Volatile profile, phytochemicals and antioxidant activity of virgin olive oils from Croatian autochthonous varieties Mašnjača and Krvavica in comparison with Italian variety Leccino

Virgin olive oils (VOOs) obtained from the fruits of Croatian autochthonous varieties Mašnjača and Krvavica were extensively characterized for the first time. Investigated oils were compared with the oil obtained from Italian variety Leccino, grown and processed under the same conditions. Headspace volatile profile, tocopherols, chlorophylls, carotenoids and total phenolic content, peroxide value, % acidity, K232, K270 as well as antioxidant activity (DPPH) of the oils’ hydrophilic fractions (HFs) including their phenolic composition were assessed by means of HS-SPME/GC-MS, HPLC-FL, HPLC-DAD and spectrophotometric methods, respectively. Most of the studied quality parameters varied between the cultivars. The main volatile compounds detected in all tested olive oils were the C6 compounds derived from polyunsaturated fatty acids through the lipoxygenase pathway. Krvavica oil was characterized by hexanal (8.8%–9.4%). Leccino oil contained the highest percentage of (E)-hex-2-enal (73.4%–74.0%), whereas (Z)-hex-3-enal (21.9%–25.0%) and (E)-hex-2-enal (27.6%–28.9%) dominated in Mašnjača oil. Leccino oil contained the highest amount of tocopherols (312.4 mg/kg), chlorophylls (7.3 mg/kg), carotenoids (4.2 mg/kg) and total phenols (246.6 mg/kg). The HF of Leccino oil showed the highest antioxidant capacity (1.3 mmol TEAC/kg), while the HFs of Mašnjača and Krvavica oils exhibited the activity of 0.5 mmol TEAC/kg

Chrysolina herbacea Modulates Terpenoid Biosynthesis of Mentha aquatica L.

Interactions between herbivorous insects and plants storing terpenoids are poorly understood. This study describes the ability of Chrysolina herbacea to use volatiles emitted by undamaged Mentha aquatica plants as attractants and the plant's response to herbivory, which involves the production of deterrent molecules. Emitted plant volatiles were analyzed by GC-MS. The insect's response to plant volatiles was tested by Y-tube olfactometer bioassays. Total RNA was extracted from control plants, mechanically damaged leaves, and leaves damaged by herbivores. The terpenoid quantitative gene expressions (qPCR) were then assayed. Upon herbivory, M. aquatica synthesizes and emits (+)-menthofuran, which acts as a deterrent to C. herbacea. Herbivory was found to up-regulate the expression of genes involved in terpenoid biosynthesis. The increased emission of (+)-menthofuran was correlated with the upregulation of (+)-menthofuran synthase

Headspace volatile profiles of willow (Salix spp.) nectar and honeydew honeys: identification of chemical biomarkers

Honey is an excellent nutritional food with health benefits. It has been used for the treatment of flue and common cold, healing of wounds and burns, as anti-microbial agent as well as the source of antioxidants [1,2]. Consumer preference, and hence the price of the honey, mainly depends on its botanical origin and organoleptic characteristics. Willow (Salix spp.) nectar and honeydew honey samples from Croatia are for the first time at the focus of this research and were characterized according to the National and EU regulations [3]. The assessment of honey botanical origin (besides melissopalynological analysis) now days is oriented toward finding marker compounds. Aroma profile is one of the most typical authenticity feature of the honey and therefore volatile component analyses of the samples were performed by means of headspace solid-phase microextraction (HS-SPME) followed by gas chromatography and mass spectrometry (GC, GC-MS). PDMS/DVB fiber coating was used and >50 compounds were identified. Willow nectar honey contained 3-methylbutanoic and 3-metltylpentanoic acids that may be considered as biomarkers as well as relatively high percentage of phenylacetonitrile and β-damascenone. Potential biomarkers of willow honeydew honey were 3-methylbutanoic and 2-methylbutanoic acids while found methyl salicylate was specific marker. Ubiquitous honey volatiles were also identified in all the samples such as hotrienol, benzaldehyde, cis- and trans-linalool oxides, lilac aldehydes and others. Acknowledgements: UKF grant 25/08, PIP, API-HERBA, KONCEPT MEDIA and GODAX-PRO. Refernces: [1] Cuevas-Glory,L. et al.(2007) Food Chem. 103:1032 - 1043. [2] Al-Mamary, M. et al. (2002) Nutr. Res. 22:1041 - 1047. [3] Official J. Eur. Communities CD2001/110/EC L10/47 - 52

HPLC-DAD fingerprinting and chemical characteristics of unifloral Croatian honeys

