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Dr. Dominic AGYEI
Department of Food Science, University of Otago, Dunedin 9054, New Zealand

Basic Info


Research Keywords & Expertise

0 Enzyme-based transformation of food molecules (proteins, lipids, carbohydrates) to improve their functional, biological and physicochemical properties
0 Design of bioprocesses for the extraction and purification of bioactive compounds
0 Use of enzymes for the valorisation and treatment of food wastes
0 Role of indigenous foods in mitigating malnutrition and food insecurity
0 Assessment of food safety knowledge and practices in educational institutions in Ghana (done in partnership with collaborators in Ghana)

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Use of enzymes for the valorisation and treatment of food wastes

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Short communication
Published: 11 February 2021 in Future Foods
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Tenebrio molitor (mealworms) and Hermetia illucens (Black soldier fly) larvae were analysed for the effect of feed composition on the fatty acid profiles. The larvae were raised on various feeds to which the basal diet had been supplemented to various levels with seed meals (flax seed, chia seed, hemp seed, and rapeseed). Fatty acid classes and composition of both insect larvae were similar in T. molitor and H. illucens larvae fat; however, the actual percentage composition differed; saturated (28.61% and 86.75%), monounsaturated (MUFA) (52.89% and 7.94%), and polyunsaturated (PUFA) fatty acids (18.49% and 5.31%). The supplementation of the basal diet resulted in larvae fat with increased omega-3 fatty acids levels, and subsequently a lower omega-6 to omega-3 ratio (T. molitor; 4.28:1 in the diet with 10% chia seed, H. illucens; 3.52:1 in the diet with 20% hemp seed) than those of the basal diets (50:1 and 9.91:1 in T. molitor and H. illucens respectively). In most of the larvae samples, the ratio achieved was closer to that recommended for a healthy diet.

ACS Style

Kehinde G Lawal; Ruchita R Kavle; Taiwo O Akanbi; Miranda Mirosa; Dominic Agyei. Enrichment in specific fatty acids profile of Tenebrio molitor and Hermetia illucens larvae through feeding. Future Foods 2021, 3, 100016 .

AMA Style

Kehinde G Lawal, Ruchita R Kavle, Taiwo O Akanbi, Miranda Mirosa, Dominic Agyei. Enrichment in specific fatty acids profile of Tenebrio molitor and Hermetia illucens larvae through feeding. Future Foods. 2021; 3 ():100016.

Chicago/Turabian Style

Kehinde G Lawal; Ruchita R Kavle; Taiwo O Akanbi; Miranda Mirosa; Dominic Agyei. 2021. "Enrichment in specific fatty acids profile of Tenebrio molitor and Hermetia illucens larvae through feeding." Future Foods 3, no. : 100016.

Journal article
Published: 29 January 2021 in Carbohydrate Polymer Technologies and Applications
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Crude β-D-galactosidase from Lactobacillus leichmannii 313 was used to synthesise galacto-oligosaccharides (GOS) from lactose. Using an initial lactose concentration of 170 g/L, the yield of GOS was 52 g/L (i.e. 62% lactose conversion) after 2 h of enzymatic reaction. The highest number of unique individual GOS were generated after 48 h of reaction. ESI-MS and HPAEC analysis of the GOS enriched fractions obtained from 48 h mixtures showed the presence of sugars with degrees of polymerization (DP) ranging from 2 to 6. Further analysis (by NMR spectroscopy) of GOS in fraction 3 (containing ~ 96% w/w GOS) showed non-reducing terminals that were mostly Galp; and reducing ends that were →4)-Glcp, and →6)-Glcp. The most abundant internal linkages in fraction 3 were deduced to be →3)-Galp-(1→, and →6)-Galp-(1→. The predominance of β-D-(1→3, or 6) linkages in GOS fractions suggests that β-D-galactosidase from LL313 is suitable for generating unique GOS from lactose.

ACS Style

Dawei Ji; Ian Sims; Min Xu; Ian Stewart; Dominic Agyei. Production and identification of galacto-oligosaccharides from lactose using β-D-galactosidases from Lactobacillus leichmannii 313. Carbohydrate Polymer Technologies and Applications 2021, 2, 100038 .

AMA Style

Dawei Ji, Ian Sims, Min Xu, Ian Stewart, Dominic Agyei. Production and identification of galacto-oligosaccharides from lactose using β-D-galactosidases from Lactobacillus leichmannii 313. Carbohydrate Polymer Technologies and Applications. 2021; 2 ():100038.

Chicago/Turabian Style

Dawei Ji; Ian Sims; Min Xu; Ian Stewart; Dominic Agyei. 2021. "Production and identification of galacto-oligosaccharides from lactose using β-D-galactosidases from Lactobacillus leichmannii 313." Carbohydrate Polymer Technologies and Applications 2, no. : 100038.

Review
Published: 15 December 2020 in Critical Reviews in Food Science and Nutrition
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Diabetes mellitus, particularly type 2 diabetes, is a major global health issue, the prevalence of which seems to be on the rise worldwide. Interventions such as healthy diet, physical activity, maintaining a healthy weight, and medication (for those with a diagnosis of diabetes) are among the most effective strategies to prevent and control diabetes. Three-quarters of patients diagnosed with diabetes are in countries with poor financial infrastructure, nutritional awareness and health care systems. Concomitantly, the cost involved in managing diabetes through the intake of antidiabetic drugs makes it prohibitive for majority of patients. Food protein-derived bioactive peptides have the potential of being formulated as nutraceuticals and drugs in combating the pathogenesis and pathophysiology of metabolic disorders with little or “no known” complications in humans. Coupled with lifestyle modifications, the potential of bioactive peptides to maintain normoglycemic range is actualized by influencing the activities of incretins, DPP-IV, α-amylase, and α-glucosidase enzymes. This article discusses the biofunctionality and clinical implications of anti-diabetic bioactive peptides in controlling the global burden of diabetes.

