Evolution of volatile profile and aroma potential of 'Gold Finger' table grapes during berry ripening.

BACKGROUND: 'Gold Finger' is a grape cultivar with a finger-like shape and a milk flavor. The process by which its aroma profile evolves during ripening is unclear. Thus, changes in the free and bound volatile compounds present in 'Gold Finger' grapes during ripening were investigated using headspace sampling-solid-phase microextraction-gas chromatography-mass spectroscopy (HS-SPME-GC-MS). RESULTS: A total of 83 volatile aroma components were identified in the grapes, with aldehydes, esters, acids, and alcohols being the main components. The total aroma compound content exhibited significant differences between the bound and free forms. The total content of bound volatile compounds did not change significantly during fruit development, although the free aroma compound content was significantly higher than the bound content. The total content of free aldehydes, free alcohols, bound norisoprenoids, and ketones gradually increased for up to 70 days after flowering (DAF), while the total free ester, terpene, and acid content decreased. The characteristic aroma compounds of 'Gold Finger' grapes were identified as hexanal, (E)-2-hexenal, and ethyl hexanoate. CONCLUSIONS: These results give a foundation for the further development of 'Gold Finger' grapes and provide a theoretical basis for the selection and breeding of novel aromatic grape varieties. © 2021 Society of Chemical Industry.

Development of Analytical Strategies for the Determination of Olive Fruit Bioactive Compounds Using UPLC-HRMS and HPLC-DAD. Chemical Characterization of Kolovi Lesvos Variety as a Case Study.

In this study, an overall survey regarding the determination of several bioactive compounds in olive fruit is presented. Two methodologies were developed, one UPLC-Q-TOF-MS method for the determination of olive fruit phenolic compounds and one HPLC-DAD methodology targeting the determination of pigments (chlorophylls and carotenoids), tocopherols (α-, ß, -γ, δ-) and squalene. Target and suspect screening workflows were developed for the thorough fingerprinting of the phenolic fraction of olives. Both methods were validated, presenting excellent performance characteristics, and can be used as reliable tools for the monitoring of bioactive compounds in olive fruit samples. The developed methodologies were utilized to chemical characterize the fruits of the Kolovi olive variety, originating from the island of Lesvos, North Aegean Region, Greece. Twenty-five phenolic compounds were identified and quantified in Kolovi olives with verbascoside, hydroxytyrosol, oleacein and oleomissional found in significantly high concentrations. Moreover, 12 new bioactive compounds were identified in the samples using an in-house suspect database. The results of pigments analysis suggested that Kolovi variety should be characterized as low pigmentation, while the tocopherol and squalene content was relatively high compared to other olive varieties. The characterization of Kolovi olive bioactive content highlighted the high nutritional and possible economic value of the Kolovi olive fruit.

Shedding Light on the Volatile Composition of Broa, a Traditional Portuguese Maize Bread.

In Portugal, maize has been used for centuries to produce an ethnic bread called broa, employing traditional maize varieties, which are preferred by the consumers in detriment of commercial hybrids. In order to evaluate the maize volatiles that can influence consumers' acceptance of broas, twelve broas were prepared from twelve maize varieties (eleven traditional and one commercial hybrid), following a traditional recipe. All maize flours and broas were analyzed by HS-SPME-GC-MS (headspace solid-phase microextraction) and broas were appraised by a consumer sensory panel. In addition, the major soluble phenolics and total carotenoids contents were quantitated in order to evaluate their influence as precursors or inhibitors of volatile compounds. Results showed that the major volatiles detected in maize flours and broas were aldehydes and alcohols, derived from lipid oxidation, and some ketones derived from carotenoids' oxidation. Both lipid and carotenoids' oxidation reactions appeared to be inhibited by soluble phenolics. In contrast, phenolic compounds appeared to increase browning reactions during bread making and, consequently, the production of pyranones. Traditional samples, especially those with higher contents in pyranones and lower contents in aldehydes, were preferred by the consumer sensory panel. These findings suggest that, without awareness, consumers prefer broas prepared from traditional maize flours with higher contents in health-promoting phenolic compounds, reinforcing the importance of preserving these valuable genetic resources.

