Tõnu Püssa

Mr. Tõnu Püssa


Research Focus & Metrics

Academic Career Length

47Years (1980-Present)

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

Representative Publications

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24 October 2018 in Plants
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Vitalijs RadenkovsVitalijs Radenkovs
Vitalijs Radenkovs
JKJorens Kviesis
Jorens Kviesis
KJKarina Juhnevica-Radenkova
Karina Juhnevica-Radenkova
AVAnda Valdovska
Anda Valdovska
TPTõnu Püssa
Tõnu Püssa
IDInese Drudze
Inese Drudze
The amplified production of fruit as well as burgeoning demand for plant-made food products have resulted in a sharp increase of waste. Currently, millions of tons of by-products are either being discarded or utilized rather ineffectively. However, these by-products may be processed and further incorporated as functional ingredients in making high-value food products with many physiological and biochemical effects. The chemical analysis of pomace oils using gas chromatography-mass spectrometry (GC/MS) and reversed-phase-liquid chromatography coupled with fluorescence detector (RP-HPLC/FLD) systems led to the identification and quantification of 56 individual lipophilic compounds including unsaturated, polyunsaturated and saturated fatty acids, as well as phytosterols and four homologs of tocopherol. The oils recovered from by-products of Malus spp. (particularly cv. “Ola”) are rich in fatty acids such as linolenic (57.8%), α-linolenic (54.3%), and oleic (25.5%). The concentration of total tocopherols varied among the Malus species and dessert apples investigated, representing the range of 16.8–30.9 mg mL−1. The highest content of total tocopherols was found in M. Bernu prieks, followed by M. cv. “Ola”, and M. × Soulardii pomace oils. A significantly higher amount of δ-tocopherol was established in the oil of M. Bernu prieks, indicating that this species could be utilized as a natural and cheap source of bioactive molecules. β-Sitosterol was the prevalent compound determined in all tested pomace oils with a percentage distribution of 10.3–94.5%. The main triterpene identified in the oils was lupeol, which varied in the range of 0.1–66.3%. A targeted utilization of apple pomace would facilitate management of tons of by-products and benefit the environment and industry.

5 April 2022 in Plants
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Ain RaalAin Raal
Ain Raal
MJMarel Jaama
Marel Jaama
MUMeeme Utt
Meeme Utt
TPTõnu Püssa
Tõnu Püssa
VŽVaidotas Žvikas
Vaidotas Žvikas
HNHoai Thi Nguyen
Hoai Thi Nguyen
The aerial parts of Anthemis tinctoria L. and Angelica sylvestris L. and the roots of A. sylvestris have been used as traditional anticancer remedies in Estonian ethnomedicine. The aim of this study was to investigate content of essential oils (by gas chromatography) and polyphenolic compounds (using two different methods of high performance liquid chromatography–mass spectrometry (HPLC–MS)) of both plant species, as well as the in vitro anti-cancer effects of their essential oils and methanolic extracts. The average (n = 5 samples) yield of essential oils was 0.15%, 0.13%, and 0.17%, respectively. The principal compounds of the essential oil from the aerial parts of A. tinctoria were palmitic acid (15.3%), p-cymene (12.6%), and α-muurolene (12.5%), and α-pinene (45.4%), p-cymene (15.5%), and β-myrcene (13.3%) in aerial parts of A. sylvestris, while isocaryophyllene oxide (31.9%), α-bisabolol (17.5%), and α-pinene (12.4%) were the main constituents in the roots. The most abundant phenolic compounds in aerial parts were the derivatives of caffeic acid, quinic acid, and quercetin; the main compounds in roots of A. sylvestris were chlorogenic acid, quinic acid, and naringenin. The strongest anticancer effects were observed in essential oils of A. sylvestris roots and aerial parts on human carcinoma in the mouth cells (KB, IC50 19.73 μg/mL and 19.84 μg/mL, respectively). The essential oil of A. tinctoria showed a strong effect on KB and LNCaP cells (27.75–29.96 μg/mL). The methanolic extracts of both plants had no effect on the cancer cells studied.

