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Zlín, Czech Republic

Cerna M.,Ustav Technology A Mikrobiologie Potravin | Kracmar S.,Ustav Biochemie A Analyzy Potravin
Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis | Year: 2010

The aim of this study was to investigate the effect of storage duration on amino acids content in potato tubers. Tubers of six cultivars were stored for 16 weeks. Crude protein was determined by the Kjeldahl method. The amino acid content was identified after acid hydrolysis; sulphur amino acids were oxidized with the mixture of hydrogen peroxide, formic acid and phenol. The essential amino acids index and chemical score was calculated. The whole egg protein was used as reference protein. The effect of storage duration and cultivar on the total amino acids content was found to be significant in all potato varieties. The level of the total amino acids contents was determined within the range of 8087%. Similar downward trend was observed in crude protein. The essential amino acids index varied considerably among the potato cultivars, ranging from 42 to 57%. Sulfur amino acids and isoleucin were the limiting amino acids in all the investigated tubers.

Pecivova P.,Ustav Technology A Mikrobio logie Potravin | Pavlinek V.,Centrum Polymernich Materialu | Hrabe J.,Ustav Technology A Mikrobio logie Potravin | Valasek P.,Ustav Biochemie A Analyzy Potravin | Bouda L.,Ustav Technology A Mikrobio logie Potravin
Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis | Year: 2011

Dynamic measurements with an oscillatory rheometer were made to study the rheological properties of wheat flour doughs and to examine how they are related to the composition of dough (the addition of oxidising and reducing agents). It was found that L-cysteine hydrochloride monohydrate (0.6 × 10 -2 - 4.0 × 10-2 wt.%), L-cysteine p. a. (0.6 × 10-2 - 1.4 × 10-2 wt.%) and glutathione-inactivated dry yeast (1.8 × 10-2- 14.0 × 10-2 wt.%) show softening effects. An interesting phenomenon was observed from the concentration of 2.4 × 10-2 wt.% of L-cysteine p. a., where proces of weakening was decelerated. L-cysteine start making cystine by reaction of two cysteine molecules and proces of weakening was decelerated. L-threonine, L-tryptophan within the concentration range of 2.0 × 10-2 - 14.0 × 10-2 wt.% and L-tyrosine, especially at concentrations 10.0 × 10-2 - 14.0 × 10-2 wt.%, have strengthening effects. L-cysteine hydrochloride monohydrate exhibited the strongest softening effect while L-tryptophan had the strongest stiffening effect on the gluten network.

Skrovankova S.,Ustav Biochemie A Analyzy Potravin | Sikorova P.,Ustav Biochemie A Analyzy Potravin
Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis | Year: 2010

Vitamin B2 (riboflavin) is a water-soluble essential vitamin. Nowadays an increased risk for riboflavin deficiency may be seen in people on special diets (diabetes mellitus), smokers or heavy alcohol drinkers. In the Czech diet the main sources of the vitamin intake are milk and dairy products followed by cereals and meat. Cereals are good source of this vitamin as it is widely and regularly consumed in different forms. Analyses of the vitamin B 2 content in different types of cereal products (flours, breads, pastries, breakfast cereals, cooked pasta) of Czech origin using HPLC with reversed phase and UV detection were done. The vitamin B2 content of chosen cereal products decreased in this progression: enriched wholemeal breakfast cereals (the best source of the vitamin), enriched wheat flours, breads - rye and wholemeal wheat breads, whole wheat and spelt flours, wheat bread, cooked whole wheat and rye spaghetti, wheat and multigrain pastries and finally scoured wheat flours.

Sipalova M.,Ustav Biochemie A Analyzy Potravin | Hanus O.,Ustav Biochemie A Analyzy Potravin | Bunka F.,Ustav Biochemie A Analyzy Potravin | Pozdisek J.,Ustav Biochemie A Analyzy Potravin | And 2 more authors.
Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis | Year: 2010

The aim of this study was to evaluate the possible effects of maize replacement in feeding rations on the amino acid content in cows milk. Cows were fed total mix ration based on the maize, clover silage and hay. There was a difference in the concentrate of the feeding ration. The first group (fed maize) was the control group, another two groups were experimental, one fed wheat and second fed triticale. During six weeks, totally 26 milk samples were taken from dairy cows of Czech Pied breed. Feed groups were preferably balanced in terms of milk yield, stage and number of lactations. The samples of feedstuffs as well as milk were modified for the analysis using acidic and oxidative hydrolyses. The analysis of amino acids content and composition of the sample hydrolysates was performed chromatographically by an AAA 400 analyzer, using Na-citrate buffers and ninhydrin detection. Total nitrogen content was determined according to Kjehldahl and the crude protein of the samples was determined by conversion from the nitrogen content multiplied by appropriate factor. The high content of crude protein in wheat did not influenced composition of milk from dairy cows fed this type of feedstuff. With respect to resulting amino acid content and composition of milk samples, none of the tested grains can be recommended as a full-value maize replacement. Each feedstuff is an abundant source of several and typical amino acids in milk. However, triticale (cultivar Kitaro) seems to be acceptable replacement of maize owing to better crude protein efficiency, composition and health indicators of milk quality.

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