Rezica Sudar

Relationship between hordein proteins and malt quality in barley cultivars grown in Croatia

The hordein proteins of ten barley (Hordeum vulgare L.) cultivars grown in region of eastern Croatia were studied for their contribution to the malting quality, particularly relating hordein influence on malt extract yield. The analysis of hordein proteins was carried out by reversed-phase high-performance liquid chromatography (RP-HPLC). The micromalting of investigated barley cultivars and malt analyses were done according to the EBC official methods. The quantitative analysis of hordein proteins has showed that B-hordein was major component, followed by C- and D-hordeins. Among investigated cultivars the malt extract yield varied from 76.8% (cv. Angora) to 82.6% (cv. Scarlett). Spring barleys had on the average higher malt extract yield in contrast to winter barleys. The significant negative correlation between the total hordein content and malt extract yield was found. Among hordein fractions the B-hordein and D-hordein significantly contributed to lower malt extract yield. RP-HPLC analysis of malt hordeins revealed that the amount of hordein degraded during malting significantly correlated with Kolbach index.

Relation between polyphenols content and skin colour in sour cherry fruits

Fruit skin colour plays a major role in quality assessment of food, significantly determining consumer`s choice. Colour of sour cherries depends on anthocyanins which are phenolic compounds (flavonoids) present in high amounts in fruits. The aim of this study was to determine a possible relation between polyphenols (total phenolics and anthocyanins) and colour parameters of fruit skin of sour cherries. The plant material used in this study was twenty two sour cherry genotypes from an orchard of Agricultural Institute Osijek. Total phenolics and anthocyanins contents as well as colour parameters (L*, a*, b*, h and C) of fruit skin were determined. Variability between sour cherry genotypes in total phenolics and anthocyanins as well as in colour parameters was revealed. Total polyphenols content varied from 462.7 to 1049.0 mg GAE/100 g of fresh weight, while total anthocyanins ranged from 160.1 to 495.6 mg CGE/100 g of fresh weight. A significant positive correlation was found between polyphenols and anthocyanins content. Total phenolics content had a significant negative correlation with colour parameters b* and h, while anthocyanins content negatively correlated with colour parameters L*, b* and h. According to the obtained results, genotypes Maraska, Heimanns Konservenweichsel and Rexelle are the richest genotypes in polyphenols and anthocyanins content.

Chlorophyll content, photosynthetic efficiency and genetic markers in two sour cherry (Prunus cerasus L.) genotypes under drought stress

Abstract - Drought is a limiting factor in fruit production today. Identification of sour cherry genotypes tolerant to drought will enable the sustainability of fruit production. The aim of our study was to select sour cherry genotypes according to their genetic background as well as drought tolerance and investigate possible mechanisms of drought tolerance through the changes in photosynthetic apparatus (i.e. photosynthetic pigment content) and photosynthesis process assessed through the chlorophyll fluorescence transient. All of them together with molecular markers (SSRs and AFLPs), relative water content (RWC) as indicator of plant water status distinguish two genotypes (Kelleris 16 and OS), which are the opposite in regards to drought tolerance. Down-regulation of photosynthesis in drought-treated Kelleris 16 plants was seen as changes in antenna complexes of PSII (decreased total chlorophylls content (a+b) and chlorophylls ratio (a/b)). Despite unchanged maximum quantum yield of PSII in drought-treated leaves of genotype OS, overall photosynthetic performance expressed as PIABS was down-regulated in both investigated genotypes. However, decrement of PIABS was much pronounced in genotype Kelleris 16, mainly because of changes in a certain fraction of RCs, which become dissipative centres, seen as increase in ABS/RC and DI0/RC, in order to avoid photooxidative damage of photosynthetic apparatus. Also, electron transport, seen as decrease in ET0/(TR0-ET0) and ET0/RC, was impaired which lead to impaired CO2 fixation and photosynthesis. The described changes in the functioning of photosynthetic apparatus in drought-treated plants of Kelleris 16 constitute the main distinction between the two investigated genotypes regarding drought adaptation mechanisms.

Impact of Ameliorative Phosphorus Fertilization on Soil, Maize and Wheat Status

Acid reaction and nutritional imbalances, mainly low levels of plant available phosphorus (P) are often limiting factors of soil fertility in Bosnia and Herzegovina (B&H). The aim of this study was testing the impact of ameliorative P fertilization on soil properties and status of maize and wheat on acid soil (pH in 1n KCl: 4.0) of Tuzla Canton in B&H. The experiment of increasing rates of P fertilization has been started in spring of 2013. The experiment was conducted by randomized complete block design in four replicates (basic plot 63 m2 ). Monoammonium phosphate (12% N + 52% P2O5) was added to standard fertilization (kg ha-1: 150 N + 50 P2O5 + 50 K2O) in amounts as follows (P2O5 kg ha-1): 75, 475, 875, 1275 and 1675. In the next two years only standard fertilization was applied for crop rotation maize (2013) – maize (2014: crop was complete damaged by flood) – winter wheat (2014/2015). By increasing P rates the contents of mobile P were increased from 7.66 mg P2O5 100 g-1 to 20.10 mg P2O5 100 g-1 or 2.6 times. Also, maize yields were considerably increased up to 17%. (6.68 and 7.82 t ha-1, for control and the highest rate of applied P, respectively). Yield of wheat was significantly increased by P fertilization up to 14% (4.35 and 5.02 t ha-1, for control and the highest P rate respectively). However, for significant improvement of baking quality parameters (protein, wet gluten and sedimentation) the lowest P rate in level 475 kg P ha-1 was sufficient.

Total phenolic and total flavonoid content variability of soybean genotypes in eastern Croatia

Phenols, along with flavonoids found in soybean seeds [Glycine max (L.) Merr.], are known as active antioxidants and are associated with numerous benefits to the human health, such as prevention of cancer, cardiovascular diseases, osteoporosis and menopausal symptoms. The aim of this study was to evaluate total phenolic content and total flavonoid content of 33 soybean genotypes grown in 2010 and 2011. Analysis of variance showed significant differences between the genotypes and genotype x year interaction for both investigated traits. The total phenolic content in 2010 ranged from 2.330 to 3.227, and in 2011 from 2.121 to 3.164 mg/g of dry weight, expressed as gallic acid equivalents. Flavonoid content in 2010 varied from 0.433 to 0.659, and in 2011 from 0.428 to 0.580 mg/g of dry weight, expressed as catechin equivalents. Genotypes OS-L-100, OS-L-12, and OS-L-17 were singled out for the highest content of total phenols while genotypes OS-L-113, OS-L-17 and OS-L-151 had the highest total flavonoid content on average for both years. Results of analyses presented in this paper contribute to the development of the genetic background for improving antioxidant properties of Croatian soybean varieties.