ACS Style

Caleb Acquah; Christian K. O. Dzuvor; Susan Tosh; Dominic Agyei. Anti-diabetic effects of bioactive peptides: recent advances and clinical implications. Critical Reviews in Food Science and Nutrition 2020, 1 -14.

AMA Style

Caleb Acquah, Christian K. O. Dzuvor, Susan Tosh, Dominic Agyei. Anti-diabetic effects of bioactive peptides: recent advances and clinical implications. Critical Reviews in Food Science and Nutrition. 2020; ():1-14.

Chicago/Turabian Style

Caleb Acquah; Christian K. O. Dzuvor; Susan Tosh; Dominic Agyei. 2020. "Anti-diabetic effects of bioactive peptides: recent advances and clinical implications." Critical Reviews in Food Science and Nutrition , no. : 1-14.

Journal article
Published: 23 November 2020 in Comprehensive Reviews in Food Science and Food Safety
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Proteins displayed on the cell surface of lactic acid bacteria (LAB) perform diverse and important biochemical roles. Among these, the cell‐envelope proteinases (CEPs) are one of the most widely studied and most exploited for biotechnological applications. CEPs are important players in the proteolytic system of LAB, because they are required by LAB to degrade proteins in the growth media into peptides and/or amino acids required for the nitrogen nutrition of LAB. The most important area of application of CEPs is therefore in protein hydrolysis, especially in dairy products. Also, the physical location of CEPs (i.e., being cell‐envelope anchored) allows for relatively easy downstream processing (e.g., extraction) of CEPs. This review describes the biochemical features and organization of CEPs and how this fits them for the purpose of protein hydrolysis. It begins with a focus on the genetic organization and expression of CEPs. The catalytic behavior and cleavage specificities of CEPs from various LAB are also discussed. Following this, the extraction and purification of most CEPs reported to date is described. The industrial applications of CEPs in food technology, health promotion, as well as in the growing area of water purification are discussed. Techniques for improving the production and catalytic efficiency of CEPs are also given an important place in this review.

ACS Style

Dawei Ji; Jingying Ma; Min Xu; Dominic Agyei. Cell‐envelope proteinases from lactic acid bacteria: Biochemical features and biotechnological applications. Comprehensive Reviews in Food Science and Food Safety 2020, 20, 369 -400.

AMA Style

Dawei Ji, Jingying Ma, Min Xu, Dominic Agyei. Cell‐envelope proteinases from lactic acid bacteria: Biochemical features and biotechnological applications. Comprehensive Reviews in Food Science and Food Safety. 2020; 20 (1):369-400.

Chicago/Turabian Style

Dawei Ji; Jingying Ma; Min Xu; Dominic Agyei. 2020. "Cell‐envelope proteinases from lactic acid bacteria: Biochemical features and biotechnological applications." Comprehensive Reviews in Food Science and Food Safety 20, no. 1: 369-400.

Journal article
Published: 19 November 2020 in Fermentation
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In this study, the physicochemical properties, pharmacokinetics properties, and drug-likeness of pigments from Monascus-fermented rice (Monascus pigments, MPs) were predicted in silico using SwissADME tool. In silico prediction of physicochemical properties showed that MPs had desirable lipophilic drug-like physicochemical properties including molecular weight (236 to 543), TPSA (44.76 to 179.77), lipophilicity (−0.81 to 4.14), and water solubility (−4.94 to −0.77). The pharmacokinetic properties of MPs (i.e., GIA, P-glycoprotein substrate, and CYP3A4 inhibitor) illustrated that most MPs had high intestinal absorption and bioavailability, but some MPs might cause pharmacokinetics-related drug–drug interactions. Following this, six main well-known MPs (monascin, ankaflavin, rubropunctatin, monascorubrin, rubropunctamine, monascorubramine) were selected for molecular docking with some enzyme receptors. The docking results were shown with the best molecular docking poses, and the interacting residues, number and distance of hydrogen bonds of the MPs and monacolin K (for docking with 3-hydroxy-3-methyl glutaryl coenzyme A reductase (HMG-CoA reductase)), or MPs and oleic acid (for docking with lipase). Dissociation constants showed that MPs had lower inhibitory potential for HMGR (compared with Monacolin K), and higher inhibitory potential for lipase. Individual pigments from Monascus-fermented rice, therefore, have the potential to be developed as drug candidates for controlling hyperlipidemia.

ACS Style

Nina Sun; Dominic Agyei; Dawei Ji. Medicinal Chemistry Friendliness of Pigments from Monascus-Fermented Rice and the Molecular Docking Analysis of Their Anti-Hyperlipidemia Properties. Fermentation 2020, 6, 111 .

AMA Style

Nina Sun, Dominic Agyei, Dawei Ji. Medicinal Chemistry Friendliness of Pigments from Monascus-Fermented Rice and the Molecular Docking Analysis of Their Anti-Hyperlipidemia Properties. Fermentation. 2020; 6 (4):111.

