Nicolas Louka

Saint Joseph University, Lebanon | USJ · Process Engineering - Chemistry

Highly valued for their nutritional benefits, sprouts are characterized by high water content, which promotes microbial proliferation, potentially leading to toxicity and a reduced shelf life. To address this challenge, the present study explores the application of a novel drying–texturizing approach, named IVDV (Intensification of Vaporization by...

(1) Background: Cumin seeds, extracted from the plant Cuminum cyminum, are abundant in phenolic compounds and have been extensively researched for their chemical makeup and biological effects. The objective of this research is to enhance the water extraction of polyphenols through the water bath (WB) technique and to evaluate the antiradical, antib...

“Intensification of Vaporization by Decompression to the Vacuum” (IVDV) has initially emerged as a technology primarily employed for expanding and enhancing the texture of biological products. However, its recent applications have showcased significant promise in the realm of extracting bioactive molecules from various plant materials. In this cont...

Colorimetric whole-cell biosensors are natural or genetically engineered microorganisms utilized to detect target molecules and ions as indicators of pollutants and biological activity in the environment. Upon detection, within specific concentration ranges which vary depending on the microorganism and its genetic circuitry among other factors, the...

Olive leaves are naturally generated as a by-product during olive harvesting and olive oil production. Usually discarded with no specific use, they are a valuable source of bioactive compounds that should not be overlooked. Their valorization must therefore be achieved through the recovery of their polyphenols using an ecological strategy. Conventi...

The present invention provides a novel process for alcoholic fermentation of wine and other fermented products using single or co-culture biofilm of yeasts. The process involves the use of a biofilm-based fermentation system, which enhances the efficiency and quality of the fermentation process by providing a stable microbial community that improve...

Accurate determination of Young’s modulus of elasticity in irregularly shaped products is quite challenging. This study introduces a novel method that can measure the elasticity in non-uniform products, such as peanuts. Variations of the contact surface between the peanut and a crosshead were precisely calculated using this technique based on kerne...

Peanuts, being crucial crops of global importance, have gained widespread recognition for their versatility and nutritional value. In addition to direct consumption, either with or without treatment, peanuts can be the subject of diverse applications focusing mainly on two distinct objectives: oil extraction and defatting processes. As a result of...

Many emerging factors and circumstances urge the need to develop and optimize the detection and quantification techniques of mycotoxins in solid food and feed. The diversity of mycotoxins, which have different properties and affinities, makes the standardization of the analytical procedures and the adoption of a single protocol that covers the attr...

As greenhouse gas emissions are continuously increasing, research is now privileging greener and more sustainable human activities. An attractive strategy in the pursuit of sustainability is the valorization of lignocellulosic biomasses for the production of bioethanol. This approach relies on the bioconversion of wood and agricultural waste, which...

Extraction of polyphenols from Centranthus longiflorus stems was conducted using ultrasound and infrared Ired-Irrad® techniques, and compared to the conventional water bath method. Response surface methodology was used to analyse the effect of time, temperature, and ethanol percentage, as well as to optimize the three extraction methods. The highes...

Violacein and deoxyviolacein are bis-indole pigments synthesized by a number of microorganisms. The present study describes the biosynthesis of a mixture of violacein and deoxyviolacein using a genetically modified Y. lipolytica strain as a production chassis, the subsequent extraction of the intracellular pigments, and ultimately their purificatio...

Formation of Lactobacillus rhamnosus GG biofilm on three different abiotic supports (glass, stainless steel, and polystyrene) over a five-day incubation period was investigated. The changes in expression of the regulatory genes were assessed at 4, 6, 8, 24, 48, and 72 h. These genes, including MaAb, LuxS, and the extracellular polysaccharides (EPS)...

Poultry waste is rich in organic matter, which allows its treatment by the process of anaerobic digestion (AD) to reinforce economic and environmental green strategies. The aim of this study is to assess the technical feasibility of poultry waste AD in semi-continuous mode and to intensify methane production by co-digestion with physico-chemical sl...

