Nancy Asen

Dr. Nancy Asen

orcid

Research Focus & Metrics

Academic Career Length

5Years (2022-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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30 October 2023 in Foods
Verified
Journal Article
Open access
PDF file
NANancy Asen
Nancy Asen
Rotimi AlukoRotimi Aluko
Rotimi Aluko
Alex MartynenkoAlex Martynenko
Alex Martynenko
AUAlphonsus C Utioh
Alphonsus C Utioh
Pankaj K BhowmikPankaj K Bhowmik
Pankaj K Bhowmik
Yellow field peas (Pisum sativum L.) hold significant value for producers, researchers, and ingredient manufacturers due to their wealthy composition of protein, starch, and micronutrients. The protein quality in peas is influenced by both intrinsic factors like amino acid composition and spatial conformations and extrinsic factors including growth and processing conditions. The existing literature substantiates that the structural modulation and optimization of functional, organoleptic, and nutritional attributes of pea proteins can be obtained through a combination of chemical, physical, and enzymatic approaches, resulting in superior protein ingredients. This review underscores recent methodologies in pea protein extraction aimed at enhancing yield and functionality for diverse food systems and also delineates existing research gaps related to mitigating off-flavor issues in pea proteins. A comprehensive examination of conventional dry and wet methods is provided, in conjunction with environmentally friendly approaches like ultrafiltration and enzyme-assisted techniques. Additionally, the innovative application of hydrodynamic cavitation technology in protein extraction is explored, focusing on its prospective role in flavor amelioration. This overview offers a nuanced understanding of the advancements in pea protein extraction methods, catering to the interests of varied stakeholders in the field.

21 October 2022 in Frontiers in Nutrition
Verified
Journal Article
Open access
NANancy Asen
Nancy Asen
Ogadimma OkaguOgadimma Okagu
Ogadimma Okagu
CUChibuike Udenigwe
Chibuike Udenigwe
Rotimi AlukoRotimi Aluko
Rotimi Aluko
Compounds with structural similarities to the neurotransmitter (acetylcholine) are mostly used to inhibit the activity of acetylcholinesterase (AChE) in Alzheimer’s disease (AD) therapy. However, the existing drugs only alleviate symptoms of moderate to mild conditions and come with side effects; hence, the search is still on for potent and safer options. In this study, High performance liquid chromatography (HPLC) fractionations of AChE-inhibitory pea protein hydrolysates obtained from alcalase, flavourzyme and pepsin digestions were carried out followed by sequence identification of the most active fractions using mass spectrometry. Subsequently, 20 novel peptide sequences identified from the active fractions were synthesized and five peptides, QSQS, LQHNA, SQSRS, ETRSQ, PQDER (IC50 = 1.53 – 1.61 μg/mL) were selected and analyzed for ability to change AChE protein conformation (fluorescence emission and circular dichroism), kinetics of enzyme inhibition, and enzyme-ligand binding configurations using molecular docking. The kinetics studies revealed different inhibition modes by the peptides with relatively low (<0.02 mM and <0.1 mM) inhibition constant and Michaelis constant, respectively, while maximum velocity was reduced. Conformational changes were confirmed by losses in fluorescence intensity and reduced α-helix content of AChE after interactions with different peptides. Molecular docking revealed binding of the peptides to both the catalytic anionic site and the peripheral anionic site. The five analyzed peptides all contained glutamine (Q) but sequences with Q in the penultimate N-terminal position (LQHNA, SQSRS, and PQDER) had stronger binding affinity. Results from the different analysis in this study confirm that the peptides obtained from enzymatic digestion of pea protein possess the potential to be used as novel AChE-inhibitory agents in AD management.

30 August 2023 in Membranes
Verified
Journal Article
Open access
PDF file
NANancy Asen
Nancy Asen
Rotimi AlukoRotimi Aluko
Rotimi Aluko
The aim of this paper was to determine the emulsification properties of protein aggregates obtained from heat pretreated yellow field pea protein concentrate (PPC). PPC dispersions were prepared in distilled water (adjusted to pH 3.0, 5.0, 7.0, or 9.0), heated in a water bath (100 °C) for 30 min, centrifuged and the supernatant passed first through a 30 kDa membrane and, then, the first retentate (>30 kDa) through a 50 kDa membrane. The 50 kDa membrane separation yielded a second retentate (>50 kDa proteins), which was isolated for emulsification studies. The near UV circular dichroic spectra of the protein samples showed more unfolded structures at pH 3.0 and 5.0 than at pH 7.0 and 9.0. The presence of small and spherical oil droplets of emulsions stabilized by the >50 kDa proteins at pH 3.0, 7.0, and 9.0 was confirmed by confocal laser scanning microscopy images. Emulsions stabilized at pH 7.0 and 9.0 had a narrower size distribution range than at pH 3.0 and 5.0. A narrow oil droplet size distribution range and lower interfacial protein concentrations of the emulsions stabilized by the >50 kDa proteins were observed at the corresponding pH of the heat treatment when compared to other pH values. Emulsions stabilized by the >50 kDa proteins exhibited a relatively low flocculation and coalescence index, which infers relative stability. The results from this work suggest that heat pretreatment of the PPC led to the formation of new protein aggregates, especially FT9 with enhanced emulsification properties, at some of the test conditions when compared to the unheated PPC.

5 October 2026 in Sustainable Food Proteins
Verified
Journal Article
Open access
NANancy Asen
Nancy Asen
Plant‐based proteins (PBPs) are increasingly recognized as sustainable alternatives to animal‐derived proteins; however, their wider adoption remains limited by undesirable sensory attributes, including beany, grassy, earthy, bitter, and astringent flavors, as well as limited umami perception. These sensory challenges arise from volatile compounds (VOCs) such as aldehydes and ketones, as well as nonvolatile compounds (non‐VOCs) including phenolics, saponins, and bitter peptides. Fermentation has emerged as an effective clean‐label strategy for improving the flavor quality of PBPs through microbial metabolism and enzymatic biotransformation. During fermentation, flavor precursors derived from proteins, lipids, and carbohydrates are converted into taste‐ and aroma‐active compounds, including amino acids, peptides, organic acids, alcohols, esters, aldehydes, ketones, and pyrazines. These transformations enhance desirable sensory characteristics such as umami, kokumi, fruity, buttery, roasted, nutty, and fermented notes while mitigating plant‐derived off‐flavors. Microbial cultures, substrate composition, fermentation conditions, and process duration influence the extent of flavor development. This review examines the principal microbial groups used in PBP fermentation, the biochemical mechanisms underlying flavor formation and off‐flavor mitigation, the sensory outcomes associated with fermentation, and the effects of key processing factors on flavor quality. The paper also discusses sensory evaluation methods and the relationships between biochemical changes and consumer perception. Finally, the paper highlights emerging opportunities in precision fermentation, microbial engineering, flavoromics, metabolomics, and advanced analytical technologies as promising approaches for designing next‐generation fermented PBPs with enhanced flavor and product appeal.