Polyphenols and resveratrol from discarded leaf biomass of grapevine (Vitis sp.): Effect of cultivar and viticultural practices in Estonia

Grapevine leaves are a major by-product of viticulture practices derived from the leaf-removal from the fruit cluster zone in all vine growing regions. These leaves can be a valuable source of antioxidants to be used in pharmaceuticals or other health-related products. In this study, the leaves of grapevine cultivars were analysed by ultra-high performance liquid chromatograph-diode array detector () for the total polyphenols (TPC) and resveratrol a ected by cultivar, leaf-removal time and viticultural practice. The e ect of cultivar varied yearly, European grapevine cv. ‘Regent’ had increased TPC and resveratrol in comparison to ‘Boskoop’s Glory’, ‘Rondo’ and ‘Solaris’ in 2017, but ‘Solaris’ in 2018. TPC (1213–1841 mg 100 g-1) and resveratrol (1.061 mg 100 g-1) were higher in leaves of interspecific hybrid cvs. ‘Zilga’ and ‘Hasansky Sladky’ during full fruit ripeness. Cv. ‘Rondo’ grown under the polytunnel had decreased TPC in leaves. In conclusion, cultivar selection, viticultural practice and leaf-removal time contribute significantly to the accumulation of total polyphenols and resveratrol. Results of this study will contribute to better utilization of biomass produced in the vineyards, help to decrease the negative environmental impacts, and provide an overview on various factors a ecting the biochemical constituents, especially in leaves.This research is funded by VALORTECH project, which has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No. 810630.This research is funded by VALORTECH project, which has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No. 810630

Comparison of polyphenols and anthocyanin content of different blackcurrant (Ribes nigrum L.) cultivars at the Polli Horticultural Research Centre in Estonia

The evaluation of blackcurrant cultivars and their fruit properties at the Polli Horticultural Research Centre has been active since 1945. In addition to the assessment of biological and economic properties of cultivars, it is essential to pay attention to fruit quality. In 2014, the laboratory building of Polli Horticultural Research Centre was reconstructed within the PlantValor competence centre project, enabling to introduce HPLC methods for the determination of polyphenolic compounds in fruit quality analysis. In 2017 and 2018, the fruit quality of 37 blackcurrant cultivars of different geographical origin (Belarus, Estonia, Finland, Latvia, Lithuania, Norway, Poland, Russia, Scotland, Sweden and Ukraine) was analysed. All cultivars were grown in the genetic resources collection (2008–2019) located at the Polli Horticultural Research Centre. The main aim of the study was to analyse the content of polyphenols and anthocyanins for selecting suitable blackcurrant genotypes for breeding programmes, fruit production and possible product development. In two consecutive years of the study, the total polyphenols content in the fruits of different cultivars varied 290–634 mg 100 g-1 fresh weight (fw) and the anthocyanins 183–471 mg 100 g-1 fw

Recovery of polyphenols from vineyard pruning wastes - shoots and cane of hybrid grapevine (Vitis sp.) cultivars

Grapevine shoots and canes represent a significant amount of biomass, considered as a waste in viticulture. In cooler climates, grapevines are pruned in the autumn (October) and spring (March) due to harsh winter conditions (e.g., snow, low temperatures), and large amounts of biomass are produced at these different pruning times. This work was undertaken in order to investigate the potential of vineyard pruning waste for recovery of polyphenolic compounds for biomass valorization. Qualitative and quantitative analyses of grapevine shoot and cane polyphenols, including flavonoids and stilbenoids were performed using UHPLC MS/MS method. The results revealed the flavonols (quercetin) to be the most abundant compounds in shoots among all the three cultivars screened (Zilga, Hasansky Sladky, Rondo). Stilbenoids (ε-viniferin) dominated in the canes, while increased level of flavonols with lower contents of stilbenoids was detected in the endodormant canes, and higher amounts of flavanols and stilbenoids were recorded in eco-dormant canes. In conclusion, the content of polyphenols in grapevine shoots and canes differed among the cultivars and dormancy phases. The results generated from the present study contribute to the sustainable and environmentally friendly viticulture practice via valorization of vineyard pruning wastes.This research received funding from the ongoing project—Valortech, which has received funding from the European Union’s Horizon 2020 research and innovation program under a grant agreement No 810630. Funding received from Mobilitas Pluss ERA-Chair support (Grant no. MOBEC006 ERA Chair for Food (By-) Products Valorisation Technologies of the Estonian University of Life Sciences) is acknowledged

Antioxidants Characterization of the Fruit, Juice, and Pomace of Sweet Rowanberry (Sorbus aucuparia L.) Cultivated in Estonia