Chicago/Turabian Style

Nina Sun; Dominic Agyei; Dawei Ji. 2020. "Medicinal Chemistry Friendliness of Pigments from Monascus-Fermented Rice and the Molecular Docking Analysis of Their Anti-Hyperlipidemia Properties." Fermentation 6, no. 4: 111.

Review
Published: 29 September 2020 in Journal of Food Biochemistry
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Microorganisms from extreme environments tend to undergo various adaptations due to environmental conditions such as extreme pH, temperature, salinity, heavy metals, and solvents. Thus, they produce enzymes with unique properties and high specificity, making them useful industrially, particularly in the food industries. Despite these enzymes' remarkable properties, only a few instances can be reported for actual exploitation in the food industry. This review's objectives are to highlight the properties of these enzymes and their prospects in the food industry. First, an introduction to extremophilic organisms is presented, followed by the categories and application of food enzymes from extremophiles. Then, the unique structural features of extremozymes are shown. This review also covers the prospective applications of extremozymes in the food industry in a broader sense, including degradation of toxins, deconstruction of polymers into monomers, and catalysis of multistep processes. Finally, the challenges in bioprocessing of extremozymes and applications in food are presented. Practical applications Enzymes are important players in food processing and preservation. Extremozymes, by their nature, are ideal for a broad range of food processing applications, particularly those that require process conditions of extreme pH, temperature, and salinity. As the global food industry grows, so too will grow the need to research and develop food products that are diverse, safe, healthy, and nutritious. There is also the need to produce food in a sustainable way that generates less waste or maximizes waste valorization. We anticipate that extremozymes can meet some of the research and development needs of the food industry.

ACS Style

Taiwo O. Akanbi; Dawei Ji; Dominic Agyei. Revisiting the scope and applications of food enzymes from extremophiles. Journal of Food Biochemistry 2020, 44, e13475 .

AMA Style

Taiwo O. Akanbi, Dawei Ji, Dominic Agyei. Revisiting the scope and applications of food enzymes from extremophiles. Journal of Food Biochemistry. 2020; 44 (11):e13475.

Chicago/Turabian Style

Taiwo O. Akanbi; Dawei Ji; Dominic Agyei. 2020. "Revisiting the scope and applications of food enzymes from extremophiles." Journal of Food Biochemistry 44, no. 11: e13475.

Journal article
Published: 22 August 2020 in Food and Bioproducts Processing
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β-galactosidases from Lactobacillus leichmannii 313 (LL 313) were immobilized for the first time by cross-linked enzyme aggregates (CLEA) technology. By using three precipitants (saturated ammonium sulfate (ASF), acetone (ACT), and isopropanol (IPA) in CLEA preparation and assessing performance in comparison with crude enzyme, recovered activities of 23% (ASF-CLEA), 18% (ACT-CLEA), 13.6% (IPA-CLEA) were obtained. Immobilization did not change the optimal pH (7.0) and temperature (55 °C), except for ACT-CLEA (60 °C). CLEA retained activity (∼ 90% for ASF-CLEA) after 2 weeks storage at 4 °C in buffer; and for ACT-CLEA and IPA-CLEA, ∼ 50% of initial activity was retained after 10 cycles of use. Plackett–Burman (PB) and Response Surface Methodology (RSM) optimization with ASF as precipitant gave 23.5 mM of glutaraldehyde, reaction pH 6.9 and reaction time of 3.4 h as the optimum conditions giving highest recovered activity of 37.7%. The kinetics (Vmax and Km) were 0.06 mmol g−1 min−1 and 4.95 mM respectively for ASF-CLEA, compared with 0.07 mmol g−1 min−1 and 4.08 mM for crude enzyme. All CLEA types exhibited the capability to hydrolyze lactose and generate GOS. This study shows that CLEA is a suitable technique to immobilize β-galactosidase from LL313, and the resulting enzyme system has promising applications in the food industry.

ACS Style

Min Xu; Dawei Ji; Yongjin Deng; Dominic Agyei. Preparation and assessment of cross-linked enzyme aggregates (CLEAs) of β-galactosidase from Lactobacillus leichmannii 313. Food and Bioproducts Processing 2020, 124, 82 -96.

AMA Style

Min Xu, Dawei Ji, Yongjin Deng, Dominic Agyei. Preparation and assessment of cross-linked enzyme aggregates (CLEAs) of β-galactosidase from Lactobacillus leichmannii 313. Food and Bioproducts Processing. 2020; 124 ():82-96.

Chicago/Turabian Style

Min Xu; Dawei Ji; Yongjin Deng; Dominic Agyei. 2020. "Preparation and assessment of cross-linked enzyme aggregates (CLEAs) of β-galactosidase from Lactobacillus leichmannii 313." Food and Bioproducts Processing 124, no. : 82-96.

Journal article
Published: 03 June 2020 in Innovative Food Science & Emerging Technologies
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This research aimed to investigate the physicochemical properties of thermally processed oat flour (TPOF) “fractions” (Supernatant, Top/S1, Middle/S2, Bottom/S3) after Pulsed Electric Fields (PEF) treatment of TPOF at 2 and 4 kV/cm between 50 and 451 kJ/kg. Supernatant from PEF-treated TPOF displayed a generally higher β-glucan content than untreated TPOF. No major changes were observed in chemical composition (in terms of total starch, protein, and fat contents) amongst “fractions”. However, S1 obtained from PEF-treated TPOF exhibited an increase in particle size, while both gelatinisation enthalpy and percent relative crystallinity were significantly lower compared to untreated counterpart. S1 from PEF-treated TPOF at 422–451 kJ/kg also manifested severe changes in granule morphology. S2 exhibited the highest gelatinisation enthalpy and S3 registered the least degree of observed changes in particle size. Findings of this study suggest the potential of PEF treatment application to produce oat “fractions” with varying physicochemical properties. This study provides indispensable scientific information that could be utilised to further investigate industrial production of customised fractionation of oat flour with targeted physicochemical properties through PEF treatment. This opens new opportunities to strategically diversify the range of oat flour ingredients based on their targeted unique properties in the food industry.

