Katleen Raes

Katleen Raes
Ghent University | UGhent · Research Unit VEG-i-TEC Departement of Food Technology Safety and Health

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206
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Publications

Publications (206)
Article
This study evaluated the composition of watermelon and mango juices fermented by Levilactobacillus (L.) brevis, Lacticaseibacillus (La.) casei and Pediococcus (P.) pentosaceus and subsequently simulated in vitro digestion and storage (4°C for 35 days). After fermentation (24 h), the microorganisms grew (~9 log CFU/mL) and fermented watermelon (FWJ)...
Article
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Atherosclerosis initiation is associated with a pro-inflammatory state of the endothelium. Quercetin is a flavonoid abundantly present in plant-based foods, with a possible impact on cardiovascular health. In this study, the effects of quercetin on lipopolysaccharide (LPS)-mediated endothelial inflammation and monocyte adhesion and migration, which...
Article
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In Kenya, agriculture is an important economic activity, which implies that a significant amount of bio-waste is generated. This is on one hand a waste management problem, but on the other hand, it is an opportunity for creating a sustainable bioeconomy. Therefore, this study investigates the potential recovery of bioresources from Kenyan bio-waste...
Article
Anthocyanidins and anthocyanins are flavonoids with nutritional, antioxidative and color properties that are present in various food products and biomass, such as food waste. The large chemical diversity amongst these molecules potentially leads to different affinities or activities in food and non-food applications. In order to characterize the ex...
Article
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Fermentation is a sustainable bio-preservation technique that can improve the organoleptic quality of fruit juices. Mango juices were fermented by monoculture strains of Lactiplantibacillus plantarum subsp. plantarum (MLP), Lacticaseibacillus rhamnosus (MLR), Lacticaseibacillus casei (MLC), Levilactobacillus brevis (MLB), and Pediococcus pentosaceu...
Article
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Synthetic dyes are by far the most widely applied colourants in industry. However, environmental and sustainability considerations have led to an increasing efforts to substitute them with safer and more sustainable equivalents. One promising class of alternatives is the natural quinones; these are class of cyclic organic compounds characterized by...
Preprint
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In Kenya, agriculture is an important economic activity, which implies that a significant amount of bio-waste is generated. This is on one hand a waste management problem, but on the other hand, it is an opportunity for creating a sustainable bioeconomy. Therefore, this study investigates the potential recovery of bioresources from Kenyan bio-waste...
Article
Background Iron, the building block of hemoglobin, plays a crucial role in facilitating tissue oxygen delivery. Iron deficiency anemia, a morbid health condition, is among the leading global health problems. In an attempt to control this, iron fortification, supplementation and dietary diversification strategies have been used. Researches show that...
Article
The influence of phenolic compounds on the enzymatic hydrolysis of cellulose was studied in depth using spectrophotometric techniques, adsorption analysis and Scanning Electron Microscopy (SEM). In this paper for the first time, both possible interactions between phenolic compounds and the enzyme or the substrate were investigated, with the use of...
Article
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Mango by-products are disregarded as waste contributing to greenhouse gas emissions. This study used mango seed and kernel to enhance the nutritional content of maize complementary porridges. Composite maize-based porridges (MBP) were formulated by fortifying maize flour with fine ground mango seed and kernel at different levels (31%, 56%, 81%). Th...
Article
Flavonoid consumption has beneficial effects on human health, however, clinical evidence remains often inconclusive due to high interindividual variability. Although this high interindividual variability has been consistently observed in flavonoid research, the potential underlying reasons are still poorly studied. Especially the knowledge on the i...
Chapter
Although dairy-based foods have been the main probiotic food sources, a range of plant-based products are currently being developed to meet the needs of vegetarians, lactose intolerant persons, individuals on low cholesterol diets or allergic to milk proteins. This chapter reviews the plant based non-alcoholic probiotic beverages in Europe and Afri...
