Ramune Bobinaite

In Europe, the green course is becoming increasingly relevant, and there are more and more suggestions for its improvement. The valorization of food waste attracts increasing attention and is one important current research area. The aim of this study was to examine oils from 16 raspberry variety seeds and to compare their yields and fatty acid contents. The next task was to extract oil from the raspberry variety ‘Polka’ by four different methods and to compare the yield, colors, fatty acids content and composition, and kinematic and dynamic viscosity. The last task was to analyze the economic profitability of oil extraction by different methods. This study demonstrates the potential of different varieties of raspberry by-products and shows the influence of different oil extraction methods on the fatty acid composition of the oil and the economic potential of such products. The analysis revealed that the predominating fatty acid in the raspberry variety ‘Polka’ seed oil was linoleic acid (44.0–44.8%), followed by α-linolenic acid (37.9–38.1%) and oleic acid (10.2–10.6%). Of the 16 raspberry cultivars tested, ‘Polka’ seed oil had the least linoleic (ω-6) (44.79%) and the most α-linolenic (ω-3) fatty acids and the best ratio of ω-6 to ω-3 fatty acids—1.2:1. Raspberry variety ‘Polka’ seed oil contains a lot of carotenoids; their total amount depending on the extraction method varies from 0.81 mg/100 g (extracted with subcritical CO₂) to 3.25 mg/100 g (extracted with supercritical CO₂). The oil yield can be increased by grinding the seeds into a finer fraction. The most expensive method of oil production is supercritical CO₂ extraction, and the cheapest method with the fastest payback of equipment is the cold-pressing method. The results of the research have revealed the influence of different oil recovery methods on the yield of oil, the composition of the fatty acid, colors, and viscosity. The results are very important for producers wishing to commercialize raspberry seed oil.

In recent years, much attention has been devoted to Vaccinium L. berries because of their substantial potential to be adapted for the development of innovative food and pharmaceutical applications. The accumulation of plant secondary metabolites is extremely dependent on climate and other environmental conditions. In order to increase the reliability of the findings, this study was conducted with samples collected in four regions in Northern Europe (Norway, Finland, Latvia, and Lithuania) and analyzed in a single laboratory using a standardized methodology. The study aims to provide a comprehensive understanding of the nutritional (biologically active compounds (phenolic (477–775 mg/100 g fw), anthocyanins (20–57 mg/100 g fw), pro-anthocyanidins (condensed tannins (141–269 mg/100 g fw)) and antioxidant activity in different systems (ABTS^•+, FRAP). Physicochemical properties (acidity, soluble solids, color) of wild Vaccinium vitis-idaea L. were also evaluated. The results may contribute to the development of functional foods and nutraceuticals with potential health benefits in the future. To the best of our knowledge, this is the first comprehensive report on the evaluation of the biologically active compounds of wild lingonberries from different Northern European countries based on one laboratory’s validated methods. The results indicated a geomorphological influence on the biochemical and physicochemical composition of wild Vaccinium vitis-idaea L. depending on their place of geographical origin.

The aim of this study was to characterize the variation in biologically active compounds, antioxidant activity and physico-chemical properties in naturally grown bilberries gathered from different sites in Northern Europe. The variability in the biologically active compounds, antioxidant capacity and physico-chemical properties, as well as the development of tools for the authenticity and quality control of wild bilberries (V. myrtillus L.) in different geographical locations was evaluated. The berries of bilberries were handpicked during the summers of 2019 and 2020 during the time periods when they are typically harvested for commercial purposes in Northern Europe (Norway (NOR), Finland (FIN), Latvia (LVA) and Lithuania (LTU)). Berries from locations in NOR were distinguished by their higher mean TPC (791 mg/100 g FW, average), whereas the mean TPC of samples from the most southern country, LTU, was the lowest (587 mg/100 g FW). The TPC of bilberries ranged from 452 to 902 mg/100 g FW. The TAC values of investigated bilberry samples varied from 233 to 476 mg/100 g FW. A high positive correlation was found between TPC and antioxidant activity of the bilberry samples (R = 0.88 and 0.91 (FRAP and ABTS assays, respectively)), whereas the correlation between TAC and antioxidant activity was lower (R = 0.65 and 0.60). There were variations in the TPC and TAC values of investigated berries, suggesting that genotype also affects the TPC and TAC in berries. In 2020, the pH values and TSS contents of berries were significantly lower than in 2019. To the best of our knowledge, this is the first comprehensive reported evaluation of the biologically active compounds in wild bilberries from different Northern European countries using one laboratory-validated method.

The influence of Pulsed Electric Field (PEF) pre-treatment of blueberry fruits (Vaccinium myrtillus L.), both on the extraction yield and antioxidant properties of juice obtained by pressing and on the on the recovery of bioactive compounds from berry by-products (press cake) by extraction with solvent, was investigated. PEF treatments carried out at field strengths of 1, 3, and 5 kV/cm and an energy input of 10 kJ/kg achieved a cell disintegration index (Z _p ) of 0.70, 0.80, and 0.87, respectively. Mechanical pressing (1.32 bar for 8 min) of PEF-treated berries (1, 3, and 5 kV/cm at 10 kJ/kg) significantly increased the juice yield (+28 %) compared with the untreated sample. The juice obtained from PEF pre-treated berries also had a significantly higher total phenolic content (+43 %), total anthocyanin content (+60 %) and antioxidant activity (+31 %). However, PEF treatment intensity higher than 1 kV/cm did not significantly improve the quantitative or qualitative characteristics of the juice. Compared to the untreated sample, higher amounts of total phenolics (+63 %), total athocyanins (+78 %) and antioxidant activity (+65 %) were detected in the press cake extracts. PEF treatment of higher intensity resulted in better extractability of bioactive compounds from blueberry press cake. The results obtained from this study demonstrate the potential of PEF as a mild pre-treatment method to improve the efficiency of the industrial processing of berry fruits.