Peanuts are the seeds of a legume crop grown for nuts and oil production. Peanut allergy has gained significant attention as a public health issue due to its increasing prevalence, high rate of sensitization, severity of the corresponding allergic symptoms, cross-reactivity with other food allergens, and lifelong persistence. Given the importance o...

Poultry waste are rich in organic matter, allowing its use as substrates for biogas production by anaerobic digestion (AD). The major difficulty in the anaerobic digestion of this protein-rich waste is the ammonia inhibition. Different results of biochemical methane potential (BMP) were obtained after the mesophilic anaerobic digestion of different...

Bacillus thuringiensis is the leading microbial-based biopesticide, thanks to its parasporal crystal proteins or δ-endotoxins, which are toxic to insect larvae upon ingestion. Once in the insect larvae midgut, the crystal is solubilized by the alkaline pH and the δ-endotoxins activated by proteolytic cleavage. Thanks to its high efficiency as a bio...

The intensification of total phenolic compound (TPC) extraction from blood orange peels was optimized using a novel green infrared-assisted extraction technique (IRAE, Ired-Irrad®) and compared to the conventional extraction using a water bath (WB). Response surface methodology (RSM) allowed for the optimization of ethanol concentration (E), time (...

Grape seeds are the wineries’ main by-products, and their disposal causes ecological and environmental problems. In this study seeds from the pomace waste of autochthonous grape varieties from Lebanon, Obeidi (white variety) and Asswad Karech (red variety) were used for a multi-step biomass fractionation. For the first step, a lipid extraction was...

Mycotoxins in solid foods and feeds jeopardize the public health of humans and animals and cause food security issues. The inefficacy of most preventive measures to control the production of fungi in foods and feeds during the pre-harvest and post-harvest stages incited interest in the mitigation of these mycotoxins that can be conducted by the app...

The gastrointestinal tract is one of the most complex microbiological niches containing beneficial and non-pathogenic bacterial strains of which some may evolve into virulent under specific conditions. Lactobacillus rhamnosus GG is of the most known beneficial species with an ability to protect the intestine as opposed to Staphylococcus epidermidis...

This study assessed the removal of aflatoxin M1 (AFM1) and ochratoxin A (OTA) from artificially contaminated whole UHT milk and red grape juice, respectively, using biofilms from Lactobacillus rhamnosus GG. Using ELISA, the level of AFM1 and OTA removal from beverages was determined depending on various factors. Biofilms of various ages demonstrate...

Valorize different food byproducts Extract polyphenols and bioactive compounds from different food waste matrices using innovative technologies. This will be followed by the use of the remaining organic material to produce biogas through anaerobic digestion but also composting. Zero waste strategy The main goal of our work is to establish initiat...

While world energy demand has certainly decreased with the beginning of the COVID-19 pandemic in 2020, the need has been significantly on the rise since 2021, all as the world’s fossil fuel resources are depleting; it is widely accepted that these resources emit greenhouse gases (GHG), which are the leading cause for the climate crisis. The main co...

(1) Background: Eryngium creticum is a plant medicinally valued, and used in pharmacopeia to treat various diseases. No previous studies have been reported on E. creticum leaf extracts using an IR-assisted technique; thus, this study aimed to intensify polyphenol extraction using Ired-Irrad®, comparing it to the conventional water bath (WB) method....

An ecofriendly extraction technology using infrared (IR) irradiation Ired-Irrad® was applied to purple corn cobs to enhance polyphenol recovery for the first time. The IR extraction efficiency was compared to that of the water bath (WB) method. Response surface methodology (RSM) using a central composite design was conducted to determine the effect...

A large amount of citrus by-products, especially peels, is generated every year by citrus processing industries. These citrus peels can however be valorized by turning them into healthy snacks in the form of crispy chips rich in vitamins and polyphenols. Such transformation requires a preliminary partial drying step combined with IVDV (Intensificat...

