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Ipek Bayram

Member of The Honor Society of Phi Kappa Phi
From Ankara, Turkey
Ipek Bayram is currently a part-time university lecturer in Food Engineering department at Middle East Technical University in Ankara, Turkey. She completed her Doctor of Philosophy (Ph.D.) degree in Food Science at the University of Massachusetts Amherst in 2023, supervised by Dr. Eric A. Decker. Her research interests are food chemistry, lipid chemistry, lipid oxidation, antioxidants, bioactive lipids, emulsions, and chromatographic methods. She became a member of several international organizations, including IFT, NEIFT, AOCS, ACS, and IAFP. She was honored with various awards, fellowships, and travel grants, notably the Fulbright Doctoral Fellowship, IFT Feeding Tomorrow Scholarship, NEIFT Graduate Scholarship, AOCS Manuchehr (Manny) Eijadi Award, AOCS Honored Student Award, AOCS Student Travel Grant, Manley Graduate Scholarship, and Love of Learning Award. Her research findings were published in prestigious journals like Trends in Food Science & Technology, Food Hydrocolloids, Food Chemistry, Food Research International and the Journal of Agricultural and Food Chemistry. Beyond her laboratory commitments, she played a vital role in co-founding the UMass Fulbright Association, fostering connections among Fulbright scholars. She also participated actively in the American Oil Chemists' Society (AOCS), contributing to educational and career development initiatives through the AOCS Student Common Interest Group (SCIG), serving as session chair at the 2023 AOCS Annual Meeting & Expo, and serving as a judge on the Edwin N. Frankel Best Paper Award Committee as a member of the Lipid Oxidation Division.
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University of Massachusetts Amherst
Middle East Technical University

The Honor Society of Phi Kappa Phi

Ipek Bayram Receives 2022 Phi Kappa Phi Love of Learning Award

Ipek Bayram of Amherst, Massachusetts, was recently awarded a Love of Learning Award worth $500 from The Honor Society of Phi Kappa Phi, the nation's oldest and most selective collegiate honor soci...

October, 06 2022 - Verified by The Honor Society of Phi Kappa Phi
Ipek Bayram Inducted into The Honor Society of Phi Kappa Phi

Ipek Bayram of Amherst, Massachusetts, was recently initiated into The Honor Society of Phi Kappa Phi, the nation's oldest and most selective all-discipline collegiate honor society. Bayram was in...

