Volatile organic compound data of ready-to-cook tuna fish-burgers: Time evolution in function of different and/or combined mild preservation technologies and relevant statistical analysis

Volatile organic compound (VOC) composition from ready-to-cook tuna fish-burgers, prepared with and without a protective microbial strain (Lactobacillus paracasei) and/or stored with modified atmosphere packaging (MAP, 5% O2 and 95% CO2), were extracted by headspace solid-phase microextraction and analyzed by gas chromatography-mass spectrometry (HS-SPME-GC-MS) during the burger shelf-life. The collected data showed volatile composition profiles in function of the mild preservation technologies employed and the storage time. Furthermore, statistical data treatment (principal component analysis and Pearson's coefficients) highlighted differences among samples and positive/negative correlations during the storage time. This paper is related to an article already published in LWT (Investigating the effects of mild preservation technology on perishable foods by volatolomics: The case study of ready-to-cook tuna-burgers” https://doi.org/10.1016/j.lwt.2019.108425)

Effects of different vinification procedures and aging containers on phenolic and volatile composition of Greco white wines

Two wines, obtained respectively from Greco grapes submitted to (a) a traditional vinification in white and (b) a vinification including cryomaceration under reductive conditions, were aged for 12 months in glass container and in 3 types of amphorae (raw, glazed, and engobe). The wines obtained by cryomaceration under reductive conditions showed the highest phenolic contents both at racking and after aging. The phenolic contents decreased with aging and proanthocyanidins exhibited the greatest decrease. Antiradical/antioxidant activity at racking and after aging was higher in cryomacerated than in traditional wines. Antioxidant activity was not affected by the type of container. Volatile acids and esters decreased with aging, while alcohols, hydrocarbons, and aromatics increased. According to the principal component analysis (PCA) of results from conventional analyses and antioxidants, the wines were homogeneously grouped as a function of the vinification method applied. The PCA of volatile compounds allows to better emphasize the differences, grouping the data into three clusters according to the type of containers

Volatolomics study of X-ray irradiated dairy products by HSSPME/GC-MS

The increasing demand for raw and fresh dairy products, such as soft cheese, with desired organoleptic characteristics and health benefits, requires alternative technologies for inactivation of pathogenic microorganisms in particular of Listeria monocytogenes [1, 2]. In a report of the European Commission [3] and in a recent review [4], the use of food irradiation in half a century of studies is well summarized highlighting the potential benefits of this preservation technique. In Europe, the general application of X-rays to dairy products has been limited to one cheese (Camembert) [5-7], but the irradiation processing of raw and fresh dairy products is of great interest to the food industry. However, irradiation treatments may cause possible biochemical changes in lipid and protein profiles that can affect the quality and safety of products [1]. For these reasons, the purpose of this work was to study the volatile organic compounds (VOC) in Xray irradiated soft cheeses. A volatolomics approach based on headspace solid-phase microextraction (HS-SPME) combined with gas chromatography-mass spectrometry (GC-MS) was developed to evaluate the irradiation effects on the volatile profile of soft cheeses, as a function of different radiation treatment parameters. Five different SPME fibres, namely polyacrylate (PA), polydimethylsiloxane (PDMS) carboxen/polydimethylsiloxane (CAR/PDMS), polydimethylsiloxane/divinylbenzene (PDMS/DVB) and divinylbenzene /carboxen/polydimethylsiloxane (DVB/CAR/PDMS), were tested in terms of number and relative amount of compounds extracted. Moreover, temperature and extraction time were evaluated for the HS-SPME process efficiency. The volatile compounds of 0, 1.5 and 3 kGy irradiated samples were extracted by the selected SPME fibre and analyzed by the optimized method. VOCs, identified by means the linear retention index and by MS data obtained from NIST library, were analyzed by a multivariate statistical approach in order to investigate the generation of off-odors and flavors induced by X-ray irradiation and to understand the quality and maintenance of the nutritional and sensorial values. Volatile compounds belonging to chemical classes of acids, alcohols, aldehydes, esters, and miscellaneous were identified in all the experimental samples and interesting variations were noted among them as a function of the irradiation dose

Simultaneous and Accurate Real-Time Monitoring of Glucose and Ethanol in Alcoholic Drinks, Must, and Biomass by a Dual-Amperometric Biosensor

In this work the optimization and application of a dual-amperometric biosensor for simultaneous monitoring of glucose and ethanol content, as quality markers in drinks and alcoholic fermentation media, are described. The biosensor is based on glucose oxidase (GOD) and alcohol oxidase (AOD) immobilized by co-cross-linking with bovine serum albumin (BSA) and glutaraldehyde (GLU) both onto a dual gold electrode, modified with a permselective overoxidized polypyrrole film (PPYox). Response, rejection of interferents, and stability of the dual biosensor were optimized in terms of PPYox thickness, BSA, and enzyme loading. The biosensor was integrated in a flow injection system coupled with an at-line microdialysis fiber as a sampling tool. Flow rates inside and outside the fiber were optimized in terms of linear responses (0.01-1 and 0.01-1.5 M) and sensitivities (27.6 ± 0.4 and 31.0 ± 0.6 μA·M-1·cm-2) for glucose and ethanol. Excellent anti-interference characteristics, the total absence of "cross-talk", and good response stability under operational conditions allowed application of the dual biosensor in accurate real-time monitoring (at least 15 samples/h) of alcoholic drinks, white grape must, and woody biomass