Ultrasound-assisted extraction is commonly used nowadays in food technology as a substitute for the conventional extraction technique, to improve the recovery of bioactive molecules from plant materials. In this study: - Thermal and mechanical effects of the ultrasound treatment on the olive leaves tissue damage were investigated. - Temperature dep...

Grape seeds are agro-industrial by-products, which if improperly managed, may be responsible for socioeconomic and environmental problems. Nevertheless, it is possible to effectively valorize them by means of extraction of the bioactive compounds, especially the antioxidant phenolic molecules, using a safe, green, and environmentally-friendly extra...

Odd-chain fatty acids (OCFA) have been studied for their therapeutic and nutritional properties, as well as for their potential use in the chemical industry for the production of biofuel. Genetic modification strategies have demonstrated an improved production of OCFA by oleaginous microorganisms. In this study, the production of OCFA-enriched lipi...

Wheat, alfalfa, and radish sprouts are well-renowned for their high nutritional content. However, their optimal imbibition and germination durations are rarely considered in the literature. In this study, reduced imbibition times of 3 h, 10 h, and 4 h were demonstrated for the wheat, alfalfa, and radish seeds, respectively. The evolution of their c...

Mycotoxins are generally found in food, feed, dairy products, and beverages, subsequently presenting serious human and animal health problems. Not surprisingly, mycotoxin contamination has been a worldwide concern for many research studies. In this regard, many biological, chemical, and physical approaches were investigated to reduce and/or remove...

This work aims to develop and simulate a novel process based on sterilizing natural air by heating at high temperatures followed by rapid cooling. The new sustainable process is called “Air Rapid Heating Rapid Cooling Sterilization” (ARHRCS). Thus, it can be used in Heating, Ventilation, and Air Conditioning (HVAC) systems in hospitals to produce s...

Brewers’ spent grains constitute a valuable byproduct of the beer industry. They are characterized by a rich nutritional composition consisting of around 70% lignocellulosic fibrous material, 20% proteins, 10% lipids, in addition to vitamins, minerals, amino acids, and phenolic compounds. These spent grains are produced in large amounts all through...

Due to its pleasant rosy scent, the aromatic alcohol 2-phenylethanol (2-PE) has a huge market demand. Since this valuable compound is used in food, cosmetics and pharmaceuticals, consumers and safety regulations tend to prefer natural methods for its production rather than the synthetic ones. Natural 2-PE can be either produced through the extracti...

Polyphenols are secondary metabolites, naturally found in plants. They are typically known for their antioxidant activity and beneficial impact on health. Extraction of polyphenols from biological matrices is the first step toward their valorization. Many methods of separation (chromatography) are used to separate the polyphenols from the undesirab...

The influence of ultrasound treatment (US) on cellular damage of olive leaf tissue was studied. Mechanical damage and thermal effect of US were characterized. The level of tissue damage was defined by the diffusivity disintegration index ZD based on the diffusivity of solutes extracted from olive leaves differently treated. The Arrhenius form using...

The increased demand for conscious, sustainable and beneficial products by the consumers has pushed researchers from both industries and universities worldwide to search for smart strategies capable of reducing the environmental footprint, especially the ones connected with industrial wastes. Among various by-products, generally considered as waste...

Citrus genus is a prominent staple crop globally. Long-term breeding and much hybridization engendered a myriad of species, each characterized by a specific metabolism generating different secondary metabolites. Citrus aurantium L., commonly recognized as sour or bitter orange, can exceptionally be distinguished from other Citrus species by unique...

A new innovative cannon puffing technology, called Vac‐Can‐Puff (VCP), consisting of a puffing gun connected to a vacuum pump, was conceived for the production of half‐popped purple corn snacks. This newly designed system was used to achieve a homogenized expansion of corn kernels in bulk. After selecting the soaking, puffing, and roasting methods,...

The production of pigments using single cell microorganisms is gaining traction as a sustainable alternative to conventional syntheses, which rely, in no negligible proportions, on petrochemicals. In addition to depending on petroleum, these syntheses involved the use of toxic organic solvents, which may be inadequately disposed of across a range o...

