HS-SPME-GC-MS and Chemometrics for the Quality Control and Clustering of Monovarietal Extra Virgin Olive Oil: A 3-Year Study on Terpenes and Pentene Dimers of Italian Cultivars.

Terpenes and pentene dimers are less studied volatile organic compounds (VOCs) but are associated with specific features of extra virgin olive oils (EVOOs). This study aimed to analyze mono- and sesquiterpenes and pentene dimers of Italian monovarietal EVOOs over 3 years (14 cultivars, 225 samples). A head space-solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) method recently validated was used for terpene and pentene dimer quantitation. The quantitative data collected were used for both the characterization and clustering of the cultivars. Sesquiterpenes were the molecules that most characterized the different cultivars, ranging from 3.908 to 38.215 mg/kg; different groups of cultivars were characterized by different groups of sesquiterpenes. Pentene dimers (1.336 and 3.860 mg/kg) and monoterpenes (0.430 and 1.794 mg/kg) showed much lower contents and variability among cultivars. The application of Kruskal-Wallis test-PCA-LDA-HCA to the experimental data allowed defining 4 clusters of cultivars and building a predictive model to classify the samples (94.3% correct classification). The model was further tested on 33 EVOOs, correctly classifying 91% of them.

Analysis of Volatile Hydrocarbons (Pentene Dimers and Terpenes) in Extra Virgin Olive Oil: Optimization by Response Surface Methodology and Validation of HS-SPME-GC-MS Method.

A head space-solid phase microextraction-gas chromatography-mass spectrometery (HS-SPME-GC-MS) method for the simultaneous analysis of pentene dimers from lipoxygenase (LOX) pathway, monoterpenes, and sesquiterpenes in extra virgin olive oil (EVOO) was proposed. A Doehlert design was performed; the conditions of the HS-SPME preconcentration step (extraction temperature, extraction time, sample amount, and desorption time) were optimized by response surface methodology, allowing defining the method operable design region. A quantitative method was set up using the multiple internal standard normalization approach: four internal standards were used, and the most suitable one was selected for area normalization of each external standard. The quantitative method was successfully validated and applied to a series of monocultivar EVOOs. This is the first paper in which a quantitative method using commercial standards has been proposed for the analysis of an important class of molecules of EVOO such as pentene dimers. The optimized method is suitable for routine analysis aimed at characterizing high quality EVOOs.

Non-volatile cysteine sulphoxides and volatile organosulphur compounds in cloves of garlic (Allium sativum L.) and elephant garlic (Allium ampeloprasum L.) local accessions from northern and central Italy.

BACKGROUND: Garlic (Allium sativum L.) and other species of genus Allium are popular vegetables and food seasonings, owing to their spicy flavour and richness in health-promoting compounds. Several local garlic types are still grown on a small scale in different Italian regions, not being however yet properly characterized for their chemical composition. RESULTS: In the present investigation ten garlic and four elephant garlic (Allium ampeloprasum L.) populations cultivated in northern and central Italy were evaluated for their alk(en)yl cysteine sulphoxide (ACSO) and volatile compound profiles. Three non-volatile ACSOs (methiin, alliin, and isoalliin) and 27 volatile compounds were identified and quantified. A high and significant within-type variability was detected, with total ACSOs in the range 2759-5756, 4533-15 520, and 6565-10 643 mg kg-1 of fresh weight (f.w.). in elephant, white and red garlic, respectively. Elephant garlic showed a total sulphoxide content and a relative alliin amount significantly lower than white and red garlic. Remarkable within-type differences were also assessed for volatile compound content, ranging 260-599, 333-981, and 618-845 mg kg-1 f.w. in elephant, white, and red garlic, respectively. Diallyl trisulphide was the major individual compound, accounting for more than 0.30 mg mg-1 of volatiles in all the analysed samples. The three garlic types were clearly separated by discriminant analysis of analytical traits. CONCLUSION: This study investigated for the first time different Italian garlic and elephant garlic populations with respect to non-volatile and volatile organosulphur compound content, allowing the possibility of selecting garlic accessions according to the bioactive content. © 2022 Society of Chemical Industry.

Exploitation of virgin olive oil by-products (Olea europaea L.): phenolic and volatile compounds transformations phenomena in fresh two-phase olive pomace ('alperujo') under different storage conditions.

