Fruitomics: The importance of combining sensory and chemical analyses in assessing cold storage responses of six peach (Prunus persica L. Batsch) cultivars

Cold storage is used to extend peach commercial life, but can affect quality. Quality changes are assessed through the content of nutritionally relevant compounds, aroma, physical characters and/or sensorially. Here, six peach and nectarine cultivars were sampled at commercial harvest and after 7 days of 1 °C storage. A trained panel was used to evaluate sensorial characters, while carotenoids, phenolics, vitamin C, total sugars, and qualitative traits including firmness, titrable acidity and soluble solid content were integrated with volatile organic compound (VOC) analysis previously reported. The different analyses reveal interesting patterns of correlation, and the six cultivars responded differently to cold storage. Sensory parameters were correlated with 64 VOCs and seven intrinsic characters. Acidity, firmness, and 10 VOCs were strongly negatively correlated with harmony and sweetness, but positively correlated with bitterness, astringency, and crunchiness. In contrast, Brix, b-carotene, and six VOCs were positively correlated with harmony and sweetness

Advanced mass spectrometric approaches for the determination of food quality and development of new methodologies for enrichment of nutraceuticals in functional foods

Dottorato di Ricerca in Medicina traslazionale. Ciclo XXXThe research works presented in this Ph.D. thesis are based on the nutraceuticals and functional foods research. The first part of the thesis deals with three main topics: 1. Structural characterization of new HMG-flavonoids in bergamot juice Two unknown 3-hydroxy-3-methylglutaryl flavanone glycosides were identified and characterized by the combination of liquid chromatography and tandem mass spectrometry experiments. 2. Preparation of extracts enriched in HMG-flavonoids A novel food-grade procedure to obtain HMG-flavonoids enriched extracts with an high purity grade was developed. The purification procedure was tested on different citrus fruits, i.e. bergamot, sour orange and chinotto. 3. Development of a new procedure for the enrichment of foodstuffs in hydroxytyrosol New functional foods are presented. They were obtained by the enrichment of foodstuffs generally used in daily diet, i.e. flour, whole wheat flour and sugar, with the nutraceutical compound hydroxytyrosol. The second part concerns the development of advanced mass spectrometric analytical procedure for quality assessment of foods, through the quantification of nutraceutical compounds and the determination of target quality molecules. The works presented in this field are the following: 1. Determination of Hydroxytyrosol and Tyrosol derivatives compounds in Extra Virgin olive oil by Microwave Hydrolysis and LC-MS/MS analysis A novel method to determine the absolute amount of hydroxytyrosol and tyrosol derivatives in EVOO samples was developed. The procedure consists in a simple and fast microwave assisted acidic hydrolysis reaction, combined with the use of liquid chromatography- tandem mass spectrometry analysis. 2. Absolute Evaluation of Hydroxytyrosol in Extra Virgin Olive Oil by Paper Sray Tandem Mass Spectrometry A novel and fast methodology for the evaluation of the absolute amount of Hydroxytyrosol in extra virgin olive oil was set up. The method is based on the exploitation of paper spray ionization (PS) tandem mass spectrometry (MS/MS). 3. Discriminant Analysis of Vegetables Oils by Paper Spray Mass Spectrometry and Statistical Approach An innovative approach for the characterization of triacylglycerols profile of different vegetable oils was developed. The method employs the paper spray ionization technique that in combination with chemometric analysis has allowed to discriminate the extra virgin olive oil from the others vegetable oils commonly used as adulterants. 4. Quantitative Evaluation of Caffeine in beverages and drugs by Paper spray tandem Mass Spectrometry A simple and fast method for the quantification of caffeine in beverages and drugs is presented. Also this analytical procedure is based on the use of paper spray tandem mass spectrometry.Università della Calabri

Paper Spray Tandem Mass Spectrometry for Assessing Oleic, Linoleic and Linolenic Acid Content in Edible Vegetable Oils

Oleic, linoleic and linolenic acids exert several beneficial effects on human health, some of which are also certified by recent European and U.S. regulations. The goal of the presented work was to develop an innovative methodology to evaluate their content in edible vegetable oils, in order to increase the value of oils from a nutraceutical perspective. The protocol is based on the use of paper spray ionization coupled with tandem mass spectrometry experiments, which allowed the recording of data very quickly and with high specificity. All investigated compounds gained a good linear relation (r2 higher than 0.98). Accuracy values are near 100% for all concentration levels examined, and the repeatability and reproducibility data result lower than 15%, highlighting the consistence of the methodology. The developed approach was successfully applied for the analysis of different real samples, and its robustness was confirmed by comparing the results obtained with those coming from the classical and official methodology

