Özgür Tarhan - Academia.edu (original) (raw)

Papers by Özgür Tarhan

The Royal Society of Chemistry eBooks, 2022

Handbook of Food Nanotechnology

Abstract Organic and inorganic nanoparticles can be used in food and food contact materials. Most... more Abstract Organic and inorganic nanoparticles can be used in food and food contact materials. Mostly, they are used to provide antimicrobial activity, nanoencapsulation of nutrients, and smart food packaging. Food products prepared through nanotechnology methods and tools have garnered great attention worldwide. Thus the number of nanofood products present in market is increasing fast and continuously. Limited knowledge about the potential risks of nanoparticles ingested, inhaled, or to which directly exposed can lead to serious consequences. These ultratiny particles may potentially cause circulatory, cardiovascular, and pulmonary diseases due to their ability to pass biological barriers in the body. Assessment of risk factors, informing the community, and establishment of regulations should be taken into consideration. There are some efforts to exhibit guidelines, recommendations, and regulations related to the management of detection, definition, toxicity, exposure, safe handling, and use of nanomaterials in foods. Legal policies and regulatory frameworks examining applicability and safety assessment of nanomaterials have been discussed for the last two decades. This chapter reviews potential risks, toxicity assessments, possible exposure routes, and worldwide regulatory frameworks, and provides some guidance to the use of nanomaterials in the food industry.

Gıda ve Yem Bilimi Teknolojisi Dergisi, Aug 29, 2021

Trends in Food Science & Technology, 2022

Usak University Journal of Engineering Sciences, 2021

Cow milk and dairy products have a great significance in human nutrition but may lead to concerns... more Cow milk and dairy products have a great significance in human nutrition but may lead to concerns due to milk protein allergy. Reduction or elimination of cow milk allergy is mainly achieved by the destruction of allergenic epitopes in the molecular structure of relevant proteins via various treatments during dairy processing. Yogurt is one of the most consumed fermented dairy foods. The purpose of this study was to investigate the effect of fermentation on the protein content and molecular structure of milk during yogurt production. Protein profiles and structural features of the dairy samples collected at various steps of yogurt manufacturing were analyzed using electrophoresis and spectroscopy. Fermentation after pasteurization treatment remarkably altered the composition and structure of allergen proteins through unfolding, denaturation, and aggregation. This might suggest a correlation with the modified allergenicity of milk proteins in the end product.

Bulletin of Biotechnology, 2021

Nano-scale fibers or films obtained by adding natural active agents to natural food proteins are ... more Nano-scale fibers or films obtained by adding natural active agents to natural food proteins are promising materials for packaging purposes. Whey proteins are one of the most popular matrices in application with their cheap and sustainable availability. They have many functional properties and their antimicrobial, antiviral and anticarcinogenic properties are highlighted as well. Enzymatic hydrolysis can increase their functionality such as inducing gelation and revealing bioactive peptides. These features can make whey proteins good candidates for the fabrication of talented fiber structures through electrospinning. Electrospinning technique based on the deposition of fine fibers on a collector surface under electrical forces can be used to form protein nanofibers. The purpose of this research is to produce whey-based protein nanofibers and determine their structural and thermal features by infra-red spectroscopy and thermogravimetric analysis. A high molecular weight polymer, polyethylene oxide (PEO) was used in combination with whey protein concentrate (WPC) to increase spinnability. Besides, enzymatic hydrolysis of WPC enhanced the viscosity of the protein/polymer solution and helped electrospinning ability. Both non-hydrolyzed and hydrolyzed WPC/PEO nanofibers exhibited promising morphological, structural and thermal properties for targeted use in food and biomedical applications. Further research will focus on the application of these protein nanofibers for the packaging of particular foods.

Encapsulation technology provides various opportunities in food applications. Functional ingredie... more Encapsulation technology provides various opportunities in food applications. Functional ingredients incorporated into food products via micro/nanoencapsulation will have an improved sensorial and textural properties, shelf life, and health benefits. Physicochemical properties of the bioactive ingredients is very important in terms of encapsulation strategy and the nature of resultant nanostructures. Size, morphology, surface charge, chemical structure, and composition are characteristic features determining encapsulation efficiency, stability, release profile, and bioaccessibility of nanoencapsulated food ingredients. A number of spectroscopic and chromatographic tools are available to analyze nanoencapsulated nutraceuticals efficiently. UV/Vis spectroscopy successively determines the loading capacity, entrapment efficiency, and stability of nanoencapsulated bioactives. High performance liquid chromatography (HPLC) is an accomplished technique to determine concentration, stability,...

