Taimsete valkude eraldamine, kontsentreerimine ja omaduste iseloomustamine

Valgud ehk proteiinid on kõrgmolekulaarsed orgaanilised ained, mille molekul koosneb paljudest peptiidsidemetega pikkadeks ahelateks seotud aminohapetest. Elusaine ehituses asuvad valgud kesksel kohal, olles organismis kudede kasvuks ja säilitamiseks vajalikuks lämmastiku ja asendamatute aminohapete allikas. Taimedes toimub valgusüntees keskkonnas leiduva CO 2, H 2 O ja NH 3 või NO3- arvel, kuid loomorganismid sarnaselt valke sünteesida ei suuda ja seetõttu on nad taimedest otseselt või kaudselt sõltuvad. Inimesel kulub väiksem osa toiduvalgust energeetiliseks otstarbeks, suurem osa aga lagundatakse organismis uuesti aminohapeteks ja kasutatakse inimorganismile vajalike valkude sünteesiks või resünteesiks.1 2 Vastavalt sellele, kas organism suudab vastavat aminohapet ise sünteesida või mitte sünteesida, jaotatakse aminohapped asendatavateks, poolasendatavateks ja asendamatuteks. Aminohappeid, mida organism ise ei sünteesi, nimetatakse asendamatuteks aminohapeteks ja nende omastamine toidust on möödapääsmatult vajalik. Asendamatuteks aminohapeteks on: Valiin, Leutsiin, Isoleutsiin, Treoniin, Metioniin, Fenüülalaniin, Trüptofaan ja Lüsiin. Aminohappeid Arginiin, Histidiin, Tsüstiin, Tsüsteiin ja Türosiin on organism võimeline mingil määral ise sünteesima ning seetõttu peetakse neid poolasendamatuteks aminohapeteks. Aminohaped Alaniin, Aspartaat, Glutamaat, Glütsiin, Proliin, Hüdroksüproliin ja Seriin on jaotatud asendatavate aminohapete hulka, sest tervele organismile on nende täielik sünteesimise võime tavapärases füsioloogilises olukorras iseloomulik.2 Erinevates toitudes varieeruvad nii valgu sisaldus kui ka valkude aminohappeline koostis. 1,3–5 Loomne toit on kõrge valgusisaldusega ning samuti on loomne toit rohke asendamatute aminohapete allikas (Joonis 1).4 Taimses toidu hulgas on suurema valgu sisaldusega liblikõieliste taimede viljad (oad, läätsed, herned) millega võrreldes teraviljade (riis, kaer) valgusisaldus jääb oluliselt madalamaks. Lühiajaliste lämmastiku tasakaalu uuringute põhjal on kindlaks tehtud, et minimaalse kehalise aktiivsusega terve täiskasvanud inimese soovitatav valgukogus päevas võiks olla 0,8 g valku kg kehamassi kohta päevas. Mõõduka ja intensiivse füüsilise aktiivsusega inimestele soovitatavaks valgu koguseks toiduga peetakse vastavalt 1,3 ja 1,6 g valku kehakaalu kilogrammi kohta päevas. 6 Maailma rahvastiku kasv ja muutuv sotsiaaldemograafia avaldab maailma toiduressurssidele suuremat survet mitte ainult toodetava toidu koguse suurendamise, vaid ka erinevat tüüpi toidu valigu osas. Eeldatakse, et suurenenud nõudlus loomsete valkude järele avaldab negatiivset keskkonnamõju, tekitades üha suuremaid kasvuhoonegaaside heitkoguseid ning nõudes rohkem vett ja rohkem maad. Olukorraga toime tulemine nõuab olemasolevate valguallikate säästvama tootmise arendamist ja alternatiivsete valguallikate leidmist ning kasutusele võttu otseseks inimtoiduks. Alternatiivsete valguallikate saamise tehnoloogiate väljaarendamisel tuleb samuti suurt tähelepanu pöörata negatiivsete keskkonnamõjude ärahoidmisele. 7 Taimsete valkude tootmise arendamine ja tootmine toidusektori jaoks on olnud viimasel aastakümnel üheks oluliseks poliitiliste arutelude teemaks ELi tasandil. Inimeste poolt tarbitavate taimsete valkude kogused on järjest kasvamas. Liha- ja piimaasendajate turu aastased kasvumäärad on kaugelt üle 10 %. Vajadus taimsete valkude tootmise arendamiseks on suur. Euroopa Parlament võttis 2018. aasta aprillis vastu raporti, milles seatakse eesmärgiks strateegia arendamist Euroopa valgurikaste kultuuride edendamise strateegia arendamine.8 Käesolevas raamatus vahendame Eesti Maaülikooli poolt MTÜ Taimsete Valkude Innovatsiooniklastrile läbi viidud innovatsioonitegevuste „Põllukultuuride valik ja sobivus valkude eraldamiseks“ ja ”Taimsete valkude eraldamine, kontsentreerimine ja omaduste iseloomustamine“ käigus saadud informatsiooni ja teadmisi. Innovatsioonitegevuse „Põllukultuuride valik ja sobivus valkude eraldamiseks“ eesmärgiks oli varasematele uuringutele tuginedes teha Eestis kasvatamiseks sobivatest sortidest eelvalik ning viia EMÜ, ETKI ja ettevõtjate koostöös kolmel aastal läbi põldkatsed kanepi, kaera, põldoa ja põldhernega, selgitamaks sordi, kasvuaasta ja kasvatustehnoloogia mõju saagi valgusisaldusele. Samuti oli eesmärk hinnata ära ka vähem viljeldud, kuid valgurikaste ja perspektiivsete kultuuride (hirsi ja läätse) sobivust taimse valgu allikana ning 5 saada teadmisi katses olnud kultuuride toorvalgu saagikusest hektari kohta, valgu aminohappelisest koostisest ja valgu omastamist takistavatest inhibiitoritest. Innovatsioonitegevuse ”Taimsete valkude eraldamine, kontsentreerimine ja omaduste iseloomustamine“ eesmärgiks oli saada ülevaade uuritavate taimsete valkude eraldamise, puhastamise ja kontsentreerimise võimalustest

