Fatih Bozkurt

Chestnut inner shell (CIS) is a phenolic-rich by-product with potential for valorization through microbial fermentation. This study investigated the effects of autoclaving and subsequent fermentation with Saccharomyces boulardii S10 on free and bound phenolics, antioxidant activity, and α-glucosidase, α-amylase, and angiotensin-converting enzyme (ACE) inhibitory activities. Furthermore, simulated in vitro gastrointestinal digestion was performed to evaluate phenolic bioaccessibility and changes in individual phenolic compounds during digestion. Autoclaving increased free total phenolic content (TPC) from 139.09 to 178.61 mg GAE/g DW. During fermentation, the free phenolic fraction exhibited the highest TPC at 48 h (190.81 mg GAE/g DW), accompanied by the lowest TPC in the bound fraction (34.89 mg GAE/g DW). Similarly, α-glucosidase inhibitory activity was highest at 48 h (IC₅₀ = 21.44 µg/mL), whereas ACE inhibitory activity progressively increased throughout fermentation, reaching its maximum at 72 h (IC₅₀ = 10.08 µg/mL). Following in vitro gastrointestinal digestion, gallic and ellagic acid concentrations increased during the intestinal phase. Notably, the 48 h fermented sample exhibited the highest intestinal TPC (218.86 ± 5.02 mg GAE/g DW) among all samples, along with the highest TPC-based bioaccessibility (96.97%) and individual phenolics-based bioaccessibility (16.93%) among the fermented samples. These findings highlight the potential of fermentation to modify phenolic distribution and bioactivities while demonstrating the importance of gastrointestinal digestion in evaluating the bioaccessibility of CIS phenolics.

Rosemary essential oil (REO) was incorporated into electrospun poly(ε-caprolactone) (PCL) nanofibers, which were subsequently modified with a thermoresponsive poly(N-isopropylacrylamide) (PNIPAM)-gel coating using an immersion-based approach. The coated fibers exhibited temperature-dependent surface wetting behavior below and above the lower critical solution temperature (LCST) of PNIPAM. PNIPAM coating reduced water vapor transmission at 25 °C and increased the water vapor transmission ratio (WVTR₄₀/WVTR₂₅) from 1.65 to 2.31, whereas thickness-normalized water vapor permeability did not show a distinct LCST-dependent transition. Headspace analysis by HS-SPME-GC-MS showed increasing accumulation of REO volatiles with incubation time and temperature. After 48 h, PNIPAM coating reduced the total headspace amount of the selected volatile markers by approximately 7.2-fold at 25 °C and 4.9-fold at 40 °C. A significant coating × temperature interaction (p < 0.05) indicated that the coating modified the temperature dependence of volatile transfer, with the 40/25 °C ratio increasing from 1.65 in uncoated fibers to 2.41 in coated fibers. In non-contact antifungal assays against toxigenic Aspergillus flavus, REO-loaded fibers produced transient growth inhibition at 25 °C, whereas inhibition persisted throughout the 10-day incubation at 40 °C and was greater for the uncoated REO-loaded fibers. None of the fiber systems significantly affected AFB₁ accumulation at 25 °C, while AFB₁ was undetected in all samples, including the untreated control, at 40 °C. Overall, the PNIPAM-gel coating provided substantial retention of REO volatiles while introducing temperature-dependent modulation of their transfer to the gas phase, although the response did not represent a simple LCST-triggered release switch.

The global demand for sustainable resources highlights agricultural wastes for their valuable biomass content. Xylan, abundant in nature, offers biomedical applications in drug delivery, wound healing, and biodegradable food coatings. This study is the first in the literature to investigate the effect of microwaves on xylan extraction. The aim of this study is to investigate the effect of microwave application and determine the purity of the extraction outcomes in terms of xylan content. The microwave-assisted extractions were performed with two different diluted alkali solutions, potassium hydroxide (KOH) and sodium hydroxide (NaOH), and corncob was the biomass source for xylan. Experiments were designed with response surface methodology (RSM) to find the optimum conditions. Microwave energy demonstrated a statistically significant impact on extraction efficiency and yield (p < 0.05). Maximum yielding conditions for xylan extractions were found as follows: 1200-watt microwave power for 20 min with 10% (w/v) alkaline solution. The results of Fourier-transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance (NMR) spectra of the KOH extract showed more resemblance to the xylan standard, with fewer indicators of impurities. However, the differential scanning calorimetry (DSC) and zeta potential analysis results of the two extracts did not differ from each other, showing similar thermal and suspension behavior. Xylan content of the KOH and NaOH extracts was determined as 77.82% and 72.01%, respectively.

