Percorrer por autor "Oztop, Mecit Halil"
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- Bacterial lipopeptides from bacillus: natural biostructuring agents for improving texture and stability in tomato-based functional foodsPublication . Gharsallah, Houda; Ngameni Tchonkouang, Rose Daphnee; Mabrouk, Aymen Ben; Jaoued, Najeh; Tas, Ozan; Boufi, Sami; Vieira, Margarida; Oztop, Mecit Halil; Zarai, ZiedIntroduction: Recent advances in functional food formulation have highlighted bacterial lipopeptides as natural biomolecules capable of replacing synthetic additives while enhancing the physicochemical properties of food systems. Their amphiphilic structure makes them promising candidates for improving texture, stability, and emulsification in complex matrices such as tomato-based products. Methods: In this study, lipopeptides produced by Bacillus strains were structurally characterized using 1 H-NMR and two-dimensional 1 H–1 H COSY spectroscopy to confirm their amphiphilic nature. Tomato-based formulations (juice and sauce) were enriched with lipopeptides at concentrations of 0.5, 1.0, and 2.0 g/L. Rheological behavior was evaluated under steady-shear conditions to assess flow properties and time-dependent structural changes. Results: Spectroscopic analysis confirmed the presence of characteristic aliphatic fatty acid chains and peptide residues, validating the lipopeptidic structure. All formulations exhibited shear-thinning behavior; however, the addition of lipopeptides significantly influenced time-dependent rheological properties. Improved texture, viscoelasticity, and stability were observed, with optimal performance achieved at low-to-moderate concentrations (H6: 0.5–1 g/kg; S15: up to 2 g/kg). Higher concentrations led to partial network disruption and reduced system stability. Discussion: These findings demonstrate that bacterial lipopeptides act as effective natural bio-structuring agents in tomato-based products. Their ability to enhance microstructural integrity and emulsification without compromising stability at optimal concentrations highlights their potential as sustainable alternatives to synthetic additives in functional food development.
- Development of a novel formulation of a functional tomato saucePublication . Ngameni Tchonkouang, Rose Daphnee; Martey, Dorcas Martekie; Bal, Murad; Oztop, Mecit Halil; Gago, Custódia; Guerreiro, Adriana; Estêvão, Maria Dulce da Mota Antunes de Oliveira ; Vieira, MargaridaA functional tomato sauce was developed through the enrichment of high-lycopene tomato pulp (TomP) with pea protein (PP), freeze-dried olive powder (OP), and tomato peel powder (TPP) to achieve good sensory acceptability and a high antioxidant level using a 4-component (X1-TomP, X2-PP, X3-OP, X4-TPP) D-optimal mixture design. Responses: Y1-color, Y2-aspect, Y3-aroma, Y4-flow/texture, Y5-taste, Y6-sourness, and Y7-aftertaste, were evaluated by a non-trained sensory panel to obtain polynomial models for all responses. Numerical optimization resulted in the formulation: TomP (93.05%), PP (1.82%), OP (1.66%), and TPP (3.47%). Sensory analyses of the developed sauce revealed that the product was appreciated by untrained and trained panelists. Sensory profile analyses by the trained panel consensus concluded that the sauce has a good flavor profile with well-balanced sweetness and saltiness, slightly perceptible astringent notes, and no off-taste. Analyses of antioxidant activity (ABTS and FRAP), polyphenols, lycopene and beta-carotene were carried out. The sauce had concentrations of 35.37±1.85 mg/100 g (lycopene), 5.72±0.52 mg/100 g (beta-carotene), and 58.30±0.91 mg GAE/100 g (phenolic content) while the pulp had concentrations of 23.54±0.76 mg/100 g, 3.03±0.01 mg/100 g and 39.06±2.99 mg GAE/100 g, respectively. The developed tomato sauce compares favorably with the pulp in terms of lycopene, beta-carotene, and phenolic content. The remarkable increase in phenolic content, lycopene, and beta-carotene (known for their antioxidant properties) in the sauce enriched with powdered additives contributes significantly to its antioxidant potential. Therefore, the developed sauce is a good source of such health-promoting compounds and has the potential to be consumed as a functional food.