Ales Rajchl

Ales Rajchl
University of Chemistry and Technology, Prague | VSCHT · Department of Food Preservation

Assoc. Prof.

About

50
Publications
26,839
Reads
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432
Citations
Citations since 2016
26 Research Items
365 Citations
20162017201820192020202120220102030405060
20162017201820192020202120220102030405060
20162017201820192020202120220102030405060
20162017201820192020202120220102030405060
Introduction
Food Reformulation, Food Technology, Food Quality and Authenticity, Food Preservation, Food Raw Materials, DART/TOF-MS, HPLC
Additional affiliations
June 2005 - present
University of Chemistry and Technology, Prague
Position
  • Researcher
January 2005 - February 2015
University of Chemistry and Technology, Prague
Position
  • Researcher
Education
September 2005 - September 2009

Publications

Publications (50)
Article
Full-text available
Fortification is one of the most important processes for the improvement of nutrients in food. This process can be a very cost-effective public health intervention. Due to the high consumption rate of fruit products, fortification of these products will effectively reduce and prevent diseases associated with nutritional deficiencies. This paper off...
Article
Salt (sodium chloride) is one of the main sources of sodium in a diet. However, high salt intake (9–12 g/day) is considered a serious health problem. In response to the urgent need for reduction in sodium intake, the World Health Organization (WHO) initiated a global movement for reducing salt intake to less than 5 g/day by 2025. This study focuses...
Article
Full-text available
The aim of this study was to evaluate the chemical composition of 17 samples of mead originating from the Czech Republic. The samples included honey wines (made only from water and honey) and dessert meads which were treated mainly by the addition of sugar or alcohol. The following chemical parameters were analysed: ethanol, sugar-free extract, hyd...
Article
Full-text available
The aim of the research was to produce edible packaging based on chitosan with the addition of various concentrations of extracts of blueberry, red grape and parsley marcs. Packaging was made from extrudate extracts, which were subsequently analyzed by physicochemical methods: zeta-potential, gas barrier properties, thickness, water content, solubi...
Article
In this study, 46 different cultivars of chilli peppers and their seeds were analysed. Capsaicin, the alkaloid responsible for the pungency of chilli peppers, was first analysed with the optimised direct analysis in real time (DART) and time of flight mass spectrometry (TOF-MS) method, and the capsaicin content values obtained were compared with th...
Article
Full-text available
Various species of the Vaccinium genus (V. corymbosum, VC; V. myrtillus, VM) are regularly subjected to adulteration with similar, blue-coloured berries such as Amelanchier alnifolia (AA) or Lonicera caerulea (LC). Thirty-one berry samples were tested to determine and verify their basic chemical composition and profile of anthocyanins. Saccharose a...
Article
An electrophoretic method (on-line coupled capillary isotachophoresis and capillary zone electrophoresis) with conductometric detection for the determination of free taurine in selected food and feed is described. Taurine is converted to isethionic acid by van Slyke method. Under optimized conditions (leading electrolyte: 5 mM HCl, 10 mM glycylglyc...
Article
Phloridzin (phloretin-2´-O-glucoside) is a phenolic compound characteristic of the genus Malus. This study aimed to evaluate phloridzin as a marker of undeclared addition of apples in fruit products. To test this proposal, the heat and oxidation stability of phloridzin was firstly confirmed. Then the distribution and variability of phloridzin in ap...
Article
The prevalence of excessive weight gain, obesity, and associated diseases are permanently increasing. Therefore, the interest in food products with a composition suitable for people with the aforementioned health problems is also on the rise. The changes in food composition, nowadays often called reformulation, are mainly focused on reducing the am...
Book
The presented publication summarises the current state of knowledge on food reformulation, whilst taking into account current nutritional aspects. The book covers all major food commodities i. e. bakery products, meat products, dairy products, confectionery, edible fats and oils, non-alcoholic drinks, fruit and vegetable products. The text itself p...
Article
Cacao and cocoa products are worldwide important commodities, which are often a subject of adulteration. Therefore, a sufficient and reliable analytical technique is required to provide fast screening results, which will accommodate the need to reveal adulteration and evaluate the quality of selected cocoa products in real time. The goal of this pa...
Article
Full-text available
Cílem práce je s použitím metody posuzování životního cyklu porovnat potenciální environmentální dopady dovozu a skladování jablek v podmínkách České republiky a odpovědět na otázku, zda se z environmentálního pohledu vyplatí podporovat místní produkci a delší skladování či naopak dovoz zahraniční produkce, která sice má horší environmentální aspek...