Article
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PurposeThis study aims to employ five marine Pseudoalteromonas strains, belonging to Psa. arctica DSM 18437T, Psa. carrageenovora DSM 6820T, Psa. issachenkonii LMG 19697T, Psa. rubra DSM 6842T and Psa. tunicata DSM 14096T to ferment brown crab processing side streams.Methods The generated hydrolysates after the fermentation were screened for their...
Article
Purpose Flavonoid bioavailability and bioactivity is associated with interindividual variability, which is partially due to differences in health status. Previously, it was demonstrated that cellular stress, especially mitochondrial stress, increases intracellular quercetin uptake and this is associated with beneficial health effects. Here, the imp...
Article
Fruit and vegetables contain molecules that have particular colors, which can potentially be an environmentally attractive substitute for their synthetic counterparts in (non-)food applications. The most sustainable source for such natural colorants would be by the valorization of by-products from the fruit and vegetable industries, but qualitative...
Article
Fermentation increases food shelf-life but is characterized by changes that affect product's perception. Watermelon juice was fermented with Lactobacillus plantarum (WJ-LP), L. rhamnosus (WJ-LR), L. casei (WJ-LC), L. brevis (WJ-LB) and Pediococcus pentosaceus (WJ-PP). Their sensory characteristics and volatile compounds were investigated by consume...
Article
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A sound fundamental knowledge of the seed and flour characteristics of pseudocereals is crucial to be able to promote their industrial use. As a first step towards a more efficient and successful application, this study focuses on the seed characteristics, chemical composition and technological properties of commercially available pseudocereals (am...
Article
This review summarizes the most common biological methods and their conditions for the recovery of bioactive compounds such as chitin/chitosan, proteins/peptides and carotenoids from marine crustaceans processing side streams (MCPS). Chitin can be efficiently extracted from MCPS by adding proteases to hydrolyze the proteins (enzymatic hydrolysis),...
Article
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The production of fermented foods enriched with γ-aminobutyric acid (GABA) is a current trend in the food industry. In this study, the release of free glutamic acid (Glu) and its conversion to GABA in soymilk were conducted through enzymatic hydrolysis using Alcalase (Al) and Flavourzyme (Fl), following by the fermentation using Lb. plantarum LMG69...
Article
Anthocyanins and pyranoanthocyanins are flavonoids that are present in various food products (e.g. fruit, vegetables, wine, etc.). The large chemical diversity amongst these molecules leads to compound specific properties such as color and stability towards external conditions. These properties are also attractive for food and non‐food applications...
Article
A new approach to extract pectin from clementine peel using citric acid/sodium citrate solutions (CSS) at different pHs as green extracting agents was proposed. In this study, the effects of extraction temperature (65–85 °C), CSS pH (2–8), and extraction time (1–3 h) on the extraction yield, uronic acid content, and degree of methyl esterification...
Article
Full-text available
A total of 92 marine bacteria belonging to Pseudomonas, Pseudoalteromonas, Psychrobacter, and Shewanella were first screened for their proteolytic activity. In total, four Pseudomonas strains belonging to Ps. fluorescens, Ps. fragi, Ps. gessardii, and Ps. marginalis; 14 Pseudoalteromonas strains belonging to Psa. arctica, Psa. carrageenovora, Psa....
Article
Quinoa kernels are generally whole-milled due to their small kernel size. However, roller milling allows the separation of the starchy perisperm from the protein- and fat-rich bran fraction. Both fractions can be used for specific food applications. Studies have focused on roller milling of quinoa but information on tempering is rather limited. Thi...
Article
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Zamnè is an Acacia seed used as a terroir food in Burkina Faso. It has been introduced as a famineresilience crop and has become a cultural diet. However, little is known about its culinary and nutritional properties. This study aimed to explore the cooking and nutritional properties of Zamnè (Senegalia macrostachya (Reichenb. ex DC.) Kyal. & Boatw...