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

Põllukultuuride valik ja sobivus valkude eraldamiseks

MTÜ Taimsete Valkude Innovatsiooniklaster viis läbi koostöö- ning teadus- ja arendustegevuse projekti, mille jaoks saadi toetust „Eesti maaelu arengukava 2014–2020“ meetmest „Innovatsiooniklaster“. Projekti teostamise periood oli veebruar 2019 kuni veebruar 2023 ja see koosnes neljast innovatsioonitegevusest. Innovatsioonitegevuse „Põllukultuuride valik ja sobivus valkude eraldamiseks“ eesmärk oli varasematele uuringutele tuginedes teha Eestis kasvatamiseks sobivatest kanepi-, kaera-, põldoa- ja põldhernesortidest eelvalik ning viia kolmel aastal läbi põldkatsed selgitamaks sordi, kasvuaasta ja kasvatustehnoloogia mõju saagi valgusisaldusele. Lisaks hinnati ka vähem viljeldud, kuid valgurikaste kultuuride (kikerherne, hirsi ja läätse) ning õlikanepi sobivust taimse valgu allikana. Määrati toorvalgusaak hektari kohta, analüüsiti valkude aminohappelist koostist ja hinnati valgu omastamist takistavate inhibiitorite sisaldust in vitro valgu seeduvuse mudeli abil.Rahastajad: Eesti maaelu arengukava 2014–2020 ja Euroopa Maaelu Arengu Põllumajandusfond (EAFRD)Rahastajad: Eesti maaelu arengukava 2014–2020 ja Euroopa Maaelu Arengu Põllumajandusfond (EAFRD

Occurrence of mycotoxin patulin and polyphenol profile of Nordic apple juices in relation to apple cultivation system and pre-processing storage temperature

The aims of this study were to find out if organic apple juice (AJ) contained higher contents of polyphenols or patulin compared to conventional AJ, and if higher storage temperature before processing increases patulin content in juice. AJ was pressed from Estonian, Danish and Norwegian apples. Additionally, three cultivars from Estonian organic and conventional orchards were stored at 3±2 °C and 9±2 °C before processing. Patulin, polyphenol content and antioxidant capacity were determined in pasteurized juices. In 2015, 33% of conventional (n=6) and 46% of organic (n=11) juices contained patulin; two of the organic juices above the legal limit (191 and 64µg l-1). In 2016, none of the AJs contained patulin. Patulin occurrence was more affected by weather conditions two weeks before harvest than by cultivation system and apple storage temperature. Polyphenol content was higher in organic than in conventional juices and was reduced at higher apple storage temperature

Hakklihatoodete riknemise pidurdamine taimsete tootmisjääkidega : [esitlus]

Ettekandes käsitleme: käimasoleva ResTA 14 projekti TAIMLOOMTOIT ühte suuremat katset •Projekti TAIMLOOMTOIT eesmärgiks o n teaduslikult põhjendatud suurima liha ja kala keemilise ja bakterioloogilise riknemise põhiprotsesside pidurdamise võimega bioaktiivsete lisandite väljaselgitamine taimse tootmise jääkides , nende jääkide võimalikult täielikuks ning eesmärgipäraseks kasutamiseks (Rätsep jt , 2021). •NB! Paljudel juhtudel on taimse tootmise jäägid hoopis rikkamad bioaktiivsete ainete poolest kui põhitooted , näiteks mahlad •Kokku tehti projekti raames 2021. aasta jooksul neli erineva suurusega katset, milleks valiti välja sea hakkliha ja taimsete materjalide segud, mis meie varasemate katsete tulemuste põhjal võisid anda parimaid tulemusi, arvestades erinevaid toime mehhanisme.•Projekti TAIMLOOMTOIT (F200143PKPA) elluviimist toetavad Euroopa Regionaalarengu Fond ja Eesti Teadusagentuur läbi Ressursside väärindamise alase TA tegevuse toetamise ” programmi ResTA14. •Loomse toidutoorme riknemise pidurdamise alast uurimistööd toiduhügieeni õppetoolis on toetanud ka Eesti Maaülikool baasfinantseeritava projektiga P180279VLTR Looduslike bioaktiivsete ainete toime ning seonduvate mehhanismide uurimine toidumaatriksites “, •ning nüüd toetab lähedast alusuuringut ka Eesti Teadusagentuur projektiga PRG1441Konverentsi "Terve loom ja tervislik toit 2022" slaidiesitlus.•Projekti TAIMLOOMTOIT (F200143PKPA) elluviimist toetavad Euroopa Regionaalarengu Fond ja Eesti Teadusagentuur läbi Ressursside väärindamise alase TA tegevuse toetamise ” programmi ResTA14. •Loomse toidutoorme riknemise pidurdamise alast uurimistööd toiduhügieeni õppetoolis on toetanud ka Eesti Maaülikool baasfinantseeritava projektiga P180279VLTR Looduslike bioaktiivsete ainete toime ning seonduvate mehhanismide uurimine toidumaatriksites “, •ning nüüd toetab lähedast alusuuringut ka Eesti Teadusagentuur projektiga PRG144