ACS Style

Sheba Mae M. Duque; Sze Ying Leong; Dominic Agyei; Jaspreet Singh; Nigel Larsen; Indrawati Oey. Modifications in the physicochemical properties of flour “fractions” after Pulsed Electric Fields treatment of thermally processed oat. Innovative Food Science & Emerging Technologies 2020, 64, 102406 .

AMA Style

Sheba Mae M. Duque, Sze Ying Leong, Dominic Agyei, Jaspreet Singh, Nigel Larsen, Indrawati Oey. Modifications in the physicochemical properties of flour “fractions” after Pulsed Electric Fields treatment of thermally processed oat. Innovative Food Science & Emerging Technologies. 2020; 64 ():102406.

Chicago/Turabian Style

Sheba Mae M. Duque; Sze Ying Leong; Dominic Agyei; Jaspreet Singh; Nigel Larsen; Indrawati Oey. 2020. "Modifications in the physicochemical properties of flour “fractions” after Pulsed Electric Fields treatment of thermally processed oat." Innovative Food Science & Emerging Technologies 64, no. : 102406.

Review
Published: 17 May 2020 in Microorganisms
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In Africa, milk production, processing and consumption are integral part of traditional food supply, with dairy products being a staple component of recommended healthy diets. This review provides an overview of the microbial safety characteristics of milk production and fermented dairy products in Africa. The object is to highlight the main microbial food safety hazards in the dairy chain and to propose appropriate preventive and control measures. Pathogens of public health concern including Mycobacterium bovis, Brucella abortus and Coxiella burnettii, which have largely been eradicated in many developed nations, still persist in the dairy chain in Africa. Factors such as the natural antimicrobial systems in milk and traditional processing technologies, including fermentation, heating and use of antimicrobial additives, that can potentially contribute to microbial safety of milk and dairy products in Africa will be discussed. Practical approaches to controlling safety hazards in the dairy chain in Africa have been proposed. Governmental regulatory bodies need to set the necessary national and regional safety standards, perform inspections and put measures in place to ensure that the standards are met, including strong enforcement programs within smallholder dairy chains. Dairy chain actors would require upgraded knowledge and training in preventive approaches such as good agricultural practices (GAP), hazard analysis and critical control points (HACCP) design and implementation and good hygienic practices (GHPs). Food safety education programs should be incorporated into school curricula, beginning at the basic school levels, to improve food safety cognition among students and promote life-long safe food handling behaviour.

ACS Style

James Owusu-Kwarteng; Fortune Akabanda; Dominic Agyei; Lene Jespersen. Microbial Safety of Milk Production and Fermented Dairy Products in Africa. Microorganisms 2020, 8, 752 .

AMA Style

James Owusu-Kwarteng, Fortune Akabanda, Dominic Agyei, Lene Jespersen. Microbial Safety of Milk Production and Fermented Dairy Products in Africa. Microorganisms. 2020; 8 (5):752.

Chicago/Turabian Style

James Owusu-Kwarteng; Fortune Akabanda; Dominic Agyei; Lene Jespersen. 2020. "Microbial Safety of Milk Production and Fermented Dairy Products in Africa." Microorganisms 8, no. 5: 752.

Journal article
Published: 14 March 2020 in Current Research in Food Science
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In this study, hypotensive peptides derived from mature flaxseed protein sequences were predicted in silico using BIOPEP-UWM with nine proteases, three each from digestive, plant and microbial sources. The physicochemical properties of 2256 ACE-inhibitory peptides and 267 renin-inhibitory peptides (including seven (7) peptides with dual inhibitory activities against both ACE and renin enzymes) were assessed in silico using the ‘Peptides’ package of R. The hypotensive peptides showed relatively low molecular weight (mol. wt.) range (132 < mol. wt. < 442 Da); broad range of isoelectric point (3.61 < pI < 12.50); both high (>2) and low (≤2) Boman indices, and a variety of hydrophobicity indices (hydrophilic, hydrophobic and amphipathic properties). Following this, the seven peptides with dual ACE and renin inhibitory activities were selected for molecular docking with the respective enzyme receptors. The binding energies of the seven hypotensive peptides with ACE and renin respectively ranged from -36.82 to -25.94 kJ/mol, and -33.05 to -27.61 kJ/mol; and compared well with values recorded for inhibitor drugs, captopril (-26.78 kJ/mol) and aliskiren (-34.73 kJ/mol). The seven peptides inhibited ACE through hydrogen bonds, electrostatic and hydrophobic interactions; and renin, mainly through hydrogen bonds and hydrophobic interactions. In silico prediction of adsorption, digestion, metabolism, excretion and toxicity (ADME/Tox) profile based on physicochemical properties and Lipinski’s rule-of-five showed that the peptides were non-toxic and had desirable drug-like properties (flexibility, lipophilicity, molecular weight, gastrointestinal absorption, and bioavailability). This study provides insight into the molecular interactions of hypotensive peptides with their physiological targets, and the potential to develop the bioactive peptides from flaxseed proteins.

