Multivariate study of raman spectral data of edible oils

The study of structural differences and thermal degradation of edible oils during heating is presented in this paper. Five types of edible oil were used for the study: extra virgin olive oil, pomace olive oil, canola, sunflower and palm oil. The data for evaluation were acquired by Raman spectroscopy as this innovative method offers rapid, nondestructive, reagent free measurements, provides specific information on chemical composition and structure of material and enables detection of structural changes. For the processing of large data sets multivariate analytical method Cluster analysis and Principal component analysis are applied to highlight the patterns within the data. The results show good agreement with the known ratio of saturated and unsaturated fatty acids in the vegetable oils. The evaluation of thermal degradation process is also based on the major decomposition product of oxidized linoleate appearing in Raman spectra via band 1640 cm -1 . Thermal degradation was observed for all the studied oils. Mathematically processed data indicate the least effect of heating for olive oils, the greatest degradation and loss of unsaturation for sunflower oil. © 2018, World Scientific and Engineering Academy and Society. All rights reserved

Measuring the lactose content in milk

Raman spectroscopy has become a powerful and popular tool for food systems analyses lately. Based on characteristic vibrations of the studied material, the information on its content and structure can be answered. In the paper, Raman spectroscopy is studied for a purpose of lactose content in milk assessment. Lactose, the milk disaccharide, in a human organism decomposes during digestion by the act of enzyme lactase to more easily digestible monosaccharides glucose and galactose. The lack of enzyme lactase causes symptoms of lactose intolerance what limits lactose-intolerant individuals in the intake of milk and dairy products. Lactose-free products in the diet can be a solution. Raman spectroscopy offers rapid measurement independent of the number of chemicals and other in the paper listed benefits. Raman spectra of lactose, glucose and galactose exhibit enough differences to distinguish the content of lactose in milk C-O-H bending mode at 1087 cm(-1) is used for lactose quantification. The method accuracy for measuring content of lactose was tested on dried milk droplets. Evaluation of the spectroscopic data was related to two different substances - phenylalanine contained generally in the milk and crystal violet used as an internal standard.Ministry of Education, Youth and Sports of the Czech Republic within the National Sustainability Programme [LO1303 (MSMT-7778/2014)]; European Regional Development Fund under the project CEBIA-Tech [CZ.1.05/2.1.00/03.0089]7778/2014, MOE, Ministry of Education; CZ.1.05/2.1.00/03.0089, ERDF, European Regional Development Fun

Thermal degradation of vegetable oils: Spectroscopic measurement and analysis

The paper deals with measuring of structural changes in edible oils during their heating giving arise to unsafe degradation products. The attention is paid to the major decomposition product of heated oxidized linoleate and content of carotenoids with antioxidant effects. Analysis is based on Raman spectral data that provide unique information about the structure of the oils. Raman spectroscopy offers effective and rapid way for oils quality control with respect to their health benefits and in terms of processes in food technology. Three most common vegetable oils were used for the thermal degradation study: sunflower, canola and olive oil. Measured were both, extra virgin and refined oils. Mathematically processed spectral data indicate the least action of thermal load for olive oils. Then due to a significant content of antioxidants it is canola oil. The worst effect in terms of thermal decomposition products formation and the loss of cis double bonds arise for sunflower oils. © 2015 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license

Spectroscopic measurement and analysis of fat in milk

The paper deals with the application of Raman spectroscopy for milk fat determination. For a quality control of milk and dairy products the monitoring and analysis of milk nutritional composition is crucial. Commonly available milk was used for analyses in form of liquid milk samples and also dried milk droplets with fat concentration 0,1 %-3,5 %. Raman spectroscopy brings benefits over traditional laboratory techniques in terms of effective, rapid and reagent free way of milk fat measurements. Acquired Raman spectra were assigned to appropriate milk elements focusing on milk fat components. Method accuracy for a content of fat in milk is discussed in paper and in comparison to results obtained by conventional Röse-Gottlieb gravimetric method and butyrometry show good agreement

Multivariate study of spectral data of oils

In this paper the study of structural differences and thermal degradation of edible oils during heating is presented. The study is performed on five types of vegetable oil: extra virgin olive oil, pomace olive oil, sunflower, canola and palm oil. The oils were measured by Raman spectroscopy. This method brings advantages as rapidity, independence on chemicals, provides specific information on chemical composition and structure of material and is able to detect structural changes. For the processing of large data sets multivariate analytical method as Principal component analysis and Cluster analysis are applied to find the patterns within the data. The evaluation of process of thermal degradation is also based on the major decomposition product of oxidized linoleate appearing in spectra via band 1640 cm-1. Mathematically processed data indicate the least effect of heating for olive oils, the greatest degradation and loss of unsaturation for sunflower oil. © The Authors, published by EDP Sciences, 2017

The effect of reduction of NaCl content on selected parameters during ripening of cheese

The aim of this work was to observe chemical and physical changes in Dutch-type cheese during ripening depending on salt concentration. Ripening is one of the most important factors influencing the sensory quality of cheese and therefore the cheese production should be studied. Among the substances which are formed during ripening belong the biogenic amines which are produced by the decarboxylation of amino acids. These amino acids are created during proteolysis. The salt content largely affects the intensity of the ripening process, but also other cheese parameters such as dry matter content, hardness or content of biogenic amines. In the course of 3 months ripening of model cheeses with different cultures and with different salt content, the effect of the salt on pH, dry matter content, free amino acids and biogenic amines content and hardness was monitored. The concentration of NaCl affected the dry matter content and the hardness of the samples. The reduction in salt content contributes to the higher accumulation of biogenic amines during ripening. © 2019 Potravinarstvo Slovak Journal of Food Sciences