April, 05 2022 - Verified by The Honor Society of Phi Kappa Phi
Ipek Bayram was recognized for enrolling
Inducted into Phi Kappa Phi due to academic achievements
Spring 2022 - Added by Ipek
Ipek Bayram was recognized for enrolling
Completed coursework with 4.00 GPA
Fall 2019 - Spring 2020 - Added by Ipek
Ipek Bayram was recognized for graduating
Ranked 3rd in graduation
Spring 2018 - Added by Ipek
Ipek Bayram was recognized for earning a spot on an honors list
Received 6 high honor student certificates by having 4.00/4.00 GPA for five consecutive semesters
Spring 2017 - Spring 2019 - Added by Ipek
Ipek Bayram was recognized for earning a spot on an honors list
Received 4 honor student certificates for outstanding GPA
Spring 2015 - Fall 2016 - Added by Ipek
Ipek Bayram was recognized for earning an academic award
University of Massachusetts Amherst 2023 Hultin Competition Award: Awarded 450$ from UMass Amherst with presentation Mechanisms of -tocopherol and myricetin antioxidant synergism in stripped soybean oil in-water emulsions as a function of pH
Added by Ipek
Ipek Bayram was recognized for earning an academic award
Awarded by Middle East Technical University, Scientific Research Funds (GAP-314-2020-10233), the highest grant award for the research "Development of pea flour based active films produced through different homogenization methods and their effects on lipid oxidation"
Added by Ipek
Ipek Bayram was recognized for earning an academic award
Fulbright Doctoral Scholarship (Awarded a very prestigious worldwide scholarship (100,000$) from Fulbright Program to cover Ph.D. tuition fees, health insurance and monthly stipends)
Added by Ipek
Ipek Bayram was recognized for earning a scholarship
NIH SF 424 (R&R) Grant CNS Fellowship: Awarded a 56,000$ grant from College of Natural Sciences (CNS) at University of Massachusetts Amherst to cover monthly stipends during two academic years
Added by Ipek
Ipek Bayram was recognized for earning an academic award
Awarded a 1000$ travel grant from American Oil Chemists Society (AOCS) to present dissertation research in 2022 AOCS Annual Meeting & Expo https://www.lipidsfatsoilssurfactantsohmy.com/2022/03/spotlight-on-ipek-bayram-recipient-of.html
Added by Ipek
Ipek Bayram was recognized for earning an academic award
Love of Learning Award (Awarded a 500$ scholarship based on academic record and life/career ambitions)
Added by Ipek
Ipek Bayram was recognized for earning a scholarship
Awarded IFT Feeding Tomorrow - Institute for Thermal Processing Specialists PhD Degree Award (2000$) based on academic record, leadership and participation in school and community activities, and commitment to the science of food
Added by Ipek
Ipek Bayram was recognized for earning an academic award
Awarded a 200$ award and free membership from American Oil Chemists Society (AOCS) Lipid Oxidation and Quality (LOQ) Division as a first-place winner with presentation Determination of antioxidant synergism between tocopherols and myricetin in bulk oil
Added by Ipek
Ipek Bayram was recognized for earning a scholarship
Awarded a 1750$ graduate scholarship from Northeastern Section of Institute of Food Technologists (NEIFT) based on academic success, achievements, and dedication to food science career
Added by Ipek
Ipek Bayram was recognized for earning an academic award
Manley Graduate Scholarship: Awarded a 2000$ scholarship based on academic record, research excellence and participation in school and community leadership activities
Added by Ipek
Ipek Bayram was recognized for earning an academic award
AOCS-2023 Manuchehr (Manny) Eijadi Award: Awarded 1000$ based on successful graduate-level research
Added by Ipek
Ipek Bayram was recognized for earning an academic award
2023 AOCS Honored Student Award: The award consists of travel allowance and lodging, a complimentary AOCS Annual Meeting registration, and an award lecture as part of the 2023 AOCS Annual Meeting & Expo in Denver, CO from April 30 to May 3, 2023.
Added by Ipek
Judge in Edwin N. Frankel Award Committee
Reviewed Lipid Oxidation and Quality papers from AOCS magazine and evaluated/recommended them for best paper award
Fall 2022 - Spring 2024 - University of Massachusetts Amherst
Added by Ipek
Lipid Oxidation and Quality Division Session Chair at the 2023 AOCS Annual Meeting
Planned the format and course of the session Contacted industry, academia, and government professionals for presentations Reviewed all submitted abstracts and made decisions to reject/accept them Moderated a live presentation session during the 2023 Annual Meeting
Summer 2022 - Spring 2023 - University of Massachusetts Amherst
Added by Ipek
AOCS Student Common Interest Group (SCIG)
Assisted in the planning of SCIGs activities during the 2023 AOCS Annual Meeting and throughout the year Contributed to the SCIGs newsletter Equipped soon-to-be-graduates with resources for getting a job in industry, academia, and government https://www.aocs.org/network-and-connect/membership/common-interest-groups/student-common-interest-group?SSO=True
Summer 2022 - Spring 2023 - University of Massachusetts Amherst
Added by Ipek
UMass Fulbright Association
Co-founder and President of UMass Fulbright Association Founded a graduate student organization (GSO) at UMass Amherst for International Fulbright Scholars to engage in meaningful cultural experience along with seeking for help or advice from their peers Planned in-person and virtual events for new Fulbright scholars to enhance networking Mentored peers in adjusting to the new realities of campus life and research restrictions during time of COVID-19 Prepared budgets for annual organization expenses https://www.facebook.com/groups/585756455490104
Winter 2020 - Spring 2022 - University of Massachusetts Amherst
Added by Ipek
Ankara Volunteers Team
Volunteer Tutor in Ankara Volunteers Team Mentored and tutored underprivileged elementary and high school students voluntarily in chemistry, physics and biology as a member of undergraduate student organization Mentored student became 1st in high-school entry exam (out of 70000 students)
Fall 2014 - Spring 2015 - Middle East Technical University
Added by Ipek
University Lecturer at Middle East Technical University, Ankara, Turkey

Courses:
FDE 313 - Food Chemistry (4-0)
FDE 428 - Food and Health (3-0)
FDE 416 - Food Engineering Operations Lab. (3-0)

September 2024 - Present
Postdoctoral Research Associate at University of Massachusetts Amherst

Research focused on lipid chemistry, particularly on lipid oxidation, shelf-life estimation, and toxicity of oxidized lipids
Collaborated with Dr. Jiakai Lu (at University of Massachusetts Amherst) to estimate the shelf-life of different oils by creating a computational model based on decrease in tocopherol concentration and DPPH/ABTS inhibition (USDA-NIFA AFRI Proposal Number: 2021-09399)
Collaborated with Dr. Hang Xiao (at University of Massachusetts Amherst) to estimate the toxicity of commercial oils at different stages of lipid oxidation based on formation of colon cancer and change in gut microbiome (USDA-NIFA AFRI Proposal Number: 2021-09399)
Collaborated with Dr. Guodong Zhang (at University of California Davis) to determine the formation of different oxylipins (such as alcohols, ketones, and epoxides) in commercial bulk oils during the process of lipid oxidation (USDA-NIFA AFRI Proposal Number: 2021-09399)
Collaborated with a company to investigate the oxidative stability of pea protein-based DHA-enriched commercial plant-based milks and use mathematical modeling to estimate shelf-life
Published research articles in well-known journals and mentored many Masters, and Ph.D. students/scholars on basics of lipid oxidation, antioxidants, laboratory equipments and designing experiments

August 2023 - August 2024
Research Assistant at University of Massachusetts Amherst