ACS Style

Dawei Ji; Min Xu; Chibuike C. Udenigwe; Dominic Agyei. Physicochemical characterisation, molecular docking, and drug-likeness evaluation of hypotensive peptides encrypted in flaxseed proteome. Current Research in Food Science 2020, 3, 41 -50.

AMA Style

Dawei Ji, Min Xu, Chibuike C. Udenigwe, Dominic Agyei. Physicochemical characterisation, molecular docking, and drug-likeness evaluation of hypotensive peptides encrypted in flaxseed proteome. Current Research in Food Science. 2020; 3 ():41-50.

Chicago/Turabian Style

Dawei Ji; Min Xu; Chibuike C. Udenigwe; Dominic Agyei. 2020. "Physicochemical characterisation, molecular docking, and drug-likeness evaluation of hypotensive peptides encrypted in flaxseed proteome." Current Research in Food Science 3, no. : 41-50.

Journal article
Published: 15 February 2020 in Fermentation
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The endoenzyme β-galactosidase (β-d-galactoside galactohydrolase; EC 3.2.1.23) has been used at industrial scales for the preparation of lactose-free milk and for the conversion of lactose to galacto-oligosaccharides (GOS) prebiotics. In this study, using Plackett–Burman (PB) design and the response surface methodology (RSM), the batch growth conditions for the production of β-galactosidase in DeMan-Rogosa-Sharpe (MRS) media have been studied and optimized for Lactobacillus leichmannii 313 (ATCC 7830™) for the first time. The incubation temperature (30 < T < 55 °C), starting pH (5.5 < pH < 7.5), and carbon source (glucose, lactose, galactose, fructose, and sucrose) were selected as the significant variables for optimization. The maximum crude β-galactosidase production (measured by specific activity) was 4.5 U/mg proteins and was obtained after 12 h of fermentation. The results of the PB design and further optimization by RSM showed that the initial pH of 7.0 and 15.29 g/L of lactose were the levels that gave the optimum observed and predicted β-galactosidase activities of 23.13 U/mg and 23.40 U/mg, respectively. Through RSM optimization, β-galactosidase production increased significantly (over five-fold) in optimized medium (23.13 U/mg), compared with unoptimized medium (4.5 U/mg). Moreover, the crude enzyme obtained was able to hydrolyze lactose and also produce galacto-oligosaccharides. Because its ability to produce β-galactosidase was significantly improved through optimization by RSM, L. leichmannii 313 can serve as a potential source of β-galactosidase for food applications at an industrial scale.

ACS Style

Yongjin Deng; Min Xu; Dawei Ji; Dominic Agyei. Optimization of β-galactosidase Production by Batch Cultures of Lactobacillus leichmannii 313 (ATCC 7830™). Fermentation 2020, 6, 27 .

AMA Style

Yongjin Deng, Min Xu, Dawei Ji, Dominic Agyei. Optimization of β-galactosidase Production by Batch Cultures of Lactobacillus leichmannii 313 (ATCC 7830™). Fermentation. 2020; 6 (1):27.

Chicago/Turabian Style

Yongjin Deng; Min Xu; Dawei Ji; Dominic Agyei. 2020. "Optimization of β-galactosidase Production by Batch Cultures of Lactobacillus leichmannii 313 (ATCC 7830™)." Fermentation 6, no. 1: 27.

Review
Published: 20 December 2019 in Fibers
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Β-glucan is a strongly hydrophilic non-starchy polysaccharide, which, when incorporated in food, is renowned for its ability to alter functional characteristics such as viscosity, rheology, texture, and sensory properties of the food product. The functional properties of β-glucans are directly linked to their origin/source, molecular weight, and structural features. The molecular weight and structural/conformational features are in turn influenced by method of extraction and modification of the β-glucan. For example, whereas physical modification techniques influence only the spatial structures, modification by chemical agents, enzyme hydrolysis, mechanical treatment, and irradiation affect both spatial conformation and primary structures of β-glucan. Consequently, β-glucan can be modified (via one or more of the aforementioned techniques) into forms that have desired morphological, rheological, and (bio)functional properties. This review describes how various modification techniques affect the structure, properties, and applications of β-glucans in the food industry.

ACS Style

RamanDeep Kaur; Minaxi Sharma; Dawei Ji; Min Xu; Dominic Agyei. Structural Features, Modification, and Functionalities of Beta-Glucan. Fibers 2019, 8, 1 .

AMA Style

RamanDeep Kaur, Minaxi Sharma, Dawei Ji, Min Xu, Dominic Agyei. Structural Features, Modification, and Functionalities of Beta-Glucan. Fibers. 2019; 8 (1):1.

Chicago/Turabian Style

RamanDeep Kaur; Minaxi Sharma; Dawei Ji; Min Xu; Dominic Agyei. 2019. "Structural Features, Modification, and Functionalities of Beta-Glucan." Fibers 8, no. 1: 1.

