Patricija Čulina

The aim of this study was to determine the retention of fatty acids, α-tocopherol, and carotenoids in sea buckthorn oil (SBO) encapsulated with gum arabic (GA), β-cyclodextrin (β-CD), and their mixture (1:1) under pre-optimized spray drying conditions in comparison to the bioactive molecule (BAM) content of the non-encapsulated oil. In addition, the color parameters in the spray-dried powders and the bioaccessibility of β-carotene, which has the highest provitamin A activity, were evaluated. The fatty acid content remained almost unchanged, while statistically significant differences in α-tocopherol and carotenoid content were found between the SBO encapsulated with different carriers and the non-encapsulated oil. The retention of tocopherols and carotenoids compared to the non-encapsulated SBO ranged from 62.13 to 87.23% and from 21.17 to 97.61%, respectively. SBO encapsulated with β-CD showed significantly higher retention of α-tocopherol (87.23%) and individual carotenoids (40.71–97.61%). In addition, the powders showed no significant differences in color parameters, and the powders encapsulated with GA and β-CD showed high bioaccessibility of β-carotene (92.50 and 90.45%, respectively). β-CD proved to be the most suitable carrier for the encapsulation of the carotenoids and α-tocopherol of SBO, resulting in powders with high bioaccessibility of β-carotene.

This study compared the efficiency of advanced supercritical CO₂ extraction (SC-CO₂) and conventional Soxhlet extraction (SE) in the isolation of lipophilic bioactive molecules (BAMs) from the oils of different sea buckthorn (SB) berries (Leikora and Ascola). A SB cake, a valuable by-product of oil extraction, was analyzed for phenolic compounds and antioxidant activity (AA). For this purpose, ultrasound-assisted extraction (UAE) with 70% (v/v) ethanol was optimized, and the following optimal UAE conditions were determined: ultrasonic power of 60%, temperature of 50 °C, and extraction time of 20 min. The individual BAMs in the oils and cake extracts were analyzed chromatographically, while the AAs were determined using the ORAC method. The oils extracted with SC-CO₂ had a higher content of lipophilic BAMs and a higher AA value than the oils extracted with SE. Palmitic and palmitoleic acids, β-sitosterol, and α-tocopherol dominated the Leikora oil, while a higher content of oleic, linoleic, and α-linolenic acids and carotenoids was found in the Ascola oil. The highest phenolic content was found in the Ascola cake, with the flavonols isorhamnetin-3-hexoside, isorhamnetin-3-rutinoside, and quercetin-3-glucoside being the most abundant. Oil and cake extracts of the Ascola variety also had a higher AA.

The aim of this study was to optimize parameters of microwave-assisted extraction (MAE) and accelerated solvent extraction (ASE) in terms of extraction temperature and time, microwave power and cycle numbers on the phenolic content of sea buckthorn leaves and berries, using 70% ethanol (v/v) as an extraction solvent. The characterization of phenolic composition in leaf and berry extracts obtained at optimal MAE and ASE conditions was performed with UPLC/ESI-MS², while antioxidant activity was determined using the ORAC method. The optimal extraction conditions for MAE were 60 °C, 500 W and 15 min for leaves and 60 °C, 300 W, and 10 min for berries. The optimal extraction conditions for ASE from both leaves and berries were 120 °C, 15 min, and 3 cycles. Total phenolic content (TPC) in MAE and ASE extracts from leaves was similar to the TPC determined in extracts obtained by conventional extraction (60 °C/30 min); however, ASE contributed to the higher TPC of the berry extracts. The flavonols kaempferol-3-rutinoside in the leaves and kaempferol in the berries were the most abundant phenols of sea buckthorn. A higher antioxidant activity was found in the leaf extracts obtained by ASE and it correlated with the phenolic content. In general, ASE favored the extraction of all polyphenols from leaves, while MAE was more suitable for the extraction of flavonols from berries, suggesting that the choice of the optimal extraction method is crucial with regard to the target molecules and future applications.