Research focused on food chemistry, particularly on lipid oxidation and antioxidant synergism
Demonstrated the synergistic antioxidant activity between tocopherols and myricetin in bulk oil and emulsions to improve shelf-life, and investigated the underlying mechanisms of synergism
Demonstrated the synergistic antioxidant interaction between tocopherols and enzymatically modified lecithin (with high phosphatidylethanolamine content) in bulk oil and emulsions to prolong shelf-life
Developed GC and HPLC methods to analyze lipid oxidation products and antioxidant degradation kinetics of various antioxidants in relation to fatty acid oxidation rates
Utilized methods to analyze different mechanisms behind synergistic antioxidant activity
Utilized protocols to measure metal chelating activity to screen and test multiple antioxidants for potential synergistic activity
Participated in research focusing on the impact of surfactant micelles on tocopherol partitioning and lipid oxidation in oil-in-water emulsions
Participated in research focusing on the antioxidant activity of acid hydrolyzed parsley and sugar beet extracts in oil-in-water emulsions
Participated in research focusing on the lipid extraction from different algae species, and performed the oxidative stability analyses in food emulsions
Participated in a USDA project to compile a nutritional database based on meat yield and conducted moisture content and fat content analyses
Led an international collaborative project and published articles with Dr. Yanxiang Gao (at China Agricultural University) to develop novel systems for curcumin and beta-carotene delivery by fabricating protein and surfactant complexes in emulsions
Published research articles in well-known journals, and participated in preparing and writing articles for scientific magazines and websites

June 2022 - August 2023
Teaching Assistant at University of Massachusetts Amherst

Teaching assistant for a general Food Chemistry Laboratory course (40 students)
Prepared eight different undergraduate level food chemistry experiments
Supervised students with using laboratory equipments and learning experimental procedures

September 2019 - January 2020
Intern at Anadolu Efes Biracilik ve Malt Sanayii A.S. (AEFES)

Investigated production lines and processes
Assessed beer quality (iodine value, degree of fermentation, filterability, pH measurement, turbidity, color, carbon dioxide, and foam analysis)
Prepared a detailed report for production process, operating conditions, raw materials, product capacity, quality control tests and mass/energy balances

August 2018 - September 2018
Intern at Uelker Biskuvi Sanayi A.S. (ULKER)

Investigated production lines and processes
Assessed biscuit/cracker quality (free fatty acid analysis, peroxide formation, moisture content, pH analysis, antibiotic test in milk, melting analysis for baby biscuits, coliform, and E. coli test in drinking water)
Participated in a project to enhance the oven efficiency during baking process
Prepared a detailed report for process descriptions, operating conditions, raw materials, product capacity, quality control tests and mass/energy balances