Safety and Regulatory Issues of Nanoencapsulated Food Ingredients, 2021

Nanotechnology-derived materials inserted in food products can introduce various opportunities an... more Nanotechnology-derived materials inserted in food products can introduce various opportunities and challenges as well. Nanotechnological applications in food industry can facilitate improvement of functionality, quality, and safety of food products by enhancing nutritional value, developing textural and sensorial properties, extending shelf life, detecting residual substances (e.g., pesticides), and screening pathogens Potential risks and hazards associated with the nanomaterials used in food matrices leading to health concerns might be designed out by the regulatory frameworks established with the global consensus. That expectedly provides standardization of the regulatory protocols, thus supports commercial potential of nanofood products and public perception. This chapter will review principles of current regulations launched by international organizations to clarify the mutual approaches in the assessment of nanofood safety.

Protein hydrogels have great potential for food and biomedical applications due to their ability ... more Protein hydrogels have great potential for food and biomedical applications due to their ability to create three dimensional gel networks. A dairy industry by-product whey contains valuable proteins capable of forming gels with the ability of holding excess amount of water and entrap active ingredients. This enables a wide use of whey proteins for various applications in food formulations. Whey protein gelation is commonly promoted by heat and the gel characteristics can be enhanced by blending whey proteins with suitable carbohydrates. Mechanical properties and microstructure of gel networks determine their availability for target applications such as entrapment of active agents by maintaining their stability, target delivery and texture improvement of food products. The objective of this study was to investigate structural and mechanical features of whey protein -sodium alginate gels using microscopy, spectroscopy and rheometry. Rheological and structural properties of gels obtain...

Akademik Gıda, 2021

Collagen is a structural protein found naturally in high amounts in poultry skin and bones. Gelat... more Collagen is a structural protein found naturally in high amounts in poultry skin and bones. Gelatin is obtained by a partial hydrolysis of collagen under controlled conditions. It is a pure protein with many functional and technological properties such as gelation, thickening, film-forming and emulsification. Besides skin and bones, mechanically deboned meat (MDM) residues are considered good sources of collagen as well. This study aimed to extract collagen and gelatin from poultry skin and MDM residues of neck, shinbone, breastbone, wingtip, shanks, upper/lower backbone and their mixture through pre-treatment (using with dilute alkali and acid), demineralization, degreasing and thermal extraction processes, and evaluate their properties comparatively. Based on Kjeldahl analysis, the protein content of poultry skin was about 15% and that of the MDM residues varied between 15-21% before the extraction process. The SDS-PAGE profiles of the extracted collagen in skin and MDM residues comprised γ, β, α, and sub-α chain protein units. Collagen solution of the upper backbone and mixed MDM residues had the highest protein content with 11.98 mg/mL and 11.33 mg/mL, respectively. The extraction yield of collagen and gelatin significantly differred (p˂0.05) within the range between 1.32 and 2.16%, and 1.03 and 1.89%, respectively. The viscosity of collagen/gelatin solutions decreased with an increase in shear rate and gelatin obtained from mix MDM residues indicated higher viscosity than that of skin. Results of this study showed successful recovery of collagen and gelatin from poultry processing by-products and residues, which could contribute to the production of high value-added alternative sources for various applications.

Alpha-lactalbumin (α-la) is one of the major proteins in whey. When partially hydrolysed with Bac... more Alpha-lactalbumin (α-la) is one of the major proteins in whey. When partially hydrolysed with Bacillus licheniformis protease, it produces nanotubular structures in the presence of calcium ions by a self-assembly process. This study presents investigation of α-la protein structure during hydrolysis and nanotube formation using optical spectroscopy. Before spectroscopic measurements, nanotubes were examined with microscopy. The observed α-la nanotubes (α-LaNTs) were in the form of regular hollow strands with a diameter of about 20 nm and the average length of 1 μm. Amide and backbone vibration bands of the Raman spectra displayed remarkable conformational changes in α and β domains in the protein structure during nanotube growth. This was confirmed by the Fouriertransform infrared (FTIR) spectroscopy data. Also, FTIR analysis revealed certain bands at calcium (Ca ++ ) binding sites of COO groups in hydrolysed protein. These sites might be critical in nanotube elongation.

