Michael Kontominas

University of Ioannina | UOI · Department of Chemistry

In the present study, the combined effect of an AgIon® antimicrobial absorbent (Ζ) pad and a chitosan coating (C) on the preservation of fresh beef stored aerobically at 5 °C was investigated. Microbiological, physicochemical, and sensory attributes were monitored for up to 10 days of storage. The microbiological data indicated that the C and chito...

In the present study, the quality characteristics of Feta cheese were investigated as a function of the packaging container (a stainless-steel tank (SST), a wooden barrel (WB), and a tin can (TC)) and ripening time. The results showed that the Feta cheese’s pH, moisture, and lactose decreased, while fat, protein, and salt increased (p < 0.05) durin...

The main objective of the present study was to determine the effect of the distillation technique: (i) fractional column distillation (FCD), (ii) copper alembic distillation (CAD), and (iii) home distillation (HD) on the aroma profile of the distilled spirit “tsipouro”. Volatile compounds were identified and semi-quantified in all above fractions f...

The present study focused on the possibility of differentiating fresh-unprocessed orange juice according to botanical origin (variety), based on the use of conventional physico-chemical parameters, flavonoids, and volatile compounds, in combination with chemometrics. For this purpose, oranges from seven different varieties were collected during the...

The combined effect of chitosan coating (CHI) and laurel essential oil (LEO) on the shelf-life extension of water buffalo meat stored under aerobic packaging conditions at 4 °C was investigated. Microbiological, physicochemical, and sensory attributes were monitored over an 18-day storage period. Microbiological data indicated that the (CHI) coatin...

The effect of (i) starter culture (sweet-Mild, Classic, and Acidic), (ii) probiotics (Bifidobacterium animalis BB-12 in cow milk and Lactobacillus acidophilus LA-5 in goat milk), and (iii) flavor additives [vanilla baccarat (VAN), lemon (LEM), orange (ORA), and mastic (MAS) essential oil] on the properties of cow and goat dessert yogurt was studied...

The catalytic transesterification of rapeseed oil toward biodiesel production was examined over four mixtures of MgO–CaO oxides as heterogeneous catalysts. The mixed oxidic system (100-x)MgO-(x)CaO, with x = 0, 1, 2, and 5 was synthesized via co-precipitation with ammonia in the presence of poly-vinyl-alcohol (PVA). The solid catalysts were charact...

Marine seaweed species represent an important source of bioactive compounds possessing antioxidant activity. This study aimed at evaluating the antioxidant capacity of the Jania rubens algal extract by means of two antioxidant assays, i.e., 2,2-diphenyl-1-picrylhydrazyl and ferric-reducing antioxidant power. The seaweeds' total phenolic and flavono...

The purpose of this study was to determine the profile of volatile compounds (aroma) and overall flavor in dessert yogurts prepared from cow and goat milk, using three different, commercially available starter cultures, in the presence or absence of probiotic bacteria and to correlate this to organoleptic evaluation results obtained using a consume...

Τhe present study was carried out to evaluate wheat bread of three different flour compositions prepared by replacing water with untreated cheese whey (WCB). Bread prepared with water was taken as the control (CB). All breads were stored at 24 ± 1 °C for up to 6 days. Microbiological, physicochemical, and sensory analyses were determined as a funct...

Full fat (4.3%) and two reduced fat (2.5% and 1.4%) milk were used to prepare white brined goat cheeses with the addition of (i) mixed mesophilic/thermophilic (MT1) or (ii) mesophilic/thermophilic (MT1) plus thermophilic adjunct culture (LH-B02) as starters. Chemical composition, proteolysis and lipolysis were determined, followed by texture profil...

The aim of the present study was to develop a rapid, simple and reliable method for the identification and quantification of ten natural antioxidants in prickly pears using liquid chromatography with electrospray ionization tandem mass spectrometry. The analytical method was fully-validated, and calibration curves were established with correlation...