Article
Full-text available
Zamn`e is an Acacia seed used as a terroir food in Burkina Faso. It has been introduced as a famine-resilience crop and has become a cultural diet. However, little is known about its culinary and nutritional properties. This study aimed to explore the cooking and nutritional properties of Zamn`e (Senegalia macrostachya (Reichenb. ex DC.) Kyal. &...
Article
Traditional alcoholic extraction from by-products always discards insoluble fiber-rich residues, generating a new ‘waste’ stream. To recover these alcohol-insoluble residues (AIRs), we used an ethanol-washing method to obtain these dietary fiber concentrates from six agro-industrial by-products (blackcurrant pomace, banana peels, clementine peel, o...
Article
The phytochemical profiles and antioxidant capacities of 14 cowpea varieties (7 improved and 7 landraces) grown in Ethiopia were studied. The total phenolic, flavonoids, and monomeric anthocyanin contents (mg/100 g flour dry matter basis, db) ranged from 1210 to 1610 gallic acid equivalents, 250 to 1110 catechin equivalents and 3 to 7 cyanidin-3-gl...
Article
Natural dyes might be more environmentally sustainable compared to their synthetic counterparts, however in general their performance is worse. Therefore, typically metallic mordants are applied to improve the natural dye's affinity towards substrates, but this is not a suitable technique in a ‘green story’. In this paper, we test the potential of...
Article
Full-text available
In this study, a high-performance liquid chromatography (HPLC) method was adapted to measure the γ-aminobutyric acid (GABA) and glutamate (Glu) content in different fermented foods. The best solvent to extract GABA and Glu from the food matrices was 75% EtOH and water, combined with 4% SSA as posttreatment. The extracted amino acids were derivatize...
Article
The objectives of this study focused on optimizing extraction conditions (i.e. type of solvent (methanol, ethanol, and water) and their concentration, temperature, time, and the effect of ultrasound-assisted extraction (UAE)) for extracting phenolic compounds of rambutan fruit peel. Furthermore, a procedure to prepare crude phenolic powder from ram...
Article
The effect of tumbling time (5 h30, 19 h and 26 h) and raw ham quality (superior, inferior or mixed quality) on the quality of polyphosphate-free cooked ham was investigated. The water holding capacity and total yield of the polyphosphate-free tumbled hams were dependent on both tumbling time and ham quality. Higher values of both parameters were o...
Article
Microbial safety in food products is not always adequately controlled. Chemical antimicrobials which are recognized as hazards to human health are gradually replaced by natural antimicrobial compounds. In the current study, the antimicrobial activity against some Gram-positive and Gram- negative bacteria by the methanolic extract from rambutan frui...
Article
The aim of the present study was to assess the effect of sex and to estimate genetic parameters for several traits related to plasma oxidative status in slaughter pigs, i.e. Ferric Reducing Ability of Plasma (FRAP), concentrations of α-tocopherol and malondialdehyde (MDA) and glutathione peroxidase (GPx) activity. Blood samples were collected at sl...
Article
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Black aspergilli newly isolated from local grape and date were investigated for production of hydrolytic enzymes including cellulase, tannase and pectinase. Isolates were morphologically and molecularly identified as Aspergillus niger, Aspergillus tubingensis, Aspergillus japonicus and Aspergillus aculeatus. Isolates were screened for enzyme produc...
Article
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The effects of food processing on γ‐aminobutyric acid (GABA) losses in GABA solution and germinated soymilk (GSM) were investigated. The different processing steps included variation in pH (2.0–8.0), temperature (70 and 90°C), storage (8 days), and sugar addition (0% and 5%). Results showed that no significant effects of temperature and sugar addit...
Article
Rambutan (Nephelium lappaceum L.) peel (RBP) is discarded as main by‐product during processing of the fruit. Increasing attention is now paid to the valorization of RBP for the recovery of valuable compounds. Geraniin, ellagic acid, quercetin, and rutin were the main phenolic compounds found in methanolic RBP extract. Extracted rambutan peel powder...