Received: 28 September 2021; Accepted: 4 November 2021; Published: 6 November 2021.This study aimed to identify promising candidates of rowanberry cultivars for a wider cultivation and utilization. Antioxidant properties and phenolic content were evaluated for fruit, juice, and pomace samples of 16 different sweet rowanberry cultivars (cvs) and wild rowanberry (S. aucuparia L.), while the antioxidant potential was assessed using three different methods, based on the capacity to scavenge ABTS + and DPPH and measure the oxygen radical absorbance capacity (ORAC). In general, the radical scavenging capacity was higher for hybrid cultivars, e.g., for cvs Likernaja, Burka, Granatnaja, and Rubinovaja in all assays. The highest value in the ABTS + assay was determined for the fruit sample Likernaja, and in DPPH assay in the pomace sample of cv. Likernaja, at 527.55 and 1068.28 M TE/g dw, respectively. The highest ORAC value was found in the fruit sample of Burka (456.53 M TE/g dw). Among the Nevezhino rowans, the highest radical scavenging values of all fractions were determined in cv. Solnechnaja. Regarding the total phenolic content (TPC), higher values were obtained in the whole fruits than in separated fractions, juice, and pomace. The tested hybrids had higher TPC values, either in fruit and pomace or in juice extracts, than those in the other analyzed S. aucuparia L. cultivars. While the fruit and juice samples showed higher anthocyanin (ACY) values, the pomace samples had higher hydroxycinnamic acid (HCA) contents on average. The results revealed that the different fractions of selected rowanberry cultivars can be a promising source of antioxidants and polyphenols for further potential applications. It is envisaged that the results of this study will serve in valorizing sweet rowanberry cultivars as value-added functional ingredients for food and non-food applications.Funding: The theme of this research article is based on the ongoing project VALORTECH, which has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No. 810630. In addition, funding was received from Mobilitas Pluss ERA-Chair support (Grant No. MOBEC006 ERA Chair for Food (By-) Products Valorisation Technologies of the Estonian University of Life Sciences)

Optimization of ultrasound-assisted extraction of phloretin and other phenolic compounds from apple tree leaves (Malus domestica Borkh.) and comparison of different cultivars from Estonia

Polyphenolic compounds, plant secondary metabolites essential for plant survival, are known for their high antioxidant and anti-inflammatory activity. In addition, several polyphenols, such as phloretin, also have potential antiviral effects, making these compounds potential ingredients of biofunctional foods. A promising source for the extraction of phloretin is a by-product of apple production—apple tree leaves. Focusing on green technologies, the first aim of the present study was to optimize the direct ultrasound-assisted extraction conditions to gain the maximum yield of phloretin from air-dried apple leaves. For the optimization of process parameters, we applied the response surface method with Box–Behnken design. The optimal extraction conditions were extraction time 14.4 min, sonication amplitude 10% and 10 g of sample per 100 mL solvent (70% ethanol, w/w). Using these conditions, we assessed the content of individual and total polyphenolic compounds along with antioxidant activity in the leaves of different autumn and winter apple cultivars grown in Estonia. The analyses were carried out with chromatographic (HPLC-DAD-MS/MS) and spectrophotometric methods. The phloretin concentration ranged from 292 to 726 µg/g and antioxidant activity from 6.06 to 11.42 mg GA eq./g, these being the highest in the local winter cultivars ‘Paide taliõun’ and ‘Tellissaare’, respectively.This research was funded by the European Union’s Horizon 2020 research and innovation program project VALORTECH under grant agreement No. 810630, and by the European Regional Development Fund’s project “PlantValor—full-scale product development service in synergy with the traditional activities of Polli Horticultural Research Centre” 2020–2023

Comparative Analyses of Bioactive Compounds in <i>Inonotus obliquus</i> Conks Growing on <i>Alnus</i> and <i>Betula</i>

Inonotus obliquus grows in the Northern Hemisphere on some living broadleaved tree species as a pathogen, causing stem rot. In Estonia, the fungus is well known in the Betula species but can also be found on Alnus. Sterile conks of I. obliquus contain different bioactive compounds, but the quantitative and comparative research of these compounds in conks on different host species is limited. In the current work, I. obliquus was isolated and, evidently, determined from Alnus incana (L.) Moench., Alnus glutinosa (L.) Gaertn., and Betula pendula Roth, and the content of bioactive compounds in conks on these hosts were analysed. All the analysed conks sampled from A. incana and B. pendula contained betulin that varied from 111 to 159 µg/g. A significantly (p A. incana when compared with B. pendula: 474–635 and 20–132 µg/g, respectively. However, the conks from Betula were richer in total polyphenols, flavonols, and glucans. The content of inotodiol was quite similar in the conks from A. incana (7455–8961 µg/g) and B. pendula (7881–9057 µg/g). Also, no significant differences in the lanosterol content were found between the samples from these two tree species. To the best of our knowledge, this study is the first investigation of the chemical composition of I. obliquus parasitizing on Alnus. The results demonstrate that the bioactive compounds are promising in conks of I. obliquus growing not only on Betula but also on the Alnus species. It supports the opportunity to cultivate I. obliquus, also on the Alnus species, thus increasing the economic value of growing this tree species in forestry

RESTA14 project TAIMLOOMTOIT – the valorisation of plant-based powders for value-added meat and fish products