Characterizing the Volatile and Sensory Profiles, and Sugar Content of Beeswax, Beebread, Bee Pollen, and Honey.

Bee products are a well-known remedy against numerous diseases. However, from the consumers' perspective, it is essential to define factors that can affect their sensory acceptance. This investigation aimed to evaluate the volatile and sensory profiles, and sugar composition of beeswax, beebread, pollen, and honey. According to the HS-SPME/GC-MS results, 20 volatiles were identified in beeswax and honey, then 32 in beebread, and 33 in pollen. Alkanes were found to dominate in beeswax, beebread, and pollen, while aldehydes and monoterpenes in honey. In the case of sugars, a higher content of fructose was determined in beebread, bee pollen, and honey, whereas the highest content of glucose was assayed in beeswax. In the QDA, the highest aroma intensity characterized as honey-like and sweet was found in honey, while the acid aroma was typical of beebread. Other odor descriptors, including waxy, pungent, and plant-based aromas were noted only in beeswax, honey, and pollen, respectively.

Characteristic Volatile Composition of Seven Seaweeds from the Yellow Sea of China.

Plant volatile organic compounds (VOCs) represent a relatively wide class of secondary metabolites. The VOC profiles of seven seaweeds (Grateloupia filicina, Polysiphonia senticulosa, Callithamnion corymbosum, Sargassum thunbergii, Dictyota dichotoma, Enteromorpha prolifera and Ulva lactuca) from the Yellow Sea of China were investigated using multifiber headspace solid phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME/GC-MS), among them, the VOCs of three red algae Grateloupia filicina, Polysiphonia senticulosa, and Callithamnion corymbosum were first reported. Principal component analysis (PCA) was used to disclose characteristic categories and molecules of VOCs and network pharmacology was performed to predict potential biomedical utilization of candidate seaweeds. Aldehyde was found to be the most abundant VOC category in the present study and (E)-ß-ionone was the only compound found to exist in all seven seaweeds. The chemical diversity of aldehydes in E. prolifera suggest its potential application in chemotaxonomy and hinted that divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) fiber is more suitable for aldehyde extraction. VOCs in D. dichotoma were characterized as sesquiterpenes and diterpenes and the most relevant pharmacological pathway was the neuroactive ligand-receptor interaction pathway, which suggests that D. dichotoma may have certain preventive and therapeutic values in cancer, especially in lung cancer, in addition to neuropsychiatric diseases.

Anticancer Potential of Damnacanthal and Nordamnacanthal from Morinda elliptica Roots on T-lymphoblastic Leukemia Cells.

BACKGROUND: This study reports on the cytotoxic properties of nordamnacanthal and damnacanthal, isolated from roots of Morinda elliptica on T-lymphoblastic leukaemia (CEM-SS) cell lines. METHODS: MTT assay, DNA fragmentation, ELISA and cell cycle analysis were carried out. RESULTS: Nordamnacanthal and damnacanthal at IC50 values of 1.7 µg/mL and10 µg/mL, respectively. At the molecular level, these compounds caused internucleosomal DNA cleavage producing multiple 180-200 bp fragments that are visible as a "ladder" on the agarose gel. This was due to the activation of the Mg2+/Ca2+-dependent endonuclease. The induction of apoptosis by nordamnacanthal was different from the one induced by damnacanthal, in a way that it occurs independently of ongoing transcription process. Nevertheless, in both cases, the process of dephosphorylation of protein phosphates 1 and 2A, the ongoing protein synthesis and the elevations of the cytosolic Ca2+ concentration were not needed for apoptosis to take place. Nordamnacanthal was found to have a cytotoxic effect by inducing apoptosis, while damnacanthal caused arrest at the G0/G1 phase of the cell cycle. CONCLUSION: Damnacanthal and nordamnacanthal have anticancer properties, and could act as potential treatment for T-lymphoblastic leukemia.

Re-Analysis of Abdominal Gland Volatilome Secretions of the African Weaver Ant, Oecophylla longinoda (Hymenoptera: Formicidae).

