Dimitris P Makris

University of Thessaly | UTH · Department of Food Science & Nutrition

The current project aimed at examining the effect of the enrichment of commercial seed oils with waste orange peel (WOP) extracts on their polyphenolic profiles and resistance against oxidation. Polyphenol-containing WOP extracts were produced using a novel combination of ethanol and triacetin, and they were incorporated into seed oils (sunflower,...

The current study aimed at developing an effective organosolv treatment, with the objective to obtain potato peel extracts highly enriched in polyphenols. To this end, two low-cost solvents were employed, 1-and 2-propanol, which are considered green, but they have been rather poorly studied compared to other conventional solvents, such as ethanol....

The examination presented herein sought to establish a novel methodology for the efficient recovery of polyphenolic antioxidants from coffee processing residues, namely coffee silverskin (CSS). The process developed was an ethanol-based organosolv treatment, assisted by acid catalysis, using sulfuric acid or oxalic acid as the catalyst. The first a...

Onion skins (OS) are a by-product of onion processing that causes both biological and environmental problems. Thus, OS could be used sustainably and as means of circular economy since they contain valuable bioactive compounds that can be used for the production of high-added-value products. This study aims to evaluate the potential antioxidant, ant...

Oat bran (OB) may be regarded as food industry by-product, with a high perspective as a bioresource in the production of high-value polyphenolic substances. On this basis, the investigation presented herein aimed at (i) using 1-and 2-propanol organosolv treatment and studying the effect of an alkali (sodium hydroxide) catalyst on releasing bound po...

Every day, more and more consumers choose to drink bottled water instead of tap water, since they believe that it is superior in quality. One of the criteria used by European consumers to choose bottled water is the geographical region of the spring. The flavor of the water is an additional factor that influences consumers' choices. As a result, de...

The aim of this study was to evaluate the efficiency of successive extraction (using solvents of increasing polarity, namely hexane, ethyl acetate, acetone, ethanol, and water) of polyphenols from Cistus creticus L. The results were compared with the ones obtained from a single-solvent extraction (ethanol, water, and 50% ethanol: water). According...

Background: Currently, the use of medicinal plants has increased. Artemisia species have been used in several applications, including medicinal use and uses in cosmetics, foods and beverages. Artemisia arborescens L. and Artemisia inculta are part of the Mediterranean diet in the form of aqueous infusions. Herein, we aimed to compare the secondary...

The current examination dealt with the development of a methodology to produce quercetin, a multifunctional bio‐flavonoid, by designing task‐specific, highly acidic deep eutectic solvents, based on glycerol and natural organic acids. The purpose was to achieve a simultaneous hydrolysis of spiraeoside, the major quercetin glycoconjugate occurring in...

To produce sufficient food for the expanding global population, natural resources are constantly being overused, and at the same time, wastes are being produced at an ever-increasing rate [...]

Apricot kernels are known to be rich in bioactive compounds such as polyphenols, which have applications in various fields such as cosmetology and the food industry. However, the extraction of these compounds has not been extensively studied. In this study, we aimed to extract oil from apricot kernels and investigate its composition and antioxidant...

The vineyard of Cyprus is comprised largely of native Vitis vinifera varieties, which are rather underexploited with regard to wine production to date. Although empirical observations concur that several of these varieties may possess a high potential for the production of quality wines, analytical data pertaining to their polyphenolic composition...

Apricots are one of the most important fruits in the Mediterranean region for both their nutritional and economic value. They are widely cultivated and consumed fresh or dried or are used in the food industry for the production of jams, juices, etc. In any case, the seeds they contain constitute waste. The kernels are very rich in bioactive compoun...

The present study examines, compares, and documents the environmental impact of five extraction techniques through Life Cycle Assessment (LCA). The material used was Moringa oleifera freeze-dried leaves and the assessment was based on their polyphenol content Three out of the five examined techniques are referred to in the literature as “green” tec...

This study had as a goal to carry out the drying of red grape pomace (RGP) using a 2 × 3 factorial design. The design of the experiment included combinations of time and temperature in order to achieve the lowest possible moisture levels and examine losses in precious polyphenols, but also the effect on the antioxidant properties of RGP extracts. D...

