Zora Kotíková

Effect of peeling and three cooking methods on the content of selected phytochemicals in potato tubers with various colour of flesh

The impact of peeling and three cooking treatments (boiling, baking and microwaving) on the content of selected phytochemicals in white-, yellow-, red- and purple-fleshed potatoes was investigated. Ascorbic acid and chlorogenic acid contents were determined by HPLC-DAD, total anthocyanin content by pH-differential spectrophotometry, glycoalkaloid, α-chaconine and α-solanine contents by HPLC-ESI/MS/MS. All cooking treatments reduced ascorbic and chlorogenic acid contents, total glycoalkaloids, α-chaconine and α-solanine with the exception of total anthocyanins. The losses of ascorbic and chlorogenic acids were minimised with boiling and total anthocyanin levels retained the highest. Boiling of peeled tubers decreased contents of total glycoalkaloids (α-chaconine and α-solanine) and appeared as the most favourable among the three tested methods. Moreover, due to higher initial levels, red- and purple-fleshed cultivars retained higher amounts of antioxidants (ascorbic acid, chlorogenic acid and total anthocyanin) after boiling and may be healthier as compared with white or yellow cultivars.

Bisphenol S negatively affects the meotic maturation of pig oocytes

Bisphenol A (BPA), a chemical component of plastics, is a widely distributed environmental pollutant and contaminant of water, air, and food that negatively impacts human health. Concerns regarding BPA have led to the use of BPA-free alternatives, one of which is bisphenol S (BPS). However, the effects of BPS are not well characterized, and its specific effects on reproduction and fertility remain unknown. It is therefore necessary to evaluate any effects of BPS on mammalian oocytes. The present study is the first to demonstrate the markedly negative effects of BPS on pig oocyte maturation in vitro, even at doses lower than those humans are exposed to in the environment. Our results demonstrate (1) an effect of BPS on the course of the meiotic cell cycle; (2) the failure of tubulin fibre formation, which controls proper chromosome movement; (3) changes in the supply of maternal mRNA; (4) changes in the protein amounts and distribution of oestrogen receptors α and β and of aromatase; and (5) disrupted cumulus cell expansion. Thus, these results confirm that BPS is an example of regrettable substitution because this substance exerts similar or even worse negative effects than those of the material it replaced.

Carotenoid profile and retention in yellow-, purple- and red-fleshed potatoes after thermal processing.

This research aimed to investigate the effect of thermal processing on carotenoid profile, quantity and stability in 22 colour-fleshed potato cultivars grown in the Czech Republic. The total of nine carotenoids was analysed by HPLC using a C30 column and PDA detection. The total carotenoid content for all cultivars ranged from 1.44 to 40.13 μg/g DM. Yellow cultivars showed a much higher average total carotenoid content (26.22 μg/g DM) when compared to red/purple-fleshed potatoes (5.69 μg/g DM). Yellow cultivars were dominated by antheraxanthin, whereas neoxanthin was the main carotenoid in red/purple cultivars. Thermal processing significantly impacted all potato cultivars. Boiling decreased the total carotenoids by 92% compared to baking (88%). Lutein was the most stable carotenoid against thermal processing (decreased by 24-43%) followed by β-carotene (decreased by 78-83%); other carotenoids were degraded nearly completely. Increased formation of (Z)-isomers by thermal processing has not been confirmed.

Free and esterified carotenoids in pigmented wheat, tritordeum and barley grains

Carotenoids are important phytonutrients responsible for the yellow endosperm color in cereal grains. Five carotenoids, namely lutein, zeaxanthin, antheraxanthin, α- and β-carotene, were quantified by HPLC-DAD-MS in fourteen genotypes of wheat, barley and tritordeum harvested in Czechia in 2014 and 2015. The highest carotenoid contents were found in yellow-grained tritordeum HT 439 (12.16μg/gDW), followed by blue-grained wheat V1-131-15 (7.46μg/gDW), and yellow-grained wheat TA 4024 (7.04μg/gDW). Comparing carotenoid contents, blue varieties had lower whereas purple ones had the same or higher levels than conventional bread wheat. Lutein was the main carotenoid found in wheat and tritordeum while zeaxanthin dominated in barley. The majority of cereals contained considerable levels of esterified forms (up to 61%) of which lutein esters prevailed. It was assessed that cereal genotype determines the proportion of free and esterified forms. High temperatures and drought during the growing season promoted carotenoid biosynthesis.