The effect of different cooking processes such as frying and roasting on the oxidative stability of sunflower seeds was evaluated under accelerated oxidation and normal storage conditions. The fatty acid composition by GC-MS showed a higher amount of linoleic acid in fried samples due to the replacement of the seed moisture by the frying oil. On th...

Seafood products are highly perishable, owing to their high water activity, close to neutral pH, and high content of unsaturated lipids and non-protein nitrogenous compounds. Thus, such products require immediate processing and/or packaging to retain their safety and quality. At the same time, consumers prefer fresh, minimally processed seafood pro...

In the present study, both yeast leavened bread (YLB) and artisanal sourdough wheat bread (SDB) were prepared. The physico-chemical, microbiological, and sensory properties of breads were monitored as a function of storage time (T = 25 °C). As expected, the titratable acidity (TA) values of SDB were higher than those of YLB. The aroma profile of SD...

Fish and fishery products are among the food commodities of high commercial value, high-quality protein content, vitamins, minerals and unsaturated fatty acids, which are beneficial to health. However, seafood products are highly perishable and thus require proper processing to maintain their quality and safety. On the other hand, consumers, nowada...

In the present study, volatile compound analysis of olive oil samples belonging to ten Greek cultivars was carried out. A total of 167 olive oil samples collected from two consecutive harvest years were analyzed by Head Space-Solid Phase Microextraction-Gas Chromatography/Mass Spectrometry (HS-SPME-GC/MS). Volatile compound data were combined with...

Packaging mainly functions by protecting and preserving its contents. In the case of food packaging, the package protects the contained food product from (i) physical/mechanical damage; (ii) physico-chemical changes due to the effect of light, oxygen, moisture and odors; and (iii) biological changes due to the presence of microorganisms and pests;...

Seventy-eight graviera cheese samples produced in five different regions of Greece were characterized and discriminated according to geographical origin. For the above purpose, pH, titratable acidity (TA), NaCl, proteins, fat on a dry weight basis, ash, fatty acid composition, volatile compounds, and minerals were determined. Both multivariate anal...

A total of 90 Graviera cheese samples, produced by selected local dairies in six different regions of Greece, were analysed for pH, titratable acidity, NaCl, proteins, fat on dry weight basis, ash, fatty acid composition by gas chromatography, volatile compounds by gas chromatography/mass spectrometry, and minerals by inductively coupled plasma - o...

The present study aimed to differentiate feta cheese samples produced in northern Greece according to geographical origin. In 2006 the EU, through Council Regulation (EC) 510/2006 succeeded in giving a competitive advantage to the quality and diversity of the Union's agricultural production by adopting PDO (Protected Designation of Origin) and PGI...

BACKGROUND The effects were studied of different inoculation strategies for selected starters –yeasts and lactic acid bacteria (LAB) – used for the fermentation process of two Greek olive cultivars, Conservolea and Kalamàta. The LAB strains applied were Leuconostoc mesenteroides K T5‐1 and L. plantarum A 135–5; the selected yeast strains were S. ce...

Novel processed whey cheese samples were prepared with the addition of different polysaccharides (0.8% w/w), namely, xanthan gum, guar gum, locust bean gum (LBG), and κ-carrageenan, used as stabilizers and added individually or in 1:1 mixtures. Chemical composition of samples was constant, as well as final pH (5.2). The effect of added stabilizers...

A total of 56 sweet cherry samples belonging to four cultivars (Ferrovia, Canada Giant, Lapins, and Germersdorfer) grown in northern Greece were characterized and differentiated according to botanical origin. For the above purpose, the following parameters were determined: conventional quality parameters (titratable acidity (TA), pH, total soluble...

In an effort to determine some undisputed markers of botanical origin, the volatile profile of Hellenic monofloral honeys was investigated using gas chromatography coupled to mass spectrometry (GC–MS) in combination with headspace solid phase microextraction (HS-SPME). Different varieties of honey (citrus, fir, pine, and thyme) were analyzed and se...

