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Effect of additives on acrylamide content in thermally treated foods
Marková, Lucie ; Ciesarová, Zuzana (referee) ; Šimko, Peter (advisor)
Acrylamide is an undesirable carcinogenic component of thermally processed foods being formed from reducing saccharides and asparagine. In this work, the effect of ammonium and sodium raising agents themselves or in their combination with L-asparaginase enzyme catalyzing the conversion of asparagine into aspartic acid resulting in the reduction of acrylamide in gingerbreads was studied. Also, the influence of selected inorganic salts on the content of acrylamide in a model matrix simulating a composition of cereal products was observed. Simultaneously, the impact of these salts on activity of L-asparaginase was examined to find optimal conditions for its application in cereal technology. Based on experiments it was found, that addition of L-asparaginase reduces acrylamide content by 40 % while inorganic salts addition decreases acrylamide content in the range of 30 - 99 % when the most effective compounds were NH4Cl and CaCl2.
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Monitoring process contaminants in coffee roasting using LC-MS
Ilyushchenkova, Alexandra ; Juglová, Zuzana (referee) ; Diviš, Pavel (advisor)
The bachelor thesis focuses on monitoring changes in the concentration of process contaminants during coffee roasting using liquid chromatography with mass detection. Green coffee was roasted at 220 °C for 14 minutes with two-minute intervals. Samples for analysis were taken from 10. by 24. minutes of roasting. Practical monitoring of the acrylamide’s formation during coffee roasting was not carried out, since it was not possible to detect acrylamide in coffee using a mass detector, even after its derivatization with thiosalicylic acid. The relevant data were taken from other scientific articles, which reported a linear increase in concentration with the roasting time up to the maximum value and a subsequent exponential decrease at the end of roasting. By monitoring 5-hydroxymethylfurfural, it was found that during roasting, this substance is gradually formed in coffee due to the decomposition of carbohydrates, however, with increasing roasting time, the degradation of this substance occurs quite quickly. The concentration of 5-hydroxymethylfurfural was also determined in coffee samples purchased in the trade network. Concentrations of 5-hydroxymethylfurfural in these samples ranged from 0,3 to 0,38 mg/kg, which are corresponded to those reported in other expert studies.
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Process contaminants in food, their occurence and negative effects
Valchová, Jana ; Bušová, Milena (advisor) ; Holcátová, Ivana (referee)
Process contaminants are yet just a few decades known substances that naturally occur in food in some heat treatments and are dangerous to human health. There are studies demonstrating their carcinogenicity and mutagenicity. Their long-term effects on human health are not yet known. The aim of the questionnaire survey, which was part of the work, was to map the eating habits of a population sample and their knowledge of food quality and safety. Questions have been asked about the frequency of usage of some of the risky heat treatments and the frequency of consumption of snacks and food, which often contain dangerous contaminants. Although the respondents are generally aware of the risks of some kinds of heat treatment of food such as frying, grilling, smoking and baking, the taste and smell of the diet often wins over the health safety. The issue of process contaminants is increasingly being addressed by institutions all around the world. However things that a common consumer can do for his health in this issue don't differ too much from the general recommendations on a healthy lifestyle - to use less harmful ways to heat food, to consume mainly fresh food, to eat enough fruits, vegetables and fiber and to be interested in the composition of the products which he purchases. keywords: process...
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Study of changes in the chemical composition of coffee during roasting
Kohoutová, Lenka ; Vítová, Eva (referee) ; Diviš, Pavel (advisor)
This bachelor thesis deals with monitoring of changes in acrylamide and hydroxymethylfurfural levels in coffee during the process of roasting. Green coffee was roasted using two separate roasting modes (medium roast: temperature 210 °C for duration of 14 minutes, City roast: temperature 220 °C for 17 minutes). Concentration of acrylamide and hydroxymethylfurfural for various roasting durations was determined by high performance liquid chromatography. For the determination of acrylamide, linear growth of the concentration was observed. The final levels of acrylamide corresponded with levels given by the literature, although the characteristic trend of acrylamide formation was not observed. Typical trend of hydroxymethylfurfural formation was observed in samples roasted with City roast mode, while the first part of the trend was also apparent in samples roasted with medium roast mode. Final levels of hydroxymethylfurfural in roasted coffee were within the limits given by the literature.
