosterols, tocochromanols, carotenoids and polyphenols that can serve as herbal drug and a valuable source of medicinally active compounds, which are important health and nutritional constituents (Nati c et al, 2020). The high oleic fatty acid content (56.6-61.8%) makes plum kernels an excellent raw material for the production of oil with all nutritionally valuable components as described by codex standard (Rabrenovi c et al, 2021). Despite its high nutritive composition, plum kernels have not been used effectively, ascribed to the presence of substantial amounts of cyanogenic glycosides (Nati c et al, 2020).…”