The nutritional aspects and the potential of aluminum (Al), calcium (Ca), copper (Cu), iron (Fe), magnesium (Mg), manganese (Mn), antimony (Sb), silicon (Si) and zinc (Zn) for the botanical origin recognition of 270 citrus, fir, multifloral, pine and thyme honeys from Greece, Cyprus, Egypt, Spain, and Morocco were investigated. The aforementioned m...

Thirty-seven olive oil samples belonging to cultivars: Ntopia, Koroneiki, Thiaki, Asprolia and Lianolia were collected from four Western Greek islands. Samples were subjected to the following physicochemical analyses: acidity, peroxide value, K232, K270, ΔK indices, chlorophyll and carotenoid contents, along with fatty acids in an effort to charact...

The effect of bag-in-box (B) packaging material on quality characteristics of extra virgin olive oil (EVOO) was studied as a function of storage time (0–120 days) and temperature (22 °C and 37 °C). Olive oil packaged in tin-plated steel (S) containers served as control. Olive oil sampling was carried out every 20 days, assessing quality deteriorati...

Τhyme, rosemary, and oregano essential oils (EOs) were incorporated into Polylactic acid resin (PLA) at a concentration of 10% (w/w) using the solvent casting method to generate antioxidant packaging films. Pure EOs showed a radical scavenging activity (RSA) ranging between 84.57% and 87.92% at 10,000 mg/L (ppm) using the 1,1‐Diphenyl‐2‐picrylhydra...

In the present work the mineral content and volatile profile of prickly pear juice prepared from wild cultivars was investigated. Fruits used in the study originated from three areas of the Peloponnese Peninsula. Twenty-five macro- and micro-minerals (K, Na, P, Ca, Mg, Al, B, Ba, Be, Co, Cr, Cu, Fe, Li, Mn, Mo, Ni, Sb, Se, Si, Sn, Ti, Tl, V, Zn) we...

The objective of the present work was the geographical discrimination of the most common honeydew honeys produced in Greece, namely pine and fir, on the basis of sugar, free amino acid and organic acid content, determined by nuclear magnetic resonance spectroscopy (¹H NMR) and high-performance liquid chromatography (HPLC), along with moisture conte...

In this study the transesterification of rapeseed oil with methanol towards methyl esters, for use as biodiesel, was investigated over various MgO oxides as heterogeneous catalysts. The solids were prepared via precipitation from Mg(NO3)2 solutions using NH3 in the presence, or absence, of Poly-Vinyl-Alcohol (PVA) at pH=10. The catalysts were chara...

Propolis is a natural bee-product with documented antimicrobial properties in vitro. The objective of this study was to develop a protocol for adding propolis into milk and to determine whether the addition of propolis can confer anti-listerial activity during the storage of milk under optimal or improper refrigeration conditions. Upon dissolving p...

Background: There are only limited studies in the literature attempting to differentiate sheep's milk originating from different sheep breeds. In the present study the physicochemical parameters (pH, % fat, % protein, % lactose and % total solids), fatty acid composition and volatile profile of raw milk from four autochthonous Greek breeds (Karago...

The flow properties of a series of kefiran aqueous solutions with concentrations ranging from 0.25 to 4.0% (w/v) were examined at 4, 25 or 40 °C under controlled shear rate mode and over six orders of magnitude.The results indicated that the flow behavior of kefiran systems in solution is that of a pseudoplastic fluid at low shear rates whereas at...

Kefiran was produced from kefir grains, on a semi-industrial scale, using UHT skimmed milk as a raw material. The conformational characteristics of the polysaccharide were assessed by means of a series of techniques such as capillary viscometry, size-exclusion chromatography coupled to multi-angle laser light scattering, static light scattering, dy...

The aim of the present study was to develop a rapid and simple method for the detection and quantification of antibiotic and antibacterial residues in honey using liquid chromatography with electronspray ionization tandem mass spectrometry. Two different extraction methods were used. The first method uses water and 1% formic acid in acetonitrile fo...