BACKGROUND: Much effort has recently been spent for re-using virgin olive oil by-products as nutraceutical ingredients for human diet thanks to their richness in bioactive phenols, but their management is not easy for producers. We aimed to provide useful information for a better management of fresh olive pomace before drying, by studying the phenolic and volatile compounds transformations phenomena of fresh olive pomace stored under different conditions planned to simulate controlled and uncontrolled temperature conditions in olive oil mills. RESULTS: The evolution of the phenolic and volatile compounds was studied by high-performance liquid chromatography-diode array detector mass spectrometry (HPLC-DAD-MS) and headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS). The phenolic profile varied rapidly during storage: the verbascoside content decreased about 70% after 17 days even at 4 °C, while the content of simple phenols such as hydroxytyrosol and caffeic acid increased over time. The low temperature was able to slow down these phenomena. A total of 94 volatile organic compounds (VOCs) were detected in the fresh olive pomace, with a prevalence of lipoxygenase (LOX) VOCs (78%), mainly aldehydes (19 490.9 µg kg-1 ) despite the higher number of alcohols. A decrease in LOX volatiles and a quick development of the ones linked to off-flavors (carboxylic acids, alcohols, acetates) were observed, in particular after 4 days of storage at room temperature. Only storage at 4 °C allowed these phenomena to be slowed down. CONCLUSION: To preserve the natural phenolic phytocomplex of fresh olive pomace before drying and to avoid off-flavors development, storage in open containers must be avoided and a short storage in cold rooms (7-10 days) is to be preferred. © 2021 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Volatile Profile of Two-Phase Olive Pomace (Alperujo) by HS-SPME-GC-MS as a Key to Defining Volatile Markers of Sensory Defects Caused by Biological Phenomena in Virgin Olive Oil.

An olive pomace from the two-phase decanter stored in different conditions was used as a model to simulate the detrimental biological phenomena occurring during olive oil processing and storage. A group of EVOO and defective oils were also analyzed. The volatile fraction was studied with HS-SPME-GC-MS; 127 volatiles were identified (55 of which tentatively identified) and evaluated over time. Seven volatiles were tentatively identified for the first time in olive oil; the role of C6 alcohols in detrimental biological phenomena was highlighted. Suitable volatile markers for defects of microbiological origin were defined, particularly the fusty/muddy sediment. They were then applied to olive oils with different quality categories; one of the markers was able to discriminate among EVOOs and all the defective samples, including the borderline ones. The marker was constituted by the sum of concentrations of 10 esters, 4 alcohols, 1 ketone, and 1 α-hydroxy-ketone but no carboxylic acids.

New Advances in the Determination of Free and Bound Phenolic Compounds of Banana Passion Fruit Pulp (Passiflora tripartita, var. Mollissima (Kunth) L.H. Bailey) and Their In Vitro Antioxidant and Hypoglycemic Capacities.

Banana passion fruit (Passiflora tripartite L.H. Bailey) is a lesser known species of the genus Passiflora. This fruit typically grows in the Andean region of Ecuador and it is locally known as tumbo, taxo or curuba. The juice of this fruit is highly appreciated in South America. Extracts of banana passion fruit were characterized for their content levels of free and bound phenolic compounds by high performance liquid chromatography coupled to high resolution mass spectrometry detector (HPLC-ESI-TOF-MS). A total of 82 polar compounds classified as phenolic acid derivatives, organic acids, benzophenones, flavan-3-ols, flavonols and flavones were detected in the extracts. The total phenolic content was 2356 mg 100 g-1 dry matter, with the bound phenolic fraction representing 37.7% of total amounts. Flavan-3-ols, such as (epi)catechin, (epi)azfelechin and their derivatives, were the main phenolic compounds in the free phenolic fraction; however, phenolic acids represented the most abundant class of bound phenolic extracts. The antioxidant and hypoglycemic capacities reported for banana passion fruit were higher than for other fruits. To our knowledge, this is the first time that bound phenolic compounds have been described in banana passion fruit pulp.

Comparison of two extraction methods (high pressure extraction vs. maceration) for the total and relative amount of hydrophilic and lipophilic organosulfur compounds in garlic cloves and stems. An application to the Italian ecotype "Aglio Rosso di Sulmona" (Sulmona Red Garlic).

