Miroslav Šlosár

Total polyphenol content and antioxidant capacity changes in dependence on chosen garden pea varieties.

The green pea is ranged between the crops with high antioxidant potential. This potential is connected with phytochemical components mainly with polyphenols. All these bioactive chemicals have disease-fighting properties. In real human diet there is no usually possibility of fresh garden pea consumption during the whole year. The total polyphenol content is significantly changed among other things by processing methods. Focus on variety, bio-fortification and other specific agricultural inputs, could be the right method of total polyphenol contents and total antioxidant capacity increasing. The main objective of the present work was to consider the changes of total polyphenols content in dependence on variety and to evaluate an antioxidant potential six garden pea varieties arranged by the ripening point of view. Variety Exzeleus belongs to very early type, Premium is early maturing, Flavora is middle ripening variety and the last three varieties Utrio , Jumbo and Ambassador are middle late types of varieties. Every variety was grown in four replications, i.e. on 24 m total plot in Botanical garden of Slovak University of Agriculture in Nitra during 2013. Total polyphenols were determined by the Lachman s method and expressed as mg of gallic acid equivalent per kg fresh mater. Total antioxidant capacity was measured by the Brand-Williams method using a compound DPPH (2.2-diphenyl-1-pikrylhydrazyl)). The highest value was reached in case of variety Jumbo 1179.995 ±28.081 mg/kg, the lowest value in case of Premium 674.505 ±26.541 mg/kg. When evaluating an antioxidant capacity in chosen varieties of garden pea, the interval estimated by our trail ranged from 0.523 ±0.206% ( Exzeleus ) to 6.844 ±0.591% ( Flavora ). Following the both observed parameters, TPC and TAC, variety Flavora (as a member of middle ripening varieties) seems to be the most optimal from the human nutrition point of view. The various varieties had significant influence on TPC and TAC according to used statistical analyzes. Within the all observed varieties, when they were arranged by ripening, there was estimated significant difference only in case of garden pea varieties early – middle late . Other couples didn t show any statistical important differences in total polyphenol content.

FERTILISATION IMPACT ON THE CONTENT OF SELECTED BIOACTIVE COMPOUNDS IN CAULIFLOWER

Nitrogen and sulphur fertilization positively affected on crop yields and bioactive compounds (vitamin C, E1 and s-carotene) content in cauliflower edible heads. Applying fertilization doses of 250 kg N.ha-1 and 60 kg S.ha-1 compared to the control improved cauliflower harvest by 15,2 t.ha-1. Increased fertilization doses of nitrogen and sulphur significantly increased vitamin C and s-carotene content in the cauliflower. High significant difference in vitamin C level was found comparing the control variant and variant of nitrogen fertilization at the level of 200 kg N.ha-1. In percentage terms this is an increase in vitamin C level by 22,4%. Fertilization with increased doses of nitrogen and sulphur affected significantly the amount of s-carotene compared to unfertilized variant. Increased doses of N and S did not respond adequately to vitamin E1 content in cauliflower.

Quality changes in organic and conventional Hokkaido pumpkin (Cucurbita maxima Duch.) during storage

Abstract Organic production of vegetables has increased in recent years. Pumpkin is a well-known edible plant, which has substantial nutritional properties due to the presence of unique natural substances. Pumpkin is one of the most commonly grown organic vegetables in the Czech Republic. The aim of this work was to compare the quality of organic and conventional Hokkaido pumpkin (Cucurbita maxima Duch.) during storage in terms of colour changes (Lab colour space), loss of mass, concentrations of ascorbic acid and total carotenoid. BIO (from organic farming) and CONV (from conventional farming) variants were tested at monthly intervals over three (2013) and four (2014) months storage after harvest. In 2013, the average loss of mass reached 19% in BIO and 23% in CONV and in 2014 it reached 12% in BIO and 20% CONV. Differences of loss of mass between BIO and CONV were only significant in 2014. In all variants and in both years, a gradual reduction in ascorbic acid (AA) during storage was noted. The reduction in concentration of ascorbic acid (AA) was slower in BIO than in CONV variants, and in both years BIO variants also showed smaller changes in concentrations of total carotenoids compared to CONV variants. The BIO pumpkins maintained their red colour (a*) better during storage than the CONV pumpkins, but the evaluation of the total colour difference (TCD) showed significant differences over time in both variants in both years.

