Monochloropropanediol (MCPD) esters and glycidyl esters (GE) are the process contaminants found in frying and baking, except the refining process. The free form MCPD and glycidol are released from their parent esters via lipase hydrolysis while they are carcinogen and genotoxic carcinogen, respectively. MCPD esters and GE are formed endogenously during vegetable oil refining process. Then, their concentration were experimented during subsequent food processing methods, especially frying and baking. This review discussed the occurrence of 2-, 3-MCPD esters and GE during frying and baking processes. Process temperature, process duration, presence of precursors, and their combined effects are highly related to MCPD esters and GE formations. An elevated temperature and processing time can increase the formation of these contaminants until an optimum rate and then followed by the decomposition. Also, other factors such as the presence of chloride ions, moisture, and partial acylglycerol can further facilitate MCPD esters and/or GE formation.

A summary of 2-, 3-MCPD esters and glycidyl ester occurrence during frying and baking processes.

Matching the texture of fat in plant-based meat alternatives requires an in-depth understanding of the rheology of animal adipose tissue which, to-date, remains under-studied. Here, we characterised the small and large deformation behaviour of back fat from pork, beef, and lamb, with the underlying goal being the establishment of the temperature-dependent structure-function relationship governing the texture and rheology of adipose tissue. The dynamic rheological behaviour of the back fats was characterised via frequency and amplitude sweeps and large amplitude oscillatory strain (LAOS), as well as texture analysis via puncture tests. At 20 °C, prior to heating, the small and large deformation properties of adipose tissue were dominated by the solid fat phase within the adipose cells. Upon heating to 80 °C, with the fat phase molten, the protein network underpinning the structure of the back fats conferred elastic behaviour to the tissues, and the now-molten oil partly leaked from the adipocytes into the surrounding interstitial space. Upon re-cooling, a bicontinuous network of fat crystals and protein contributed to back fat rheology. Large deformation rheology revealed animal species-specific differences. Prior to heating, pork back fat was characterised by soft yielding behaviour while beef and lamb back fat showed abrupt yielding and intra-cycle strain stiffening. Post-heating, lamb showed the highest stiffness, compared to pork and beef, as well as non-linearities in its stress-strain relationship obtained via LAOS. Such fundamental understanding is essential to provide the required insights to replicate the functionality of adipose tissue using plant-based materials.

Temperature-dependent properties of fat in adipose tissue from pork, beef and lamb. Part 2: rheology and texture.

Putative health effects of dietary trans fatty acids (TFAs) receive a growing attention; while very little is known about the metabolism of these special food components. In vitro studies carried out in cultured cells provide an efficient and standardizable approach to follow the metabolic fate of TFAs, but it requires suitable techniques for the quantitative measurement of FAs in cell samples. Here, the development and validation of a simple and reliable method for the quantification of a group of relevant FAs by gas chromatography and flame ionization detection is presented. Sample preparation used a fast one-step and chloroform-free process for simultaneous extraction and esterification, and chromatographic separation was achieved in 25 min using a Zebron ZB-88 capillary column. A linear calibration (of R2 >0.99) was obtained in the concentration range of 1-200 μg/mL for each FA. Recovery rate was 82 % for samples of non-esterified FAs and >95 % for complex lipids, such as ceramides, diglycerides and triglycerides. The LOD and LOQ were below 0.5 μg/mL, and a robust method precision was achieved (RSD % was below 6 % for each lipid classes). The present method was also tested on a cultured cell line with or without FA treatment at close to physiological concentration, and the observed changes in the metabolite concentration levels revealed characteristic differences between the metabolism of cis and trans unsaturated FAs.

/pdf/application-of-gas-chromatography-flame-ionization-detection-crnzt0mmcv.pdf

Application of Gas Chromatography – Flame Ionization Detection to Study Cellular Incorporation of Dietary Trans Fatty Acids of Medical Importance