Journal article
Published: 10 December 2019 in Food Research International
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The aim of this research was to investigate the effect of Pulsed Electric Fields (PEF) treatments (electric field strengths 2 and 4.4 kV/cm combined with specific energy inputs between 48 and 484 kJ/kg) on the thermal and pasting properties of oat flours. Colour, β-glucan content, particle size distribution, morphological characteristics, starch short-range molecular order, protein secondary structure, thermal, and pasting properties of raw (dehulled and milled) and thermally processed (kilned at 115 °C for 30 min and steamed at 100–104 °C for 18 min under industrial process condition) oat flours under the influence of PEF treatment were evaluated. Results showed that PEF treatment, applied at any intensity, led to considerable changes in the structural properties especially when applied on raw oat flour. Both types of oat flour experienced an increase in particle size (up to four-fold), damage of starch granule morphology, and modifications in starch short-range molecular order and protein secondary structures as a result of PEF treatment. These physical changes observed after PEF treatment, particularly at increasing specific energy input, coincided with the thermal and pasting behaviour of PEF-treated oat flours, which include a decrease in gelatinisation enthalpy (up to 80%), increase in thermal transition temperatures (at least 3 °C), decrease in overall viscosity profile, and reduction in pasting temperature (up to 12 °C). Overall results suggested that PEF treatment improved majorly on starch-related functionality of oat, such as increased the pasting stability of raw and thermally processed oat flours and at the same time enhanced the retrogradation property (reduced syneresis and hardness) of raw oat flour, under lower temperature requirement without affecting pasting time. This research demonstrated the potential of PEF treatment in modifying the thermal and pasting properties of oat flour, thereby offering opportunities for novel products for food industry.

ACS Style

Sheba Mae Duque; Sze Ying Leong; Dominic Agyei; Jaspreet Singh; Nigel Larsen; Indrawati Oey. Understanding the impact of Pulsed Electric Fields treatment on the thermal and pasting properties of raw and thermally processed oat flours. Food Research International 2019, 129, 108839 .

AMA Style

Sheba Mae Duque, Sze Ying Leong, Dominic Agyei, Jaspreet Singh, Nigel Larsen, Indrawati Oey. Understanding the impact of Pulsed Electric Fields treatment on the thermal and pasting properties of raw and thermally processed oat flours. Food Research International. 2019; 129 ():108839.

Chicago/Turabian Style

Sheba Mae Duque; Sze Ying Leong; Dominic Agyei; Jaspreet Singh; Nigel Larsen; Indrawati Oey. 2019. "Understanding the impact of Pulsed Electric Fields treatment on the thermal and pasting properties of raw and thermally processed oat flours." Food Research International 129, no. : 108839.

Journal article
Published: 27 August 2019 in LWT
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β-galactosidase from Lactobacillus leichmannii 313 (LL313) was purified (4.5-fold, 11% purification yield), and characterised, giving optimal enzyme activity at pH 5.5 and 55 °C. Thermal inactivation of crude and purified enzyme showed first order inactivation kinetics. Deactivation energy (Ed) of 390.58 ± 34.94 kJ/mol (crude enzyme) and 404.17 ± 46.19 kJ/mol (purified enzyme), based on the Arrhenius equation were not significantly different. Thermal stability, determined by decimal reduction time (D value), z value, and half-life (t1/2) of purified enzyme were significantly lower than those of crude enzyme. This, together with thermodynamic parameters (ΔH#, ΔG# and ΔS#) suggested that the purification procedure affected the thermal stability of the enzyme. The purified enzyme gave Vmax and Km values of 9.15 ± 0.23 mol g−1.min−1 and 2.97 ± 0.32 mM respectively, with ο-nitrophenol-β-d-galactopyranoside as substrate. The purified enzyme was activated by Na+ ions (>1 mM); remained unaffected by K+; and was inhibited by Ca2+ and Mn2+ (1–100 mM). Inhibition by EDTA (1 mM) and activation by 2-mercaptoethanol (1 mM) demonstrated respectively that the enzyme is a metalloenzyme and required cysteine in the active site. The enzyme exhibited hydrolytic and transgalactosylation activities with lactose as substrate, demonstrating its potential for use in the food industry.

ACS Style

Dawei Ji; Indrawati Oey; Dominic Agyei. Purification, characterization and thermal inactivation kinetics of β-galactosidase from Lactobacillus leichmannii 313. LWT 2019, 116, 108545 .

AMA Style

Dawei Ji, Indrawati Oey, Dominic Agyei. Purification, characterization and thermal inactivation kinetics of β-galactosidase from Lactobacillus leichmannii 313. LWT. 2019; 116 ():108545.

Chicago/Turabian Style

Dawei Ji; Indrawati Oey; Dominic Agyei. 2019. "Purification, characterization and thermal inactivation kinetics of β-galactosidase from Lactobacillus leichmannii 313." LWT 116, no. : 108545.

Journal article
Published: 10 May 2019 in Foods
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The purpose of this study was to investigate the properties of starch in potatoes (Solanum tuberosum cv. Agria) after being treated with pulsed electric fields (PEF). Potatoes were treated at 50 and 150 kJ/kg specific energies with various electric field strengths of 0, 0.5, 0.7, 0.9 and 1.1 kV/cm. Distilled water was used as the processing medium. Starches were isolated from potato tissue and from the PEF processing medium. To assess the starch properties, various methods were used, i.e., the birefringence capability using a polarised light microscopy, gelatinisation behaviour using hot-stage light microscopy and differential scanning calorimetry (DSC), thermal stability using thermogravimetry (TGA), enzyme susceptibility towards α-amylase and the extent of starch hydrolysis under in vitro simulated human digestion conditions. The findings showed that PEF did not change the properties of starch inside the potatoes, but it narrowed the temperature range of gelatinisation and reduced the digestibility of starch collected in the processing medium. Therefore, this study confirms that, when used as a processing aid for potato, PEF does not result in detrimental effects on the properties of potato starch.