Ageing of plasticized poly(lactic acid)/poly(β-hydroxybutyrate) blend films under artificial UV irradiation and under real agricultural conditions during their application as mulches

The paper is aimed on the investigation of natural ageing of plasticized poly(lactic acid)/poly(β-hydroxybutyrate) PLA/PHB blend films during their one-season application as mulches under real field conditions in the western part of Slovakia. Acetyl tributyl citrate (ATBC) was used as the plasticizer. The analysis was performed on three differently exposed parts of the foil: i) buried in soil, ii) exposed to sunlight, and iii) shadowed by plants. In parallel, UV irradiation of the blend under laboratory controlled conditions (constant temperature of 30°C and relative humidity of 55 %) was carried out. The degradation effect was followed by changes in the molar mass, chemical and crystalline structures, as well as in thermal and mechanical properties. The ternary PLA/PHB/ATBC blend lost its tensile properties faster when buried in soil than when exposed to sunlight. This result is in agreement with the data obtained for the UV-irradiated materials. Young’s modulus values showed a significant mechanical degradation under the UV irradiation as well as during natural ageing. The study was also focused on the influence of mulches on the yield and quality of sweet pepper production, characterized by carotenoids and vitamin C content.

Changes of vitamin C content in celery and parsley herb after processing

Humans and other primates have lost the ability to synthesize vitamin C and therefore the only source is diet. Vitamin C or ascorbic acid has labile nature, it is removed or destroyed in specific degree immediately after harvest, but storage and post - harvest processing also contribute to its degradation. The aim of work was to determine the vitamin C content in the herb of selected celery and parsley varieties in dependence on chosen postharvest processing and to compare it with fresh herb. There were chosen five bulb forms varieties of celery (Apium graveolens) - Makara, Ilonaa, Hegy Koi, Talar and Diamant. In case of parsley (Petroselinum crispum) there were evaluated one variety of curly parsley, one variety of herb parsley - Petra, and five varieties of root parsley - Lenka, Eagle, Ginate D´Italia, Titana and Arat. Every variety was harvested in three terms, followed by vitamin C content estimation in fresh herb, after drying and after freezing. The content of vitamin C was estimated by HPLC method by the help of liquid chromatograph with UV detector. There was found the significant difference in content of vitamin C in parsley as well as in celery when comparing the fresh herb with herbs after post - harvest processes - drying (by air circulation in laboratory hall) and freezing. After processing of herbs in both observed species the vitamin C content decreased, in case of freezing it was about 65% (celery) and 61% (parsley), after drying about 86% (celery) and 82% (parsley) in comparison with fresh herb. The effect of processing played more important role in influencing of vitamin C content than variety in case of both selected species. For using of celery and parsley not only as culinary herb, but as a notable source of ascorbic acid it is the most important fresh herb intake.

Examination of Basic Variety Characteristics of Sweet Corn in Conditions of the Southern Slovakia

Abstract The production of sweet corn has been increased recently. It is a very delicious vegetable species with wide variety assortment. Nowadays, new varieties which come to markets are characterized by improved properties, higher sugar content and their stability in storage. Thus, it is necessary to know basic variety parameters for better orientation in wide corn assortment. According to earliness, sweet corn varieties were classified to following groups: very early or early (RISING SUN F1; 874 F1; SF 1073 F1; SF 583 F1); middle-late (SF 681 F1; 1027 F1; ASTRONAUT F1); late (GALAXY F1; SPACE SHIP F1) and very late (MATADOR F1). The day number from tassel anthesis to harvest is an important parameter of sweet corn for potential grower and its lowest value was found at variety RISING SUN F1. On the basis of gained results, we classified all evaluated varieties to the group of super-sweet corn (sh-2) with slow decline of sugar content and storage possibility in cold conditions from 4 to 7 days after harvest. The sugar content of sweet corn is a parameter having important role for purchase by consumers. The variety had statistically significant impact to the sugar content and its highest value was determined at variety 874 F1.

Qualitative and quantitative characteristics of Serbian tomato varieties grown in conditions of Slovak Republic.

