Melinda Kovacs

Dr. Melinda Kovacs


Research Focus & Metrics

Academic Career Length

12Years (2015-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

View All Publications
10 October 2022 in Foods
Verified
Journal Article
Open access
PDF file
Thomas DippongThomas Dippong
Thomas Dippong
MDMonica Dan
Monica Dan
MKMelinda Kovacs
Melinda Kovacs
Emoke Dalma KovacsEmoke Dalma Kovacs
Emoke Dalma Kovacs
Erika LeveiErika Levei
Erika Levei
Oana CadarOana Cadar
Oana Cadar
This study aimed to investigate the ways in which the thermal behavior, composition, and volatile compound contents of roasted coffee beans depend on variety and roasting intensity. The thermal analysis revealed various transformations in coffee composition, namely, drying, water loss, and decomposition of polysaccharides, lipids, amino acids, and proteins. The results showed that volatile compounds are released differently in coffee depending on coffee type and degree of roasting. The most abundant volatile compounds present in the samples were 2-butanone, furan, 2-methylfuran, methyl formate, 2.3-pentanedione, methylpyrazine, acetic acid, furfural, 5-methyl furfural, and 2-furanmethanol. The total polyphenol contents ranged between 13.3 and 18.9 g gallic acid/kg, being slightly higher in Robusta than in Arabica varieties and in more intensely roasted beans compared to medium-roasted beans. The Robusta variety has higher mineral contents than Arabica, and the contents of most minerals (K, Ca, Mg, Fe, Cu, P, N, and S) increased with roasting intensity. Discrimination between coffee varieties and roasting intensities is possible based on mineral and polyphenol contents.

20 June 2022 in Molecules
Verified
Journal Article
Open access
PDF file
Marin SenilaMarin Senila
Marin Senila
ENEmilia Neag
Emilia Neag
Oana CadarOana Cadar
Oana Cadar
Emoke Dalma KovacsEmoke Dalma Kovacs
Emoke Dalma Kovacs
Ioan AschileanIoan Aschilean
Ioan Aschilean
MKMelinda Kovacs
Melinda Kovacs
Increased concentrations of heavy metals in the environment are of public health concern, their removal from waters receiving considerable interest. The aim of this paper was to study the simultaneous adsorption of heavy metals (Cu, Cd, Cr, Ni, Zn and Pb) from aqueous solutions using the zeolitic volcanic tuffs as adsorbents. The effect of thermal treatment temperature, particle size and initial metal concentrations on the metal ions sorption was investigated. The selectivity of used zeolite for the adsorption of studied heavy metals followed the order: Pb > Cr > Cu > Zn > Cd > Ni. The removal efficiency of the heavy metals was strongly influenced by the particle sizes, the samples with smaller particle size (0–0.05 mm) being more efficient in heavy metals removal than those with larger particle size (1–3 mm). Generally, no relevant changes were observed in heavy metals removal efficiency for the treatment temperatures of 200 °C and 350 °C. Moreover, at a higher temperature (550 °C), a decrease in the removal efficiencies was observed. The Cd, Zn, Cu, Cr, Zn and Ni sorption was best described by Langmuir model according to the high values of correlation coefficient. The pseudo-first-order kinetic model presented the best correlation of the experimental data.

27 February 2020 in Applied Sciences
Verified
Journal Article
Open access
PDF file
LSLacrimioara Senila
Lacrimioara Senila
ENEmilia Neag
Emilia Neag
Oana CadarOana Cadar
Oana Cadar
MKMelinda Kovacs
Melinda Kovacs
Anca BeczeAnca Becze
Anca Becze
Marin SenilaMarin Senila
Marin Senila
The objective of this study was to determine the chemical composition of five different food seeds (sunflower, poppy, hemp, flax and sesame) regarding fatty acid, mineral (Fe, Cu, Zn, Na, Mg, K, Ca, Al) and protein content. In addition, the total antioxidant capacity of the seeds was evaluated using the photochemiluminescent assay. The food seeds were subjected to lipid extraction and converted into fatty acid methyl esters before the gas chromatography analysis. In all food seeds, the saturated (SFAs), monounsaturated (MUFAs) and polyunsaturated fatty acids (PUFAs) were identified, respectively. PUFAs were the most abundant fatty acids (61.2% ± 0.07% and 84.8% ± 0.08% of total fatty acids), with the highest content in flax and hemp seed oil. Also, high amounts of omega-3 from PUFAs were determined in flax and hempseed oil. Based on the obtained results the sunflower, sesame and poppy seeds are good sources of omega-6, while flax and hemp seeds are good sources of omega-3. All samples are rich in minerals (Na, K, Ca, Mg) and have more than 20% protein content.