ACS Style

Setya B.M. Abduh; Sze Ying Leong; Dominic Agyei; Indrawati Oey. Understanding the Properties of Starch in Potatoes (Solanum tuberosum var. Agria) after Being Treated with Pulsed Electric Field Processing. Foods 2019, 8, 159 .

AMA Style

Setya B.M. Abduh, Sze Ying Leong, Dominic Agyei, Indrawati Oey. Understanding the Properties of Starch in Potatoes (Solanum tuberosum var. Agria) after Being Treated with Pulsed Electric Field Processing. Foods. 2019; 8 (5):159.

Chicago/Turabian Style

Setya B.M. Abduh; Sze Ying Leong; Dominic Agyei; Indrawati Oey. 2019. "Understanding the Properties of Starch in Potatoes (Solanum tuberosum var. Agria) after Being Treated with Pulsed Electric Field Processing." Foods 8, no. 5: 159.

Review
Published: 04 February 2019 in Critical Reviews in Food Science and Nutrition
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The food and health applications of bioactive peptides have grown remarkably in the past few decades. Current elucidations have shown that bioactive peptides have unique structural arrangement of amino acids, conferring distinct functionalities, and molecular affinity characteristics. However, whereas interest in the biological potency of bioactive peptides has grown, cost-effective techniques for monitoring the structural changes in these peptides and how these changes affect the biological properties have not grown at the same rate. Due to the high binding affinity of aptamers for other biomolecules, they have a huge potential for use in tracking the structural, conformational, and compositional changes in bioactive peptides. This review provides an overview of bioactive peptides and their essential structure-activity relationship. The review further highlights on the types and methods of synthesis of aptamers before the discussion of the prospects, merits, and challenges in the use of aptamers for bioaffinity interactions with bioactive peptides.

ACS Style

Caleb Acquah; Dominic Agyei; Eugene Marfo Obeng; Sharadwata Pan; Kei Xian Tan; Michael Danquah. Aptamers: an emerging class of bioaffinity ligands in bioactive peptide applications. Critical Reviews in Food Science and Nutrition 2019, 60, 1195 -1206.

AMA Style

Caleb Acquah, Dominic Agyei, Eugene Marfo Obeng, Sharadwata Pan, Kei Xian Tan, Michael Danquah. Aptamers: an emerging class of bioaffinity ligands in bioactive peptide applications. Critical Reviews in Food Science and Nutrition. 2019; 60 (7):1195-1206.

Chicago/Turabian Style

Caleb Acquah; Dominic Agyei; Eugene Marfo Obeng; Sharadwata Pan; Kei Xian Tan; Michael Danquah. 2019. "Aptamers: an emerging class of bioaffinity ligands in bioactive peptide applications." Critical Reviews in Food Science and Nutrition 60, no. 7: 1195-1206.

Review
Published: 22 January 2019 in Critical Reviews in Food Science and Nutrition
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Africa is known for its rich, ancient tradition in fermented foods. Among these, fermented dairy products represent one category that is widely consumed, contributing to the socio-economic development and food security of the people. In Africa, traditional food fermentation lends itself as a relatively cheap food processing technology that often improves shelf life/food safety as well as nutrition and health via improvement in the levels of specific micronutrients and the action of probiotics. A range of African fermented dairy products (mainly yoghurt-like products) are produced by spontaneous fermentation, and these fermented dairy products harbor rich and valuable microbial diversity, predominated by lactic acid bacteria and yeasts. Detailed knowledge of the production processes, microbiological and biochemical aspects of traditional African dairy fermentation is critical for the development of products with enhanced quality, safety and health benefits for a sustainable food security in the region. This review therefore provides a comprehensive overview of the traditional African fermented dairy processing technology, as well as technologically relevant microorganisms and health benefits associated with fermented dairy products. Efforts aimed at harnessing the functional food potential of these fermented products could help control some food and health challenges facing many countries in the region.

ACS Style

Dominic Agyei; James Owusu-Kwarteng; Fortune Akabanda; Samuel Akomea-Frempong. Indigenous African fermented dairy products: Processing technology, microbiology and health benefits. Critical Reviews in Food Science and Nutrition 2019, 60, 991 -1006.

AMA Style

Dominic Agyei, James Owusu-Kwarteng, Fortune Akabanda, Samuel Akomea-Frempong. Indigenous African fermented dairy products: Processing technology, microbiology and health benefits. Critical Reviews in Food Science and Nutrition. 2019; 60 (6):991-1006.

Chicago/Turabian Style

Dominic Agyei; James Owusu-Kwarteng; Fortune Akabanda; Samuel Akomea-Frempong. 2019. "Indigenous African fermented dairy products: Processing technology, microbiology and health benefits." Critical Reviews in Food Science and Nutrition 60, no. 6: 991-1006.