In this study, an alternative debittering technique for olives, invented and patented by Prof. Vassilis Dourtoglou, was employed. Olive fruits (Olea europaea cv. Megaritiki) were stored under CO2 atmosphere immediately after harvest for a period of 15 days. After the treatment, a sensory evaluation between the olives stored under CO2 and those stor...

Wheat bran (WB) is globally a major food industry waste, with a high prospect as a bioresource in the production of precious polyphenolic phytochemicals. In this framework, the current investigation had as objectives (i) to use ethanol organosolv treatment and study the effect of acid and alkali catalysts on releasing bound polyphenols, (ii) establ...

Peppermint (Mentha × piperita L.) is a popular medicinal and aromatic plant, cultivated in several areas around the globe. Its functional and therapeutic potential has been largely attributed to its polyphenolic composition, yet rather a few investigations have delt with the preparation of polyphenol-enriched extracts from this plant. On this groun...

Onion solid wastes (OSW) are a food side-stream with high polyphenolic load and distinguished polyphenolic profile. This study was conducted in order to explore a novel methodology of production of polyphenol-enriched extracts with antioxidant properties from OSW, using glyc-erol and green deep eutectic solvents (DES), composed of glycerol/citric a...

Waste orange peels (WOP) are a food processing residue rich in bioactive polyphenols. However, data on aqueous extraction processes for efficient polyphenol recovery are rather limited. The present study dealt with the optimization of WOP polyphenols, using a batch stirred-tank mode and water as solvent. After a preliminary single-factor examinatio...

The interest in extracting bioactive compounds from food processing waste is growing unabated. Apricots are widely consumed worldwide, and many tons of waste are produced annually. Therefore, apricot pulp waste (APW) may serve as a rich source of bioactive compounds. In the present study, we investigated the extraction of antioxidant polyphenols an...

To date, many studies have been published, aiming to extract bioactive compounds from plants. Lately, research focuses on maximizing the extraction yield, using environmentally friendly techniques and solvents. In this study, the extraction of polyphenolic compounds from Cistus creticus is discussed. Extraction of the compounds has been carried out...

In this study, the use of pulsed electric field (PEF) for the extraction of polyphenols from mature Elaeagnus pungens ‘Limelight’ leaves is discussed. Optimization of the main parameters that affect the extraction process was carried out. More specifically, the composition of the solvent (ethanol, water, and mixtures of the two at a 25% v/v step gr...

Rhodosporidium toruloides NRRL Y-27012 grown in glycerol, produced yeast biomass and secondary metabolites as lipids (L) and intra-cellular polysaccharides (IPS) in trials under nitrogen limitation (initial C/N molar ratios ≈50, ≈100, ≈160 and ≈240). Initial glycerol (Glol0) concentration for all experiments was ≈90 g/L. The yeast demonstrated very...

This study explored the use of β-cyclodextrin (β-CD) as an additive to improve the aqueous extraction of antioxidant polyphenols from peppermint (Mentha χ piperita). For this purpose, an initial single-factor screening was performed to test the effect of β-CD concentration on the yield of polyphenol extraction. In the following step, the extraction...

Extraction of polyphenolic compounds from lemon peels using deep eutectic solvents (DES) was investigated. A choline chloride-based DES paired with glycerol was used as the extraction solvent, alternative to conventional ones. Response surface methodology (RSM) was employed to optimize the extraction parameters, namely, the water concentration (CW)...

Agricultural practices, industrial manufacturing, and household consumption are just a few of the activities that contribute to the production of food waste biomass. Modern environmental theories, like the circular economy, are thought to be the impulse behind the implementation of zero-waste policies. A huge percentage of this residual biomass has...

The valorization of red grape pomace is significant as grape is one of the most cultivated fruits worldwide and generated by-product quantities are enormous. For this purpose, numerous encapsulation techniques have been developed. However, the studies on microemulsions composed with deep eutectic solvent extracts are very limited. In this study, re...