Article
Full-text available
Cílem práce je s použitím metody posuzování životního cyklu porovnat potenciální environmentální dopady dovozu a skladování jablek v podmínkách České republiky a odpovědět na otázku, zda se z environmentálního pohledu vyplatí podporovat místní produkci a delší skladování či naopak dovoz zahraniční produkce, která sice má horší environmentální aspek...
Article
Full-text available
Commercial fruit baby food is a preserved fruit product usually made with fruit purees, sugar, water and variable additives (thickening agents, antioxidants, etc.). As the foodstuffs intended for particular nutritional uses, baby foods for infants and young children conforms to a set of strict guidelines e.g. maximum levels for pesticide residues,...
Article
Full-text available
Off-flavour in soft drinks is one of the main threats to manufacturers, which can result in expensive recalls, and discredit the brand. Off-flavours can occur for a variety of reasons (e.g. chemical contamination of raw material). The presented case study has proved there is a relationship between the identification of biphenyl and its derivatives...
Patent
NOVELTY - Preparing a prebiotic, gluten-free and lactose-free fruit product, comprises producing a product with probiotic properties from a fruit material, preferably from byproducts of fruit processing e.g. peels, puddings and moldings, mixing the homogenized fruit raw material with flour and water in a same ratio, and fermenting the resulting sus...
Patent
NOVELTY - Preparing a probiotic productwith a high proportion of fruit-based prebiotics, comprises processing afruit materialobtained from byproducts of fruits including peel, puddings and moldings to form a product with probiotic properties, mixing the homogenized fruit raw material with butter and whey in a same ratio, and fermenting the resultin...
Article
Yacon [Smallanthus sonchifolius (Poepp. et Endl.) H. Robinson] is a plant grown worldwide originating in the Andes region. Yacon is grown for its sweet tuberous roots and leaves used for the preparation of herbal infusions. Twenty-six yacon landraceś leaves and roots (both peeled and unpeeled) have been analysed by DART-TOF/MS. The method has been...
Article
Full-text available
Fast evaluation of honey quality is a topical and significant problem of the food industry, bee keepers and consumers. In this work, 22 samples of commercially available honey aromas (with methyl and ethyl esters of phenylacetic acid predominated), 13 samples of authentic honey collected directly from bee keepers (characterised by high content of b...
Article
The paper focuses on the optimization, settings and validation of direct analysis in real time (DART) coupled with time of flight detector (TOF) when used for the evaluation of the quality of selected herbal teas (fennel, chamomile, nettle, linden, peppermint, thyme, lemon balm, marigold, sage, rose hip, St. John's Wort). The ionization mode, the o...
Article
Full-text available
The identification of yacon, a medicinal plant, in tea mixtures by rapid Polymerase Chain Reaction (PCR) and the Direct Analysis in Real Time coupled with Time-of-Flight Mass Spectrometry (DART/TOF-MS) method were evaluated. Three tea products and a pure yacon tea were analysed using the molecular method PCR, concretely the intraspecific variation...
Article
The paper describes laboratory deodorization of rapeseed oil (Ro), model sunflower (SoM) and model rapeseed (RoM) oils, its effect on the tocopherol content and the kinetics of tocopherol degradation. We now present a novel approach to analysis of alpha-tocopherol degradation product as well as kinetic study esters of alpha-tocopherol with fatty ac...
Article
Previous studies have shown that a large number of polyvinylchloride (PVC) lid gaskets exceed the existing migration limits for epoxidised soybean oil (ESBO) and correct prediction of ESBO release into food therefore appears to be a difficult issue. ESBO migration from PVC gaskets of metal closures into food simulants and food products from the Cze...
Article
Full-text available
Food adulteration remains a great concern for consumers in the developed countries; examples include products of red and blue berries as fruit drinks, syrups or jams. Undeclared coloring can mask a lower proportion of fruits in the final product or the use of lower quality raw materials. Black carrot, chokeberry, elderberry, grapes, pomegranate and...
Article
Full-text available
Fruit baby food is an important food source in infant nutrition. This ambient stable product is processed using heat treatment and can be stored for one or more years at ambient temperature. An accelerated shelf-life storage test of fruit baby food was carried out. Sets of samples were stored at various storage temperatures (40, 55, 70 and 90 °C) f...
Article
DART (Direct Analysis in Real Time) coupled with Time-of-Flight Mass Spectrometry (TOF/MS) has been used for analyses of ice-teas. The article focuses on quality and authenticity of ice-teas as one of the most important tea-based products on the market. Twenty-one samples of ice-teas (black and green) were analysed. Selected compounds of ice-teas w...