Review
Published: 07 January 2019 in Journal of Food Biochemistry
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The application of proteomic and peptidomic technologies for food‐derived bioactive peptides is an emerging field in food sciences. These technologies include the use of separation tools coupled to a high‐resolution spectrometric and bioinformatic tools for prediction, identification, sequencing, and characterization of peptides. To a large extent, one‐dimensional separation technologies have been extensively used as a continuous tool under different optimized conditions for the identification and analysis of food peptides. However, most one‐dimensional separation technologies are fraught with significant bottlenecks such as insufficient sensitivity and specificity limits for complex samples. To address this limitation, separation systems based on orthogonal, multidimensional principles, which allow for the coupling of more than one analytical separation tool with different operational principles, provide a higher separation power than one‐dimensional separation tools. This review describes the structure‐informed separation and purification of protein hydrolyzates to obtain peptides with desirable bioactivities. Practical applications Application of bioactive peptides in the formulation of functional foods, nutraceuticals, and therapeutic agents have increasingly gained scholarly and industrial attention. The bioactive peptides exist originally in protein sources and are only active after hydrolysis of the parent protein. Currently, several tools can be configured in one‐dimensional or multidimensional systems for the separation and purification of protein hydrolyzates. The separations are informed by the structural properties such as the molecular weight, charge, hydrophobicity or hydrophilicity, and the solubility of peptides. This review provides a concise discussion on the commonly used analytical tools, their configurations, advantages and challenges in peptide separation. Emphasis is placed on how the structural properties of peptides assist in the separation and purification processes and the concomitant effect of the separation on peptide bioactivity.

ACS Style

Caleb Acquah; Yi Wei Chan; Sharadwata Pan; Dominic Agyei; Chibuike C. Udenigwe. Structure-informed separation of bioactive peptides. Journal of Food Biochemistry 2019, 43, e12765 .

AMA Style

Caleb Acquah, Yi Wei Chan, Sharadwata Pan, Dominic Agyei, Chibuike C. Udenigwe. Structure-informed separation of bioactive peptides. Journal of Food Biochemistry. 2019; 43 (1):e12765.

Chicago/Turabian Style

Caleb Acquah; Yi Wei Chan; Sharadwata Pan; Dominic Agyei; Chibuike C. Udenigwe. 2019. "Structure-informed separation of bioactive peptides." Journal of Food Biochemistry 43, no. 1: e12765.

Review
Published: 24 September 2018 in Molecules
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Flaxseeds (Linum usitatissimum L.) are oilseeds endowed with nutritional constituents such as lignans, lipids, proteins, fibre, carbohydrates, and micronutrients. Owing to their established high nutritional profile, flaxseeds have gained an established reputation as a dietary source of high value functional ingredients. Through the application of varied bioprocessing techniques, these essential constituents in flaxseeds can be made bioavailable for different applications such as nutraceuticals, cosmetics, and food industry. However, despite their food and health applications, flaxseeds contain high levels of phytotoxic compounds such as linatine, phytic acids, protease inhibitors, and cyanogenic glycosides. Epidemiological studies have shown that the consumption of these compounds can lead to poor bioavailability of essential nutrients and/or health complications. As such, these components must be removed or inactivated to physiologically undetectable limits to render flaxseeds safe for consumption. Herein, critical description of the types, characteristics, and bioprocessing of functional ingredients in flaxseed is presented.

ACS Style

Christian Kwesi Ofotsu Dzuvor; Jordan Tauai Taylor; Caleb Acquah; Sharadwata Pan; Dominic Agyei. Bioprocessing of Functional Ingredients from Flaxseed. Molecules 2018, 23, 2444 .

AMA Style

Christian Kwesi Ofotsu Dzuvor, Jordan Tauai Taylor, Caleb Acquah, Sharadwata Pan, Dominic Agyei. Bioprocessing of Functional Ingredients from Flaxseed. Molecules. 2018; 23 (10):2444.

Chicago/Turabian Style

Christian Kwesi Ofotsu Dzuvor; Jordan Tauai Taylor; Caleb Acquah; Sharadwata Pan; Dominic Agyei. 2018. "Bioprocessing of Functional Ingredients from Flaxseed." Molecules 23, no. 10: 2444.

Review
Published: 30 November 2017 in Journal of Food Biochemistry
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Peptides with biological properties, that is, bioactive peptides, are a class of biomolecules whose health-promoting properties are increasingly being exploited in food and health products. However, research on targeted techniques for the detection and quantification of these peptides is still in its infancy. Such information is needed in order to enhance the biological and chemometric characterization of peptides and their subsequent application in the functional food and pharmaceutical industries. In this review, the role of classic techniques such as electrophoretic, chromatographic, and peptide mass spectrometry in the structure-informed detection and quantitation of bioactive peptides are discussed. Prospects for the use of aptamers in the characterization of bioactive peptides are also discussed. Although bioactive peptides have huge potential applications in the functional foods and health area, there are limited techniques in enhancing throughput detection, quantification, and characterization of these peptides. This review discusses state-of-the-art techniques relevant in complementing bioactive detection and profiling irrespective of the small number of amino acid units. Insights into challenges, possible remedies and prevailing areas requiring thorough research in the extant literature for food chemists and biotechnologists are also presented.

ACS Style

Dominic Agyei; Sharadwata Pan; Caleb Acquah; Alaa El-Din Bekhit; Michael Danquah. Structure-informed detection and quantification of peptides in food and biological fluids. Journal of Food Biochemistry 2017, 43, e12482 .

AMA Style

Dominic Agyei, Sharadwata Pan, Caleb Acquah, Alaa El-Din Bekhit, Michael Danquah. Structure-informed detection and quantification of peptides in food and biological fluids. Journal of Food Biochemistry. 2017; 43 (1):e12482.

Chicago/Turabian Style

Dominic Agyei; Sharadwata Pan; Caleb Acquah; Alaa El-Din Bekhit; Michael Danquah. 2017. "Structure-informed detection and quantification of peptides in food and biological fluids." Journal of Food Biochemistry 43, no. 1: e12482.