BACKGROUND: Bioactive peptides derived from protein hydrolysates provide various health benefits; however, their practical application is limited by low gastrointestinal stability, enzymatic degradation, and poor intestinal absorption. Overcoming these challenges remains a key bottleneck for oral peptide delivery. This study aimed to develop and systematically compare uni‐axial and co‐axial electrospun pullulan/carboxymethylcellulose fibers incorporating liposome‐encapsulated glutenin hydrolysate (GH) to enhance its stability, mucoadhesion, and controlled release along the gastrointestinal system. RESULTS: GH (7.5 mg mL ⁻¹ ) was encapsulated into lecithin–phytosterol (1:0.5, w/w) liposomes, yielding an average size of 76 nm and an encapsulation efficiency of 57.52%. These liposomes were successfully embedded into nanofibers, showing homogeneous distribution and GH loading efficiencies of 61.04–85.22%. Compared with free GH, liposomal systems preserved the antioxidant activity (ABTS and FRAP values) of GH during gastrointestinal digestion, while the non‐hybrid formulation demonstrated reduced preservation. Liposome‐loaded nanofibers exhibited markedly lower GH release under gastric conditions (21.05–25.85%) than free‐GH fibers (42.69%), while co‐axial fibers provided the most sustained intestinal release. Additionally, liposomal incorporation significantly enhanced mucoadhesive properties. CONCLUSION: The hybrid liposome–nanofiber approach integrates protective and controlled‐delivery mechanisms, resulting in enhanced preservation of antioxidant activity and sustained release compared with conventional fibers. This food‐grade strategy shows strong potential for oral delivery of bioactive peptides in functional food and nutraceutical applications requiring gastrointestinal stability. © 2026 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

The invasive fish Atherina boyeri constitutes an ecologically disruptive yet underexploited biomass with strong potential for transformation into value-added biofunctional ingredients. This study investigates the functional, antioxidant, and antimicrobial properties of protein hydrolysates that were produced from fish collected in the Hirfanlı and Yamula reservoirs using three commercial proteases (alcalase, bromelain, and flavourzyme). Bromelain produced the highest degree of hydrolysis, yielding higher proportions of low-molecular-weight peptides and greater radical-scavenging activity. Flavourzyme hydrolysates exhibited the most favorable emulsifying properties, Alcalase hydrolysates produced the highest foaming capacity and stability. All hydrolysates showed high absolute zeta-potential values across pH 3–9, demonstrating strong colloidal stability. Protein solubility remained above 80% across most pH levels, indicating extensive peptide release and improved compatibility with aqueous media. The Oil-binding capacity (2.78–3.75 mL/g) was consistent with reported values for marine hydrolysates. Antioxidant and antimicrobial evaluations revealed clear enzyme-dependent patterns, with Bromelain exhibiting the strongest DPPH activity and Alcalase and Flavourzyme showing the most pronounced inhibition of major foodborne pathogens. Additionally, all hydrolysates exhibited measurable ACE-inhibitory activity, with flavourzyme-derived peptides showing the highest inhibitory activity, underscoring their potential relevance for antihypertensive applications. These findings highlight the strategic valorization of A. boyeri through enzymatic hydrolysis, demonstrating its potential as a sustainable, clean-label functional ingredient source.

Mycotoxigenic molds pose a threat to human health and cause economic losses in bread production. To address this issue, postbiotics have emerged as promising natural bioprotective agents due to their antifungal properties. In this study, postbiotics were obtained from Lactiplantibacillus (Lp.) plantarum Y48, Liquorilactobacillus (Lq.) hordei SK-6, and Lp. plantarum VB-29 strains and subsequently lyophilized. The functional groups of the bioactive components in these postbiotics were identified using FTIR spectroscopy. Samples extracted with different solvents were analyzed for their volatile compound profiles by GC-MS, and the results were compared using principal component analysis (PCA). The antifungal activities of postbiotics were tested. Subsequently, the antifungal activity of Lp. plantarum Y48 postbiotic was evaluated on bread contaminated with Aspergillus niger and Penicillium expansum. The postbiotic was incorporated into the bread formulation both alone and in combination with potassium sorbate, and it was also applied to the bread surface as a spray. Notably, the formulation containing 3% postbiotic + 0.1% potassium sorbate completely inhibited the growth of A. niger and P. expansum. These results indicate that the combined use of Lp. plantarum Y48 postbiotic and potassium sorbate can effectively prevent mold growth in bread and holds potential as a natural bioprotective approach in food preservation applications.