Supplementary table for Kaldmäe et al. in the International Journal of Fruit Science with the title Influence of pollination conditions on fruit set of selected blackcurrant genotypes and recently released cultivars

Data collection 2006-2007. Fruit set of blackcurrant (Ribes nigrum L.) cultivars ‘Almo’, ‘ Ats’, ‘ Elo’, and ‘ Karri’ and four breeder's selections was investigated under open pollination, artificial, and natural self-pollination conditions in 2006–2007

Responses of Aspen Leaves to Heatflecks: Both Damaging and Non-Damaging Rapid Temperature Excursions Reduce Photosynthesis

During exposure to direct sunlight, leaf temperature increases rapidly and can reach values well above air temperature in temperate forest understories, especially when transpiration is limited due to drought stress, but the physiological effects of such high-temperature events are imperfectly understood. To gain insight into leaf temperature changes in the field and the effects of temperature variation on plant photosynthetic processes, we studied leaf temperature dynamics under field conditions in European aspen (Populus tremula L.) and under nursery conditions in hybrid aspen (P. tremula × P. tremuloides Michaux), and further investigated the heat response of photosynthetic activity in hybrid aspen leaves under laboratory conditions. To simulate the complex fluctuating temperature environment in the field, intact, attached leaves were subjected to short temperature increases (“heat pulses”) of varying duration over the temperature range of 30 °C−53 °C either under constant light intensity or by simultaneously raising the light intensity from 600 μmol m−2 s−1 to 1000 μmol m−2 s−1 during the heat pulse. On a warm summer day, leaf temperatures of up to 44 °C were measured in aspen leaves growing in the hemiboreal climate of Estonia. Laboratory experiments demonstrated that a moderate heat pulse of 2 min and up to 44 °C resulted in a reversible decrease of photosynthesis. The decrease in photosynthesis resulted from a combination of suppression of photosynthesis directly caused by the heat pulse and a further decrease, for a time period of 10−40 min after the heat pulse, caused by subsequent transient stomatal closure and delayed recovery of photosystem II (PSII) quantum yield. Longer and hotter heat pulses resulted in sustained inhibition of photosynthesis, primarily due to reduced PSII activity. However, cellular damage as indicated by increased membrane conductivity was not found below 50 °C. These data demonstrate that aspen is remarkably resistant to short-term heat pulses that are frequent under strongly fluctuating light regimes. Although the heat pulses did not result in cellular damage, heatflecks can significantly reduce the whole plant carbon gain in the field due to the delayed photosynthetic recovery after the heat pulse

Antibacterial and antioxidative properties of different parts of garden rhubarb, blackcurrant, chokeberry and blue honeysuckle

BACKGROUND It is important to find plant materials that can inhibit the growth of Listeria monocytogenes and other food-spoiling bacteria both in vitro and in situ. The aim of the study was to compare antibacterial and antioxidative activity of selected plant-ethanol infusions: leaves and berries of blackcurrant (Ribes nigrum L.), berries of chokeberry (Aronia melanocarpa (Michx.) Elliott) and blue honeysuckle (Lonicera caerulea L. var. edulis); petioles and dark and light roots of garden rhubarb (Rheum rhaponticum L.) for potential use in food matrices as antibacterial and antioxidative additives. RESULTS The strongest bacterial growth inhibition was observed in 96% ethanol infusions of the dark roots of rhubarbs. In 96% ethanol, nine out of ten studied plant infusions had antibacterial effect against L. monocytogenes, but in 20% ethanol only the infusions of dark rhubarb roots had a similar effect. Chokeberry and other berries had the highest antioxidative activity, both in 20% and 96% ethanol infusions. CONCLUSION The combination of dark rhubarb roots or petioles and berries of black chokeberry, blackcurrant or some other anthocyanin-rich berries would have potential as both antibacterial and antioxidative additives in food. (c) 2018 Society of Chemical IndustryPeer reviewe

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