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Assessment of fatty acids in processed cheese
Mitra, Michal ; Sýkora, Michal (referee) ; Vítová, Eva (advisor)
This bachelor thesis deals with determination of fatty acids in samples of processed cheeses made at Tomas Bata University in Zlín. In the theoretical part, lipids and fatty acids are characterized. Subsequently, the issue of production, distribution and composition of natural and processed cheeses is discussed. The conclusion of the theoretical part is focused on the assessment of fatty acids, i.e. their extraction and the determination by gas chromatography. In the experimental part, the fatty acid content of the seven samples of processed cheese was compared on the basis of different temperatures and the time of their production. The ČSN EN ISO 1735 method was used for extraction of fat. The method with methanolic potassium hydroxide solution was used for esterification. The determination of fatty acid methyl esters alone was accomplished by gas chromatography with a flame ionization detector. Based on the comparison with the standards, 17 fatty acids were identified in the samples.
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Assessment of fatty acids in processed cheese
Pruknerová, Kateřina ; Zemanová, Jana (referee) ; Vítová, Eva (advisor)
This thesis is focused on determination of fatty acids in processed and/or processed cheese analogues using gas chromatography with FID detection. Characterization of fatty acids, various methods for lipid extraction and the possibilities of determination of fatty acids are described in the theoretical part. Simple and rapid method for the determination of fatty acids in natural and/or processed cheese was optimized and validated in the experimental part. The modified Folch method (by mixture of chloroform - methanol) was selected for lipid extraction from the samples. The standard method (ISO 5509), using a methanol solution of potassium hydroxide, was selected for lipid esterification. Type of the stationary phase and parameters of the column, flow of carrier gas, temperature of the injector, injection technique, temperature of the detector and temperature program were optimized. Calibration curves were constructed from five calibration points (in the concentration range of 0.01 - 60 g.ml-1), all correlation coefficients R2 were higher than 0,99. The limits of detection and quantification of individual fatty acids ranged from 0.002 - 6 g.ml-1. The repeatability of the method was good, all the relative standard deviations of the peaks were below 9 %. The optimized and validated method was applied to selected samples of processed cheese analogues. In total five types of analogues containing different kinds of fat (butter, apricot, linseed, black currant and grape seed oils) were analyzed. In samples 34 fatty acids were identified based on a comparison of retention times of standards.
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The factors influencing sensory quality of processed cheese analogues
Sůkalová, Kateřina ; Kráčmar, Stanislav (referee) ; Diviš, Pavel (referee) ; Buňka,, František (advisor)
The presented thesis deals with the monitoring sensory quality of processed cheese analogues, focusing mainly on the taste (flavour) and related content of volatile (aroma active) substances. Model samples of analogues were produced by a standard procedure at Tomas Bata University in Zlín. The experimental part was divided into two experiments, which differed in the composition of model samples of analogues. In the first experiment, the traditional fat (butter) was completely replaced by selected vegetable fats (palm, coconut, mixed), in the second experiment only a part (1% w/w - expressed on the total weight of the sample) of butter was replaced by vegetable oils (apricot, flax seed, currant, grape seed). Solid phase microextraction in conjunction with gas chromatography with flame ionization detection was used to determine volatiles. Methods based on valid international standards were used to evaluate the sensory quality of samples, focusing mainly on flavor, namely evaluation using scales (ISO 4121), profile test (EN ISO 13299) and ranking test (ISO 8587). The aim of the work was to assess the effect of the addition of various vegetable fats/oils on the above parameters, at the same time their changes were monitored during 6 months of storage (at 6 ° C). The results showed that the vegetable oil used affects both the sensory quality and the content and composition of volatile substances of analogues. Significant differences between samples were mainly in taste, aroma and overall acceptability. The decreasing overall acceptability of the samples can be expressed in experiment I by the order: product with butter coconut palm mixed fat; in the case of experiment II: product with butter apricot = flax = grape currant oil. Mixed fat, currant and grape seed oil proved to be unsuitable for the production of analogues, on the contrary, analogues with coconut fat and apricot oil were evaluated best. Based on the results of sensory analyses, it was shown that the samples maintain a good sensory quality min. for 3 months while maintaining a low storage temperature ( 6 ° C). An analogue with coconut fat, whose taste, aroma and acceptability were rated as very good, and apricot oil, whose taste, aroma and acceptability were even rated as excellent, could enrich the food offer on the market.