August 2017 - September 2017
Advancing microalgal applications: Process optimization and functional integration of lyophilized Spirulina biomass in formation of protein-enriched cheddar-type cheese
Spirulina is a well-known food supplement renowned for its high protein content, bioactive compounds, and enzymes that are pivotal in its metabolic processes. This study explores the potential of Spirulina as a sustainable alternative to animal rennet, proposing it as a vegetarian functional ingredient in cheddar-type cheese production. The research utilized response surface methodology (RSM) to optimize the incorporation of lyophilized Spirulina biomass, focusing on maximizing protein content and antioxidant potential. The optimized process resulted in cheese yields ranging from 1.96 % to 6.01 % and protein contents between 14.29 % and 39.21 %. We identified and standardized conditions for achieving these optimal outcomes. Analysis of milk clotting activity (MCA) and proteolytic activity (PA) showed pH and temperature-dependent variations, with traditional rennet and acetic acid cheeses demonstrating superior MCA. In contrast, Spirulina-enriched cheeses exhibited enhanced antioxidant activity (20.69 % to 37.66 %), improved protein retention, and lower fat content, attributed to its inherent bioactive compounds. Fourier-transform infrared (FTIR) and Raman spectroscopy provided insights into the molecular composition and structural changes during storage, highlighting the distinctive properties of Spirulina-derived cheese. This study underscores the viability of integrating Spirulina biomass into cheese production, offering a pathway to create nutritious, antioxidant-rich products with elevated protein content and functional benefits.
December 2024 - Articles
A strategy to minimize the chlorophyll content in the phenolic extract of sugar beet leaves: Can this extract work as a natural antioxidant in vegetable oils?
The presence of chlorophylls in phenolic extracts may limit their use in food products due to undesirable coloration. This project seeks to minimize the co-extraction of chlorophylls during the ultrasonic-assisted extraction (UAE) of polyphenols from sugar beet leaves (SBLs) by optimizing the extraction condition using response surface methodology (RSM). Optimization aimed to minimize the chlorophyll yield (CY) of the extraction while maximizing the total phenolic content (TPC) and total flavonoid content (TFC) with the lowest possible amount of sample. Optimized extraction parameters were 25% ethanol as solvent, 8 min extraction time, and 3.98% (w/v) solid:liquid ratio. The experimental values at optimized condition were 11.49 ± 0.66 mmol gallic acid equivalent (GAE)/L TPC, 2.09 ± 0.06 mmol quercetin equivalent/L TFC, and 0.05 ± 0.01 mg/g CY. In the optimized extract, the ferric reducing antioxidant power (FRAP) was 3.16 ± 0.25 mmol trolox equivalent/L, and trans-ferulic acid had the highest concentration (123.39 ± 4.13 µmol/L) among the detected phenolic compounds. The optimized extract, at a phenolic concentration of 300 µmol GAE/L, chelated cupric and ferrous ions by 48.95 ± 1.06%, and 66.18 ± 1.31%, respectively. Adding the optimized extract to vegetable oils increased their oxidative stability significantly (p < 0.05). The antioxidant activity index of the optimized extract in all the cases was comparable to butylated hydroxytoluene (BHT), confirming that the obtained extract could be a reliable substitute for synthetic antioxidants. The results of this study are important in enhancing the utilization of extracts recovered from food by-products in the food industry.
September 2024 - Articles
A machine learning-guided modeling approach to the kinetics of α-tocopherol and myricetin synergism in bulk oil oxidation
The shelf-life and quality of food products depend heavily on antioxidants, which protect lipids from free radical degradation. α-Tocopherol and myricetin, two potent antioxidants, synergistically enhance the prevention of oxidative rancidity in bulk oil systems. Understanding their degradation kinetics is essential for deepening our knowledge of their mechanisms and developing strategies to predict shelf-life before expiration. This paper introduces a generalized mathematical model to describe the degradation kinetics of α-tocopherol in the presence of myricetin. Using direct differential methods guided by a machine learning approach based on neural differential equations, we uncover two distinct phases of α-tocopherol degradation when coexisting with myricetin at varying concentration ratios. These findings inform the development of a mixed Weibull model that accurately captures the degradation process. Our study enhances the understanding of antioxidant interactions and provides a reliable method for predicting food system stability, offering valuable insights for optimizing natural antioxidants in food preservation.
September 2024 - Articles
Oxidized polyunsaturated fatty acid promotes colitis and colitis-associated tumorigenesis in mice
Human studies suggest that a high intake of polyunsaturated fatty acid (PUFA) is associated with an increased risk of inflammatory bowel disease (IBD). PUFA is highly prone to oxidation. To date, it is unclear whether unoxidized or oxidized PUFA is involved in the development of IBD. Here, we aim to compare the effects of unoxidized PUFA vs oxidized PUFA on the development of IBD and associated colorectal cancer. We evaluated the effects of unoxidized and oxidized PUFA on dextran sodium sulfate (DSS)-induced and IL-10 knockout-induced colitis, and azoxymethane/DSS-induced colon tumorigenesis in mice. Additionally, we studied the roles of gut microbiota and Toll-like receptor 4 (TLR4) signaling involved. Administration of a diet containing oxidized PUFA, at human consumption-relevant levels, increases the severity of colitis and exacerbates the development of colitis-associated colon tumorigenesis in mice. Conversely, a diet rich in unoxidized PUFA does not promote colitis. Furthermore, oxidized PUFA worsens colitis-associated intestinal barrier dysfunction and leads to increased bacterial translocation, and it fails to promote colitis in TLR4 knockout mice. Finally, oxidized PUFA alters the diversity and composition of gut microbiota, and it fails to promote colitis in mice lacking the microbiota. These results support that oxidized PUFA promotes the development of colitis and associated tumorigenesis in mouse models via TLR4- and gut microbiota-dependent mechanisms. Our findings highlight the potential need to update regulation policies and industrial standards for oxidized PUFA levels in food.