Article
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Enzymatic browning of Iceberg lettuce was studied by subjecting midrib tissues to a series of mild heat treatments. The effects of wounding and subsequent application of a mild heat treatment were examined by monitoring the browning potential (BP) and the activity of three browning‐related enzymes (i.e., phenylalanine ammonia lyase [PAL], polypheno...
Article
As the interface between the luminal and internal environment, the intestinal epithelium is strongly exposed to food-related, host-related and microbial stress. Furthermore, the endothelial stress response plays an important role in vascular disease development, which may be improved upon consumption of dietary bioactives such as polyphenols. The i...
Article
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Background Water quality in the drinking water system (DWS) plays an important role in the general health and performance of broiler chickens. Conditions in the DWS of broilers are ideal for microbial biofilm formation. Since pathogens might reside within these biofilms, they serve as potential source of waterborne transmission of pathogens to live...
Article
Terasies are traditional Indonesian condiments based on rebon (planktonic shrimp), typically added to chili sauce (sambal-terasi). Terasies vary highly in composition and quality and therefore it is difficult to standardize sambal-terasi production. A hedonic test using 118 untrained panelists showed that the salty and the rebon flavor were key att...
Data
The data include the growth of lactic acid bacteria in soymilk in term of log CFU/ml, the effect of fermentation on pH, Titratable acidity, total phenolic compounds, oligosaccharides, antioxidant activity.
Article
Full-text available
Soymilk is a good source of proteins and health-promoting isoflavones, but it contains oligosaccharides that cause flatulence. Fermenting it with probiotic bacteria may reduce the oligosaccharides and enhance its health benefits.The present study determined the growth of different lactic acid bacteria (LAB) in soymilk obtained from soybean varietie...
Article
Peel and seeds of red‐skinned passion fruit, mango, longan, rambutan, white‐flesh and red‐flesh dragon fruit were screened for their in vitro antioxidant activity, and determination of a detailed profile of phenolic compounds. Rambutan peel and mango seed extracts exhibited the highest total phenolic content and antioxidant activities (DPPH, ABTS a...
Article
Simulated static in vitro digestion of tef injeras, sampled after different fermentation times, was performed to measure the dialyzable (D) and soluble nondialyzable total phenolic (TPC), total flavonoid contents (TFC), and their total antioxidants using ABTS, DPPH and FRAP assays. The %TPC and %TFC of D and SND fractions of the in vitro digested i...
Article
Full-text available
The potential of selected industrial food wastes from juice and nut production including apple peel, apple pomace, pomegranate peel, pomegranate seed, chestnut shell, and black carrot pomace as resources for natural antioxidants was investigated. Soluble free and insoluble-bound phenolics were extracted from the wastes and analyzed for total phenol...
Article
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Soybean is a critical food and nutritional security crop in Rwanda. Promoted by the Rwandan National Agricultural Research System for both adults and as an infant weaning food, soybean is grown by approximately 40% of households. Soybean may be susceptible to the growth of mycotoxin-producing moulds; however, data has been contradictory. Mycotoxin...
Article
The goal of this study was to investigate changes in nutritional quality of fish silage during refractance window (RW) drying. Furthermore, the effect of protein hydrolysis-degree of fish silage on production efficiency (%-moisture evaporated and production rate) was determined. To acquire a dried product, fish silage was conveyed (30 cm/min) on a...
Article
Full-text available
Fermentation with filamentous fungi is known for the ability to convert bioactive compounds. The aim of this research was to investigate the metabolism of glycosidic derivatives of kaempferol and quercetin during fungal fermentation of extracts from cauliflower outer leaves and onion by Rhizopus oryzae and R. azygosporus. The highest release of kae...
Article
Maize, sorghum and millet fermented porridges are important as complementary foods for young children in Africa. The objective of the present study was to gain some insights into the bacterial communities of fermented slurries prepared from maize, sorghum and millets originating from different locations in Zimbabwe, and prepared either at household...