Seventy-four monovarietal olive oil samples belonging to the Koroneiki cultivar were collected from four selected olive oil-producing regions of Greece (Messinia, Lakonia, Irakleio and Etoloakarnania), during two harvesting periods (2012/2013 and 2013/2014) at the stage of full maturation (maturation index 5–6). Determination of volatile compounds...

Commercial PET films were surface treated and subsequently coated with either rosemary (RME) or clove (CE) extracts. Surface treatments involved a) corona treatment, b) chemical modification and c) plasma treatment. Radical scavenging activity (RSA) of both pure plant extracts and coated film extracts were determined using the 1,1-diphenyl-2-picryl...

The aim of the present study was to provide information on physicochemical (pH, free, lactonic, and total acidity, electrical conductivity, moisture, ash, lactonic/free acidity), colour parameters (L*, a*, b*), and mineral content (Ag, Al, As, B, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe, Hg, Mg, Mn, Mo, Ni, Pb, Sb, Se, Si, Ti, Tl, V, Zn) of 34 commercial thy...

The aim of the present study was to develop a rapid and simple method for the detection and quantification of antibiotic and antibacterial residues in honey using liquid chromatography with electronspray ionization tandem mass spectrometry. Two different extraction methods were used. The first method uses water and 1% formic acid in acetonitrile fo...

BACKGROUND The antioxidant and antibacterial activity of fermented sarshir (traditional dairy food), with three probiotic Lactobacillus plantarum strains (LP3, AF1, and LU5) were investigated. The oxidative stability and lipid profile of non-fermented and fermented sarshir were compared, as well as radical scavenging activity, peroxide, anisidine,...

In the present study, the effect of different parameters on the correct geographical differentiation of Greek fir honey, was investigated. Forty three honey samples were collected from 4 regions and subjected to physicochemical, and melissopalynological analyses, using official and instrumental methods. Results showed that fir honeys met the Europe...

In the present study saffron samples from Greece, Spain, Iran, and Morocco, collected during harvesting years 2005–2014, were characterized and classified according to geographical origin using volatile compounds and selected bioactivity parameters. The volatile compounds of saffron were semi-quantified using headspace solid-phase microextraction i...

The objective of the present study was: i) to characterize Mediterranean citrus honeys based on conventional physicochemical parameter values, volatile compounds, and mineral content ii) to investigate the potential of above parameters to differentiate citrus honeys according to geographical origin using chemometrics. Thus, 37 citrus honey samples...

The aim of the present study was: (1) to determine the mineral content of pine and thyme honeys produced in different regions in Greece and (2) differentiate pine and thyme honeys according to their geographical origin, based on selected minerals using multivariate analysis of variance (MANOVA) and linear discriminant analysis (LDA). For this purpo...

The objective of the present study was to characterize commercial fir honey produced in different regions in Greece and investigate the possibility of geographical classification using data sets of physicochemical parameters, colour attributes, and volatile compounds using multivariate analysis techniques. For this purpose, 43 fir honey samples wer...

The aim of the present study was to differentiate fresh Greek orange juice prepared from the Merlin cultivar according to geographical origin, based on organic acid/sugar content, and physicochemical parameter analysis, using chemometrics. For this purpose, oranges were collected during the harvesting period 2013–2014 from four different regions in...

The aim of the present study was to investigate the volatile fraction and discriminate 34 commercial thyme honeys from Morocco, Egypt, Spain, and Greece according to geographical origin, using key volatile compounds in combination with chemometrics. Sixty two volatile compounds belonging to different classes were identified and semi quantified usin...

The aim of this study was to investigate the impact of botanical origin and harvesting period on carbon stable isotope ratio (13C/12C), colour intensity (CI), radical scavenging activity (%RSA), P and Sn content of Greek unifloral honeys. Thus, twenty-four honey samples were collected during harvesting periods 2011–2012 and 2012–2013, from four dif...

The present study was designed to investigate the antioxidant properties [selected polyphenol content (SPC), radical scavenging activity] and colour intensity of Greek unifloral honeys. For this purpose, one hundred and seventy honey samples of different botanical origin (thyme, pine, orange blossom, and fir) were collected during the harvesting pe...