September 2024 - Articles
Antioxidant and prooxidant activity of acid-hydrolyzed phenolic extracts of sugar beet leaves in oil-in-water emulsions
This study aimed to enhance the oxidative stability of soybean oil-in-water emulsions using acid-hydrolyzed and unhydrolyzed extracts obtained from sugar beet leaves. The optimum extraction process, which includes 8 min of ultrasonication followed by a 2-h acid hydrolysis, released new phenolics (e.g., catechin, myricetin, etc.) and increased the total phenolic content (TPC) from 586.24 ± 11.45 to 982.42 ± 6.61 μmol gallic acid equivalent (GAE)/L, and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical inhibition from 46.63 ± 1.39 to 60.87 ± 1.12%. Acid hydrolysis increased the cupric chelating activity of the extracts while decreasing ferrous chelating activity and trans-ferulic acid concentration significantly (p < 0.05). The acid-hydrolyzed extract at a TPC of 100 μmol GAE/L prolonged the lag phase of hexanal accumulation in the emulsion from 0 to 8 days, while 400 μmol GAE/L TPC of unhydrolyzed extract increased the lag phase to 12 days. The results show that acid-hydrolyzed extracts in high concentrations may act as prooxidants.
August 2024 - Articles
Acid-hydrolyzed phenolic extract of parsley (Petroselinum crispum L.) leaves inhibits lipid oxidation in soybean oil-in-water emulsions
The antioxidant activity of the natural phenolic extracts is limited in particular food systems due to the existence of phenolic compounds in glycoside form. Acid hydrolysis post-treatment could be a tool to convert the glycosidic polyphenols in the extracts to aglycones. Therefore, this research investigated the effects of an acid hydrolysis post-treatment on the composition and antioxidant activity of parsley extracts obtained by an ultrasound-assisted extraction method to delay lipid oxidation in a real food system (i.e., soybean oil-in-water emulsion). Acid hydrolysis conditions were varied to maximize total phenolic content (TPC) and 2,2-diphenyl1-picrylhydrazyl (DPPH) radical scavenging activity. When extracts were exposed to 0.6 M HCl for 2 h at 80℃, TPC was 716.92 ± 24.43 µmol gallic acid equivalent (GAE)/L, and DPPH radical scavenging activity was 66.89 ± 1.63 %. Not only did acid hydrolysis increase the concentrations of individual polyphenols, but it also resulted in the release of new phenolics such as myricetin and gallic acid. The extract’s metal chelating and ferric-reducing activity increased significantly after acid hydrolysis. In soybean oil-in-water emulsion containing a TPC of 400 µmol GAE/L, the acid-hydrolyzed extract had an 11-day lag phase for headspace hexanal compared to the 6-day lag phase of unhydrolyzed extract. The findings indicated that the conversion of glycosidic polyphenols to aglycones in phenolic extracts can help extend the shelf-life of emulsion-based foods.
May 2024 - Articles
Mathematical modeling of alpha-tocopherol early degradation kinetics to predict the shelf-life of bulk oils
The kinetics of lipid oxidation includes a lag phase followed by an exponential increase in oxidation products, which cause rancidity. Current models focus on the slope of this exponential curve for shelf-life estimation, which still requires the measurement of full oxidation kinetics. In this paper, we analyzed the formation of lipid oxidation products in stripped soybean oil containing different levels of α-tocopherol. The lag phases of lipid hydroperoxides and headspace hexanal formation were found to have a strong positive correlation with the α-tocopherol depletion time. We propose that the kinetics of antioxidant (α-tocopherol) depletion occur during the lag phase and could serve as an early shelf-life indicator. Our results showed that α-tocopherol degradation can be described by Weibull kinetics over a wide range of initial concentrations. Furthermore, we conducted in silico investigations using Monte Carlo simulations to critically evaluate the feasibility and sensitivity of the shelf-life prediction using early antioxidant degradation kinetics. Our results revealed that the shelf life of soybean oil may be accurately predicted as early as 20% of the overall shelf life. This innovative approach provides a more efficient and faster assessment of shelf life, ultimately reducing waste and enhancing product quality.
February 2024 - Articles
Analysis of antioxidant synergism and its mechanisms in different food systems
Lipid oxidation results in off-flavors, toxic aldehydes, and co-oxidation of proteins and color compounds. Combining antioxidants to achieve synergistic interactions has been practiced for decades to improve oxidative stability. Nevertheless, synergism mechanisms have been poorly understood and rarely studied. This dissertation examines the mechanisms of antioxidant synergism in a model system with α-tocopherol (α-TOC) and myricetin (MYR). The interactions between α-tocopherol and taxifolin (TAX) were also tested because it has structural similarities to myricetin but has a higher redox potential. The first part of this research focused on the antioxidant interactions between α-tocopherol and myricetin in stripped soybean oil-in-water emulsions at pH 4.0 and pH 7.0. At pH 7.0, α-tocopherol: myricetin ratios of 2:1 and 1:1 yielded interaction indices of 3.00 and 3.63 for lipid hydroperoxides, and 2.44 and 3.00 for hexanal formation, indicating synergism. Myricetin's ability to regenerate oxidized α-tocopherol and slow its degradation was identified as the synergism mechanism. At pH 4.0, an antagonistic interaction was observed, which was associated with high ferric-reducing activity of myricetin in acidic environment. α-Tocopherol and taxifolin exhibited non-synergistic effects both in acidic and neutral emulsions. This was due to taxifolin's inability to recycle α-tocopherol at both pHs, unlike myricetin, and taxifolin's high ferric-reducing activity at pH 4.0, similar to