The African weaver ant, Oecophylla longinoda, is used as a biological control agent for the management of pests. The ant has several exocrine glands in the abdomen, including Dufour's, poison, rectal, and sternal glands, which are associated with pheromone secretions for intra-specific communication. Previous studies have analyzed the gland secretions of Dufour's and poison glands. The chemistry of the rectal and sternal glands is unknown. We re-analyzed the secretions from Dufour's and poison glands plus the rectal and sternal glands to compare their chemistries and identify additional components. We used the solid-phase microextraction (SPME) technique to collect gland headspace volatiles and solvent extraction for the secretions. Coupled gas chromatography-mass spectrometry (GC-MS) analysis detected a total of 78 components, of which 62 were being reported for the first time. These additional components included 32 hydrocarbons, 12 carboxylic acids, 5 aldehydes, 3 alcohols, 2 ketones, 4 terpenes, 3 sterols, and 1 benzenoid. The chemistry of Dufour's and poison glands showed a strong overlap and was distinct from that of the rectal and sternal glands. The different gland mixtures may contribute to the different physiological and behavioral functions in this ant species.

Simultaneous isolation and selective encapsulation of volatile compounds from essential oil during electrospraying of ß-Cyclodextrin.

This study's primary purpose was to develop a new technique to stabilize high value-added bioactive volatile compounds present in essential oils to ensure their usability as chemical raw materials with enhanced stability. Selective isolation and encapsulation of various volatile compounds by changing the electrospraying process parameter, including voltage, flow rate, and ß-Cyclodextrin concentration, were attributed to the formation of inclusion complexes between ß-cyclodextrin and volatile compounds. Investigations regarding the effects of independent process variables on simultaneous isolation and selective encapsulation of volatile compounds during electrospraying of ß-cyclodextrins were carried out mainly with TLC analyses. The TLC analyses were confirmed with GC, GC-MS, and 1H NMR analyses. It was possible to obtain nanoparticles with an average particle size between 25-160 nm with the designed system. Obtained data revealed that isolation and encapsulation of cumin aldehyde, camphene, isoborneol, and hexadecanoic acid, benzyl benzoate from labdanum essential oil were successfully achieved.

Hybrid ZIF-8-90 for Selective Solid-Phase Microextraction of Exhaled Breath from Gastric Cancer Patients.

Metal-organic frameworks (MOFs) are a new kind of microporous materials whose unique properties make them promising as coatings for solid phase microextraction (SPME). However, previous MOF coatings for SPME exclusively focus on single-linker MOFs, and the selective enrichment of polar or nonpolar targets depends on the polarity of linker on the surface of MOFs, which greatly limits the application of MOF coating for SPME in real samples. Here, we report a hybrid MOF-coated stainless steel fiber for SPME of biomarkers in exhaled breath from gastric cancer patients. Zeolitic imidazolate framework-8-90 (ZIF-8-90) possesses the aldehyde groups and methyl groups in the framework as a model MOF, and eight biomarkers (ethanol, acetone, hexanal, hexanol, nonane, isoprene, heptane, and decane) were used as the target analytes. The ZIF-8-90-coated fiber shows high enrichment efficiency for hydrophilic targets and hydrophobic targets, wide linearity (three orders of magnitude), and low detection limits (0.82-2.64 µg L-1). The ZIF-8-90-coated fiber exhibited higher enrichment performance for all the investigated analytes as a result of the synergy of methyl and aldehyde groups, the porous structure, and the suitable pore size of ZIF-8-90 (4-5 Å). The relative standard deviation (RSD) of six repetitions for extractions using the same ZIF-8-90-coated fiber ranged from 2.5 to 7.3%. The reproducibility between the three fibers prepared in parallel varied in the range of 4.8-12% (RSD). The fabricated ZIF-8-90-coated fiber lasted for at least 120 cycles of extraction/desorption/conditioning without an obvious reduction in extraction efficiency and precision. Finally, the developed ZIF-8-90-coated SPME fiber has been successfully used for the analysis of exhaled breath samples from gastric patients with satisfied recoveries (88-106%).

YMR152W from Saccharomyces cerevisiae encoding a novel aldehyde reductase for detoxification of aldehydes derived from lignocellulosic biomass.