Garlic-based extracts have been surveyed as healthy promoting supplements in relation to their content of organosulfur compounds. The present study investigated the effect of high pressure extraction and maceration, and four extraction solvents (three hydroalcoholic mixtures and sunflower oil) on the total and relative amounts of the main organosulfur compounds of clove and stem extracts of the Italian ecotype "Aglio Rosso di Sulmona" (Sulmona Red Garlic). Organosulfur compounds were more abundant in cloves than in stem extracts. High pressure extraction led to higher recoveries of hydrophilic compounds than maceration whereas the highest amounts of lipophilic compounds were detected in macerates. A higher alliin-to-allicin conversion ratio was detected in clove, in comparison to stem extracts. Sunflower oil fostered allicin decay to compounds such as ajoenes, vinyldithiins and sulfides. The use of specific extraction methods may lead to standardised grade extracts, both from native raw materials and by-products.

New Volatile Molecular Markers of Rancidity in Virgin Olive Oils under Nonaccelerated Oxidative Storage Conditions.

Evolution of the volatile profile of two extra-virgin olive oils with very different fatty acid composition (monounsaturated fatty acid/polyunsaturated fatty acid ratio) stored in several nonaccelerated oxidative conditions was studied by a validated headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) method. The role of C8 volatile compounds in oxidative processes was highlighted, and controversial aspects regarding the origin of some volatiles were clarified. Specific volatile markers for rancidity were proposed: sum of pentanal, hexanal, nonanal, E-2-heptenal, propanoic acid, and hexanoic acid for oils stored in the dark; sum of pentanal, heptanal, nonanal, decanal, E-2-heptenal, E-2-decenal, E,E-hepta-2,4-dienal, and E,E-deca-2,4-dienal, octane for oils stored under light exposure; sum of pentanal, nonanal, decanal, E-2-heptenal, E-2-decenal, E,E-hepta-2,4-dienal, nonan-1-ol, propanoic acid, octane, 6-methylhept-5-en-2-one, and oct-1-en-3-ol for oils stored under light exposure with oxygen in headspace. A simplified marker (sum of pentanal, nonanal and E-2-heptenal) suitable for all conditions was also proposed.

Headspace Solid-Phase Microextraction-Gas Chromatography-Mass Spectrometry Quantification of the Volatile Profile of More than 1200 Virgin Olive Oils for Supporting the Panel Test in Their Classification: Comparison of Different Chemometric Approaches.

A reliable and robust tool for supporting the panel test in virgin olive oil classification is still required. We propose four chemometric approaches based on t test, principal component analysis (PCA) and linear discriminant analysis (LDA), applied for combining sensorial data, and chemical measurements. The former was from the panel test, and the latter was from headspace solid-phase microextraction-gas chromatography-mass spectrometry quantitation of 73 volatile organic compounds (VOCs) of 1223 typical commercial virgin olive oils, with most of them recognized as difficult to classify with accuracy by the panel test. The approaches were developed and validated, and the best results, with 83.5% correct classification, were using the PCA-LDA approach. Among the other methods, developed for proposing simplified procedures based on a smaller number of VOCs, the best method gave 80.1% correct classification only using 10 VOCs. All of the approaches suggested that octane, heptanal, pent-1-en-3-ol, Z-3-hexenal, nonanal, and 4-ethylphenol should be considered as a basis of volatiles for classification of olive oil samples.

Identification and quantification of phenolic compounds in edible wild leafy vegetables by UHPLC/Orbitrap-MS.

BACKGROUND: A recent interest in edible wild leafy vegetables has been documented. Consumers often associate these species with health promotion. In this study, several wild species of the Asteraceae family and Knautia integrifolia (Dipsacaceae) were locally documented for their use in traditional cuisine and sampled from the wild. RESULTS: Phenolic compounds were identified and quantified by ultra-high-performance liquid chromatography coupled to Orbitrap high-resolution mass spectrometry. Hydroxycinnamic acids ranging from 1388 to 53 076 mg kg-1 dry weight (DW) were the most abundant compounds in all species (69-98% of the total phenolic content) except Tragopogon pratensis. Thirty compounds were identified as flavonoids, mostly as glycosidic forms of luteolin, apigenin, kaempferol and quercetin. The sum of flavonoids ranged between 212 and 12 598 mg kg-1 DW; they represented 65% of the total phenolic content for T. pratensis. Three anthocyanins were detected, representing in most cases less than 1% of the total phenolic content (3-627 mg kg-1 DW). Higher anthocyanin contents were observed for Cichorium types. CONCLUSION: Different phenolic profiles were observed between species, especially considering the class of flavonoids. Individual species may be of some interest for their content of specific minor flavonoids. © 2017 Society of Chemical Industry.