This review aims to pin out the importance of developing a technique for rapid detection of antioxidants, based on molecular imprinting techniques. It covers three major areas that have made great progress over the years in the field of research, namely: antioxidants characterization, molecular imprinting and electrochemistry, alone or combined. It...

Fermentation is a complex bioreaction that implicates all parts of microorganisms to transform a substrate into a product, which can be a molecule, a produced microorganism, or an energy form. The fermentation principle is based on electrochemical and biochemical transfers that require a delicate stoichiometry and medium equilibrium. The culture me...

This study proposed to investigate the impact of ripening on the physical properties of mango purees. An extensive study of the particle size and rheological properties of mango purees and their dispersed phase was performed using particle size measurements, small deformation rheology, and an innovative technology combining simultaneous rheometry a...

Mango is one of the most produced fruits and consumed worldwide, known for its color, taste, flavor and rich nutritional composition. However, its abundant production leads to post-harvest losses that can be estimated up to 40% in some countries (Tiyayon & Paull, 2017). Hence, processing mango can be an alternative to reduce losses and generate sig...

Impact of the “Intensification of Vaporization by Decompression to the Vacuum” (IVDV) on extraction of polyphenols from olive leaves was investigated. Using Response Surface Methodology, the effect of three variables were studied: initial water content of leaves, processing time and steam pressure on total phenolic content (TPC). Extractions of TPC...

The aim of this work is to develop and simulate a novel process based on sterilizing natural air by heating at high temperatures followed by a rapid cooling. The new sustainable process is called “Air Rapid Heating Rapid Cooling Sterilization” (ARHRCS). Thus, it can be used in Heating, Ventilation, and Air Conditioning (HVAC) system in hospitals to...

Fermented apple beverages are produced all over the world with diverse characteristics associated with each country. Despite the diversifications, cider producers are confronted with similar issues and risks. The nature of the raw material, also known as the fermentation medium, plays a key role in fermentation. A well-defined composition of apples...

Treatment and management of lactoserum from dairy industry has become a global issue. In fact, generated effluents have high organic loads (lactose, protein, vitamin, minerals ... etc.) constituting a major source of environmental pollution. In a sustainable green approach, anaerobic digestion is considered a promising solution for the treatment of...

A novel process, 'mechanical expression preserving shape integrity', was conceived to prepare low-fat peanuts in response to health-conscious consumer demands. The main purpose of this study was to preserve the taste, aroma, and oxidative stability of the defatted product. Results generated from a central composite rotatable design showed that high...

The present work studied the fermentative potential and carbon metabolism of an indigenous yeast isolated from Lebanese apples for cider production. The indigenous yeast strain was isolated from a spontaneous fermented juice of the Lebanese apple variety 'Ace spur'. The sequencing of the Internal Transcribed Spacer (ITS) domain of ribosomal DNA ide...

Mango has an abundant production leading to important post-harvest losses. Mango processing is an alternative to reduce these losses. Nowadays, the lack of instrumental tools suitable to sort mangos according to their ability to be processed into products with specific quality is a main setback for their processing. The aim of this study was to dev...

In an era where plants based and healthy diets are more adopted by the consumers and where the environment-friendly processes are are prevailing, preservation of nutritious natural sprouts by a time and energy saving treatment prompted us to conduct this study. Optimization of the germination of common wheat and Kamut grains was first presented...

he aim of this study is to optimize the conventional solid-liquid extraction of total phenolic compounds and anthocyanins from purple corn cobs using response surface methodology (RSM). The effects of time, temperature and 𝛽-cyclodextrin concentration on polyphenol recovery were studied. Results of the central composite design showed that the o...

Optimization of the defatting process of peanuts was conducted using response surface methodology, varying the time and temperature of the solvent-free infrared (Ired-Irrad®) pretreatment. Results of the central composite design, exploited in Statgraphics centurion®, showed that the peanut oil extraction yield increased from 30% to 45% when pe...