International Journal of Biological Macromolecules, 2021

Phycocyanins (PCYs) are a group of luxuriant bioactive compounds found in blue-green algae with a... more Phycocyanins (PCYs) are a group of luxuriant bioactive compounds found in blue-green algae with an estimated global market of about US$250 million within this decade. The multifarious markets of PCYs noted by form (e.g. powder or aqueous forms), by grade (e.g. analytical, cosmetic, or food grades), and by application (such as biomedical, diagnostics, beverages, foods, nutraceuticals and pharmaceuticals), show that the importance of PCYs cannot be undermined. In this comprehensive study, an overview on PCY, its structure, and health-promoting features are diligently discussed. Methods of purification including chromatography, ammonium sulfate precipitation and membrane filtration, as well as characterization and measurement of PCYs are described. PCYs could have many applications in food colorants, fluorescent markers, nanotechnology, nutraceutical and pharmaceutical industries. It is concluded that PCYs offer significant potentials, although more investigations regarding its purity and safety are encouraged.

Critical Reviews in Food Science and Nutrition, 2021

To date, there exists a debate on the effect of milk added to coffee infusions/beverages concerni... more To date, there exists a debate on the effect of milk added to coffee infusions/beverages concerning the nutritional quality of coffee and the functional properties of its phenolic compounds. Yet, the full nutritional quality and functional properties of a coffee beverage without a significant negative impact on its sensorial profile are highly desired by the consumers. Negative/masking, positive, and neutral effects of milk on the antioxidant activity and bioavailability of coffee phenolics (particularly, chlorogenic acids) have been reported. Some potential factors including the type and amount of milk added, type of coffee beverage, the composition of both milk (protein and fat) and coffee (phenolic compounds), preparation method, assays used to measure antioxidant properties, and sampling size may account for the various reported findings. Interactions between phenolic compounds in coffee and milk proteins could account as the main responsible aspect for the reported masking/negative impact of milk on the antioxidant activity and bioaccessibility/bioavailability of coffee bioactives. However, considering the interactions between milk components and coffee phenolics, which result in the loss of their functionality, the role of milk fat globules and the milk fat globule membrane can also be crucial, but this has not been addressed in the literature so far.HighlightsIn most cases, milk is added to the coffee beverages in several various ways.Effect of milk on the nutritional/functional properties of coffee is controversial.Enough evidence suggests negative effects of milk addition on properties of coffee.Interactions of coffee phenolics and milk proteins could account as the main aspect.The role of milk fat globules and milk fat globule membrane may also be crucial.

Biotechnology Progress, 2021

Partial hydrolysis of whey‐based α‐lactalbumin (α‐La) with Bacillus licheniformis protease (BLP) ... more Partial hydrolysis of whey‐based α‐lactalbumin (α‐La) with Bacillus licheniformis protease (BLP) induces the formation of nanotubular structures in the presence of calcium ions by a self‐assembly process. α‐La nanotubes (α‐LaNTs) exist in the form of regular hollow strands with well‐defined average dimensions. The growth of nanotubes induces the formation of stiff transparent protein gels due to the well‐arranged networks that the strands can form; these gels can be used for entrapment, transportation, and target delivery of bioactive agents in the industry. High purity of α‐La (free of other whey protein fractions) is desirable for nanotube formation; however, pure proteins are very expensive and not practically obtained for industrial applications. Thus, the purpose of this research was to construct α‐LaNTs from an α‐La preparation with lower purity and to study the gelation phenomena triggered by the self‐assembled nanotubes. Some structural features of nanotube gels and their active agent‐binding abilities were also investigated. A lower amount of α‐LaNTs was observed when low purity α‐La was used for nanotube formation. Nanotube growth induced gel formation and higher gel stiffness was obtained when compared to α‐La hydrolysates. α‐La was denatured after hydrolysis and self‐assembly, and remarkable changes were observed in the α‐helix and β‐sheet domains of α‐La structure. Increased intensity in Amide I and II regions indicated potential locations for binding of active agents to α‐LaNTs. Whey‐based α‐La without much purification can be used to produce nanotubular gels and these gels can be considered carrying matrices for active agents in various industrial applications.