Fennel (Foeniculum vulgare Mill. subsp. piperitum) florets, a traditional culinary spice in Italy: evaluation of phenolics and volatiles in local populations, and comparison with the composition of other plant parts.

BACKGROUND: Wild fennel (Foeniculum vulgare Mill. subsp. piperitum) florets are used as a typical spice in central and southern Italy. Although fennel (Foeniculum vulgare Mill.), belonging to the Apiaceae (syn. Umbelliferae) family, is a well-known vegetable and aromatic plant, whose main phytochemical compounds have been extensively analysed and investigated as flavouring agents and for their putative health promoting functions, its florets have not been specifically considered up to now. Therefore, the volatile and phenolic composition of florets from an Italian wild fennel crop was determined at different developmental stages, and compared to that of leaves and fruits. Moreover, florets of nine Italian wild fennel populations of different geographical origin from northern-central Italy were also analysed. RESULTS: The total phenolic amount increased from leaves to florets, reaching its highest value in early florets, at 58 012 mg kg-1 of dry matter (DM), then constantly decreased in fruits. In florets of wild populations, phenolics ranged from 6666 to 43 368 mg kg-1 DM. The total amount of volatile compounds was more than twice higher in florets (21 449 mg kg-1 DM) than in leaves (10 470 mg kg-1 DM), reaching its highest value in fruits (50 533 mg kg-1 DM). Estragole and trans-anethole were the main compounds of the volatile fraction. Total volatiles ranged from 24 367 to 60 468 mg kg-1 DM in florets of local populations. CONCLUSION: Significant changes in the total amount and profile of both phenolic and volatile compounds occurred during plant development. The consistent increase of estragole at later developmental stages supported the claim of different sensory properties of florets and fruits. Geographical origin significantly affected phenolic and volatile composition of wild fennel florets. © 2017 Society of Chemical Industry.

The kinetic of key phytochemical compounds of non-heading and heading leafy Brassica oleracea landraces as affected by traditional cooking methods.

BACKGROUND: Kales are often a key ingredient of traditional foods, containing high amounts of indolic glucosinolates (precursors of indole-3-carbinol and ascorbigen), carotenoids and phenolics. The present trend to associate traditional foods crops with health-promoting properties suggested to investigate the degradation kinetic of three Brassica oleracea landraces' phytochemicals subjected to boiling, steaming and stir-frying. RESULTS: Boiling led to substantial losses due to leaching. Glucosinolates followed a second-order degradation kinetic (20% of their initial values after 10 min in Nero di Toscana). Phenolic content in leaves + cooking water remained unchanged, whereas their antioxidant capacity was reduced. Carotenoid content increased during the first minutes of boiling. Steaming showed the highest retention of phytochemicals, with often zero-order degradation kinetic, having however a strong effect on colour. Stir-frying produced high losses for all measured compounds; also, ß-carotene reduced its content to 10-23% independently of variety. Conversion values for indole-derived compounds ranged from non-detectable to 23.5%. CONCLUSION: Variety strongly affected observed degradation rates because of a different glucosinolate composition and leaf structure. With this research, more information has been gained on the degradation kinetic of B. oleracea landraces' phytochemical compounds upon cooking, highlighting the possibility of improving bioactive component retention. © 2016 Society of Chemical Industry.

A comparative study of bioactive compounds in primitive wheat populations from Italy, Turkey, Georgia, Bulgaria and Armenia.

BACKGROUND: In recent years there has been a considerable interest in the consumption of ancient wheats, often referred to as having superior health-promoting properties than modern cultivars. The BaSeFood project allowed us to explore the use of primitive wheats in the Black Sea area region and in Italy, with special regard to emmer (Triticum dicoccum) and einkorn (T. monococcum), and to collect seed samples to be grown and compared for their bioactive content, together with some other primitive wheat genotypes (T. timopheevi, T. palaeo-colchicum, T. macha). RESULTS: The data show that genotype was an important factor controlling phytochemical content. Variability ranges were as follows: lipids (18.0-28.5 g kg(-1)), tocols (26.6-72.8 mg kg(-1)), carotenoids (1.6-8.4 mg kg(-1)), sterols (441-929 mg kg(-1)) and phenolic compounds (819-1465 mg kg(-1)) content (dry matter basis). The fraction of individual components, within each class, was also variable; however, the species were well discriminated by their overall composition. CONCLUSIONS: The present research represents a further contribution to the available literature about the analytical composition of primitive wheats, including the complete range of relevant bioactives and lesser investigated species. The data do not support an overall superiority of primitive forms, but evidenced interesting, potentially exploitable, between- and within-species variability.