Monofloral honey is obtained from the nectar of single-source plants and has a higher market value due to its polyphenol content associated with its biological properties, especially its antioxidant capacity. In this work, advanced extraction techniques using microwave- (MAE) and ultrasound-assisted (UAE) extraction of phenolic compounds in monofloral honey were optimized and compared. Optimal parameters for MAE were an irradiation time of 15 min, a temperature of 60 °C, and a microwave power of 300 W, and for UAE, a sonication time of 10 min, a temperature of 35 °C, and an ultrasound amplitude of 60%. The extraction solvent used was 70% ethanol. In the extracts of different monofloral honey samples (mint, fennel, raspberry, lavender, sage, buckwheat, maroon, heaven) obtained at optimal MAE and UAE conditions, polyphenolic compounds were determined using UPLC-ESI/MS² analysis and antioxidant capacity using ORAC, ABTS, and DPPH assays. The results showed that UAE was the more efficient technique for the extraction of total flavanones, flavones, hydroxycinnamic acids, and total phenols, and MAE for total flavonols and hydroxybenzoic acids. The antioxidant ORAC and DPPH capacity was higher for the extracts obtained with MAE, while the ABTS capacity was higher for those obtained with UAE.

The aim of this study was to evaluate the effect of spray-drying parameters on the physicochemical properties of encapsulated sea buckthorn berry oil. Different carriers (gum arabic, β-cyclodextrin, and their mixture (1:1, w/w)), inlet air temperatures (120, 150, and 180 °C), and carrier-to-oil ratios (2, 3, and 4, w/w) were evaluated. The obtained powders were characterized in terms of the product yield (36.79–64.60%), encapsulation efficiency (73.08–93.18%), moisture content (0.23–3.70%), hygroscopicity (1.5–7.06 g/100 g), solubility (19.55–74.70%), bulk density (0.25–0.44 g/L), total carotenoid content (mg/100 g dm), and antioxidant capacity (871.83–1454.39 μmol TE/100 g dm). All physicochemical properties were significantly affected by the carrier-to-oil ratio and inlet air temperature. Higher carrier-to-oil ratios increased the product yield, encapsulation efficiency, solubility, and bulk density and decreased the powder hygroscopicity. Elevating the drying temperatures during spray drying also increased the product yield, encapsulation efficiency, and solubility, while it decreased the powder moisture content, total carotenoid content, and antioxidant capacity. Based on the physicochemical properties, the use of β-cyclodextrin as a carrier, a drying temperature of 120 °C, and a carrier-to-oil ratio of 4 were selected as optimal conditions for the production of sea buckthorn berry oil powder. The obtained powder is a valuable material for a wide range of applications in the food and nutraceutical industries.

Pistacia lentiscus is an evergreen shrub widely used in folk medicine due to the high biological potential of the leaves’ phenolic compounds. Since phenolic compounds are susceptible to degradation under different heat, light and oxygen conditions, various microencapsulation techniques, such as spray drying, can be used to increase their stability. The objective of this study was to examine the influence of different carriers (gum arabic (GA), maltodextrin 13–17 DE (MD), β-cyclodextrin (BCD) and their mixtures), carrier concentrations in feed (12.8, 16 and 19.2% (m/V)) and drying temperatures (120, 150 and 180 °C) on the physiochemical properties, total phenolic content (TPC) and antioxidant activity (AOA) of Pistacia lentiscus leaf extract powders. Product yields of powders ranged from 23.53 to 65.51%, moisture content from 2.89 to 12.03%, hygroscopicity up to 4.45 g/100 g, solubility from 27.11 to 86.84% and bulk density from 0.24 to 0.45 g/mL. All obtained powders had satisfactory physicochemical properties, except BCD powders, which resulted in the lowest product yield, solubility and bulk density. However, BCD powders and those produced with GA containing mixtures retained the highest amounts of TPC and AOA. Thereby, the carrier mixtures with GA at a concentration of 19.2% and dried at 150 °C are recommended as the most suitable for the production of encapsulated Pistacia lentiscus leaf extracts with desirable physicochemical properties, rich in phenolics and with high antioxidant activity.