Actinidia kolomikta (Maxim. and Rupr.) Maxim fruits are very beneficial for the health, but their wide use is limited by short shelf life. One way of fruit preservation is drying, but Actinidia fruits have quite firm skin, which results in a long drying time. Pulsed electric field (PEF) is a promising nonthermal food stuff processing method, based on a very short time (μs to ms range), but high‐voltage (1–10 kV/cm) treatment, allowing increased mass transfer from plant tissues. In this study PEF‐pretreated A. kolomikta fruits were dried in a fluid bed hot air dryer. The weight difference after PEF pretreatment of the fruits was 13%, after 3 h of drying, with a 5‐kV/cm strong electric field strength, pulse width of 20 μs, pulse repetition rate of 20 Hz and a total treatment time of 120 s. PEF pretreatment did not influence the color parameters or ascorbic acid content of A. kolomikta fruits.Practical Applications: Actinidia kolomikta (Maxim. and Rupr.) Maxim show high frost resistance (up to −30C during the dormant period), and exhibit short growth and maturation time; therefore, they could be cultivated in colder climate countries. A. kolomikta fruits are healthy and valuable, but their wide use is limited by its short shelf life. One way of fruit preservation is drying, but Actinidia fruits have quite firm skin, which results in a long drying time. In this study, we presented pulsed electric field (PEF) pretreatment in order to increase the drying efficiency of A. kolomikta fruits. Using PEF pretreatment, the same dryness could be reached almost two times faster. This allowed for the saving of time and energy, while fruit quality parameters (color parameters and ascorbic acid content) remained unchanged. Thus, PEF pretreatment prior to drying is a promising technology for increased quality of A. kolomikta fruit preservation.

Actinidia kolomikta (Maxim. & Rupr.) fruits are valuable medicinal and edible fruits, containing high amounts of vitamins C, E and K, lutein, minerals and phenolics. The plants exhibit short growth and maturation time (2 – 3 month), however the widespread usage of Actinidia fruits is limited due to their short shelf life. Drying is one of the most common methods of food preservation. However, A. kolomikta fruits have quite firm skin, which results in long drying time. Pulsed electric field (PEF) is a new non thermal processing method, based on short duration (µs to ms range), but high voltage (1 – 10 kV/cm) treatment, allowing increased water and mass transfer from the cells. The aim of this study was to evaluate the influence of PEF pre-treatment on drying of A. kolomikta fruits. Three different drying methods were used: freeze-drying (lyophylization), fluid bed hot air and infrared drying. The moisture loss, color coordinates and extures were analyzed. PEF pre-treated (5 kV/cm, 20 Hz, 20 ms, 2 min) A. kolomikta moisture loss was 14% higher after 20 hours of freeze-drying, 13% higher after 3 hours of hot air drying, and 6% higher after 30 min of infrared drying, when compared to the respective controls. In the CIELAB color scale, the only parameter which was influenced by PEF treatment was L* color coordinate, measuring lightness. For PEF pre-treated vs. control conditions L* was 42.0 vs. 34.3 for infrared heating, and 66.7 vs. 41.8 for freeze-drying, while after hot air drying L* did not change. Texture analyzer showed that freeze-dried PEF-pretreated fruits required smaller maximal penetration force, which was 163 ± 20.2 N/cm2, in comparison to control without PEF 120 ± 7.9 N/cm2. In conclusion, PEF pre-pretreatment accelerated drying process of A. kolomikta fruits when applying all three drying methods, thus saving time and energy. The effect of PEF-pretreatment on drying rate was mostly pronounced for the freeze-drying. Acknowledgement: This work was supported by the grant SVE-08/2014 from the Research Council of Lithuania. Keywords: Actinidia kolomikta, PEF, Hot air drying, Freeze-drying, Infrared drying.

The mechanism of action of polyphenolic compounds is attributed to their antioxidant, anti-inflammatory, and anti-proliferative properties and their effects on subcellular signal transduction, cell cycle impairment and apoptosis. A raspberry (Rubus idaeus L.) fruit extract contains various antioxidant active compounds, particularly ellagic acid (EA); however the exact intracellular mechanism of their action is not fully understood. The aim of the study was to evaluate the antioxidant effect of raspberry extracts, and that of ellagic acid by assessment of the production of the reactive oxygen species (ROS) by murine macrophage J774 cells. Raspberry extracts and their active compound EA did not affect or had very minor effects on cell viability. No significant difference in the ROS generation in arachidonic acid stimulated macrophages was determined for raspberry extracts and EA whereas in the phorbol-12 myristate-13 acetate model ROS generation was significantly (p < 0.05) reduced. Our observation that raspberry pomace extracts in vitro reduce ROS production in a J774 macrophage culture suggests that raspberry extract and ellagic acid mediated antioxidant effects may be due to the regulation of NADPH oxidase activity.