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- Fatty acids profile in the honeybee: metabolic pathways, stressor interactions, and analytical approachesPublication . Mutlu, Ceren; Vilas-Boas, MiguelFatty acids play a crucial role in the metabolic activities, health, cognitive development, and behaviors of honeybees. The primary source of fatty acids for honeybees is the pollen consumed, though they can also produce specific fatty acids through de novo synthesis. Among the saturated fatty acids in honeybees, palmitic and stearic acids are the most abundant, while common unsaturated fatty acids include oleic, eicosenoic, palmitoleic, linoleic, and linolenic acids, which are present in various body parts and tissues. The composition and concentration of these fatty acids can be influenced by multiple biotic and abiotic factors such as developmental stage, nutrition, pathogens, season, temperature, sanitation conditions, industrial pollution, pesticides, and radiation. Therefore, monitoring the fatty acid profile of honeybees can be used as a bioindicator for monitoring the environmental conditions and the health status, enabling management actions that could improve honeybee sustainability. This study aims to provide foundational knowledge on the fatty acids identified in honeybees, examining their physiological roles, the impact of environmental stressors, and the analytical techniques used to determine their composition.
- Bioactivity of honey: phenolic composition, antioxidant trends and carcinoma cell lines effects through digestionPublication . Mutlu, Ceren; Demir, Zeynep; Aylanc, Volkan; Özkan, Aysun; Erbaş, MustafaHoney is not only a food source but also a valuable substance for health and medicine, owing to its complex composition and bioactive properties. However, there is very limited information on the changes in the active compounds of honey during digestion and their antioxidant capacity and effect on cancer cells at the end of digestion. Herein, we investigate the dynamic changes in their bioactive compound composition and antioxidant activity during in vitro gastrointestinal digestion and the effect of digested honey on several cancer cell lines, after determining the antimicrobial and anti-inflammatory effects of mono- and multifloral kinds of honey. The tested raw honey samples exhibited higher anti-inflammatory properties (36 %–80 %) with increasing total phenolic content (78–132 mg GAE/100 g), along with significant antimicrobial activity against E. coli (6–9 mm) and S. aureus (6–14 mm) bacterial species. The findings showed that total phenolic and flavonoid contents increased significantly during digestion, with a peaking value of 258 mg GAE/100 g in the intestinal phase, while TEAC and CUPRAC analysis exhibited variable trends depending on the digestion stage. Moreover, the concentration of compounds such as gallic, syringic, caffeic, p-coumaric, trans-cinnamic acid, and methyl-3,4,5-trihydroxybenzoate identified by HPLC-DAD showed some fluctuations at different stages of digestion. Cyto-toxicity analysis revealed that digested honey samples, particularly those with higher phenolic content, exhibited pronounced antiproliferative effects on cancer cells at higher concentrations, with minimal effects on healthy cells. These findings underscore the importance of honey’s bioactive compounds, their transformation during digestion, and their potential health benefits.
- Optimisation of Catalytic Oxidation Conditions for the 2‐Keto‐L‐Gulonic Acid Production Using Response Surface MethodologyPublication . Mutlu, Ceren; Candal‐Uslu, Cihadiye; Erbaş, MustafaL-Ascorbic acid, also known as vitamin C, is a very important antioxidant ingredient situated many usage areas in different industries. 2-keto-L-gulonic acid (2-KLG) is the main precursor component of L-ascorbic acid production and it can be produced from L-sorbose via microbial fermentation or chemical (catalytic) oxidation. While some special strains are used in microbial fermentation, it is benefitted from some catalysts in chemical oxidation. Herein, it was aimed to determine the optimum reaction temperature, pH, and time conditions to produce maximum 2-KLG compound with the catalytic oxidation of L-sorbose in the presence of Pt/Al2O3 catalyst with response surface methodology approach. For this aim, the reaction temperature, pH, and time used as variable factors. The limit values of variable factors were applied as 40–60°C for the temperature, 7.00–9.00 for the pH value, and 3–9 h for the time. The analyses results demonstrated that the increasing temperature and time negatively effected the conversion of L-sorbose into the 2-KLG. The optimum conditions of variable factors were determined as 41.30 °C for the temperature, 8.23 for the pH, and 3.25 h for the reaction time by the central composite design. Under these optimum conditions, L-sorbose was converted into 2-KLG with an average yield of 43.70%.