Article
Successful strategies to improve iron and zinc bioaccessibility of cereals can only be realized based on a thorough understanding of the mineral to mineral binder interactions. Therefore, exogenous enzymes were used i.e. phytase and a multiple enzyme system comprising of phytase, laccase and tannase (P + L + T) to degrade phytic acid and phenolic c...
Article
The effect of sourdough amount and storage time on starch digestibility and estimated glycemic index (eGI) of tef bread was investigated. The rapidly digestible starch (RDS), slowly digestible starch (SDS) and resistant starch (RS) of 0-30% sourdough fresh tef breads ranged from 49 to 58, 16 to 29 and 20 to 26 g/100 g starch, respectively. Storage...
Article
Cereals are of low iron and zinc bioavailability because of high phytic acid (PA) and phenolic compounds (PC). Affordable and sustainable food based strategies are crucial in alleviating mineral deficiencies. In the present study, we evaluated the effect of enriching fermented cereals commonly consumed in Zimbabwe with baobab fruit pulp as a source...
Article
Hydrolysis of lignocellulosic substrates is impeded by the lignin polymer, acting as a seal around the cellulose and hemicellulose polymer. To facilitate hydrolysis and improve biomethane production, pretreatment of the substrate is required. However harsh pretreatments prior to anaerobic digestion can cause a release of inhibitory phenolic compoun...
Chapter
Non-extractable polyphenols (NEPP) are polyphenols remaining in the solid residues after aqueous-organic extraction, which are mostly proanthocyanidins, hydrolysable tannins and phenolic acids bound to the food matrix. The aim of this chapter is to provide an overview on current extraction and analysis methods of NEPP. Advantages and drawbacks of e...
Article
Full-text available
This review covers the nutritional significance of tef cereal as compared to other common cereals with emphasis on carbohydrate content and starch digestibility, protein content, iron and zinc bioavailability and antioxidant potentials. Tef is a gluten free cereal and contains the highest iron and calcium among other cereals. It has high micro- and...
Article
Producing fish silage for animal feed is an excellent way of valorizing underutilized fishery byproducts. However, the nutritional quality of fish silage strongly depends on the freshness and composition of the raw materials. The purpose of this study was to determine the effect of raw material composition (RMC) on nutritional quality and stability...
Article
Full-text available
Biofilms are an important source of contamination in food companies, yet the composition of biofilms in practice is still mostly unknown. The chemical and microbiological characterization of surface samples taken after cleaning and disinfection is very important to distinguish free-living bacteria from the attached bacteria in biofilms. In this stu...
Article
Full-text available
In this study, SDS-PAGE characterization of total protein and Osborne fractionation, in-vitro digestibility and immunogenicity of tef protein of seven different varieties were investigated. The contribution of globulin fraction alone ranged from 51 to 61% making it as the major storage protein in tef flour. The Osborne fractionation method resulted...
Article
Full-text available
Abstract Tef [Eragrostis tef (Zucc.) Trotter], an ancient cereal mainly produced in Ethiopia, is increasingly getting higher acceptance in the global market because it is gluten free and has high iron content. The aim of this study was to evaluate the in vitro dialysability of Fe and Zn in a backslop fermented gluten free flat bread known as injera...
Article
The present study is an evaluation of iron and zinc bioaccessibility of fermented maize, sorghum, pearl millet and finger millet from five different locations in Zimbabwe. Iron and zinc contents ranged between 3.22 and 49.7 and 1.25–4.39 mg/100 g dm, respectively. Fermentation caused a reduction of between 20 and 88% of phytic acid (PA) while a gen...
Article
Aronia phenolics are considered to be beneficial for cardiovascular health, but are not always bioavailable. In this study, we evaluated the in vitro bioavailability of Aronia juice phenolics by combination of intestinal digestion models with Caco-2 absorption models. First, intestinal luminal stability and microbial metabolism of Aronia phenolics...