BACKGROUND: One of the major contributors to postharvest losses in tomatoes is the development of infectious mold diseases. In this study, four distinct biodegradable film formulations were developed incorporating postbiotics derived from Lactiplantibacillus plantarum Y48 and the polysaccharide alternan. The formulations included alternan, sodium alginate and glycerol (AAG), alternan, postbiotic, sodium alginate and glycerol (APAG), postbiotic, sodium alginate and glycerol (PAG), and sodium alginate and glycerol (AG) as a control. The films were characterized in terms of their physical, mechanical, thermal, and morphological properties. To assess antifungal efficacy, tomatoes artificially inoculated with Alternaria alternata were coated with each film and stored at ambient temperature for 8 days. RESULTS: The incorporation of alternan and postbiotics enhanced both the mechanical strength and thermal stability of the films. Fourier‐transform infrared (FTIR) analysis confirmed the successful integration of the bioactive components into the polymer matrix. Scanning electron microscopy (SEM) imaging revealed that postbiotic addition contributed to a rougher and more rigid surface morphology, while alternan improved the structural cohesion of the films. All film formulations exhibited significant inhibitory effects against A. alternata , with the PAG formulation demonstrating the most pronounced antifungal activity. CONCLUSION: These results suggest that the PAG film, enriched with postbiotics, represents a promising biocontrol strategy for mitigating fungal spoilage in tomatoes. In conclusion, this study underscores the potential of combining postbiotics and alternan for the development of active, biodegradable edible films with antifungal functionality for postharvest preservation. © 2025 Society of Chemical Industry.

Yeast derived EPSs have gained much popularity due to their techno-functional properties in recent years. In this context, six different S. boulardii strains, proven for their probiotic properties, were used to obtain EPS. HPLC results showed that the Sb EPSs had the heteropolysaccharide structure, and were mainly composed of mannose and glucose units. Besides this, fructose (only detected in S3 and S6), rhamnose (S4, S6, S7, S8, and S9) and galactose (S3, S6, S7, S8, and S9) were detected. However, xylose was not detected in any Sb EPS samples. FT-IR results confirmed the polysaccharide structure of Sb EPSs. The Sb EPSs exhibited more than 100% water holding capacity, and high-water solubility index. Within this context, the WHC and WSI values for the Sb EPSs ranged from 104.02±1.40 % to 102.38±0.89 % and 89.41±0.71 % to 82.14±6.60 %, respectively. The Sb EPSs exhibited shear thinning flow behaviour, and their viscosities were lower than those of guar gum. The Sb EPSs had excellent antioxidant activity for all tested three antioxidant methods of ABTS, DPPH, and FRAP. Accordingly, the antioxidant activities for the Sb EPSs, determined by the DPPH, ABTS, and FRAP assays, were found to be in the ranges of 53.59±0.29% (S6) to 49.25±0.44% (S9); 84.71±0.64% (S3) to 69.08±1.99% (S7); and is 121.33±2.20 (S6) to 97.16±3.33 (S9) mg TE/100 g, respectively. Especially the S6 EPS sample displayed high antioxidant activity in all three methods (P≤0.05). These results showed that Sb EPSs may be a good alternative in food applications.

This study employed response surface methodology for the first-time optimization of the ultrasound-assisted extraction (UAE) of the total phenolic content (TPC) and ABTS from edible lichens, including Evernia divaricata, Evernia prunastri, Pseudevernia furfuracea, Bryoria fuscescens, and Lobaria pulmonaria. Fourteen experimental points were generated using Design Expert Software, with the extraction temperature (25–40 °C), extraction time (5–20 min), and ethanol concentration (0–80%) as independent variables, and TPC and ABTS as dependent variables. The phenolic profile and mineral and antibacterial properties of the optimized lichen extracts were determined. Evernic and usnic acid were found in Evernia species. Atranorin was detected only in P. furfuracea. Fumarprotocetraric acid was found exclusively in B. fuscescens and was not detected in any of the other lichens. Calcium was found to have the highest mineral content in all the lichens, followed by potassium. L. pulmonaria, showing the lowest inhibition effect against all tested bacteria, while E. divaricata exhibited the most effective inhibition.

The present study aimed to determine the risk levels affecting food safety and security in foods distributed to earthquake victims by organizations. This descriptive and cross-sectional study was conducted in food distribution organizations in Kahramanmaraş and Hatay between 20–24 February 2023 (N = 40). The data were collected face-to-face by using the Descriptive Data Form and Food Safety and Security Observation Form (FSSOF) developed by the researchers. According to FSSOF, organizations had a 41.6% risk concerning food safety and security. According to the multiple linear regression analysis, organizations that did not control the foods were found to be associated with an increased total score of FSSOF (β: -0.527, p = 0.010). No relationships could be found between the type of organization, the population served, having a food technologist and/or dietitian, the distance between the organization and waste, and the total scores of FSSOF (p > 0.05). The organizations that did not control the food were found to be associated with Organization-specific conditions (β: -0.623, p = 0.002), Food distribution conditions (β: -0.531, p = 0.015), Personnel hygiene (β: -0.608, p = 0.005), Food security (β: -0.480, p = 0.036) and Environmental conditions (β: -0.537, p = 0.018) were found to be associated with an increased level of risks. Also, not having an engineer and/or dietitian was associated with an increased risk of Food storage practices (β: -0.469, p = 0.005), and increased the number of staff was associated with an increased risk of Organization-specific conditions (β: 0.348, p = 0.007). The level of risk of the organizations concerning food safety and security was found to be relatively high. Control of the food provided was the most important determinant of food safety and security.