myricetin. The second part of this research focused on antioxidant interactions between α-tocopherol and myricetin in stripped soybean oil. α-Tocopherol and myricetin ratios of 5:1, 2:1, 1:1, 1:2, and 1:5 resulted in interaction indexes of 1.14, 1.50, 1.55, 1.30, and 1.16, showing synergistic activity for both lipid hydroperoxide and hexanal formation. Synergism was also observed in phospholipid-containing bulk oils, both in the absence and presence of reverse micelles. α-Tocopherol and taxifolin, however, had additive effect at all antioxidant ratios. Antioxidant degradation results showed that myricetin delayed α-tocopherol oxidation, whereas taxifolin did not. These results revealed that myricetin's lower redox potential allowed it to cause synergism through regenerating oxidized α-tocopherol rather than by decreasing oxidation by metal chelation since both myricetin and taxifolin chelated iron. Thus, this study advises combining α-tocopherol with myricetin in bulk oils and neutral oil-in-water emulsions to improve oxidative stability and reduce food waste.
November 2023 - Others
Analysis of the mechanism of antioxidant synergism between α-tocopherol and myricetin in bulk oil
α-Tocopherol (α-TOC) and myricetin (MYR) synergistically inhibit lipid oxidation in bulk oil but the mechanism underlying this effect is unknown. In this research, stripped soybean oil (SSO) was treated with α-tocopherol (50μM), myricetin (10–250μM), and their combinations. Taxifolin (TAX) was also tested because it has structural similarities to myricetin but with a higher redox potential. α-Tocopherol: myricetin ratios of 5:1, 2:1, 1:1, 1:2, and 1:5 resulted in extended lag phases ranging from 16 to 99 days, with lag phase increasing with increasing myricetin concentrations. Synergism between α-tocopherol and myricetin was also observed in phospholipid-containing bulk oils both in the absence and presence of reverse micelles, although the reverse micelles shortened the lag phases. Myricetin (redox potential=360 mV) delayed the oxidation of α-tocopherol (redox potential=500 mV) whereas taxifolin (redox potential=500 mV) did not. Both myricetin and taxifolin were able to chelate iron as determined by UV–VIS spectroscopy. These results suggested that the lower redox potential of myricetin allowed it to produce synergistic antioxidant activity potentially by regenerating oxidized α-tocopherol and through its ability to decrease oxidation by metal chelation.
November 2023 - Articles
Oxidative stability of emulsions made with self-extracted oil from euryhaline microalgae Spirulina and Scenedesmus
The fatty acid compositions and tocochromanol concentrations (α-, γ + β-, δ-tocopherol and δ-tocotrienol) of oil extracted from euryhaline microalgal strains (Spirulina subsalsa (Spi A), Scenedesmus MKB (Scnd) and Spirulina sp. (Spi B)) were analyzed. The oxidative stability of microalgae-based oil-in-water emulsions at pH 7 was also determined by measuring lipid hydroperoxide and headspace hexanal formation. The content of saturated fatty acids was highest in Spi B oil whereas n-3 linolenic and eicosapentaenoic acids were high in Spi A. No significant difference was reported in the total tocochromanol homolog contents of Spi A and Scnd oils, but it was significantly higher in Spi B oil. Tocochromanol depletion analysis revealed that δ-tocopherol and δ-tocotrienol had a slower depletion rate than other homologs and that their high content prolonged the hexanal lag phase of Spi B oil-in-water emulsions up to 21 days. The fact that Spi B had the lowest unsaturated fatty acid content and the highest tocochromanol concentration resulted in greater oxidative stability. Spi A oxidized faster than Scnd irrespective of their similar tocochromanol content which might be due to the higher amounts of unstable 18:3 and 20:5 fatty acids. These data suggest that these microalgal oils could have applications in sustainable food systems.
September 2023 - Articles
Synergistic mechanisms of interactions between myricetin or taxifolin with α-tocopherol in oil-in-water emulsions
The antioxidant interactions between α-tocopherol and myricetin in stripped soybean oil-in-water emulsions at pH 4.0 and pH 7.0 were analyzed. At pH 7.0, α-tocopherol (α-TOC):myricetin (MYR) ratios of 2:1 and 1:1 yielded interaction indices of 3.00 and 3.63 for lipid hydroperoxides and 2.44 and 3.00 for hexanal formation, indicating synergism. Myricetin’s ability to regenerate oxidized α-tocopherol and slow its degradation was identified as the synergism mechanism. Antagonism was observed at pH 4.0 due to high ferric-reducing activity of myricetin in acidic environment. The interaction between α-tocopherol and taxifolin (TAX) was also investigated due to structural similarities of myricetin and taxifolin. α-Tocopherol and taxifolin combinations exhibited antagonism at both pH 4.0 and pH 7.0. This was associated with taxifolin’s inability to recycle α-tocopherol while still increasing the prooxidant activity of iron. The combination of α-tocopherol and myricetin was found to be an excellent antioxidant strategy for oil-in-water emulsions at pH values near neutrality.
June 2023 - Articles
Underlying mechanisms of synergistic antioxidant interactions during lipid oxidation
Background: Unsaturated lipids undergo radical-initiated oxidative deterioration during lipid oxidation, which is one of the most significant food quality and waste issues. Lipid oxidation results in off-flavors, toxic aldehydes, and the co-oxidation of proteins and color compounds. Various antioxidant strategies are utilized by the food industry to reduce lipid oxidation and increase shelf-life. Combining antioxidants to achieve synergistic interactions has been practiced for decades to improve oxidative stability. Nevertheless, underlying mechanisms of synergistic interactions between antioxidants are poorly understood and rarely studied. Scope and approach: This review examines the main hypothesized mechanisms of antioxidant synergism, which include: 1) Regeneration of an oxidized antioxidant by another compound, 2) Differences in antioxidant partitioning in homogeneous and heterogeneous systems, 3) Combination of free radical scavenging and metal chelating activities to provide two distinct protection pathways, and 4) Formation of additional antioxidant compounds, such as phenolics, dimers, or adducts, upon oxidation which can further inhibit lipid oxidation. Key findings and conclusions: In complex food systems, it is often difficult to predict which antioxidant combinations will work synergistically. Understanding the mechanisms of synergism will aid the food industry in the production of effective antioxidant mixtures to improve oxidative stability and shelf-life, as well as in the development of simple, rapid, and reliable methods for determining and evaluating synergism.