In the framework of introducing green strategies for food processing, the industrial orientation has shifted towards the replacement of conventional petroleum-based solvents with alternative eco-friendly ones. On this basis, the objective of this study was to synthesize a novel, tertiary, food-grade deep eutectic solvent, composed of glycerol, citr...

This study was focused on the simultaneous organosolv treatment/extraction of waste orange peels (WOP) for the effective recovery of polyphenolic antioxidants. The treatments were performed with aqueous glycerol mixtures, which were acidified either with citric acid or Hydrochloric acid (HCl). Process optimization was carried out using response sur...

Polyphenols are an important class of compounds, due to their excellent antioxidant properties. Lately, much effort has been placed into developing new extraction techniques and optimizing them, so that polyphenols can be retrieved more efficiently from the plant materials. One of the most recent advances in extraction techniques is pulsed electric...

Sweet potatoes have multiple uses as food, feed, and in industrial production. They are characterized by their need for high temperatures for optimal development. This study aimed to analyze the quantitative and qualitative aspects of growing sweet potato cultivars in southwest Romania using mulching and non-mulching systems. The effects of mulchin...

Olive leaves (OLL) are an agri-food waste that may be regarded as a bioresource rich in bioactive polyphenolic metabolites. In this examination, simultaneous organosolv treatment/extraction of OLL polyphenols at elevated temperatures (>110 �C) has been optimized using glycerol, but also two glycerol-based deep eutectic solvents (DES). The assessmen...

In the current study, Hibiscus sabdariffa has been extracted by microwave-assisted extraction (MAEX). Citric acid-based deep eutectic solvents (DES) have been specially designed, where a hydrogen bond donor (HBD) (glycerol and ethylene glycol) and a hydrogen bond acceptor (HBA) (citric acid) with a certain molar ratio (1/4) were used. After the bes...

The extraction of phenolic compounds from olive leaves was optimized using three glycerol-based deep eutectic solvents (DESs) with lysine, proline, and arginine. A three-level Box–Behnken design was used to examine the influence of the liquid/solid ratio, concentration of DESs, and extraction temperature on the yield of the extraction process. A se...

Fοllow up with our previous study on the extraction of saffron processing waste polyphenols using deep eutectic solvents, the objective of this examination was a comparative evaluation of pressurized liquid extraction (PLE), stirred-tank extraction (STE) and stirred-tank extraction with ultrasonication pretreatment (STE/UP) with respect to the reco...

This investigation was carried out with the scope to examine three commonly used cyclodextrins (CDs), β-cyclodextrin (β-CD), methyl β-cyclodextrin (m-β-CD) and 2-hydroxypropyl β-cyclodextrin (HP-β-CD) as green co-solvents for the effective extraction of polyphenols and pigment from onion solid wastes (OSW). Efficiency appraisal was based on the “ex...

The aim of this study was to reach the optimal conditions for whey proteins hydrolysis using the digestive enzymes, either separately or combined in order to generate peptides with higher antioxidant activity. A full factorial design was employed for the single enzymatic hydrolysis in order to evaluate the effect of two independent factors on the p...

Abstract The hydrolysis of bovine whey proteins was optimized using chymotrypsin, trypsin, and pepsin. The aim of this study was to reach the optimal conditions for whey proteins hydrolysis using the digestive enzymes, either separately or combined in order to generate peptides with higher antioxidant activity. The optimum conditions were applied o...

Olive leaves (OLL) are reported as a source of valuable antioxidants and as an agricultural by-product/waste. Thus, a twofold objective with multi-level cost and environmental benefits arises for a “green” standalone extraction technology. This study evaluates the OLL waste valorization through maximizing OLL extracts polyphenol concentration utili...

Our paper was selected to be the cover page of the BEVERAGES forthcoming issue.

The current study evaluates the Pulsed Electric Field (PEF) technique for the extraction of polyphenols from the plants Rosa canina, Calendulaofficinalis and Castanea sativa. These plants are traditionally used both for the preparation of therapeutic decoctions and the aromatization of beverages (alcoholic or not). Pulses of 10 μs duration were use...

In this examination, two glycerol-based deep eutectic solvents (DESs) were tested for their efficiency in the recovery of antioxidant polyphenols and anthocyanin pigments from red grape pomace (RGP). The two DESs synthesized had sodium acetate and sodium benzoate as hydrogen bond acceptors, to test the role of the hydrogen bond acceptor polarity on...