Effect of cultivar, flesh colour, locality and year on carotenoid content in potato tubers

In this study, twelve cultivars of potato with different flesh colour (yellow, purple and red) were cultivated in 2012 and 2013 in two trial localities in the Czech Republic and evaluated for the main individual carotenoids. The con tent of total carotenoids (TC) in analysed cultivars ranged in 1.1–12.2 mg/kg in dry matter (DM) and was influ enced by genotype cultivar, locality and year. Cv. Agria (yellow flesh) reached 1.8 to 11.8 times higher levels of TC compared with cultivars of coloured flesh. Locality and year of higher average temperatures during the growing season produced higher TC contents in tubers. Genotype significantly influenced the content and composition of individual carotenoids. As in cv. Agria, violaxanthin (41%) and lutein (55–78%) dominated in all cultivars with coloured flesh. The relative content of β-carotene in cv. Agria represented 2% of TC, in cultivars with coloured flesh 5–12% TC.

Resveratrol and piceid isomers concentrations in grapevine shoots, leaves, and tendrils

Lachman J., Kotikova Z., Hejtmankova A., Pivec V., Psenicnaja O., Sulc M., Střalkova R., Dědina M.

Effect of cadmium stress on barley tissue damage and essential metal transport into plant

Abstract Conductometric assessment of electrolyte leakage from spring barley plant organs subjected to higher cadmium concentrations 10-2 – 10-4 mol l-1 revealed serious tissue damage. Therefore plants were grown under controlled environment conditions in a phytotron in Knop´s nutrient solution in two variants – the control variant without cadmium and experimental variant treated during the growth of plants with CdCl2 solution of 10-5 mol l-1. Barley plants were then separated into roots, residual caryopses, leaf bases, and leaves. Lyophilized samples were analyzed for the uptake and redistribution of cadmium, calcium, copper, iron, zinc, and manganese in plant organs by spectrometric methods. Cadmium caused significant decrease of calcium and manganese levels in all analyzed plant parts indicating that cadmium was a distinctive antagonist to intake of these metals. Cadmium treatment also lowered amounts of zinc and iron in roots. An opposite trend was characteristic for Cu, where Cd stress caused significant Cu increase and retention in roots and significant decrease in leaves. The combined usage of the electroanalytical technique - conductometry and spectrometric methods (ICP-OES, AAS) proved to be a useful tool for monitoring of tissue damage and intake and transfer of cadmium and macro- and microelements into barley organs. Graphical Abstract

Changes in anthocyanidin levels during the maturation of color-fleshed potato (Solanum tuberosum L.) tubers

Certain potato cultivars are capable of producing anthocyanin pigments in the potato skin and flesh and those pigments have been shown, together with other phytochemicals, to promote good health. Six common anthocyanidins (cyanidin, delphinidin, petunidin, pelargonidin, malvidin and peonidin) were analyzed weekly for 15weeks in red- and purple-fleshed potato cultivars (Red Emma, Königspurpur, Valfi and Blaue de la Mancha) grown in field conditions using a validated LC-(+ESI)MS/MS method. Pelargonidin was the major type detected in red-fleshed cultivars whereas petunidin was the major type detected in the purple ones. Neither cyanidin nor delphinidin were found in any of the cultivars. The anthocyanidin levels observed were as high as 78mg/100g FW during tuber growth; however, fully matured tubers contained only 10-39mg anthocyanidins/100gFW. Anthocyanidin levels were moderately correlated with global solar irradiation (r<0.6252) but not with rainfall or daily temperature.

Carotenoids in potatoes – a short overview

Carotenoids are one of major lipophilic constituents contributing to total antioxidant activity and provitamin content of potato, a major non-cereal staple food. The review briefly discusses health promoting properties of carotenoids and especially their contents and composition in different potato cultivars affected by flesh colour (white-, yellow-, purpleand red-fleshed) and the effect of selected factors on carotenoid total and individual levels, such as genotype, breeding, tuber development, heat processing – cooking, storage, effect of year, locality, etc. The aim of the recent research is obtaining potatoes with higher levels of beneficial carotenoids to improve one the most popular vegetables in the world.