Article
We verified applicability of direct analysis in real time ionization coupled with a time-of-flight mass spectrometer (DART-MS) for detection of anabolic androgenic steroids in supplements and pharmaceuticals. DART-MS was optimized for the analysis of eleven frequently misused anabolic androgenic steroids and their derivatives. Real supplement table...
Article
Full-text available
Čerstvost je jednou z důležitých vlastností masa, proto se dnes hledají nové metody, které by hodnotily čerstvost na základě velkého počtu markerů. Jako jedna z možností se nabízí technika DART ve spojení s TOF-MS. Výstupem je hmotnostní spektrum, ve kterém je možné sledovat nespočet markerů. Pro extrakci nízkomolekulárních látek bylo vyzkoušeno pě...
Article
Meat freshness is an important property and so new methods for freshness evaluation are sought. Unfortunately, the known methods are restricted and so we tried to use quite a new technique – direct analysis in real time (DART) coupled with time-of-flight mass spectroscopy (TOF-MS). This technique using plasma-excited He atoms and atmosphere compone...
Article
Full-text available
Honey crystallization is considered to be a natural process during its maturing and an indicator of natural honey composition. However, consumer evaluation of honey crystallization is usually negative. Crystallization depends on honey composition and it is influenced by methods and conditions of honey processing and storage (mechanical and thermal...
Article
DART (direct analysis in real time) is a novel technique with great potential for rapid screening analysis. The DART ionization method coupled with high/resolution time/of/flight mass spectrometry (TOF/MS) has been used for characterization of mustard seeds and table mustard. The possibility to use DART to analyse glucosinolates was confirmed on de...
Article
To ensure that egg-containing products, such as dried eggs and egg pasta, conform to the technological and legislative requirements for egg content, methods are needed to determine the amount of cholesterol in such products. The conventional approach, direct saponification and hexane extraction followed by cholesterol determination by gas chromatog...
Article
Full-text available
For almost 20 years, it has been known that if soft drinks are preserved with benzoic acid, it reacts under certain circumstances with ascorbic acid in drinks forming carcinogenic benzene. The concentrations of benzene in 49 soft drinks analysed within the five-year survey, obtained from the Czech market, were below 10 µg∙l-1; the average benzene c...
Article
Epoxidized soybean oil (ESBO) is widely used as a plasticizer and stabilizer mainly in food contact materials on the base of polyvinylchloride, especially in the gaskets of jar lids. PVC gaskets containing 10-37% of ESBO were prepared by baking of PVC plastisols at various process temperatures (180-240°C) in the laboratory. ESBO migration into oliv...
Article
Full-text available
There are several studies which reported the flavonoid and phenolic acid contents of chokeberry. However, limited reports have been focused on the anthocyanins and antioxidant activity of chokeberry products although chokeberries are generally consumed as processed. In order to determine the health related constituents of different chokeberry produ...
Article
Full-text available
The aim of the presented study was to verify the variability of characteristic components of aronia (Aronia melanocarpa, black chokeberry) and to evaluate the chemical composition and quality of aronia products in order to complete the already available data and to facilitate authentication of fruit products. The mean values obtained for the set of...
Article
Full-text available
Garlic (Allium sativum L.) is one of the oldest cultivated crops, widely used around the world for its pungent flavour as a seasoning. Currently, the Czech growers are trying to return the traditional Czech varieties of garlic to the market and to expand garlic cultivation areas. Despite an increased consumer demand for local garlic, the import of...
Article
Full-text available
Fructooligosaccharides (FOS) are important tuberous root constituents of yacon (Smallanthus sonchifolius) with beneficial nutritional and prebiotic effects on human health. That is why landraces originally cultivated in Andes are explored with the aim to obtain new ones with high FOS content. In this study eighteen octoploid and five dodecaploid la...
Article
DART (direct analysis in real time), a novel technique with wide potential for rapid screening analysis, coupled with high-resolution time-of-flight mass spectrometry (TOF-MS) has been used for quantitative analysis of 5-hydroxymethylfurfural (5-HMF), a typical temperature marker of food. The DART/TOF-MS method was optimised and validated. Quantifi...
Article
Full-text available