15 August 2023 in Foods
Verified
Journal Article
Open access
PDF file
Thomas DippongThomas Dippong
Thomas Dippong
Oana CadarOana Cadar
Oana Cadar
MKMelinda Kovacs
Melinda Kovacs
MDMonica Dan
Monica Dan
LSLacrimioara Senila
Lacrimioara Senila
Tea is the most consumed drink worldwide due to its pleasant taste and various beneficial effects on human health. This paper assesses the physicochemical analysis of different varieties of tea (leaves, flowers, and instant) after prior drying and fine grinding. The thermal decomposition behavior of the tea components shows that the tea has three stages of decomposition, depending on temperature. The first stage was attributed to the volatilization of water, while the second stage involved the degradation of volatiles, polyphenols, and fatty acids. The degradation of cellulose, hemicellulose, and lignin content occurs at the highest temperature of 400 °C in the third stage. A total of 66 volatile compounds, divided into eight classes, were identified in the tea samples. The volatile compounds were classified into nine odor classes: floral, fruity, green, sweet, chemical, woody, citrus, roasted, and alcohol. In all flower and leaf tea samples, monounsaturated (MUFAs), polyunsaturated (PUFAs), and saturated fatty acids (SFAs) were identified. A high content of omega-6 was quantified in acacia, Saint John’s Wort, rose, and yarrow, while omega-3 was found in mint, Saint John’s Wort, green, blueberry, and lavender samples. The flower and leaf tea samples studied could be a good dietary source of polyphenolic compounds, essential elements. In instant tea samples, a low quantity of polyphenols and major elements were identified. The physicochemical analysis demonstrated that both flower and leaf teas have high-quality properties when compared to instant tea.

24 June 2022 in Insects
Verified
Journal Article
Open access
PDF file
BBBeldean Tatar Bianca
Beldean Tatar Bianca
Maria Simona ChisMaria Simona Chis
Maria Simona Chis
Ersilia AlexaErsilia Alexa
Ersilia Alexa
Carmen PopCarmen Pop
Carmen Pop
Adriana PauceanAdriana Paucean
Adriana Paucean
SMSevastița Muste
Sevastița Muste
Acheta domesticus (L.1758) has been recently accepted by the European Union as a novel food, being the third insect that has been approved for human consumption. Nowadays, researchers’ attention is focused on exploiting new protein sustainable sources, and, therefore, insect flour has gained more and more interest. Organic acids, fatty acids, amino acids, aroma volatile compounds, and minerals were analyzed through HPLC-RID (High-performance liquid chromatography), GC-MS (Gas chromatography-mass spectrometry), LC-MS (Liquid chromatography–mass spectrometry), ITEX/GC-MS and AAS (Atomic Absorption Spectrophotometry), respectively. Fermentation of the insect flour with Lactobacillus plantarum ATCC 8014 strain (Lp) leads to an increase in organic acids such as lactic, acetic, and oxalic, whilst citric acid decreases its value. SFA (saturated fatty acids) and MUFA (monosaturated fatty acids) groups were positively influenced by Lp fermentation; meanwhile, PUFA (polysaturated fatty acids) decreased during fermentation. A positive trend was observed for amino acids, aroma volatile content, and minerals enhancement during insect sourdough fermentation, mainly at 24 h of fermentation. Acheta domesticus (A. domesticus) sourdough fermentation represents a new tool that needs to be further exploited aiming to improve the nutritional qualities of the final products.

5 September 2022 in Ultrasonics Sonochemistry
Verified
Journal Article
Open access
ADAnca Dumuta
Anca Dumuta
ZVZorica Vosgan
Zorica Vosgan
CMCristina Mihali
Cristina Mihali
LGLiviu Giurgiulescu
Liviu Giurgiulescu
MKMelinda Kovacs
Melinda Kovacs
LMLucia Mihalescu
Lucia Mihalescu
• The ultrasound power-time regimes of pasteurization improved the microbiological quality of goat cheeses and completely inactivated the coagulase-positive staphylococci. • The curds obtained from milk treated for 6 min at 320 and 881 W suffered an accentuated syneresis process. • The unsaturated fatty acids proportion increased as the intensity of the applied ultrasound regime became more accentuated. • The AI, TI and H/H lipid quality indices were improved by applying of the ultrasound pasteurization regimes. • Goat milk treated with 0.6 % beta-cyclodextrin recorded a cholesterol reduction of 92.1 %.