Colloids and Surfaces B: Biointerfaces, 2021

Nanostructured emulsions have a significant potential for encasing, transport and delivery of hyd... more Nanostructured emulsions have a significant potential for encasing, transport and delivery of hydrophilic and lipophilic nutraceuticals and other bioactive compounds by providing enhanced stability and functionality in food and pharmaceutical applications. As highlighted in recent researches, essential fatty acids (EFA) and oils (EO), antioxidants, vitamins, minerals, pro and prebiotics, and co-enzymes, are common bioactives encapsulated in nanoscale delivery systems in order to protect them from degradation during processing and storage, and to improve bioavailability after their consumption. Nanoemulsions (NEs) as delivery systems for nutraceuticals comprise either oil-in-water (O/W) or water-in-oil (W/O) biphasic dispersion with nano-sized droplets, which are stabilized through an active surfactant. Both high- and low- energy methods are used to produce well-structured and stable NEs with advanced structural and rheological features. The in vitro and in vivo studies are focused to assess the nutraceutical releasing profile, gastrointestinal transportation and cytotoxicity of nutraceutical loaded NE. Within the last three decades, a number of NE systems have been developed for certain purposes and submitted for patent approval. Currently, there are many issued patents published as well as and applications under process. This review focus on the current status of food-grade NEs in terms of formation, characterization, relevant applications of nutraceutical delivery, and the recent developments including patented systems.

Akademik Gıda, 2020

Poultry eggs are highly important in human nutrition due to their content of essential amino acid... more Poultry eggs are highly important in human nutrition due to their content of essential amino acids, vitamins, minerals, and enzymes. Eggs of edible poultries such as hen, turkey, quail, and goose may have some differences in their nutritional composition. Various heat treatments applied before consumption lead to some alterations in their nutrients, especially proteins. The purpose of this study was to investigate compositional and structural changes in the protein fractions of hen, quail, turkey, and goose eggs when exposed to soft-and hard-boiling (11-16 min and 18-19 min), and frying (2-7 min). Electrophoresis and spectroscopy were used to determine the effects of these heat treatments on egg white and yolk proteins separately. It was observed that the heat degradation of proteins in egg white was higher than that in egg yolk. As expected, protein degradation was increased when heat exposure was extended. Hard-boiling treatment completely denatured egg white proteins almost in all poultry species. Ovomucoid was the most resistant fraction against heat denaturation in white proteins, while livetins in yolk. Soft-boiling under the given conditions resulted in mostly retained profiles of proteins in egg yolk of all species. Relevant to protein degradation, remarkable structural changes were detected in the protein secondary structure of hard-boiled and fried egg samples. Significant data obtained in this research revealed the influence of heat treatment on the protein content of edible eggs. Those findings are expected to help in developing the processes and consumption methods of egg products for dietary purposes and improvement of human health.

Mugla Journal of Science and Technology, 2020

Electrospun nanofibers with their large surface area, high porosity, small pore sizes, and abilit... more Electrospun nanofibers with their large surface area, high porosity, small pore sizes, and ability of the high loading of active agents possess many structural and functional advantages for food applications. Proteins play significant roles in physicochemical and structural properties in foods. There has been a great interest in using proteins for the fabrication of nanofibers through electrospinning technique. Due to their molecular weight, most of the proteins are non-spinnable alone however; their spinnability can be enhanced by the incorporation of food-grade biocompatible polymers. In this review, the basics of the electrospinning technique were introduced first, followed by detailed information about electrospun nanofibers formed using plant and animal proteins. Common polymers blended with proteins to enhance their spinnability were also discussed. It the last part, the use of electrospun nanofibers in various food applications such as encapsulation of bioactive components, enzyme immobilization, and food packaging was emphasized.