A method was proposed for the authenticity evaluation of the hazelnut based products, in which the hazelnut paste content is the principle qualitative parameter. The procedure is based on the determination of filbertone ((E)-5-methylhept- 2-en-4-one), the natural, unique, and characteristic aroma component of the hazelnuts. A set of authentic hazel...
Article
Full-text available
Plum (Prunus domestica L.) is a nutritionally and technologically important fruit. In the Czech Republic, there has been a long tradition of growing plum trees and manufacturing plum-based products. Plum paste is traditionally produced by boiling for a long period of time and contains only plums. In this study, we measured chemical composition and...
Article
Full-text available
The brief history of food adulteration in Czech towns from the Middle Ages, from the beginning of systematic approach (F. Accum, A. H. Hassall), to recent situation in the Czech Republic, is given. The examples of health consequences in some recent cases are summarized. The activities of the title Faculty in detection of food adulteration are descr...
Article
Full-text available
According to the requirements of the European legislation, fruit juice from concentrate must display organoleptic and analytical characteristics equivalent to those of an average direct juice. The evaporation during the concentration process, the thermal treatment and aroma restoration step are critical factors that may contribute to aroma loss or...
Article
Full-text available
Frying practices at 135 Czech food services were investigated. The quality of their frying oil baths was evaluated by two rapid tests: Testo 265 (Testo, Lenzkirch, Germany), which determines content of total polar compounds (% TPC) and 3M LRSM (3M, Maplewood, Minnesota, USA), which determines the concentration of free fatty acids (FFA). Firstly, pe...
Article
Ketchup is an important source of tomato antioxidants in human nutrition, this ambient stable product is processed using several relatively important heat treatments and can be stored for one or more years at ambient temperature. Model storage experiments were carried out with two sets of commercial ketchup produced according to the Czech recipe: (...
Article
Full-text available
Rajchl A., Čížková H., Voldřich M., Lukešová D., Panovská Z. (2009): Methoxypyrazines in Sau-vignon blanc wines, detection of addition of artificial aroma. Czech J. Food Sci., 27: 256–266. Methoxypyrazines are the principal aroma components responsible for the vegetative and herbaceous green bell-pep-per flavour of Sauvignon blanc wines produced in...
Article
Full-text available
Natural honey contains several enzymes, which are produced by bees (salivary secretion) and some are found in the nectar or pollen. The most important enzymes are amylases, invertases, glusidases, catalases, fosfatases and other. The activity of diastase (α-, ß-, γ-amylase) is the important quality parameter of honey, according to the Directive 200...
Article
Full-text available
Commercial fruit baby food is a preserved fruit product usually made with fruit purees, sugar, water and variable additives (thickening agents, antioxidants, etc.). As the foodstuffs intended for particular nutritional uses, baby foods for infants and young children conforms to a set of strict guidelines e.g. maximum levels for pesticide residues,...
Article
Full-text available
Model storage experiments of pasteurised tomato puree and ketchup were carried out. The sets of samples were boiled at 100oC, during the heating the changes of selected markers were followed and correlated with the sensory evaluation, the markers were: furosine, 2-furaldehyde, 5-hydroxymethyl-2-furaldehyde (HMF) and colour (expressed as: L, a*, b*,...

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Projects

Projects (2)
Project
Industrial isolation and processing of crude oils significantly impact their sensory and functional properties, which to a large extent affect their application in food industry as well as household uses. The goals: 1. Evaluation of edible oil industry final product marketability based on oilseeds grown and harvested in the Czech Republic. 2. Development and optimization of innovative methods of obtaining and processing vegetable oils. 3. Evaluate the nutritional value (fatty acids and the minor biologically active compounds) and the possibilities of oil utilization in food industry and in households. 4. Evaluate the sensory properties and thermal stability of oils under mild conditions. 5. Design the procedures to improve vegetable oils shelf life.
Project
The aim of the project is to evaluate the influence of reformulation of selected food products on their stability and quality. The issue of reformulated food production technology and the effect of these reformulations on the food product shelf-life will be addressed. The project is focused on reformulation of key food categories, especially of dairy products, meat products and bakery products. Specific product reformulations will be addressed with regard to nutritional composition, production technology, physicochemical and sensory properties and the shelf life of the product. Other aim of the project is to inform consumers about the issue of reformulated food products, including benefits of reformulation on human health.