February 2023 - Articles
Enzymatic modification of lecithin for improved antioxidant activity in combination with tocopherol in emulsions and bulk oil
Industry attempts to meet consumers' clean label demands by removing synthetic antioxidants (e.g. EDTA) frequently result in deleterious effects on oil quality, causing the formation of toxic oxidation derivatives as well as off-flavors and aromas. Thus, there is an urgent need for novel and natural antioxidant systems. For example, after becoming oxidized, α-tocopherol can be recharged to its active form by phosphatidylethanolamine (PE) for increased efficacy. Unfortunately, plant-based lecithin is mostly phosphatidylcholine (PC), which lacks the amine group necessary to recharge tocopherol. Purified phospholipids are typically too expensive for food products, however enzymatic conversion of PC to PE is more cost effective.The aims of the present study are 1) to determine the optimal reaction conditions for converting high PC lecithin into modified high PE lecithin (MHPEL) and 2) to validate the MHPEL's synergism with tocopherol in delaying lipid oxidation in model emulsion systems at pH 7, and 4, and in bulk oil. High PC lecithin was incubated with phospholipase D from Streptomyces chromofuscus and ethanolamine at varied pH, temperature, and time and then analyzed for compositional changes by HPLC. To assess shelf life, aliquots of 1% o/w emulsions buffered to pH 7 and 4 as well as bulk oil were prepared and stored at 32 and 55°C, respectively. Treatment groups included control, MHPEL, purified PE standard, tocopherol, tocopherol + MHPEL, and tocopherol + purified PE standard. Lipid hydroperoxide formation was measured spectrophotometrically, and hexanal formation was measured using GC headspace analysis. Maximum conversion occurred at pH 9 and 37°C, reaching >73% PE after 4 hours. The combination of MHPEL and tocopherol increased shelf-life by 75% compared to tocopherol alone in o/w emulsions at pH 7, 50% in o/w emulsions at pH 4, and 100% in bulk oil. This approach represents an exciting and clean-label antioxidant system with commercialization potential.
October 2022 - Conferences
Enzymatic modification of lecithin for improved antioxidant activity in combination with tocopherol in emulsions and bulk oil
Oxidized α-tocopherol can be regenerated by phosphatidylethanolamine (PE), but current commercial sources of PE are too expensive for use as a food additive. The present study aims to determine the optimal reaction conditions for generating high PE lecithin (MHPEL) enzymatically and to validate the MHPEL’s synergism with tocopherol in delaying lipid oxidation in an oil-in-water emulsion system at pH 7 and 4 and in bulk oil. Under optimal conditions of pH 9.0, 37 °C and 4 h, a MHPEL with ∼71.6% PE was obtained from 96% phosphatidylcholine lecithin using phospholipase D from Streptomyces chromofuscus. Mixed tocopherols (300 μmol/kg oil) and MHPEL (1500 μmol/kg oil) synergistically increased both the hydroperoxide and hexanal lag phase of lipid oxidation in stripped soybean oil-in-water emulsions at pH 7 by 3 days. At pH 4, this combination increased the hydroperoxide and hexanal lag phases by 3 and 2 days, respectively. The combination of 50 μmol/kg oil α-tocopherol and 1000 μmol/kg oil MHPEL also synergistically increased the hydroperoxide (5 days) and hexanal (4 days) lag phases in stripped bulk soybean oil. This approach represents a potential clean-label antioxidant system that could have commercial applications to decrease food waste.
October 2022 - Articles
Determination of antioxidant synergism between tocopherols and myricetin in bulk oil
Lipid oxidation is a series of reactions affecting food quality and shelf life since it impacts flavor, color, and nutrition. The food industry utilizes different antioxidants to retard oxidation. Interaction between antioxidants can improve the ability of the industry to protect foods if the antioxidant combination is synergistic. This research aims to determine the conditions where tocopherols and myricetin exhibit synergistic activity in bulk oils. Soybean oil was stripped to remove present endogenous antioxidants to better understand tocopherol-myricetin interaction. The oxidative stability of the oil was determined by spectroscopically measuring lipid hydroperoxides and monitoring aldehyde formation by gas chromatography. Antioxidant degradation was determined by HPLC. α or mixed tocopherols (50 µM), myricetin (10, 25, 50, 100, 250 µM), and their combinations were added to stripped oil to determine how antioxidant ratios impacted synergism. The interaction index is the ratio of the observed lag phase to the expected lag phase of the antioxidant combination. Interaction indexes were 1.14, 1.50, 1.55, 1.30, and 1.16 when tocopherol: myricetin ratio was 5:1, 2:1, 1:1, 1:2, and 1:5, respectively, implicating synergistic activity (interaction index >1). Synergism was greatest when antioxidant concentrations were similar. Tocopherol and myricetin degraded at different rates, suggesting that synergism could be due to either regeneration of one antioxidant by another or preferential oxidation of one antioxidant followed by another. Tocopherols were found to be completely degraded just before the oxidation of fatty acids. Synergism could also occur by chelating properties of myricetin, which could decrease the tocopherol loss.
October 2022 - Conferences
Modeling the kinetics of tocopherol degradation during the lag phase to predict shelf-life
September 2022 - Conferences
Food lipid oxidation and health
This blog post discusses the factors affecting lipid oxidation, main consequences of oxidation reactions, the impacts of lipid oxidation in biological tissues, potentially toxic lipid oxidation products and ways to avoid the toxic effects of oxidized lipids.
