HS-SPME-GC-MS technique for FFA and hexanal analysis in different cheese packaging in the course of long term storage (original) (raw)
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Food Analytical Methods, 2018
Cheese as milk derivate plays a key role in our diet due to their nutritional and functional properties; free fatty acids (FFAs) and especially conjugated linoleic acids (CLAs) represent important healthy components in a dairy matrix. In this study, with the aim to detect FFAs in dairy products, we have developed a fast and accurate analytical protocol based on a matrix solid-phase dispersion (MSPD) extraction followed by ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) analysis. The proposed method provides a rapid and selective sample pretreatment and a reliable instrumental analysis. The use of MSPD extraction with a suitable dispersing phase as C 18 , allowed the retention of triglycerides, which are the main cause of interference and matrix effect in this type of analysis and permits a selective elution of the FFAs. The whole method was validated demonstrating the feasibility of the proposed method: correlation coefficients greater than 0.99 were obtained for all analytes; matrix effects were minimized and recoveries ranged between 75 and 105%, with good reproducibility (≤ 12%).
Molecules
The fatty acid profile of cheese influences its sensory parameters, such as color, texture, or flavor. Examining the fatty acid profile also helps to assess the nutritional value of the cheese that is being tested. However, the determination of fatty acids in cheese samples is a multi-stage and time-consuming task. In addition, large amounts of toxic organic solvents are used to prepare samples for analysis purposes. This paper presents the results of a study to determine the fatty acid profile of yellow cheese samples. Six different methods of sample preparation were compared for analysis purposes. The profile of fatty acids was determined using gas chromatography with flame ionization detection (GC-FID). The study showed significant differences (p > 0.05) in the resulting fatty acid profile between the methods used. It was found that the most reliable fatty acid profile results were obtained using methods derived from the Folch method. In addition, tools such as the Analytical ...
Open Journal of Animal Sciences, 2011
goat cheeses were evaluated during 3 months at 4˚C refrigeration. The two types of cheeses were manufactured using a bulk milk from the mixed herd of Saanen, Alpine, and Nubian goat breeds. LF cheeses were made using LF milk after cream separation. FFAs of all cheeses were extracted in diisoprophyl ether using polypropylene chromatography column, and FFA concentrations were quantified using a gas chromatograph equipped with a fused silica capillary column. Moisture, fat, protein contents %) and pH of fresh LF and FF cheeses were: 55.1, 52.3; 1.30, 25.6; 35.7, 22.5; 5.40, 5.42, respectively. The FFA contents (mg/g cheese) of fresh FF and LF cheeses prior to storage treatments for C4:0, C6:0, C8:0, C10:0, C12:0, C14:0, C16:0, C18:0, C18:1, and C18:2 were: 0.020, 0.072; 0.070, 0.035; 0.061, 0.055; 0.181, 0.167; 0.073, 0.047; 0.174, 0.112; 0.579, 0.152; 0.308, 0.202; 0.521, 0.174; and 0.057, 0.026, respectively. The respective FFA to total fatty acid ratios for 0, 1 and 3 months aged FF and LF cheeses were 8.44, 12.4; 6.31, 16.91; 12.03, 14.19. The LF cheeses generated more FFA than FF cheeses, while actual FFA content in FF cheese was significantly higher than in LF cheese. The FFA contents of LF cheese at 0, 1 and 3 months storage were 48.0, 96.8 and 36.
Food Control, 2012
An alternative method for monitoring total trans fatty acids (TTFA) in hydrogenated vegetable fat (HVF) and spreadable processed cheese (SPC) using capillary zone electrophoresis (CZE) and indirect UV detection is proposed. This method is a simple, efficient and rapid way to monitor both raw materials and the final SPC product. The importance of printing nutritional tables on product labels, to provide more accurate information to consumers, and incorporation of stricter quality controls during food processing is emphasised. Following calculation of the response factor (R f), the CE method was applied to TTFA analysis in SPC samples, and compared with the accepted AOCS gas chromatography (GC) method. According to a paired sample t test, no significant difference was found between the CE and GC methods within the 95% confidence interval for five different brands analysed in genuine duplicate (p-value > 0.05). The optimised CE method was applied to analyse the TTFA content of the hydrogenated vegetable fat raw material and the SPC final product. Based on our results, this optimised CE method can be successfully used for routine analysis of TTFA in SPC samples with a run time of 7.5 min.