Aldehydes are the main inhibitors generated during the pretreatment of lignocellulosic biomass, which can inhibit cell growth and disturb subsequent fermentation. Saccharomyces cerevisiae has the intrinsic ability to in situ detoxify aldehydes to their less toxic or nontoxic alcohols by numerous aldehyde dehydrogenases/reductases during the lag phase. Herein, we report that an uncharacterized open reading frame YMR152W from S. cerevisiae encodes a novel aldehyde reductase with catalytic functions for reduction of at least six aldehydes, including two furan aldehydes (furfural and 5-hydroxymethylfurfural), three aliphatic aldehydes (acetaldehyde, glycolaldehyde, and 3-methylbutanal), and an aromatic aldehyde (benzaldehyde) with NADH or NADPH as the co-factor. Particularly, Ymr152wp displayed the highest specific activity (190.86 U/mg), and the best catalytic rate constant (Kcat), catalytic efficiency (Kcat/Km), and affinity (Km) when acetaldehyde was used as the substrate with NADH as the co-factor. The optimum pH of Ymr152wp is acidic (pH 5.0-6.0), but this enzyme is more stable in alkaline conditions (pH 8.0). Metal ions, chemical protective additives, salts, and substrates could stimulate or inhibit enzyme activities of Ymr152wp in varying degrees. Ymr152wp was classified into the quinone oxidoreductase (QOR) subfamily of the medium-chain dehydrogenase/reductase (MDR) family based on the results of amino acid sequence analysis and phylogenetic analysis. Although Ymr152wp was grouped into the QOR family, no quinone reductase activity was observed using typical quinones (9,10-phenanthrenequinone, 1,2-naphthoquinone, and p-benzoquinone) as the substrates. This study provides guidelines for exploring more uncharacterized aldehyde reductases in S. cerevisiae for in situ detoxification of aldehyde inhibitors derived from lignocellulosic hydrolysis.

Chemical Composition and Bioactivity of Essential Oil of Ten Labiatae Species.

Using antibiotics as feed additives have been successively banned worldwide from 1986; therefore, it is an urgent task to finding safe and effective alternatives. As natural products of plant origin, essential oils (EOs) are an outstanding option due to their reported bioactivity. In this research, ten EOs of Labiatae species were extracted by steam distillation and its chemical constituents were identified by gas chromatography-mass spectrometry (GC-MS). A total of 123 chemical compounds, including alkenes, phenols, aldehydes and ketones, were identified. The results of antioxidant activity carried out through DPPH free radical scavenging (DPPH) and ferric reducing antioxidant power (FRAP), showing that EOs of Ocimum basilicum Linn. (ObEO), Thymus mongolicus Ronn. (TmEO), Origanum vulgare Linn. (OvEO) and Mosla chinensis Maxim. (McEO) have strong antioxidant activities. Their 50%-inhibitory concentration (IC50) value was <1.00, 1.42, 1.47 and 1.92 µg/mL, respectively; and their FRAP value was 1536.67 ± 24.22, 271.84 ± 4.93, 633.71 ± 13.14 and 480.66 ± 29.90, respectively. The results of filter paper diffusion showing that McEO, OvEO and TmEO inhibition zone diameter (IZD) are all over 30 mm. The results of two-fold dilution method showed that McEO, OvEO and TmEO have strong antibacterial activities against Staphylococcus aureus (S. aureus) and their minimal inhibitory concentrations (MIC) value was 1 µL/mL, 2 µL/mL, and 2 µL/mL, respectively. In conclusion, the results in this work demonstrate the possibility for development and application of EOs as potential feed additives.

Green Route for the Isolation and Purification of Hyrdoxytyrosol, Tyrosol, Oleacein and Oleocanthal from Extra Virgin Olive Oil.

