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    Effects of Non-Thermal Treatment on Gilaburu Vinegar (Viburnum opulus L.): Polyphenols, Amino Acid, Antimicrobial, and Anticancer Properties
    (Mdpi, 2022) Erdal, Berna; Yikmis, Seydi; Demirok, Nazan Tokatli; Bozgeyik, Esra; Levent, Okan
    Simple Summary In this study, traditionally produced vinegar made from gilaburu (C-GV) and thermally pasteurized gilaburu vinegar (P-GV), and (ultrasound-treated gilaburu vinegar (UT-GV) were evaluated. At the same time, ultrasound treatment enriched 11 phenolic compounds (gallic acid, protocatechuic acid, hydroxybenzoic acid, vanillic acid, p-coumaric acid, rutin, ferulic acid, o-coumaric acid, neohesperidin, quercetin, trans-cinnamic). Ultrasound showed different effects on free amino acids and volatile profiles. In general, ultrasound showed more positive results than thermal pasteurization. Six important minerals (Ca, Fe, K, Mg, Mn, and Zn) were detected in gilaburu vinegar, and ultrasound treatment increased the Fe content. Gilaburu vinegar, prepared by different methods, had potential antibacterial and anti-cancer activity. Gilaburu (Viburnum opulus L.) is an important fruit that has been studied in recent years due to its phytochemicals and health benefits. In this study, traditionally produced vinegar made from gilaburu fruit (C-GV) was evaluated. Vinegar with higher levels of bioactive components optimized by response surface methodology (RSM) was also produced using ultrasound (UT-GV). The maximum optimization result for the bioactive components was achieved at 14 min and 61.2 amplitude. The effectiveness of thermal pasteurization (P-GV) on gilaburu vinegar was evaluated. An increase was detected for every organic acid with ultrasound treatment. In the UT-GV and C-GV samples, arabinose was present, which is useful for stimulating the immune system. Gilaburu vinegar samples contained 29-31 volatile compounds. The smallest amount of volatile compounds was found in P-GV (1280.9 mu g/kg), and the largest amounts of volatile compounds were found in C-GV (1566.9 mu g/kg) and UT-GV (1244.10 mu g/kg). In the UT-GV sample, Fe was increased, but Ca, K, Mg, and Mn were decreased. A total of 15 polyphenols were detected in C-GV, P-GV, and UT-GV samples, and gallic acid was the most common. A total of 17 free amino acids were detected in gilaburu vinegar samples. Ultrasound provided enrichment in total phenolic compounds and total free amino acids. All three vinegar samples had good antimicrobial activity against pathogens. The efficacy of C-GV, P-GV, and UT-GV samples against colon and stomach cancer was determined, but there were no significant differences between them. As a result, ultrasound treatment is notable due to its antimicrobial and anticancer activity, especially for the enrichment of phenolic compounds and amino acids in gilaburu vinegar.
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    Impact of thermal pasteurization and thermosonication treatments on black grape juice (Vitis vinifera L): ICP-OES, GC-MS/MS and HPLC analyses
    (Cell Press, 2023) Yikmis, Seydi; Demirok, Nazan Tokatli; Levent, Okan; Apaydin, Demet
    Grape juice is a widely consumed fruit due to its bioactive compounds, minerals, and aroma components. Our objective was to investigate ultrasound treatment of black grape juice affects its bioactive components due to using response surface methodology (RSM) and artificial neural network (ANN) optimization. At the same time, mineral components, sugar components, organic acids, and volatile aroma profiles were compared in black grape juice treated with thermal and ultrasound pasteurization. ANN showed superior predictive values (>99%) to RSM. Optimal combinations were obtained at 40 degrees C, 12 min, and 65% amplitude for thermosonication. Under these conditions, phenolic, flavonoid, antioxidant activity, and anthocyanin values were 822.80 mg GAE/L, 97.50 mg CE/L, 24.51 mmol Trolox/L, and 368, 81 mg of mv-3-glu/L, respectively. Thermosonicated grape juice (TT-BGJ) was tested against black grape juice (P-BGJ) produced with conventional thermal methods. This study investigated the effects of thermal pasteurization and thermosonication on black grape juice bioactive compounds and minerals, aroma profile, and sensory evaluation. Thermosonication affected the aroma profile less, 329.98 mu g/kg (P-BGJ) and 495.31 mu g/kg (TT-BGJ). TT-BGJ was detected to contain seven different mineral elements (Mn, K, Fe, Mg, Cu, Zn, and Na). Thermosonication caused an increase in Fe, Zn, Mn, and K minerals. Panelists generally liked the TT-BGJ sample. These results suggest that the thermosonication process may potentially replace the traditional black grape juice processing thermal process.