Sensor systems for detecting dough properties fortified with grape pomace and mealworm powders

The present article dealt with the fortification of plain wheat flour by the addition of grape pomace flour and mealworm larvae powder, focusing on the mineral content and selected properties of the dough. The work also analyzed the properties of one mixture in a weight combination of 80% wheat flour, 10% grape pomace, and 10% mealworm. X-ray analysis was used to measure the mineral content of calcium, iron, copper, and zinc. The properties of the individual mixture were monitored using an experimental electronic nose and a thermodynamic sensor system during the leavening. The results showed that a combination of 50% grape pomace and 50% mealworm larvae was advantageous from the viewpoint of the favorable representation of minerals. The analyzed mixture contained a high proportion of calcium (3976.7 ± 362.9 mg·kg−1), iron (209.3 ± 25.7 mg·kg−1), and copper (65.0 ± 100.1 mg·kg−1) for grape pomace as well as a high proportion of zinc (277.0 ± 21.9 mg·kg−1) for the mealworm larvae. However, this mixture showed a small change in the heat flux response when analyzed with thermodynamic sensors (lower yeast activity and worse gas formation properties resulted from the sensor characteristic with a lower response). The 100% wheat flour had the highest response, and the second highest response was recorded for a mixture of wheat flour with 10% grape pomace and 10% mealworm larvae. This combination also often had one of the highest responses when measured with an experimental electronic nose, so this combination was considered as one of the most advantageous options for processing from the mixtures mentioned in the article. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.TBU in Zlin [IGA/FT/2020/010]; project BUT in Brno [FEKT-S-20-6215

3D printed Fused Deposition Modeling (FDM) capillaries for chemiresistive gas sensors

This paper discusses the possible use of 3D fused deposition modeling (FDM) to fabricate capillaries for low-cost chemiresistive gas sensors that are often used in various applications. The disadvantage of these sensors is low selectivity, but 3D printed FDM capillaries have the potential to increase their selectivity. Capillaries with 1, 2 and 3 tiers with a length of 1.5 m, 3.1 m and 4.7 m were designed and manufactured. Food and goods available in the general trade network were used as samples (alcohol, seafood, chicken thigh meat, acetone-free nail polish remover and gas from a gas lighter) were also tested. The "Vodka" sample was used as a standard for determining the effect of capillary parameters on the output signal of the MiCS6814 sensor. The results show the shift of individual parts of the signal in time depending on the parameters of the capillary and the carrier air flow. A three-tier capillary was chosen for the comparison of gas samples with each other. The graphs show the differences between individual samples, not only in the height of the output signal but also in its time characteristic. The tested 3D printed FDM capillaries thus made it possible to characterize the output response by also using an inexpensive chemiresistive gas sensor in the time domain.Internal Grant Agency of Tomas Bata University in Zlín, (IGA/FT/2023/003); Vysoké Učení Technické v Brně, BUT, (FEKT-S-20-6215

Sensory evaluation and acceptance of food made of edible insects

This paper discusses the sensory analysis of food enriched with selected edible insect species which are labelled as a novel food–house cricket (Acheta domesticus) and mealworm (Tenebrio molitor). Energy bars of two different compositions with the addition of cricket flour and puff pastry bars sprinkled with the whole roasted mealworm larvae were evaluated by consumer tests performed via a questionnaire survey. Respondents represented both men and women in equal numbers and included consumers with the experience of the sensory analysis and edible insects to ensure accurate results. Sensory analyses revealed that respondents associated their tastes with already known flavors (salty, sweet, bitter, fish, French fries, chicken, and mushrooms). The most common answer from respondents was a salty taste, followed by a sweet taste. There were also unusual comparisons such as pine seeds. Consumers’ positive attitude to these energy bars has been registered which shows that the Czech consumer accepts edible insects in a suitable form as a novel food and possible part of the food basket. © 2020 Potravinarstvo Slovak Journal of Food Sciences, License: CC BY 3.0FEKT-S-20-6215, IGA/FT/2020/01

Biologically active compounds contained in grape pomace

A healthy lifestyle and gastronomic trends based on traditional and local foods accompanied by waste-free technologies are currently in the primary focus. One of the raw materials with properties in alignment with such requirements is grape pomace. This paper evaluates the antioxidant activity of grape pomace (which is homogenized into a brown powder) and selected commonly available commercial flours — wheat bread, rye plain, and rye whole grain flour — using DPPH (2,2-diphenyl-1-picryl-hydrazyl-hydrate) and total polyphenol content method, where was used Folin-Ciocalteaure agent and then it was determined by spectrophotometric method (the measure of absorbance). The total amount of polyphenols in grape pomace was measured of 47.94 mg GAE.g-1, but the value 0.27 mg GAE.g-1 was measured in wheat bread flour. Grape pomace performed the antioxidant activity of 57.45 mg AAE.g-1, whereas wheat bread flour of only 0.21 mg AAE.g-1 Compared to selected commercial flours, the total amount of polyphenols in grape pomace was up to 150 times higher and the ratio of antioxidant activity between grape pomace and wheat bread flour was even more than 280 times higher. This makes it possible to fortify commercial, commonly available flours with different amount of grape pomace so that products with a higher amount of biologically active substances can be prepared. Another benefit could be a reduction in health risks and a contribution to improving consumer health. © 2020 Potravinarstvo Slovak Journal of Food Sciences, License: CC BY 3.