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In the present study, advanced extraction techniques, microwave (MAE), ultrasound (UAE), and high pressure (HPAE)-assisted extraction, were applied to improve extraction efficiency of olive (Olea europaea L.) leaves polyphenols. The effect of sample mass (1.5 and 3 g), MAE—time (2, 8.5, and 15 min) and temperature (45 and 80 °C), UAE—time (7, 14, and 21 min) and amplitude (50 and 100%) and HPAE—time (1, 5.5, and 10 min) and pressure (300 and 500 MPa) on the concentration of each analyzed polyphenol compound was examined. Identified polyphenols were oleuropein, hydroxytyrosol, chlorogenic acid, caffeic acid, verbascoside, and rutin. All three advanced extraction techniques yielded higher content of total polyphenols when compared to the conventional heat-reflux extraction (CE) along with a significant reduction of extraction time from 60 (CE) to 2, 21, and 5.5 min in MAE, UAE, and HPAE, respectively. The most intensive values of tested parameters in each technique were the ones that promoted cell wall disruption, e.g., temperature of 80 °C in MAE, 100% amplitude in UAE and 500 MPa in HPAE. MAE and UAE were more efficient in total polyphenols’ recovery than HPAE.

The possibility of proving the undeclared addition of pumpkin puree in apricot nectars and jams has been investigated by using the phenol compound fingerprint and sensory evaluation. The cheaper pumpkin admixtures in apricot nectars and jams could not be detected by the sensory evaluation, particularly if present in quantities of <15%. The lower admixtures of pumpkin puree in apricot nectars and jams could be detected by the presence of syringic acid, a phenolic compound characteristic of the investigated pumpkins (Cucurbita pepo cv. Gleisdorff and Table Gold, Cucurbita maxima cv. Turkinja, and Cucurbita moschata cv. Argenta). Syringic acid was isolated from pumpkin puree and determined by using HPLC with diode array detection. By using the phenolic profile, undeclared pumpkin admixture (> or =5%) in the apricot nectars and jams could be proven.

The present investigation tested the in vivo antioxidant efficacy (superoxide dismutase, SOD; catalase, CAT; glutathione peroxidase; Gpx), lipid peroxidation (LPO) and anti-inflammatory properties (cyclooxygenase-2; COX-2) of sour cherry juices obtained from an autochthonous cultivar (Prunus cerasus cv. Maraska) that is grown in coastal parts of Croatia. Antioxidant potential was tested in mouse tissue (blood, liver, and brain), LPO (liver, brain) and anti-inflammatory properties in glycogen elicited macrophages. Additionally, the concentration of cyanidin-3-glucoside, cyanidin-3-rutinoside, pelargonidin-3-glucoside, pelargonidin-3-rutinoside and total anthocyanins present in Prunus cerasus cv. Maraska cherry juice was determined. Mice were randomly divided into a control group (fed with commercial food pellets) and 2 experimental groups (fed with commercial food pellets with 10% or 50% of cherry juice added). Among the anthocyanins, the cyanidin-3-glucoside was present in the highest concentration. These results show antioxidant action of cherry juice through increased SOD (liver, blood) and Gpx (liver) activity and decreased LPO concentration. The study highlights cherry juice as a potent COX-2 inhibitor and antioxidant in the liver and blood of mice, but not in the brain. Thus, according to our study, Prunus cerasus cv. Maraska cherry juice might potentially be used as an antioxidant and anti-inflammatory product with beneficial health-promoting properties.