14 January 2023 in Chemosensors
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AKArtur Ivan Kuznetsov
Artur Ivan Kuznetsov
AFAleksandr Frorip
Aleksandr Frorip
ASAlar Sünter
Alar Sünter
NKNensi Kasvand
Nensi Kasvand
VKVadim Korsakov
Vadim Korsakov
NMNikolay Mukhin
Nikolay Mukhin
Fast protein and metabolite liquid chromatography (FPLMC) was introduced years ago to enable the easy separation of high-molecular compounds such as proteins from small molecules and the identification of the low-molecular substances. In this paper, the method is applied for the rapid evaluation of freshness and monitoring the aging of animal meat and fish. A novel chromatographic sensor was developed with a deep UV LED-based photometric detection unit (255–265 nm), an original flow cuvette and registration scheme; the processing of a chromatogram with the sensor takes approximately 15 min. Strict isochronism between the elution of ATP metabolites, mainly hypoxanthine (Hx) and inosine monophosphate (IMP), and the time of maturation of meat or fish, was discovered. A new freshness index H* = [Hx]/[IMP] was introduced, which is proportional to the instrumental delay time in the FPMLC chromatograms: the H* index < 0.5 indicates the presence of inosine monophosphate (IMP) and the high quality of the meat or fish. Reasonably strong correlations were revealed between data obtained by FPMLC and total volatile basic nitrogen TVB-N (for fish) or volatile fatty acids VFA (for meat) content. Moreover, putative nucleotide salvage and an increase in the concentration of IMP were observed in fish after heat treatment using the FPMLC sensor and NMR technique.

9 December 2019 in Foods
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DADea Anton
Dea Anton
JKJulia Koskar
Julia Koskar
PRPiret Raudsepp
Piret Raudsepp
KMKadrin Meremäe
Kadrin Meremäe
TKTanel Kaart
Tanel Kaart
MRMati Roasto
Mati Roasto
It is a challenge for scientists to find new plant-based food constituents simultaneously possessing antimicrobial and antioxidative properties to prolong the shelf life of meat products. In this study, various plant powders and their blends were added to minced pork to carry out a complex study of their effect on sensory characteristics, microbial growth, and lipid oxidation of the meat in raw and cooked forms during storage. Microbiological shelf life parameters were evaluated by determining the total counts of microorganisms, yeasts, and molds. The growth potential of Listeria monocytogenes was estimated by challenge testing. The impact on lipid oxidation processes was assessed using thiobarbituric acid reactive substances (TBARS) and high performance liquid chromatography (HPLC) methods. The results showed that the blend of rhubarb petioles and tomato powder added a pleasant color and a combined taste to the product, similar to the taste of salt. In raw samples, considerable microbial growth inhibition was achieved with rhubarb petioles, tomato, and their mixture. Nine treatments of cooked samples had a stronger inhibitory effect on microbial growth compared to control treatments. Among all plant powders, tomato was the most effective inhibitor of yeast and mold growth. However, the challenge test revealed that L. monocytogenes growth in cooked samples was not inhibited during shelf life. In raw samples, rhubarb roots combined with blackcurrant or chokeberry berries effectively inhibited lipid oxidation, and in cooked samples, rhubarb petioles showed a similar effect. In conclusion, it was found that powdered plant materials are well suited for use as antimicrobial and antioxidative agents in minced meat products.

21 October 2003 in Proceedings of the Estonian Academy of Sciences. Chemistry
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AAAavo Aaviksaar
Aavo Aaviksaar
MHMati Haga
Mati Haga
TPTõnu Püssa
Tõnu Püssa
MRMati Roasto
Mati Roasto
GTGeorge Tsoupras
George Tsoupras

21 October 2003 in Proceedings of the Estonian Academy of Sciences. Chemistry
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AAAavo Aaviksaar
Aavo Aaviksaar
MHMati Haga
Mati Haga
KKKristina Kuzina
Kristina Kuzina
TPTõnu Püssa
Tõnu Püssa
Ain RaalAin Raal
Ain Raal
GTGeorge Tsoupras
George Tsoupras