The present study aimed to evaluate the pulsed electric field (PEF)-assisted extraction of phytochemicals from Salvia officinalis L. leaves. The study parameters included a PEF pulse duration of 10 or 100 μs for 30 min, using different “green” extraction solvents: pure ethanol, pure water, and their mixtures at 25, 50, and 75% v/v concentrations. T...

Winemaking is a process that generates a large volume of solid waste biomass, which is currently under extensive investigation as a bioresource of precious polyphenolic compounds. These substances are retrieved from vinification side streams principally by deploying solid-liquid extraction methods. In this frame, the present investigation had as ob...

This investigation had as objective to study the effective recovery of olive leaf (OLL) polyphenols using a blend of an L-lactic acid/ammonium acetate deep eutectic solvent (DES) with β-cyclodextrin (β-CD). Following an initial DES screening, the extraction process was optimised with response surface methodology by implementing Box-Behnken design....

Medicinal and aromatic plants (MAPs) have always been a source of a vast variety of secondary metabolites with high biological potency. There is to-date an enormous ongoing research on the development of sophisticated methodologies for the production of bioactive MAP extracts, which may be applied in a spectrum of products, such as foods, pharmaceu...

The aim of the present study was to evaluate the physical and antioxidant properties of microemulsions containing Moringa oleifera leaf extract (MLE) produced by the means of a deep eutectic solvent. Selected microemulsions containing MLE were incorporated in chocolate products to enrich them. Their color properties including CIE L*, a*, b* paramet...

Olive leaves (OLL), an agricultural waste by-product, are considered a significant biore-source of polyphenols, known as bioactive compounds. This study evaluates the pulsed electric field (PEF) technique for the extraction of polyphenols from OLL. The study parameters included a series of "green" solvents (ethanol, water as well as mixtures of the...

The aim of the present study was to evaluate the physical and antioxidant properties of chocolate alginate beads containing Moringa oleifera leaf extract (MLE) produced with ecofriendly solvent extraction technology (Deep Eutectic Solvents). The concentration of MLE incorporated was 0, 2, 4, and 6% w/w, and hardening time for ionotropic gelation wi...

Pomegranate peel is a byproduct of pomegranate juice production, and is rich in polyphenol compounds. The objective of this study was to investigate the incorporation of pomegranate peel extract in chitosan films. Green deep eutectic solvents (DESs) were used as extraction solvents. Choline chloride (ChCl) and glycerol (Gly) were used as the hydrog...

This study exploited the application of pulsed electric field (PEF) on the recovery of polyphenols from aerial parts of Sideritis scardica, tepals of Crocus sativus, and fruits of Vitis vinifera. Short pulses of 10 μs in a period of 1 ms were applied to the plant material, while different electric field intensities, 1.2 to 2.0 kV/cm were tested to...

Quercetin (Qt) is a natural flavonoid of high biological significance, and it occurs in a wide variety of plant foods. Although its oxidation by various means has been extensively studied, its behavior with regard to thermal treatments remains a challenge. The study described herein aimed at investigating Qt thermal decomposition, by proposing an e...

Food-processing by-products’ exploitation includes the recovery of fine chemicals and production of precious metabolites, such as natural antioxidants, enzymes, starch, pigments, etc., which are value-added products of high significance to the pharmaceutical, cosmetics, and food industries. Contemporary biocatalysis is based upon new tools and meth...

The acknowledgement that uncontrolled and excessive use of fossil resources has become a prime concern with regard to environmental deterioration, has shifted the orientation of economies towards the implementation of sustainable routes of production, through the valorization of biomass. Green chemistry plays a key role in this regard, defining the...

In a previous study, it was demonstrated that a novel deep eutectic solvent (DES), composed of lactic acid and sodium citrate dibasic at a molar ratio of 15:1 (LA-SCDB15), was a high-performing system with regard to polyphenol extraction from the medicinal plant Salvia fruticosa Mill. (Greek or Cretan sage). However, an issue of particular importan...