Extra virgin olive oil (EVOO) phenols represent a significant part of the intake of antioxidants and bioactive compounds in the Mediterranean diet. In particular, hydroxytyrosol (HTyr), tyrosol (Tyr), and the secoiridoids oleacein and oleocanthal play central roles as anti-inflammatory, neuro-protective and anti-cancer agents. These compounds cannot be easily obtained via chemical synthesis, and their isolation and purification from EVOO is cumbersome. Indeed, both processes involve the use of large volumes of organic solvents, hazardous reagents and several chromatographic steps. In this work we propose a novel optimized procedure for the green extraction, isolation and purification of HTyr, Tyr, oleacein and oleocanthal directly from EVOO, by using a Natural Deep Eutectic Solvent (NaDES) as an extracting phase, coupled with preparative high-performance liquid chromatography. This purification method allows the total recovery of the four components as single pure compounds directly from EVOO, in a rapid, economic and ecologically sustainable way, which utilizes biocompatible reagents and strongly limits the use or generation of hazardous substances.

Determination of malondialdehyde, acrolein and four other products of lipid peroxidation in edible oils by Gas-Diffusion Microextraction combined with Dispersive Liquid-Liquid Microextraction.

A new and sensitive analytical method for the simultaneous determination of secondary lipid peroxidation aldehydes has been successfully developed and validated. Malondialdehyde, acrolein, formaldehyde, acetaldehyde, propanal, and pentanal were extracted and derivatized using 2,4-dinitrophenylhydrazine (DNPH) by gas-diffusion microextraction (GDME) combined with dispersive liquid-liquid microextraction (DLLME) for gas chromatography-mass spectrometry (GC-MS) analysis. The experimental conditions have been optimized by experimental designs. The analytical method validation, in accordance to the Food and Drug Administration (FDA) guidance, provided good results in terms of linearity with r2≥0.9974, in the range from 0.15 or 0.3 µg·g-1 to 3 µg·g-1. Limits of detection and limits of quantification were 0.05 or 0.10 and 0.15 or 0.3 µg·g-1, respectively. Precision was tested as a relative standard deviation (RSD≤ 9.5%) and recoveries were between 95% and 110%. The method was applied in the characterization of aldehydes in forty-eight edible oil samples; with the highest concentration found in pomace olive oil for malondialdehyde at 6.64 µg·g-1.

Chemical Components and Antibacterial Activity of the Essential Oil of Six Pyrrosia Species.

The present study was aimed at analyzing the chemical components of the essential oil from six Pyrrosia species by GC/MS and evaluating their in vitro antibacterial activities. Seventy volatile compounds were identified in the essential oil of six Pyrrosia samples. The identified volatile components were divided into following nine categories: aldehydes, terpenoids, fatty acids, ketones, furans, hydrocarbons, alcohols, esters, and phenols. The major components of the essential oil were 2,4-pentadienal, phytol and nonanal. The antimicrobial assays showed that the essential oils from Pyrrosia samples exhibited a broad-spectrum antimicrobial activity. However, P. lingua had the highest antibacterial activity against Staphylococcus aureus (ATCC 25923) with a minimum inhibitory concentration (MIC) of 2.5 µL/mL. This article is the first report of the chemical components and antimicrobial activity of the essential oil from six Pyrrosia species, which will lay the foundation for developing medicinal resources from Pyrrosia fronds.

Removal of Trans-2-nonenal Using Hen Egg White Lysosomal-Related Enzymes.

2-Nonenal is a long-chain aliphatic aldehyde containing nine carbons and an unsaturated bond. 2-Nonenal is the primary cause of odor associated with aging, with an unpleasant greasy and grassy odor. Lysosome, mitochondria, and peroxisome are significant organelles in eukaryotic cells that contain various hydrolases that degrade biomolecules. Proteins in mitochondria and peroxisome also contain aldehyde dehydrogenase. We performed trans-2-nonenal treatment using lysosomal-related enzymes extracted from hen egg white (HEW). As trans-2-nonenal is more structurally stable than cis-2-nonenal, it was selected as the target aldehyde. HEW contains various biologically active proteins and materials such as albumin, ovotransferrin, lysosome, peroxisome, and mitochondria. Here, complementary experiments were conducted to evaluate the role of lysosomal-related enzymes in the treatment of trans-2-nonenal. The activity of lysosomal-related enzymes was confirmed via antimicrobial test against E. coli. HPLC analysis was used to determine the reduction of trans-2-nonenal. The trans-2-nonenal treatment depended on the reaction time and enzyme concentration. Materials considered as an intermediate from trans-2-nonenal treatment were detected by GC/MS spectrometer. Under acidic conditions (pH 6), lysosomal-related enzymes were the most efficient in the treatment of trans-2-nonenal. Furthermore, based on differential pH testing, we found the conditions under which all the 50 ppm trans-2-nonenal was removed. Therefore, our results suggest that the lysosomal-related enzymes reduced trans-2-nonenal, suggesting clinical application as anti-aging deodorants.