Toidu tootmise kõrvalsaaduste väärindamine ja teaduspõhiste tervislike toidutoodete teadus- ja arendustegevus on viimastel aastatel hoogustunud ning ring- ja biomajanduse kontekstis väga oluline. Tarbijate usaldus ja nõudmised seoses teaduspõhiste naturaalsete ja tervislike toidutoodetega pidevalt tõusevad, mistõttu on mõistlik otsida keskkonnasõbralikke ja lisandväärtust loovaid lahendusi, seda nii kohaliku taimse kui ka loomse toidutoorme kui ressursi täielikumaks ärakasutamiseks. Aiandus- ja põllukultuuride kasvatamisel tekib põhitoodete kõrval märkimisväärne kogus (30‒50%) tervisele kasulikke aineid (nt polüfenoole, karotenoide) sisaldavaid taimseid jääke või kõrvalsaadusi (kestad, seemned, pressjäägid jne), mis võiksid leida kasutust loomset päritolu toiduainetele lisandväärtuse andmiseks ja nende kvaliteedi tõstmiseks. Taimse bioaktiivsete ühendite rikka materjali lisamisega on võimalik oluliselt pidurdada mikroorganismide kasvu ning rasvhapete ja kolesterooli oksüdatsiooni liha- ja kalatoodetes, millega pikeneb ka toodete säilivusaeg. Taimsete lisandite funktsionaalsuse ja kasutamise alased uuringud on aktuaalsed üle maailma, kuid siiski on seni jõutud uurida vaid suhteliselt väikest osa nii maailmas kui ka Eestis saadaolevast potentsiaalsest taimsest materjalist. Seetõttu on väga oluline sellealase teadus- ja arendustööga jätkamine, kaasates aktiivselt ka põllumajandus- ja aiandustootjaid, kelle ettevõtetes nimetatud saadusi tekib ning toiduettevõtteid, kus valmivates toodetes on võimalik kõrvalsaadusi ära kasutada. Käesolevaga anname ülevaate RESTA14 programmi teadus- ja arendusprojekti TAIMLOOMTOIT tegevustest ja tulemustest taimsete kõrvalsaaduste väärindamisel liha- ja kalatoodetes. Tegevused viidi läbi EMÜ PKI Polli aiandusuuringute keskuse ning VLI veterinaarse biomeditsiini ja toiduhügieeni ning toiduteaduse ja toiduainete tehnoloogia õppetooli teadlaste vahelises koostöös.Projekti TAIMLOOMTOIT (F200143PKPA) elluviimist toetasid Euroopa Regionaalarengu Fond ja Eesti Teadusagentuur läbi „Ressursside väärindamise alase TA-tegevuse toetamise” programmi ResTA14. Uurimustööd on finantseerinud ka Eesti Teadusagentuur (PRG1441) projekti “Looduslike bioaktiivsete ainete toimete mehhanismide uurimine loomsetes toitudes” raames. Autorid tänavad koostöö ja toormaterjali eest järgmisi ettevõtteid: Marimarta OÜ (tomatimahla pressjääk), Konspek OÜ (mustasõstramahla pressjääk), Rabafarm OÜ (rabarberimahla pressjääk), Ldiamon AS (liha ja kala värskuse hindamise seade ja metoodika), HKScan Estonia AS (tootearenduse ideed ja huvi), Kalatalu Härjanurmes (värske vikerforell).The valorisation of plant-based by-products and research and development of science-based healthy food products has accelerated in recent years and is very important in the context of the circular and bioeconomy. Consumers’ trust and demands regarding science-based natural and healthy food products are increasing, therefore it is reasonable to look for environmentally friendly and value-creating solutions, both for the better use of local plant and animal food raw materials as a resource. The results of the RESTA14 project TAIMLOOMTOIT, revealed that it is possible to use plant additives for valorisation of meat and fish products, but all the variables and influencing factors have not yet been fully clarified. The aim for following project is to find out even more effective recipes and storage conditions in terms of addition of natural and healthy plant-based powders to meat and fish products. The additives help to minimize oxidation processes, stop the growth of L. monocytogenes, and to ensure a sufficiently long shelf life, while using a minimum concentrations of food additives in the food composition.Projekti TAIMLOOMTOIT (F200143PKPA) elluviimist toetasid Euroopa Regionaalarengu Fond ja Eesti Teadusagentuur läbi „Ressursside väärindamise alase TA-tegevuse toetamise” programmi ResTA14. Uurimustööd on finantseerinud ka Eesti Teadusagentuur (PRG1441) projekti “Looduslike bioaktiivsete ainete toimete mehhanismide uurimine loomsetes toitudes” raames. Autorid tänavad koostöö ja toormaterjali eest järgmisi ettevõtteid: Marimarta OÜ (tomatimahla pressjääk), Konspek OÜ (mustasõstramahla pressjääk), Rabafarm OÜ (rabarberimahla pressjääk), Ldiamon AS (liha ja kala värskuse hindamise seade ja metoodika), HKScan Estonia AS (tootearenduse ideed ja huvi), Kalatalu Härjanurmes (värske vikerforell)