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.

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.

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.

Chemical composition and antioxidant activity of the volatile fraction extracted from air-dried fruits of Tunisian Eryngium maritimum L. ecotypes

BACKGROUND

Eryngium maritimum L., also known as 'sea holly', is a typical dune plant species belonging to the Apiaceae family and commonly used in Tunisia for therapeutic purposes in folk medicine. In the present study, the chemical composition and antioxidant activity of the volatile fraction extracted from air-dried fruits of five Tunisian E. maritimum ecotypes were determined.

RESULTS

The total volatile amount ranged from 0.31% to 0.93% (w d.w.^-1 ). Sixty-six volatile components were identified by means of GC-MS and accounted for 77.05-86.65% of the total extracted volatile oil. The majority of the identified metabolites were hydrocarbon sesquiterpenes and oxygenated sesquiterpenes, amounting on average to 46.69% and 30.01% of total volatiles, respectively. The principal individual components were germacrene D (13.62-31.71%), 15-hydroxy-α-muurolene (12.04-18.58%), and germacrene B (6.77-15.04%). Significant differences were noticed among E. maritimum populations. The volatile profile of E. maritimum fruits was consistently different from those of the aerial parts and roots of plants of the same species reported in previous investigations. Average radical scavenging capacity of the volatile fraction, as determined by DPPH and ABTS tests, was twice higher than that of the Trolox control.

CONCLUSION

This study characterised for the first time the fruits of E. maritimum for the composition and radical-scavenging capacity of their volatile fraction. The growth location confirmed as a pivotal factor in influencing the volatile profile of the fruits. © 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, β-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.

New nutritional composition data on selected traditional foods consumed in Black Sea Area countries

BACKGROUND

Traditional foods are an important part of the culture, history, identity and heritage of a region or country and are key elements in dietary patterns. In most countries there is limited information on the nutritional composition of such foods and therefore there is a need to investigate, register and promote traditional foods. One of the aims within the 'Sustainable exploitation of bioactive components from the Black Sea Area traditional foods' (BaSeFood) project is to generate for the first time new data on the nutritional composition of traditional foods from six Black Sea Area countries to promote their sustainable development and exploitation.

RESULTS

Thirty-three traditional foods were analysed in an accredited laboratory to determine their nutritional composition, and the data were fully documented. The nutrient content varied widely because of the nature and variety of the analysed foods. The energy content ranged between 4 kcal per 100 g for kvass southern and 900 kcal per 100 g for mustard oil, with the exception of the analysed teas, which did not contribute to energy intake.

CONCLUSION

The use of a common methodology for the study of traditional foods will enable countries to further investigate these foods. Moreover, a new nutritional knowledge base of traditional foods from Black Sea Area countries will contribute to promote local biodiversity and sustainable diets by maintaining healthy dietary patterns within local cultures.

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.

Carotenoids, vitamins (A, B2, C and E) and total folate of traditional foods from Black Sea Area countries

BACKGROUND

Carotenoids, vitamins (A, B2, C and E) and total folate are related to health promotion. However, there are still many food matrices for which the content of these compounds is not available. In order to fill this gap, traditional foods from Black Sea Area countries (BSAC) were analysed in order to investigate their potential health benefits.

RESULTS

The most abundant carotenoid was β-carotene. Plum jam was the sample with the highest β-carotene content (608 µg 100 g(-1) edible portion). The group of vegetables and vegetable-based foods contributed most to β-carotene content. Evergreen cherry laurel presented the highest l-ascorbic acid content (29.9 mg 100 g(-1) edible portion), while the highest riboflavin and total folate contents were found for roasted sunflower seeds. Approximately 61% of the analysed samples showed quantifiable amounts of α-tocopherol but did not contain retinol.

CONCLUSION

Despite the great variability in the content of carotenoids, vitamins and total folate, most of the analysed traditional foods from BSAC can be considered good sources of these compounds. Therefore, owing to their putative health benefits, the consumption of those with higher contents of these compounds should be encouraged and promoted.

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.

Preliminary sensory evaluation of edible flowers from wild Allium species

BACKGROUND

The use of edible flowers as an aesthetic and flavour component of specific dishes is gaining popularity, and their production is becoming an interesting niche market activity for growers. Allium is an important genus of flowering plants, also including traditional wild food species. The combination of tradition with the new uses of flowers is appealing, requiring, however, explorative acceptance assays for its exploitation.