Comparison of leafy kale populations from Italy, Portugal, and Turkey for their bioactive compound content: phenolics, glucosinolates, carotenoids, and chlorophylls.

BACKGROUND: Kales are primitive leafy Brassica oleracea L. forms, widespread in local farming systems of several European countries and employed in the preparation of traditional recipes. Kales are also potential sources of healthy bioactive phytochemical components. The present study compared the bioactive compound content of kale populations from Italy, Portugal, and Turkey, either from local sources or grown in an experimental field. RESULTS: Total phenolics, glucosinolates (GLS), carotenoids, and chlorophylls were in the ranges 8310-38 110, 755-8580, 135-2354, and 1740-16,924 mg kg(-1) dry matter, respectively. On average, locally harvested samples showed a total GLS content about twice as high as populations from the experiment. Conversely, pigments were significantly more abundant in experimental than in local kales, owing to the higher soil fertility. Portuguese samples showed higher phenolic and GLS amounts than Italian and Turkish kales, whereas some of the Italian samples were the richest in carotenoids. CONCLUSION: This paper represented the first cross-country comparison of local kale accessions with respect to bioactive compound amounts. Both geographic origin and growing environment appeared to be remarkable and discriminating factors in determining bioactive levels in leafy kales, with possible effects on their health-promoting and sensorial attributes.

An on-site comparative study of yield factors during glume removal, a primary step in the traditional processing of hulled wheats.

BACKGROUND: Glume removal represents the preliminary step of hulled wheat grain processing for human consumption. Einkorn and emmer wheat are two hulled species, cultivated in marginal areas, from the Mediterranean to the Caucasian region, and the subject of investigation in this paper. An experiment has been carried out to compare the yield of the traditional process, used in Turkey and Armenia, and an updated Italian procedure, by means of on-plant samplings. RESULTS: Crushed grains represent a product from all the plants examined. However, the relative amounts of fractions of different size and use, according to each country, varied consistently. The main Italian product is whole pearled grain. The calculated yield factors varied in the following ranges: dehulling: 0.73-0.81 kg kg(-1); food product: 0.82-0.96 kg kg(-1); overall yield: 0.56-0.95 kg kg(-1) excluding unwanted losses, and 0.42-0.74 kg kg(-1) including unwanted losses. CONCLUSIONS: This first comparative assay of hulled wheat processing showed that, not considering the kind of product obtained, glume removal can be carried out with good efficiency in continuously operating traditional plants. Modern schemes, however, allow yielding of intact kernels. Some yield factors were highly affected by the available technology, especially when the process was operating discontinuously.

Wastes generated during the storage of extra virgin olive oil as a natural source of phenolic compounds.

Phenolic compounds in extra virgin olive oil (EVOO) have been associated with beneficial effects for health. Indeed, these compounds exert strong antiproliferative effects on many pathological processes, which has stimulated chemical characterization of the large quantities of wastes generated during olive oil production. In this investigation, the potential of byproducts generated during storage of EVOO as a natural source of antioxidant compounds has been evaluated using solid-liquid and liquid-liquid extraction processes followed by rapid resolution liquid chromatography (RRLC) coupled to electrospray time-of-flight and ion trap mass spectrometry (TOF/IT-MS). These wastes contain polyphenols belonging to different classes such as phenolic acids and alcohols, secoiridoids, lignans, and flavones. The relationship between phenolic and derived compounds has been tentatively established on the basis of proposed degradation pathways. Finally, qualitative and quantitative characterizations of solid and aqueous wastes suggest that these byproducts can be considered an important natural source of phenolic compounds, mainly hydroxytyrosol, tyrosol, decarboxymethyl oleuropein aglycone, and luteolin, which, after suitable purification, could be used as food antioxidants or as ingredients in nutraceutical products due to their interesting technological and pharmaceutical properties.