Maximization of polyphenols recovery from olive leaves by conventional water bath extraction was investigated using infrared irradiation as a pretreatment. A multivariate study enabled us to define the best experimental parameters for polyphenol extraction: 1:20 (w/v) for the solid to liquid ratio; 60°C and 75% ethanol/water. Untreated and infr...

In this study, the optimization of ultrasound‐assisted aqueous extraction of polyphenols from pomegranate peels and seeds was conducted. A 10‐min sonication (tu) pre‐treatment (≈60 W) accelerated the extraction kinetics and intensified the polyphenol recovery from peels and seeds. Ultrasound pre‐treatment permitted the selective recovery of polyphe...

In the present research work, the physicochemical and fermentative properties of the “Ace spur” apple variety, obtained from a Lebanese farm, and the “Kermerrien” variety, obtained from a French cider industry, were investigated. The pomological properties were first determined for both varieties showing significant differences in the shapes and si...

Background: Saussurea lappa is a traditionally well-known plant appreciated for its biological activities and medicinal uses. Objective: In the present study, the recovery of antioxidants from Saussurea lappa was optimized using Response Surface Methodology (RSM). The efficiency of a newly-patented infrared (IR) technology, Ired-Irrad®, was compar...

Background: Saussurea lappa is a traditionally well-known plant appreciated for its biological activities and medicinal uses. Objective: In the present study, the recovery of antioxidants from Saussurea lappa was optimized using Response Surface Methodology (RSM). The efficiency of a newly-patented Infrared (IR) technology, Ired-Irrad®, was compar...

Les feuilles d’oliviers sont des coproduits issus de l’industrie d’huile d’olive, généralement éliminées comme déchets. L'extraction assistée par infrarouge est une nouvelle génération de machines respectueuses de l'environnement qui améliore l'extraction des composés bioactifs des matrices naturelles en utilisant un émetteur infrarouge en céramiqu...

This study aims to evaluate the impact of a nonconventional pretreatment technique “infrareds free solvent” on the intensification of polyphenols extraction from orange peels. Orange peels were pretreated with infrared heating using a ceramic infrared transmitter from 5 to 25 min at 50 °C. After the addition of the solvent on the pretreated peels,...

The present work studies the impact of low-intensity ultrasound (US) on Hanseniaspora sp. yeast fermentations. The effect of pulse duration and growth phase on US application was first evaluated using a synthetic medium. The optimal conditions were then applied to apple juice US-assisted fermentation. An US treatment chamber was first designed to a...

Mango has abundant seasonal production which leads to fruit postharvest waste up to 50% for some countries, particularly in West Africa. Processing mango into stabilized products such as purees or dried mangos could be an alternative to reduce this postharvest loss. Nevertheless, selection of mangos to be processed is largely based on objective cri...

The effect of moderate pulsed electric fields (PEF) on Hanseniaspora sp. fermentations in apple juice was examined. The treatments were applied prior to or during the fermentation using a field strength of 285 V/cm. A significant increase (p < 0.05) in the biomass growth was observed during all the treatments along with a significant decrease (p <...

Hanseniaspora sp. yeast was stimulated using pulsed electric field (PEF) during the different fermentation phases. The impact of PEF parameters on the growth rate and substrate consumption was studied. The PEF intensities chosen for this study were mainly in the range of 72-285 V.cm-1. A PEF treatment chamber was designed for this study with a rati...

Mango has abundant seasonal production which leads to fruit post-harvest waste up to 50% for some countries, particularly in West Africa. Processing mango into stabilized products such as purees could be an alternative to reduce this post-harvest loss. Nevertheless, selection of mangos to be processed is largely based on objective criteria (softnes...

Mango has abundant seasonal production which leads to fruit post-harvest waste up to 50% for some countries, particularly in West Africa. Processing mango into stabilized products such as purees could be an alternative to reduce this post-harvest loss. Nevertheless, selection of mangos to be processed is largely based on objective criteria (softnes...