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    Improving nutritional quality, aroma profile and bioactive retention of rocket juice via thermosonication: a support vector regression-based optimization
    (Frontiers Media Sa, 2026) Levent, Okan; Simsek, Mehmet Ali; Yikmis, Seydi; Demirel, Selinay; Turkol, Melikenur; Demirok, Nazan Tokatli; Er, Hatice
    This study investigates the application of thermosonication (TS) to improve the functional properties of roka (Eruca vesicaria subsp. sativia) water. Processing parameters, including time (8-16 min), amplitude (60-100%), and temperature (40-60 degrees C), were optimised using a comparative approach combining the response surface method (RSM) and support vector regression (SVR). The total phenolic content (TPC) increased to 86.04 mg GAE/100 mL with TS, representing an 8.1% rise compared to the control group and an 18.3% increase over pasteurization. Likewise, the total chlorophyll level reached 16.98 mmol TE/L from 9.67 g/100 mL, and beta-carotene rose to 24.90 mg/100 mL (p < 0.05). Pasteurization caused losses of 15-30% in these components. In the phenolic profile, significant increases were observed in chlorogenic acid (42.05 mu g/mL), caffeic acid (15.66 mu g/mL), and quercetin (4.28 mu g/mL). A total of 31 compounds were identified in aroma analysis; with TS treatment, levels of 3-Hexen-1-ol (15.70 mu g/kg) and 1-hexanol (2.01 mu g/kg) were preserved or increased. In in vitro digestion tests, the TS group demonstrated the highest bioavailability, even during the intestinal phase. For example, RSM demonstrated high compliance coefficients (R2 = 0.99), while SVR showed strong predictive performance (CV R2 = 0.84), particularly for FRAP. Overall, the results suggest that thermosonication is an innovative method for protecting and enhancing bioactive compounds in rocket juice.
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    Thermosonication Processing of Purple Onion Juice (Allium cepa L.): Anticancer, Antibacterial, Antihypertensive, and Antidiabetic Effects
    (Mdpi, 2024) Yikmis, Seydi; Erdal, Berna; Doguer, Caglar; Levent, Okan; Turkol, Melikenur; Demirok, Nazan Tokatli
    Onion (Allium cepa L.) juice is an important product used in gastronomy and food formulations. The first objective of this study was to optimize the content of bioactive compounds in purple onion juice (POJ) after the thermosonication process using response surface methodology (RSM) and artificial neural network (ANN) application models. Second, the anticancer, antibacterial, antihypertensive, and antidiabetic effects of POJ obtained after thermal pasteurization (P-POJ) or thermosonication (TS-POJ) were investigated after obtaining the ANN and RSM analysis reports. The optimization process for TS-POJ was carried out at 44 degrees C, for 13 min, with a 68% amplitude. The findings demonstrated that the angiotensin-converting enzyme (ACE) inhibition level was greater in TS-POJ samples than in the untreated control (C-POJ) sample (p > 0.05). C-POJ, TS-POJ, and P-POJ exhibited the inhibition of cell proliferation in vitro in a dose-dependent manner in lung (A549), cervical (HeLa), and colon cancer cells following 24 h incubation. Thermosonication or thermal pasteurization did not markedly affect the cell proliferation of the examined cancer cells compared to the untreated control group. While no antibacterial effect was observed with low concentrations of samples, they showed an antibacterial effect at pure concentrations (100%). The thermosonication treatment for processing purple onion juice was successful in this study's results.
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    Thermosonication-enhanced bioaccessibility and functional quality of dill juice: an in vitro digestion approach
    (Frontiers Media Sa, 2025) Yikmis, Seydi; Ates, Abdullah; Demirel, Selinay; Levent, Okan; Tokatli, Nazli; Demirok, Nazan Tokatli; Aljobair, Moneera O.
    The effects of thermosonication - a non-thermal method considered an alternative to conventional thermal treatments - on the functional components in dill (Anethum graveolens) juice were comprehensively investigated in this study, as well as the post-digestion bioaccessibility levels of these components. In this study, samples from three different treatment groups- thermosonicated (TS-DJ), control (CDJ), and thermally pasteurized (P-DJ) were compared in terms of key parameters such as total chlorophyll content, total phenolic content (TPC), iron reducing capacity (FRAP), and beta-carotene. Additionally, a controlled in vitro digestion system was used to analyze the stability and recovery rates of bioactive substances and volatile aroma compounds at different stages of the digestion process (gastric, oral, and intestinal phases). The findings revealed that thermosonication was highly effective in preserving the bioactive components both at the initial level and during the 21-day storage period and significantly increased their post-digestion bioaccessibility levels. Optimization of application parameters was achieved using a combination of Equilibrium Optimization algorithms and Response Surface Methodology (RSM), and the resulting prediction models were validated with high statistical confidence. The Pearson correlation analysis revealed significant positive correlations among beta-carotene, characteristic volatile compounds, and total phenolic compounds. This suggests that the increase in these bioactive compounds may be directly related to the improvement in the aroma profile of dill juice. The data obtained indicate that thermosonication may offer an effective alternative to conventional thermal treatments in enhancing the functional quality of dill juice and its post-digestive bioaccessibility. However, further studies are needed to assess its potential for consumer acceptance and industrial integration. In this context, the study reveals important findings that will help develop new technologies for processing plant-based beverages.