Proteomic Strategies for the Identification of Proteins in Durum Wheat

Although the fulfillment of genome sequences of several green plants has not yet been completed, there are many researches focused on the determination of the functional network of proteins by proteome analysis. In the last decade, a wide identification of proteins by MS was performed in rice, Arabidopsis, maize, barrel medic (Medicago truncatula) The relatively small genome size of rice (420 Mb) and its importance as a food grain have made rice a primary target for genome sequencing and proteomic studies. On the contrary, proteomic studies in wheat are in progress and the database of wheat is incomplete also owing to the large genome size (16,000 Mb). In a recent work, to broaden the knowledge of the durum wheat gluten proteome, three cultivars were compared in two different growing seasons by a proteomic approach. Most of the wheat proteins are very difficult to identify because they have homologous sequences to other proteins. For that reasons, new proteomic approaches have to be developed for the study of these wheat proteins. In this work, two different enzymatic digestion methods and bioinformatics approaches coupled with nanoLC and electrospray ionization ion trap mass spectrometry is described for the identification of metabolic and gluten proteins of durum wheat cultivars, in order to increase the final number of identified proteins. The use of MS techniques in combination with the Swissprot, NCBI and EST Viridiplantae databases allowed us to identify wheat proteins minimizing the risk of false-positive identifications

Changes in volatile compounds of Ayvalık (Edremit) and Uslu olive oils depending on conditions and time of storage

Introduction. Volatile aromatic compounds present in olive oils extracted from Turkish olive cultivars including Edremit (Ayvalık) and Uslu were determined qualitatively. Materials and methods. The olives were harvested from Akhisar/Manisa region, which is one of most important Turkish olive-growing locations, at almost the same maturity stage by hand. Harvested olives were put in case and nylon sacks and were stored under the same conditions until they analyzed. Determination of the volatile aroma compounds were done with the aim of Headspace Solid-Phase Microextraction (HS-SPME) and Gas Chromatography-Mass Spectrometry (GC–MS). Results and discussion. 46 different volatile compounds were identified. The inappropriate storage conditions of olives had a negative impact on the aroma profiles of oils. The most abundant compounds were hexanal, α-farnesene, dimethylpalmitamine, and α-Farnesene, 2-hexanal, hexanal in olive oils extracted from Edremit (Ayvalık) and Uslu varieties, respectively.1-Hexanol was mostly increased compound in Edremit olive oils extracted from olives stored at nylon sacks during 14 days. The increase of concentration of 2-hexanal during holding periods could be explained by the activity of the fungal enzymes in Lipoxygenase pathway of olive fruits. While 5-Hepten-2-one 6-methyl and 1-Butanol 3-methyl were not detected in Edremit and Uslu olive oils at initial day, they formed during both sack and box holding due to the microbial activity in olives. Three principal components (PCs) were extracted representing 81.27% of the total variance of olive oil samples extracted from Uslu cultivar and 80.14 % of the total variance of olive oil samples extracted from Edremit cultivar. The first PCs, PC1, PC2 and PC3 represented 45.15 and 41.31%, 21.90 and 21.39%, 14.21 and 17.43%, for Uslu and Edremit varieties, respectively. Conclusions. It is recommended to store olives at 5 °C in air conditioning boxes for at least 30 days to reduce fungal development and to maintain the desired aroma

Optimizing accelerated solvent extraction combined with liquid chromatography-Orbitrap mass spectrometry for efficient lipid profile characterization of mozzarella cheese

In this study, a novel Accelerated Solvent Extraction (ASE) procedure combined with UHPLC-Q-Orbitrap-MS was developed for detailed untargeted lipid profile of mozzarella cheese. Response Surface Methodology and Pareto front, using a Central Composite Design (CCD), were employed to define the optimised combination of extraction temperature, number of extraction cycles and mix of solvents. LipidSearch™ software was used for a reliable and accurate lipid identification. A total of 13 subclasses, including ceramides, diacylglycerols, triacylglycerols, lysophosphatidylcholines, lysophosphatidylethanolamines, phosphatidylcholines, phosphatidylethanolamines, phosphatidylinositols, sphingomyelins, bismethyl phosphatidic acids, cholesterol ester, zymosterol ester, hexosyl ceramides were measured. The elaboration of the CCD showed that the solvents ratio was the main factor affecting the extraction efficiency. The optimised ASE method, together with the Folch extraction, synergistically contributed to a complete characterization of lipid profile of mozzarella cheese, confirming ASE technique, associated with high resolution mass spectrometry detection, as an efficient tool for Lipidomics in food science

Investigating the effects of mild preservation technology on perishable foods by volatolomics: The case study of ready-to-cook tuna-burgers

Volatile organic compounds (VOCs) in ready-to-cook tuna-burgers, prepared with and without a protective microbial strain (Lactobacillus paracasei) and in combination with modified atmosphere packaging (MAP, 5% O2 and 95% CO2), were analysed during their shelf life by headspace solid-phase microextraction coupled with a gas chromatography-mass spectrometry (HS-SPME-GC-MS). The results, processed by a statistical multivariate approach (Analysis of Variance, Principal Component Analysis obtained for compounds and chemical classes, and Pearson analysis), proved that the application of both L. paracasei microbial inoculation and MAP significantly influenced the aroma profile of fish-burgers during storage, showing marked differences in almost all the compound classes. In particular, a decrease of aldehyde contents, together with an increase of acids and ketones were observed in L. paracasei samples with respect to the control samples, while the samples under MAP differed from the others in the higher content in alcohols. Furthermore, positive and negative correlations among compounds during the storage time were found by means of Pearson correlation coefficients, suggesting in some cases the existence of specific chemical pathways. The proposed volatolomic approach has proved to be an easy and efficient tool to study the effects of the preservation strategies on perishable food