Monofloral honeys are products connected with defined botanic species and geographical areas. Croatia, due to its peculiar climate and specific botanical species, produces several unifloral honeys. The aim of this work was to develop a direct and accurate HPLC-DAD method to study the non volatile components of honeys in order to use the chromatographic profile as a marker of the monofloral origin of the Croatian honeys. Moreover, CIE L*C*h* (lightness, chroma, hue) chromatic coordinates, total phenols, diastase activity and 5-(hydroxymethyl)furfural (HMF) were determined. The antioxidant and antiradical activities of honeys were also evaluated with FRAP and DPPH tests, respectively [1]. Honey samples of Paliurus spina-christy, Salvia officinalis, Mentha spp., and Satureja honeys selected for this investigation were obtained from professional beekeepers. The melissopalynological and sensorial characteristics were evaluated as the first step to assess the botanical origin of the monofloral honeys. HPLC-DAD fingerprinting was performed with an HPLC Varian system ProStar using a Licrocart Purosher Star RP-18e column (250 x 4.0 mm 5 μm) and samples did not need any purification step. Absorbance was recorded in the range 200-600 nm and chromatograms were acquired at 280, 313 and 360 nm. Chromatograms obtained for the studied Croatian monofloral honeys showed strong differences according to the botanical origin, allowing to easily discriminating the studied honeys. Also L*C*h* chromatic coordinates proved to be useful to easily discriminate the studied honeys. Mentha spp. honeys showed the highest total polyphenols amount (702.1±26.6 mg/kg), antioxidant (6.47±0.59 mmol Fe2+/kg) and antiradical (1.81±0.38 mmol TEAC/kg) activities. HMF highest value was 15.1±0.7 mg/kg, while the lowest diastase activity was 11.9±1.1: those values respected the legal limit fixed by the EC [2] and indicate a proper way of production and storage. Acknowledgements: This paper was supported by UKF grant 25/08. References: 1. C. I.G. Tuberoso, E. Bifulco, et al. (2009) J. Agric. Food Chem. (in press); 2. Official J. Eur. Communities CD 2001/110/EC L10/47-52

Contribution to the characterization of honey-based Sardinian product abbamele: volatile aroma composition, honey marker compounds and antioxidant activity

Sardinian abbamele is a typical product obtained from the honey recuperation from combs (traditional procedure) or by concentration of the honey diluted in water (industrial procedure). Seven abbamele samples were obtained to study the volatiles' composition, the presence of honey marker compounds and their relationship with the production procedures. The long thermal treatment applied in abbamele production caused very high (1007.0-4405.8mg/kg) HMF content (HPLC-DAD), while glucose and fructose amounts were quite similar to the honey ones (HPLC-RI). Total antioxidant activity (FRAP assay) of the samples ranged between 13.3 and 71.2mmol Fe2+/kg, while antiradical activity (DPPH assay) ranged between 3.8 and 23.3mmol TEAC/kg. Such high antioxidant values were linearly correlated with total phenol amount (1297.8-4469.5mg GAE/kg) determined by Folin-Ciocalteau method. Thermally derived furan derivatives and terpenes were abundant among the headspace volatiles (HS-SPME), particularly limonene (0.5-76.0%) that probably originated from citrus rinds' addition during abbamele production. GC and GC-MS analyses of USE isolates revealed HMF predominance as well as the honey marker compounds (if/when existing) such as methyl syringate (up to 49.2%), marker of Asphodelus microcarpus honey. High isophorone percentage (up to 30.9%) determined by HS-SPME followed by minor percentage of 4-ketoisophorone and norisoprenoids in one sample indicated Arbutus unedo L. honey use in the production. HPLC-DAD analysis confirmed the presence of specific honey markers: two samples showed high methyl syringate concentrations (150.4-120.1mg/kg) while homogentisic acid and other specific markers of A. unedo honey were found in one sample. The compared GC-MS and HPLC-DAD data proved to be useful to obtain information about the use of specific honey in the production and to verify citrus addition

Volatile Compounds of Asphodelus microcarpus Salzm. et Viv. Honey Obtained by HS-SPME or USE and Analyzed by GC/MS

Chemical analysis of Asphodelus microcarpus Salzm. et Viv. honey is of great importance, since melissopalynology does not allow the unambiguous determination of its botanical origin. Therefore, the volatile compounds of eight unifloral asphodel honeys have been investigated for the first time. The honey extracts were obtained by headspace solid-phase microextraction (HS-SPME) and ultrasonic solvent extraction (USE) and analyzed by GC and GC/MS. In the honey headspace, 31 volatile compounds were identified with high percentages of 2-phenylacetaldehyde (2; 14.8-34.7%), followed by somewhat lower percentages of methyl syringate (1; 10.5-11.5%). Compound 2 is not a specific marker of the botanical origin of the honey, but its high percentage can be emphasized as headspace characteristic of asphodel honey. The extraction solvent for all the samples was selected after extracting a representative sample with pentane, Et 2O, pentane/Et 2O 1 : 2 (v/v), and CH 2Cl 2. Compound 1 was the major constituent of all the USE extracts (46.8-87.0%). According to these preliminary results, all the honey samples were extracted by USE with the solvent pentane/Et 2O 1 : 2. A total of 60 volatile compounds were identified with 1 as predominant compound (69.4-87.0%), pointing out 1 as Asphodelus honey volatile marker

Headspace, volatile and semi-volatile patterns of Paliurus spina–christi unifloral honey as markers of botanical origin

The samples of unifloral Paliurus spina-christi honey were analysed by means of headspace solid-phase microextraction (HS-SPME) and ultrasonic solvent extraction (USE) followed by gas chromatography and mass spectrometry (GC, GC-MS) in order to obtain complete patterns of headspace, volatile and semi-volatile compounds. In headspace pattern the most abundant compounds and possible markers were nonanal, four isomers of lilac aldehyde, decanal, methyl nonanoate, hexanoic and 2-ethylhexanoic acids. Although the main components of USE extracts were higher saturated aliphatic hydrocarbons, higher aliphatic alcohols and acids, they can not be considered reliable biomarkers due to their probable origin from bee wax or bee cuticle. Although present in small quantities, the more reliable markers in the extracts were benzene derivatives (particularly 4-hydroxy-3,5-dimethylbenzaldehyde, 4-hydroxybenzoic acid and 4-methoxybenzoic acid) along with lower aliphatic acids (butanoic, hexanoic, octanoic and nonanoic)