Applying pulsed electric field (PEF) at low intensities to microorganisms, considered at sub-lethal levels, may involve microbial stimulation rather than inactivation. Several observations have been reported compared to the non-stimulated controls, such as the acceleration of fermentation, a better production of the metabolites of interest, and a l...

The effects of aqueous extraction of bioactive compounds from pomegranate peels using conventional extraction (CE) and extraction assisted by infrared irradiation (IR), ultrasound (US), pulsed electric fields (PEF), and high-voltage electrical discharges (HVED) have been compared. For the extractions assisted by US, PEF and HVED, the saturation in...

Optimization of infrared-assisted extraction was conducted using Response Surface Methodology (RSM) in order to intensify polyphenol recovery from olive leaves. The extraction efficiency using Ired-Irrad®, a newly-patented infrared apparatus (IR), was compared to water bath (WB) conventional extraction. Under optimal conditions, as suggested by the...

Aflatoxins (AF) are carcinogenic metabolites produced by different species of Aspergillus which readily colonize crops. AFM1 is secreted in the milk of lactating mammals through the ingestion of feedstuffs contaminated by aflatoxin B1 (AFB1). Therefore, its presence in milk, even in small amounts, presents a real concern for dairy industries and co...

This invention reveals the novel ability of the biofilm matrix to bind mycotoxins produced by different kinds of fungi. Our method consists of using partial or full biofilm’s matrices produced by any non-harmful microorganisms including lactic acid bacteria and yeast in order to decontaminate beverages from mycotoxins. This method proposes the use...

In this study, polyphenols were extracted from pomegranate peels with solid-liquid (SL), ultrasound (US) and Ired-Irad® a newly-patented infrared (IR) extraction technique. Deep eutectic solvents were used as green alternatives to conventional aqueous or organic solvents. The extraction process was conducted at 50 °C for 90 min. The biological (ant...

Background: Saussurea lappa (S. lappa, Asteraceae) have immunomodulatory-effects, and used in the management of many metabolic-disorders. Gestational-diabetes is one of metabolic-disorders affecting globally one in seven pregnant-women. Objectives - The aim of the current-study is to optimize an infrared-assisted extraction (IR-AE) method for S. la...

Introduction: Olives are one of the most produced crops worldwide. According to the FAOSTAT, Lebanon produced almost 117,000 tons in 2014; it is standing at the 11th place in the world. Olive fruits are consumed entirely, or crushed to extract their oil. During harvesting, olive leaves lost represent up to 25% of the total weight of olives (dependi...

This study aimed to develop a new method for detoxification of milk from aflatoxin M1 (AFM1) by using Lactobacillus rhamnosus GG biofilm. After inoculation of milk contaminated with AFM1 into L. rhamnosus GG biofilm, the unbound AFM1 was extracted and quantified by HPLC. The stability of the formed AFM1/biofilm complex using different AFM1 contamin...

With the onset of advanced age, cardiac‐associated pathologies have increased in prevalence. The hallmarks of cardiac aging include cardiomyocyte senescence, fibroblast proliferation, inflammation, and hypertrophy. The imbalance between levels of reactive oxygen species (ROS) and antioxidant enzymes is greatly enhanced in aging cells, promoting car...

The valorization of industrial food byproducts by means of environment-friendly extraction methods is becoming a major interest because of its environmental and economic values. In this study, the efficiency of many technologies, such as ultrasounds (US), microwaves (MW), and infrared (IR), was compared, in terms of polyphenol yield and bioactivity...

Organic waste generation is constantly increasing due to industrialization and various treatment processes. Nowadays, anaerobic digestion, as a green technology, is widely used to convert organic waste, into methane, and subsequently, into bioenergy. In this study, our main objective was to evaluate the feasibility of applying anaerobic digestion t...

Coffee is one of the most popular beverages in the world. Over 50% of this mass is discarded after use, becoming a significant waste source known as spent coffee grounds (SCG). SCG usage as a raw material for biogas production emerges with great potential. In this study, we investigated the biochemical composition of SCG and its potential as a gree...