- Bee bread: sorption isotherms, thermodynamic characteristics of moisture adsorption and evaluation of adsorbed waterPublication . Mutlu, CerenBee bread is a value-added apiculture product produced from bee pollen by mixed lactic acid fermentation. Although many studies focused on the bioactive components and health effects of the bee bread, there is no study concerned with understanding its moisture adsorption properties. Herein, it was aimed to evaluate moisture adsorption properties and thermodynamics of bee bread using different sorption models at 25 and 35 °C. The water adsorption of bee bread had Type II characteristics, and the monolayer moisture content was calculated with BET, GAB, and Caurie models between 3.58 and 5.80 g/100 g. The Peleg and Caurie models ensured better prediction for adsorption. The stability of bee bread was high at 25 °C according to the smaller ratio of Type III to Type II-bound water. The entropy of adsorption was 16.01–25.78 kJ/ mol.K and it decreased with the moisture adsorption. Besides, the moisture adsorption needs external energy from the environment because of ΔG > 0.
- Safflower Protein Hydrolysates: Physicochemical, Functional Properties and Antioxidant ActivitiesPublication . Korkmaz, Fatma; Mutlu, CerenThis study aimed to investigate the effect of enzymatic hydrolysis on the physicochemical, functional, and antioxidant properties of safflower protein isolate and hydrolysates. Isolated safflower protein was hydrolyzed by both Alcalase and Flavourzyme at the degree of hydrolysis of 2%, 4%, 6%, 8%, and 10%. Safflower protein hydrolysates exhibited a lighter color (3.74%–8.79%) and reduced redness (69.11%–102.85%) with lower cohesiveness (15.29%–21.76%) and better flowability (25.91%–40.27%) compared to the protein isolate. Moreover, the surface hydrophobicity of safflower protein isolate decreased up to 73.18% with hydrolysis, while solubility increased up to 54.42% at pH 4–7. Safflower proteins hydrolyzed with Alcalase had higher oil binding, foaming, and emulsion capacities than samples hydrolyzed with Flavourzyme, while their water holding capacities were lower. Furthermore, safflower proteins hydrolyzed with Alcalase at an 8% degree of hydrolysis displayed the highest foaming capacity (up to 3.89 times) and emulsion capacity (up to 1.23 times) in all samples. However, it had poor foam (up to 67.06%) and emulsion stability (up to 74.35%). Additionally, safflower protein hydrolysates demonstrated higher ABTS•+ and DPPH radical scavenging activity. Overall, safflower protein hydrolysates showed better physicochemical, functional, and antioxidant properties than protein isolates, depending on enzyme types and degree of hydrolysis.
- Bee Pollen as a Dietary Mineral Source: In Vitro Bioaccessibility and Health Risk EvaluationPublication . Mutlu, Ceren; Aylanc, Volkan; Vilas-Boas, MiguelPollen, the male gametophyte of flowering plants, is collected by honeybees as a primary source of protein and converted into bee pollen through the enzymatic activity of digestive secretions. The nutrients in bee pollen are available in amounts well beyond those of proteins, comprising macronutrients such as carbohydrates, lipids and dietary fiber, as well as micronutrients such as minerals, vitamins, organic acids, and phenolic compounds. This study aimed to determine the macro and trace mineral content of bee pollen from different botanical and geographical origins, and to assess their bioaccessibility through simulated in vitro digestion, their dietary contribution, and potential health risks. Seven bee pollen samples were investigated, three with a monofloral origin of above 80%, from Nigella spp., Helianthus annuus and Castanea sativa, and four with a multifloral origin. Mineral composition revealed potassium as the most abundant element, while iron, manganese, and copper were found at trace levels. Castanea sativa pollen had the highest overall mineral content, whereas Nigella spp. showed the lowest values for calcium, magnesium, and copper. The bioaccessibility of bee pollen was highest during the gastric phase for most minerals except copper, where most of the samples peaked in the intestinal phase. Overall, mineral bioaccessibility after simulated digestion followed the order K > Mg > Cu > Ca > Mn > Fe > Zn. While for manganese, the consumption of bee pollen showed the highest contribution to recommended dietary intake (16% for women and 12% for men), calcium had the lowest, with less than 1% of the RDA at a consumption level of 40 g/day. Health risk assessment confirmed that consuming 40 g/day of bee pollen poses no risk because the target hazard quotient and hazard index are below the risk threshold of 1.0.