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The factors influencing sensory quality of processed cheese analogues
Sůkalová, Kateřina ; Kráčmar, Stanislav (referee) ; Diviš, Pavel (referee) ; Buňka,, František (advisor)
The presented thesis deals with the monitoring sensory quality of processed cheese analogues, focusing mainly on the taste (flavour) and related content of volatile (aroma active) substances. Model samples of analogues were produced by a standard procedure at Tomas Bata University in Zlín. The experimental part was divided into two experiments, which differed in the composition of model samples of analogues. In the first experiment, the traditional fat (butter) was completely replaced by selected vegetable fats (palm, coconut, mixed), in the second experiment only a part (1% w/w - expressed on the total weight of the sample) of butter was replaced by vegetable oils (apricot, flax seed, currant, grape seed). Solid phase microextraction in conjunction with gas chromatography with flame ionization detection was used to determine volatiles. Methods based on valid international standards were used to evaluate the sensory quality of samples, focusing mainly on flavor, namely evaluation using scales (ISO 4121), profile test (EN ISO 13299) and ranking test (ISO 8587). The aim of the work was to assess the effect of the addition of various vegetable fats/oils on the above parameters, at the same time their changes were monitored during 6 months of storage (at 6 ° C). The results showed that the vegetable oil used affects both the sensory quality and the content and composition of volatile substances of analogues. Significant differences between samples were mainly in taste, aroma and overall acceptability. The decreasing overall acceptability of the samples can be expressed in experiment I by the order: product with butter coconut palm mixed fat; in the case of experiment II: product with butter apricot = flax = grape currant oil. Mixed fat, currant and grape seed oil proved to be unsuitable for the production of analogues, on the contrary, analogues with coconut fat and apricot oil were evaluated best. Based on the results of sensory analyses, it was shown that the samples maintain a good sensory quality min. for 3 months while maintaining a low storage temperature ( 6 ° C). An analogue with coconut fat, whose taste, aroma and acceptability were rated as very good, and apricot oil, whose taste, aroma and acceptability were even rated as excellent, could enrich the food offer on the market.
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Assessment of fatty acids in processed cheese
Mitra, Michal ; Sýkora, Michal (referee) ; Vítová, Eva (advisor)
This bachelor thesis deals with determination of fatty acids in samples of processed cheeses made at Tomas Bata University in Zlín. In the theoretical part, lipids and fatty acids are characterized. Subsequently, the issue of production, distribution and composition of natural and processed cheeses is discussed. The conclusion of the theoretical part is focused on the assessment of fatty acids, i.e. their extraction and the determination by gas chromatography. In the experimental part, the fatty acid content of the seven samples of processed cheese was compared on the basis of different temperatures and the time of their production. The ČSN EN ISO 1735 method was used for extraction of fat. The method with methanolic potassium hydroxide solution was used for esterification. The determination of fatty acid methyl esters alone was accomplished by gas chromatography with a flame ionization detector. Based on the comparison with the standards, 17 fatty acids were identified in the samples.
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Assessment of fatty acids in processed cheese
Pruknerová, Kateřina ; Zemanová, Jana (referee) ; Vítová, Eva (advisor)
This thesis is focused on determination of fatty acids in processed and/or processed cheese analogues using gas chromatography with FID detection. Characterization of fatty acids, various methods for lipid extraction and the possibilities of determination of fatty acids are described in the theoretical part. Simple and rapid method for the determination of fatty acids in natural and/or processed cheese was optimized and validated in the experimental part. The modified Folch method (by mixture of chloroform - methanol) was selected for lipid extraction from the samples. The standard method (ISO 5509), using a methanol solution of potassium hydroxide, was selected for lipid esterification. Type of the stationary phase and parameters of the column, flow of carrier gas, temperature of the injector, injection technique, temperature of the detector and temperature program were optimized. Calibration curves were constructed from five calibration points (in the concentration range of 0.01 - 60 g.ml-1), all correlation coefficients R2 were higher than 0,99. The limits of detection and quantification of individual fatty acids ranged from 0.002 - 6 g.ml-1. The repeatability of the method was good, all the relative standard deviations of the peaks were below 9 %. The optimized and validated method was applied to selected samples of processed cheese analogues. In total five types of analogues containing different kinds of fat (butter, apricot, linseed, black currant and grape seed oils) were analyzed. In samples 34 fatty acids were identified based on a comparison of retention times of standards.
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Consumer behaviour on the market with processed cheese
STRNÁDKOVÁ, Martina
The main object of my thesis was to analyse shopping and consumer behaviour on the market with processed cheese. On the basis of this analysis I worked out on the recommendations for producer of processed cheese. First I studied expert literature and secondary sources. It the second part of my thesis I have done a consumer research. I received 305 completed questionnaires. I processed results into coding format to create the graphs. I made a recommendations for producer of processed cheese.
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Processed cheeses and spreads and their sensory evaluation
BÍLKOVÁ, Kateřina
The bachelor thesis deals with the history of processed cheese and their classifications. Fat in dry matter is very important for the processed cheese and also its raw materials (natural cheese, melting salt, milk proteins, dyes, etc.). Cheese can be classified according to the method of production, composition, consistency and packaging. The thesis describes the consumption of processed cheese in certain years in these units and methods of sensory evaluation, involving sensory perception.
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