The aim of submitted article was to estimate qualitative and quantitative characteristic of Serbian tomato varieties grown in conditions of Slovak republic and to compare the results with control tomato variety and evaluate their potential for the Slovak market. There were included 6 Serbian tomato varieties: ´Fantom VFCTm F1´, ´Marathon ASVF F1´, ´Honey Heart VF F1´, ´Uragan SVF F1´, ´Kazanova F1 VF´, ´Dinka F1´ and ´Tornado F1´ in control variant, which is wide spread in Slovak tomato production. As qualitative characteristic for every variety total yields (in kg) per every plant, total number of harvested fruits (in pieces for each plant) and average weight of one fruit in kg were evaluated. In Department of vegetable growing laboratory qualitative characteristics in case of all chosen tomato varieties were estimated (included firmness of fruits, total carotenoids estimation, ascorbic acid estimation). Serbian varieties reached lower total yields per plant. From the ´fruit weight´ point of view they created more or less homogenous group of bigger and heavier fruits in comparison with ´Tornado F1´ and statistically significant homogenous group when focusing on total number of fruits per plant in comparison with ´Tornado F1´ variety. Differences between control variant and chosen Serbian varieties were even more considerable in case of qualitative characteristics, where ´Tornado F1´ reached the lowest values in case of all observed characteristics - firmness of fruits, total carotenoids and ascorbic acid content. According to increasing importance of antioxidants in human diet, all tested Serbian varieties appeared to be very interesting for Slovak consumers from following both qualitative and quantitative characteristics.

the effect of nitrogen and sulphur nutrition on the yield and content of antioxidants in broccoli vplyv dusíkatej a sírnatej výživy na úrodu a obsah antioxidantov v brokolici

Abstract The small field experiment with broccoli (variety ‚Tiburon F1‘) was established in The Botanical Garden of Slovak University of Agriculture in Nitra. In this experiment, we investigated the effect of four variants of nutrition on the broccoli yield, content of sulforaphane and vitamin C in broccoli florets. The first variant of nutrition was a control one - without application of fertilizers. The second one was fertilized at nitrogen level 200 kg.ha-1. The third one had level of nutriments N : S = 200 : 50 kg.ha-1 and fourth one N : S = 200 : 60 kg.ha-1. In each variant of nutrition, the yield of broccoli was significantly increased in comparison with the control variant. The highest yield of broccoli florets was reached in variant 4 (27.87 t.ha-1). The highest amount of sulforaphane was also determined in variant 4 - 50.93 mg.kg-1 of fresh matter. However, this value did not represent significant increase of sulforaphane content compared to the control variant. The highest content of vitamin C was determined in variant 2 (585.78 mg.kg-1 of fresh matter). In this variant, we achieved significant increase of vitamin C content in comparison with the control variant. Thus, by application of nitrogen and sulphur nutrition, we reached significant increase of broccoli yield compared to the control variant. At the same time, the applied nutrition assisted to enhanced accumulation of sulforaphane and vitamin C in broccoli florets Maloparcelkový poľný pokus s brokolicou (odroda Tiburon F1) bol založený v roku 2008 v areáli Demonštračnej záhrady SPU v Nitre. V pokuse sme skúmali vplyv štyroch variantov výživy na úrodu, obsah sulforafanu a vitamínu C v ružiciach brokolice. Prvý variant (1) bol kontrolný - neboli na ňom aplikované priemyselné hnojivá. Variant 2 bol vyhnojený na úroveň N 200 kg.ha-1. Pri 3. a 4 variante boli živiny doplnené na úroveň N : S = 200 : 50 kg.ha-1, resp. 200 : 60 kg.ha-1. Na všetkých variantoch výživy sa úroda ružíc brokolice preukazne zvýšila v porovnaní s kontrolou. Najvyššia úroda ružíc brokolice bola dosiahnutá na variante 4 - 27,87 t.ha-1. Najväčšie množstvo sulforafanu bolo taktiež zistené vo variante 4 - 50,93 mg.kg-1 čerstvej hmoty. Táto hodnota však nepredstavovala preukazné zvýšenie obsahu sulforafanu oproti kontrolnému variantu. Najväčší obsah vitamínu C bol dosiahnutý na variante 2, pričom sme zaznamenali preukazné zvýšenie obsahu vitamínu v porovnaní s kontrolou. A teda, aplikáciou dusíkatej a sírnatej výživy sme dosiahli preukazné zvýšenie úrody oproti kontrolnému variantu, ale zároveň aplikovaná výživa prispela k zvýšenej kumulácii sulforafanu a vitamínu C v ružiciach brokolice