Blackberry (Rubus fruticosus L.) and raspberry (Rubus idaeus L.) seed oils extracted from dried press pomace after longterm frozen storage of berries can be used as functional food ingredients

Abstract

Prolonged storage of frozen berries had some impact on the quality of the oils compared to the fresh sample. Free fatty acid content (FFA) and peroxide values (PV) increased in blackberry oil (BO) (from 1.18 to 3.54% oleic acid) and in raspberry oil (RO) (from 2.66 to 8.84% oleic acid). PV values were higher in the RO (increased from 4.82 to 13.97 mmol/kg) than in the BO (increased from 3.73 to 11.14 mmol/kg). Both oils were very high in omega‐6 FA (%): 63.66 ± 0.49 for BO and 54.94 ± 0.18 for RO, and omega‐3 FA (%): 14.77 ± 0.42 for BO and 32.38 ± 0.38 for RO, with their ratio of 1.8 and 4.5. Both oils have shown a very high level of α, β + γ, and δ‐tocopherols. Much higher levels of campesterols and stigmasterols were found in the BO, while the content of β‐sitosterols was much higher in the RO. Total phenolic content was much higher in the BO (∼27%). Our results demonstrated that pomace, despite longterm frozen storage, is a good raw material for oil extraction, as its oil composition remains stable. Chemical characteristics suggested that oils are of high quality and a possible source of functional ingredients. Practical applications: Pomace is a fruit processing waste, which is currently underutilized, and not used much for food production. Blackberry and raspberry seed pomaces that mostly consist of seeds are generated in large quantities. Both seed oils are of high quality and rich in essential omega fatty acids and very high content of bioactive compounds such as tocopherols, phenols, sterols, and carotenoids that have antioxidant properties. Due to their nutritional and antioxidant properties they are considered value‐added products that can be successfully used for functional and nutraceutical food products. The oils have high levels of oleic, omega‐6, and omega‐3 fatty acids and bioactive compounds including tocopherols, phenols, sterols, and carotenoids. Based on the research results, prolonged storage (8 months) of frozen blackberries and raspberries in sealed plastic bags at −18°C before further processing and use of the pomace as a by‐product can be recommended to the food industry.

Viability of fruit seed oil O/W emulsions in personal care products

“…It was found that the LA and ALA are the main components of the tested oils. These measurements are comparable to literature [10,15,32]. The FA composition may be slightly different due to the fruit origin, but despite this, a high PUFA content remained in all cases.…”

“…Polyphenols have potentially beneficial effects on health including antiviral, antimicrobial, and antioxidant activity. These properties are usually due to tocopherols, phytosterols and phenolics [15]. Most of the fruit originate from China, and the oils are extracted with solvents or by supercritical CO 2 .…”

Dietary Supplementation with Raspberry Seed Oil Modulates Liver Functions, Inflammatory State, and Lipid Metabolism in Rats

“…The RO used in this study was especially rich in linoleic and a-linolenic acids (18:3n23; 50.7% and 29.2%, respectively), which is similar to the results obtained by other authors who determined the FA profile of RO (6,10,26). However, in the aforementioned studies, the contents of linoleic and a-linolenic acid were higher by up to 4% and 5.5%, respectively, which can be a consequence of the different growth conditions of raspberries or the extraction method that was applied.…”

A comparative study on composition and antioxidant activities of supercritical carbon dioxide, hexane and ethanol extracts from blackberry (Rubus fruticosus) growing in Poland

“…Stigmasterol and campesterol were also detected but in much smaller quantities, 70–119 mg 100 g −1 and 50–80 mg 100 g −1 extract, respectively. These sterols, which also constituted the main sterol fraction, had been identified previously, using a GC‐MS method (Table ) . Blackberry cultivated in Poland seems to be the richest source of sterols; the amount is more than two times higher than in plants cultivated in Serbia …”