Essential oils derived from plant materials are a mixture of compounds that exhibit antibacterial properties. Due to their distinct aroma, they also serve as a desirable natural additive for various food products, including dairy products. In this study, the essential oils of lemon peels, clove buds, and juniper berries were obtained by steam distillation and characterized using gas chromatography–mass spectrometry to determine their chemical compositions and effects on the viability of seven Bifidobacterium strains. Furthermore, the effect of essential oils on the viability of Bifidobacterium animalis subsp. lactis Bb-12 was investigated in cream samples during fermentation and after storage for 21 days at 6 °C. The fatty acid composition of fat extracted from essential oils containing sour cream samples and the volatile aroma compound profile of the sour cream samples were also determined chromatographically. Among the 120 compounds identified, monoterpene hydrocarbons were dominant in the essential oils of lemon peels (limonene and γ-terpinene) and juniper berries (sabinene and β-myrcene), while eugenol and eugenol acetate were abundant in the essential oil of clove buds. In addition to these compounds, butanoic and acetic acids were found in the tested sour cream samples. In turn, fat extracted from these samples was rich in saturated fatty acids, mainly palmitic acid. Among the tested strains of the genus Bifidobacterium, B. animalis subsp. lactis Bb-12 was the most sensitive to the essential oils of clove and juniper, as indicated by the larger growth inhibition zones. However, both the concentration and type of essential oils used had no effect on the number of cells of this strain present in the cream samples immediately after fermentation and after its 21-day storage, which suggests that the tested essential oils could be a natural additive to dairy products.

/pdf/the-effect-of-essential-oils-on-the-survival-of-2n1tvo0y.pdf

The Effect of Essential Oils on the Survival of Bifidobacterium in In Vitro Conditions and in Fermented Cream

A sensitive, reproducible reverse-phased high performance liquid chromatography electrospray tandem mass spectrometry (HPLCESI-MS/MS) method with simple sample preparation was developed for the simultaneous determination of a wide range of ceramides, diacylglycerols (DAGs) in cultured cells. Chromatographic separation of the compounds was achieved in a 14-minute run using a C8 column with a gradient elution by methanol and 10 mM ammonium acetate buffer as mobile phase at a flow rate of 0.5 ml/min. Various ceramides, DAGs were detected with a triple quadrupol system in multiple reaction monitoring mode, which is based on a soft positive electrospray ionization. The usual sample preparation process was shortened by the application of pure methanol for the extraction instead of the widely used methanol/chloroform mixture. C17:0 ceramide which does not occur in the cell samples, was used as an internal standard. The sample preparation process was optimized and the methodology was tested on a human hepatocarcinoma cell culture. Our results clearly showed accumulation of some ceramides and DAGs in the cells treated with BSA-conjugated palmitate for 8 hours. Since both ceramides and DAGs are important lipid intermediates and signal messengers, alteration in their cellular levels have major impact on cell functions, and thus our novel analytic method can be widely used in lipotoxicity research. The presented technique can be further developed to measure other intermediates of ceramide synthesis and other derivatives of DAGs as well.

/pdf/simultaneous-quantitative-determination-of-different-4f3xbpctu9.pdf

Simultaneous Quantitative Determination of Different Ceramide and Diacylglycerol Species in Cultured Cells by Using Liquid Chromatography–Electrospray Tandem Mass Spectrometry

Modification of dairy products’ fat composition or replacement by other fats are common practices in the industry. Products in which milkfat is partially or wholly substituted by vegetable fats are defined as dairy analogues. This study delivers gap-filling information about sour cream analogues in nutritional aspects, focusing on the fat-related attributes. Analogue sour creams contained 29.6% less saturated fatty acids, 88.4% less cholesterol and 88.7% more mono- and poly-unsaturated fatty acids than the sour creams. Trans fatty acids were present in both products, which could not be linked to artificial hydrogenation in either case. Digestibility of the examined samples might be different, as sour creams had more short and medium chain fatty acids than the analogues. Overall, sour cream analogues, besides serving as an alternative to sour cream, have particular advantages based on their nutritional values.

/pdf/differences-between-fat-related-characteristics-of-sour-1dft0t4fay.pdf

Differences Between Fat-Related Characteristics of Sour Cream and Sour Cream Analogues