RESULTS

The flowers of the native Mediterranean species Allium neapolitanum, A. roseum and A. triquetrum were subject to hedonic visual, smell and flavour evaluation. Panellists also indicated specific flavour notes and their opinion about the more suitable uses. All the species were positively rated. A. roseum was preferred for all respects; A. triquetrum obtained the lowest visual rating, whereas A. neapolitanum had the lowest flavour rating. A spicy note was the main determinant of high flavour ratings. Dishes retaining the visual appearance of flowers were indicated as more suitable to combine with Allium flowers.

CONCLUSION

This is the first attempt at sensory evaluation of Allium flowers. Nutritional and health promotion properties and toxicity risks do not represent major issues for these products, because of potentially low consumption levels. The main constraint for a wider use of Allium flowers is represented by the absence of a consolidated consumption habit and regular supply.

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.

Traditional foods and food systems: a revision of concepts emerging from qualitative surveys on-site in the Black Sea area and Italy

BACKGROUND

The European FP7 BaSeFood project included a traditional food study contextually analysing their function in local food systems to stimulate consumers' awareness and indicate co-existence options for different scale exploitation. Background concepts were (1) the available traditional foods definitions; (2) the theoretical background of food quality perceptions; and (3) the different levels of food functions.

METHODS

Field investigations were carried out by face-to-face in-depth qualitative interviews with local stakeholders, in the Black Sea region and Italy, on all aspects of traditional food production chains: raw materials, products, processes and perceptions. Critical and intercultural comparisons represented the basis of data analysis.

RESULTS

Eight hundred and thirty-nine foods were documented. The direct experience perception of traditional food value observed in local contexts is somewhat contrasting with the present European tendency to communicate traditional food nature through registration or proprietary standards. Traditional foods are generally a combination of energetic staples with other available ingredients; their intrinsic variability makes the definition of 'standard' recipes little more than an artefact of convenience; cross-country variations are determined by available ingredients, social conditions and nutritional needs. Commercial production requires some degree of raw material and process standardisation. New technologies and rules may stimulate traditional food evolution, but may also represent a barrier for local stakeholders. A trend to work within supply chains by local stakeholders was detected. Specific health promoting values were rarely perceived as a fundamental character. The stable inclusion of traditional food systems in present food supply chains requires a recovery of consumers' awareness of traditional food quality appreciation.

Glucosinolates in Diplotaxis and Eruca leaves: diversity, taxonomic relations and applied aspects

Leaf glucosinolates of 42 Diplotaxis and 21 Eruca accessions were studied. Total content ranged from 0.25 to more than 70 g kg(-1) dry wt. The 13 clusters, defined on the basis of glucosinolate composition, belonged to two glucosinolate-rich groups, characterised by the prevalence of a single component, and one low-glucosinolate group, with a profile not dominated by any individual component. A sinigrin-rich cluster (D. ibicensis, D. berthautii, D. ilorcitana, D. siettiana, D. tenuisiliqua, D. brevisiliqua, and D. virgata) and a gluconapin-rich cluster (D. catholica, D.siifolia, D. virgata, and D. ollivieri) included all the species previously classified in the nigra phylogenetic lineage. D. virgata was confirmed to be a critical taxon, with one accession slightly diverging from the others. D. siifolia subsp. vicentina was separated from the others in a glucobrassicin-rich cluster. D. harra, a rather isolated representative of sub-genus Hesperidium, clustered together D. assurgens in a sinalbin-rich cluster. Another well defined cluster was represented by D. brachycarpa (gluconasturtin). The two sub-species of D. erucoides were well differentiated by their glucosinolate profile. The low glucosinolate species: D. tenuifolia, D. viminea, D. cretacea, D. muralis (subgenus Diplotaxis), and E. vesicaria, all previously included in the rapa/oleracea lineage, belonged to seven less defined clusters, mainly differing on the presence/absence or the relative abundance of some components (glucoraphanin, glucolepidin, 4-hydroxy-glucobrassicin, 4-phenylbutyl gls, glucoerucin and neoglucobrassicin). The data support previous taxonomic works. Glucosinolate-rich taxa, with well characterised profiles may be suitable for industrial uses, whereas the variability of edible D. tenuifolia and E. vesicaria may represent a basis for breeding horticultural types.