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Determination of acrylamide in coffee by high performance liquid chromatography
Vajdíková, Tereza ; Vítová, Eva (referee) ; Diviš, Pavel (advisor)
The bachelor's thesis aimed to optimize the method of determining acrylamide in coffee using high-efficiency liquid chromatography with a diode-array detector. In the theoretical part of the bachelor's thesis, attention was paid to the taxonomic distribution of coffee, it's processing and chemical composition. Part of the theoretical frequency of the work involved describing the formation of acrylamide in coffee and possible methods of determining it. The practical part looked at validating the method, which was used in the analysis of coffee samples. The individual samples of coffee varied in the type of coffee and the societies where the coffee was obtained. Determination of the acrylamide content has been carried out on commercial, franchised, and selective coffees of the arabica species. Finally, the determination of acrylamide was made in the coffee of various types, in robusta and arabica.
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Process contaminants in food, their occurence and negative effects
Valchová, Jana ; Bušová, Milena (advisor) ; Holcátová, Ivana (referee)
Process contaminants are yet just a few decades known substances that naturally occur in food in some heat treatments and are dangerous to human health. There are studies demonstrating their carcinogenicity and mutagenicity. Their long-term effects on human health are not yet known. The aim of the questionnaire survey, which was part of the work, was to map the eating habits of a population sample and their knowledge of food quality and safety. Questions have been asked about the frequency of usage of some of the risky heat treatments and the frequency of consumption of snacks and food, which often contain dangerous contaminants. Although the respondents are generally aware of the risks of some kinds of heat treatment of food such as frying, grilling, smoking and baking, the taste and smell of the diet often wins over the health safety. The issue of process contaminants is increasingly being addressed by institutions all around the world. However things that a common consumer can do for his health in this issue don't differ too much from the general recommendations on a healthy lifestyle - to use less harmful ways to heat food, to consume mainly fresh food, to eat enough fruits, vegetables and fiber and to be interested in the composition of the products which he purchases. keywords: process...
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The occurence and adverse health effects of acrylamide in food
Grassová, Sandra ; Bušová, Milena (advisor) ; Holcátová, Ivana (referee)
AJ Acrylamide belongs to the group of process contaminants originating in foods with a high carbohydrate content during the heat process, as baking, frying, grilling, etc. For people is industrially producing acrylamide neurotoxic and according to IARC is classified probably as human carcinogen. Acrylamide which is occured in foods, probably makes up 1/3 of daily energy supply. The Bachelor thesis tries to give a comprehensive overview in the theoretical part information about Acrylamide - a description of its physical and chemical character, possibility of its industrial use, possibility of its exposure and dietary intake, information on its toxicity, occurrence and incidence in foods, the way of its elimination and finally its posibility of analytical determination. In the laboratory, the amount of acrylamide was determinated by the LC/MS method in selected foods. Of the 42 samples, acrylamide was not detected in 2 samples of extruded breakfast cereals. The lowest content of acrylamide was determined in extruded breakfast cereals (45 μg.kg-1 ), roasted muesli and cornflakes. The amount of acrylamide in these commodities ranged from 45-279 μg.kg-1 . Average values Acrylamide were contained in biscuits. The highest values were measured for potato chips and corn popcorn, from 83 to 1550 μg.kg-1 and...
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Acrylamide in potato products
Jiruška, Jan ; Sedláková, Vladimíra (advisor) ; Dvořák, Petr (referee)
This thesis provides a review describing acrylamide (AA), its detection and reduction. Botanical description and list of registered varieties of Solanum tuberosum in the Czech Republic is provided. Attention is payed to chemical composition of tubers. Next step is about AA. AA can cause carcinogenic and neurotoxic effects, particularly because it can be converted to a more reactive compound glycidamide in a human body. Thanks to animal experiments, we can reveal negative effects on the human body.
AA is formed by heat treatment over 120 °C in potatoes. Therefore, it is in potato chips and crisps. It is reaction of the free amino acids (especially asparagine) and reducing sugars (mostly glucose or fructose). It is all about several consecutive reactions that are included in the Maillard reaction. This reaction causes typical taste and aroma in products. Unfortunately, AA is one of the byproducts.
Today, formation of acrylamide has growing attention, because scientists want to reduce it as much as possible. Growing, industrial processing of potatoes and addition of additives during heat treatment is included. Antioxidants can significantly prevent formation of AA in food. There are also gathered informations on advanced analytical methods to detect AA in food. Rapid methods of detection are becoming more popular by scientits, that is why they are also included.
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