Replacement of milk fat with vegetable fats (e.g. coconut oil or palm fat) in sour cream is a well-established practice among producers – these products are called sour cream imitations or sour cream analogues. Although sour cream imitations are legitimate products, consumers might be confused by them. The purpose of this paper is to assess the familiarity of sour cream imitations, the opinion of consumers, and to map the factors that may affect purchasing decision.,A quantitative consumer survey (n=1,000) has been conducted in 2017 based on personal interviews. Data were analysed by descriptive statistics and partial least squares structural equation modelling.,Results showed that the majority of Hungarian consumers have already purchased a sour cream imitation. In total, 69.65 per cent of them bought the imitation product accidentally: packaging and placement on the shelves were mentioned as major reasons. And 44.68 per cent of the respondents consider this product category to be misleading. Path modelling revealed that the perceived price-value ratio of the product and the respondent’s culinary skill, knowledge, consciousness and general preference of sour cream have a significant impact on the willingness to buy of sour cream imitations.,Sour cream imitations are accepted as reasonable cheaper alternatives to sour cream as it has been revealed by descriptive statistical methods and structural equation modelling. However, producers and retailers should avoid misleading packaging and product placement. General communication to broaden consumer knowledge would be also important. The study provides evidence-based input for producers, retailers, marketing experts and policy makers on consumer behaviour regarding food product analogues.

Consumers’ willingness to buy dairy product imitations (analogues) based on structural equation modelling

Coconut oil is one of the generally used edible fats in food industries. To modify its texture, coconut oil is frequently treated by full-hydrogenation. Since full-hydrogenation results in extremely hard fat; therefore, blending with more soft material is a good option to reach the required texture. The aim of the present study was to establish the solidification characters of the blends containing both fully hydrogenated and non-hydrogenated coconut oils. Investigations were carried out by means of pulsed nuclear magnetic resonance spectroscopy (pNMR) and differential scanning calorimetry (DSC). Solidification phenomenon was interpreted by the Avrami model. Based on the results, parameters of the Avrami model were calculated. The results proved that these two fats are completely miscible and the equilibrium SFC value of their blends modified in accordance to the blending ratios and temperature gradient. DSC measurements did not show any significant difference in crystallization curves of the samples. Our results may be utilized in food technology, especially when production of fat containing foods needs cooling, for example in the manufacturing of margarine, shortenings, and confectionary fats.

/pdf/solidification-of-the-blends-of-fully-hydrogenated-coconut-4qmll3mi40.pdf

Solidification of the Blends of Fully Hydrogenated Coconut Oil and Non-hydrogenated Coconut Oil

Butter and anhydrous milk fat are considered valuable raw materials, therefore it is important to detect the presence of foreign fats and declare their purity. In this study, the authors compared the physical properties of pure anhydrous milk fat and its contaminated forms which were binary blends made with lard and palm fat. Tests with pulsed NMR and DSC were carried out ignoring any solvents or chemicals to observe melting and crystallization processes. Based on the results, small amounts (5-10 V/V %) of lard or palm fat can modify milk fat’s behavior in perceptible extent. Despite of this, a completely unknown fat cannot be identified by these methods only. However, with multiple replications and using statistical methods pNMR and DSC can be utilized for quality control purposes.

/pdf/the-effect-of-foreign-fats-on-the-physical-properties-of-2ajguu8n66.pdf

The Effect of Foreign Fats on the Physical Properties of Anhydrous Milk Fat

Palm fat is one of the most commonly used fats in food industry. The main role of palm fat is to develop the desired texture of food products. Fat blends were developed to find the most appropriate mixture fitting the technological needs. In our work palm mid fraction (PMF) was mixed with anhydrous milk fat (AMF), goose fat (G), and lard (L) in a 1:1 ratio. Anhydrous milk fat represents fat consisting of a wide range of fatty acids. Goose fat is a soft, easily melting fat, and lard is characterized as animal fat with wide melting temperature interval. The measurements aimed to establish the miscibility of the fats and the effect of animal fats on the melting-solidification profile of palm mid fraction. SFC vs temperature curves, Differential Scanning Calorimetry (DSC) melting thermograms describe the melting profile of the samples. Isotherm crystallization by SFC vs time curves and DSC cooling thermograms were measured to characterize the solidification of pure fats and the blends. Since the SFC curves di...

/pdf/effect-of-animal-fats-on-the-physical-properties-of-palm-fat-22e4hyb0kv.pdf

László Somogyi

Papers

Differences Between Fat-Related Characteristics of Sour Cream and Sour Cream Analogues

Consumers’ willingness to buy dairy product imitations (analogues) based on structural equation modelling

Solidification of the Blends of Fully Hydrogenated Coconut Oil and Non-hydrogenated Coconut Oil

The Effect of Foreign Fats on the Physical Properties of Anhydrous Milk Fat

Effect of animal fats on the physical properties of palm fat