January 2022 - Articles
Improvement of stability and bioaccessibility of β-carotene by curcumin in pea protein isolate-based complexes-stabilized emulsions: Effect of protein complexation by pectin and small molecular surfactants
The impact of different complexes on the properties of β-carotene-loaded emulsions was investigated by measuring the droplet size, encapsulation efficiency, droplet morphology, and physical stability. The photo and thermal stability of β-carotene and its bioaccessibility during digestion were also analyzed. Comparing to the emulsions stabilized by other complexes, the emulsion stabilized by the high methoxyl pectin-rhamnolipid-pea protein isolate-curcumin (HMP-Rha-PPI-Cur) complex had the smallest droplet size (17.53 ± 0.15 μm) and the maximum encapsulation efficiency for curcumin (90.33 ± 0.03 %) and β-carotene (92.16 ± 0.01 %). The emulsion stabilized by the HMP-Rha-PPI-Cur complex exhibited better physical stability against creaming. The retention rate of β-carotene in the HMP-Rha-PPI-Cur complex-stabilized emulsion was 17.75 ± 0.02 and 33.64 ± 0.02 % after UV irradiation and thermal treatment. The HMP-Rha-PPI-Cur complex-stabilized emulsion also had a higher level of free fatty acid released (43.67 %) and higher bioaccessibility of β-carotene (32.35 ± 0.02 %).
August 2021 - Articles
Why does lipid oxidation in foods continue to be such a challenge?
Lipid reactions are extremely complex because they involve numerous prooxidants, antioxidants, and lipid substrates whose reactivity is impacted by the physical properties of complex food systems. Understanding the interactions between the factors impacting lipid oxidation reactions is key to developing novel antioxidant strategies. Synergistic antioxidant combinations represent a promising approach to decreasing oxidative rancidity if how and where they work can be better understood.
May 2021 - Articles
Ability of Sodium Dodecyl Sulfate (SDS) Micelles to Increase the Antioxidant Activity of α-Tocopherol
As emulsifiers become saturated on the surface of an emulsion droplet, any additional emulsifier migrates to the aqueous phase. Continuous phase surfactants have been shown to increase α-tocopherol efficacy, but it is unclear if this is the result of chemical or physical effects. The addition of α-tocopherol to an oil-in-water emulsion after homogenization resulted in a 70% increase of α-tocopherol in the continuous phase when sodium dodecyl sulfate (SDS) was at levels that were greater than the SDS critical micelle concentration. Conversely, when α-tocopherol was dissolved in the lipid before emulsification, continuous phase SDS concentrations did not increase. When SDS concentration led to an increase in the aqueous phase α-tocopherol, the oxidative stability of oil-in-water emulsions increased. Data indicated that the increased antioxidant activity was the result of surfactant micelles being able to decrease the prooxidant activity of α-tocopherol. Considering these results, surfactant micelles could be an important tool to increase the effectiveness of α-tocopherol.
May 2021 - Articles
Fabrication and characterization of curcumin-loaded pea protein isolate-surfactant complexes at neutral pH
The purpose of this study was to fabricate the binary complexes as novel delivery systems for curcumin (Cur) using pea protein isolate (PPI) and individual surfactants (rhamnolipid (Rha), tea saponin (TS) and ethyl lauroyl arginate hydrochloride (ELA)) by a pH-driven method. The effects of type and concentration of surfactants on the functional attributes of the complexes were investigated. The optimum mass ratio of PPI to Rha, TS, and ELA was 1:3, 1:2, and 1:5, respectively. The PPI-Cur-Rha1:3, PPI-Cur-TS1:2, and PPI-Cur-ELA1:5 complexes with the particle sizes of 176.53, 160.23 and 191.20 nm exhibited the highest encapsulation efficiencies of 93.69, 91.66, and 89.91% among different PPI to surfactant mass ratios. Both hydrogen bonds and hydrophobic effects were dominant forces for the formation of PPI-Cur-surfactant complexes. Apart from this, the electrostatic interactions also played an important role in the formation of PPI-Cur-ELA complexes. The XRD results verified that curcumin was successfully entrapped in the complex and transformed into an amorphous state. The curcumin in the PPI-Cur-Rha1:3 complex exhibited higher photo- and thermal stability. Moreover, the PPI-Cur-Rha1:3 complex possessed a controlled release of curcumin and higher acid stability in gastric juice during the in vitro digestion.
August 2020 - Articles
Development of pea flour based active films produced through different homogenization methods and their effects on lipid oxidation
The objective of this study was to investigate the effects of gallic acid incorporation and homogenization method (high-speed homogenization and ultrasonication) on the physicochemical characteristics of pea flour based active films and the activity of the films against lipid oxidation. The water vapor permeability results of the active films increased by approximately 16% with the addition of gallic acid. Furthermore, active films had higher elongation and flexibility due to the plasticizing effect of gallic acid and an increase in the free volume of the film structure. Although the phenolic content of the films prepared by ultrasonication was higher than the ones prepared by high-speed homogenization, their antioxidant activities were the same. The films were immersed in a model food, olive oil, and stored at 40 ◦C for 2 weeks. Peroxide value, TBARS, p-anisidine value, and totox analysis were carried out to test the effects of films on lipid oxidation. Active films reduced the formation of primary lipid oxidation products, hydrogen peroxides, up to 28%. In addition, the use of active films reduced totox values up to 20% as compared to control samples. Regardless of the homogenization method, gallic acid incorporation reduced olive oil oxidation significantly. Therefore, gallic acid incorporated pea flour films can be used as a packaging material to minimize the oxidation of susceptible foods.
August 2020 - Articles

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