International Dairy Journal, 2009
From each of twenty wheels of Parmigiano-Reggiano cheese of different ages (1-24 months), samples representative of the inner part (I, 10 cm from the round side and 7 cm from the flat side) and of the outer part (O, the rest of the cheese after removing the rind) were collected. For each sample, free fatty acids (FFAs, expressed as mg kg À1 cheese fat) were determined by quantitative capillary gas chromatography. In 18-and 24-month-old cheese, total levels of FFAs (as sum of individual FFAs) were significantly (P 0.05) higher in O than I, whereas no differences between regions were observed in 1-, 6-and 12month-old cheeses. In terms of short (C4-C8) and medium (C10-C14) chain FFAs, levels in the outer regions were higher (P 0.05) than inner regions for cheeses from 6-to 24-month-old. The content of long-chain FFAs (C16-C18:2) was higher in O than I in 18-and 24-month-old cheeses.
International Dairy Journal, 2003
Cheese flavour is a mixture of many (volatile) compounds, mostly formed during ripening. The current method was developed to qualify and quantify fat-derived compounds in cheese. Cheese samples were extracted with acetonitrile, which led to a concentrated solution of potential flavour compounds, mainly derived from milk fat. The solution was virtually free from triglycerides, protein and salt from the cheese matrix. Therefore, such an extract could be analysed directly by gas chromatography/mass spectroscopy (GC/MS). In the samples of the three cheese varieties analysed, 61 different compounds were identified, including 23 fatty acids, 14 lactones, 9 esters, 5 ketones, 10 alcohols, and several miscellaneous compounds. Furthermore, most compounds could be quantified by determining their distribution coefficients and thus correcting for their loss during extraction. This method was shown to be suitable for both qualitative and quantitative analysis of medium and low-volatile compounds.
Journal of Agricultural and Food Chemistry, 2016
Cyclopropane fatty acids (CPFA), as lactobacillic acid and dihydrosterculic acid, are components of bacterial membranes and have been recently detected in milk and in dairy products from cows fed with corn silage. In this paper, a specific quantitative GC-MS method for the detection of CPFA in cheeses was developed and the quality parameters of the method (LOD, LOQ, linearity, intralaboratory precision) were assessed. Limit of detection and quantitation of CPFA were respectively 60 and 200 mg/kg of cheese fat, and the intralaboratory precision, determined on three concentration levels, satisfied the Horwitz equation. Method was applied to 304 samples of PDO cheeses of certified origin, comprising Parmigiano Reggiano (Italy), Grana Padano (Italy), Fontina (Italy), Comté (France), Gruyère (Switzerland). Results showed that CPFA were absent in all the cheeses whose Production Specification Rules expressly forbid the use of silages (Parmigiano Reggiano, Fontina, Comté and Gruyère). CPFA were instead present, in variable concentrations (300-830 mg/kg of fat), in all the samples of Grana Padano cheese (silages admitted). Mix of grated Parmigiano Reggiano and Grana Padano were also prepared, showing that the method is able to detect the counterfeiting of Parmigiano Reggiano with other cheeses until 10-20 %. These results comfort the hypothesis that CPFA can be used as a marker of silage feedings for cheeses, and the data reported can be considered a first attempt to create a database for CPFA presence in PDO cheeses.
Acs Symposium Series, 2007
The main purpose of these studies was to assess the possibility of applying the technique of solid phase microextraction (SPME)-gas chromatography (GC)-mass spectrometry (MS) to detect the activity of moulds on historical objects, based on the analysis of microbial volatile organic compounds (MVOCs). The studies were performed for selected species of moulds, which were inoculated onto model samples of silk, cellulose, parchment and wool that had been prepared on microbiological medium, in vials for headspace sampling. After a few days of incubation, the MVOCs in the vials were sampled by using SPME fibre, and then they were analysed in the GC-MS system. The acquired chromatograms were qualitatively and quantitatively assessed, and it was ascertained that among the identified compounds are markers of mould activity which can be used to detect the vital mould growing on actual historic items. This usefulness of the method was additionally confirmed by analysis of MVOCs emitted by keratinolytically active mould inoculated on a sample of historical wool prepared in a Petri dish without a medium.