Hydroxytyrosol-Fortified Foods Obtained by Supercritical Fluid Extraction of Olive Oil

A new original process has been set-up to obtain hydroxytyrosol-enriched food by means of CO2 supercritical fluid extraction. The process is based on the direct adsorption of hydroxytyrosol on selected foodstuff (e.g., flour, whole-wheat flour, and sugar) when placed in contact with olive oil (which is known to contain this phenol) under controlled temperature and pressure conditions of supercritical CO2. The transfer of the nutraceutical to the foodstuff was initially evaluated using a fortified olive oil model and was then applied to commercial olive oil and foodstuff. The yield of the hydroxytyrosol transfer was demonstrated to be quantitative. In order to prove the suitability of the final products, hydroxytyrosol-enriched flour was used to prepare a bread roll, which maintained the nutraceutical characteristics after the cooking. Finally, DPPH based experiments were performed to prove the radical scavenging activity of the functionalized foodstuff

Structural Characterization of Peripolin and Study of Antioxidant Activity of HMG Flavonoids from Bergamot Fruit

The structural characterization of a new flavonoid from bergamot fruit (Citrus bergamia Risso) carrying the 3-hydroxy-3-methyl glutaryl (HMG) ester moiety has been accomplished, and its antioxidant ability was tested from a chemical point of view. The peculiarity of the new molecule, named peripolin, relies on the presence of the HMG chemical group linked to the sugar portion of neoeriocitrin; the structure was elucidated using both high-resolution mass spectrometry and nuclear magnetic resonance experiments performed on the purified molecule extracted from the fruit. The antioxidant ability of the new molecule was tested by classical chemical approaches, such as DPPH, ABTS and FRAP assays, and from a theoretical point of view. 1H and 13C NMR experiments and HR-ESI-MS/MS experiments show unequivocally that the HMG moiety is linked to the primary position of the glucose unit of neohesperidose, while the chemical tests and the computational results show that peripolin possesses strong antioxidant behavior, similar to that of neoeriocitrin and remarkably higher respect to the other flavonoids present in the fruit. Furthermore, the quantitative assays carried out by UPLC-MS/MS showed that its amount in the fruit is similar to that of the other main flavonoids. Furthermore, molecular dynamics simulations allowed us to investigate the possible conformations adopted by the antioxidants in the presence of water molecules. In particular, the switch of open-closed conformations of HMG-containing species was evidenced. As far as the reaction with DPPH, the calculation of ΔGrea supported the experimental outcomes regarding the peripolin and neoeriocitrin activity. In conclusion, bergamot fruit, already known for its potential to lower the level of blood cholesterol, has been proven to contain molecules such as neoeriocitrin and the newly characterized peripolin, which could have important in-vivo antioxidant characteristics

Vinegar production from Citrus bergamia by-products and preservation of bioactive compounds

Processing citrus fruits results in significant amount of wastes; however, citrus by-products still contain high amounts of polyphenolic and other bioactive value-added compounds. In addition, bergamot (Citrus bergamia) wastes contain two compounds—brutieridin and melitidin—which exhibit statin-like properties. Recently, novel fermented products containing bioactive compounds received increasing attention because of their health-promoting functions. In this study, the bioconversion of citrus wastes in vinegars with high content in bioactive and aromatic compounds was performed, detecting a high permanence at the end of the process of the main compounds of interest, especially brutieridin and melitidin. In addition, the sensory analysis of the vinegars was performed, obtaining good performances. According to the adopted preselection procedure, 50 out of the 54 strains of acetic acid bacteria were excluded because of their low aptitude to grow in the tested conditions. The best vinegar was produced from citrus wine at pH 2.90 using the Acetobacter aceti strain DSM_3508T as microbial starter. This research has demonstrated—for the first time—the possibility to produce citrus vinegar at high content of brutieridin and melitidin and other bioactive compounds using selected microbial starters

Hydrolase–like catalysis and structural resolution of natural products by a metal–organic framework

Elucidation of the chemical structure of natural products constitutes one of the main challenges in Natural Sciences. Here, the authors show that an amino acid-based metal–organic framework exhibits hydrolase-like catalytic activity and crystallographic determination of the resulting products

Publisher Correction: Hydrolase–like catalysis and structural resolution of natural products by a metal–organic framework

An amendment to this paper has been published and can be accessed via a link at the top of the paper