(-)-Oleocanthal as a Dual c-MET-COX2 Inhibitor for the Control of Lung Cancer.

Lung cancer (LC) represents the topmost mortality-causing cancer in the U.S. LC patients have overall poor survival rate with limited available treatment options. Dysregulation of the mesenchymal epithelial transition factor (c-MET) and cyclooxygenase 2 (COX2) initiates aggressive LC profile in a subset of patients. The Mediterranean extra-virgin olive oil (EVOO)-rich diet already documented to reduce multiple malignancies incidence. (-)-Oleocanthal (OC) is a naturally occurring phenolic secoiridoid exclusively occurring in EVOO and showed documented anti-breast and other cancer activities via targeting c-MET. This study shows the novel ability of OC to suppress LC progression and metastasis through dual targeting of c-MET and COX-2. Western blot analysis and COX enzymatic assay showed significant reduction in the total and activated c-MET levels and inhibition of COX1/2 activity in the lung adenocarcinoma cells A549 and NCI-H322M, in vitro. In addition, OC treatment caused a dose-dependent inhibition of the HGF-induced LC cells migration. Daily oral treatment with 10 mg/kg OC for 8 weeks significantly suppressed the LC A549-Luc progression and prevented metastasis to brain and other organs in a nude mouse tail vein injection model. Further, microarray data of OC-treated lung tumors showed a distinct gene signature that confirmed the dual targeting of c-MET and COX2. Thus, the EVOO-based OC is an effective lead with translational potential for use as a prospective nutraceutical to control LC progression and metastasis.

The characteristic smell emitted from two scale insects, Ceroplastes japonicus and Ceroplastes rubens.

The volatile components emitted from two scale insects, Ceroplastes japonicus and Ceroplastes rubens, were identified using GC-MS analysis. The major volatile components of the solvent extract from C. japonicus were α-humulene (35.8%) and δ-cadinene (17.0%), while those of C. rubens were ß-selinene (10.3%) and ß-elemene (5.1%). In GC/olfactometry, linalool, butyric acid, 3-methylbutyric acid, 2-methylbutyric acid, and vanillin were identified as the odor-active components of the extract from C. japonicus, in addition to trace amounts of trans-4,5-epoxy-(2E)-decenal, 4-methyl-(3E)-hexenoic acid, and phenylacetic acid. With regard to C. rubens, trans-4,5-epoxy-(2E)-decenal, 3-methylbutyric acid, and phenylacetic acid were identified as the odor-active components. Besides, decan-1,4-olide (γ-decalactone) with milky cherry-like note and 3-hydroxy-4,5-dimethylfuran-2(5H)-one (sotolone) with brown sugar-like note were also detected as the characteristic cherry-like sweet-and-sour note of these two scale insects. ABBREVIATIONS: GC: Gas chromatography; GC/O: gas chromatography/olfactometry.

Volatile Profile in Yogurt Obtained from Saanen Goats Fed with Olive Leaves.

The aim of this study was to evaluate the development of volatile compounds in yogurt samples obtained from goats fed a dietary supplementation with olive leaves (OL). For this purpose, thirty Saanen goats were divided into two homogeneous groups of 15 goats each: a control group that received a standard diet (CG) and an experimental group whose diet was supplemented with olive leaves (OLG). The trial lasted 28 days, at the end of which the milk of each group was collected and used for yogurt production. Immediately after production, and after 7 days of storage at 4 °C in the absence of light, the yogurt samples were characterized in terms of fatty acid profile, oxidative stability and volatile compounds by the solid-phase microextraction (SPME)-GC/MS technique. Dietary OL supplementation positively affected the fatty acid composition, inducing a significant increase in the relative proportion of unsaturated fatty acids, mainly oleic acid (C18:1 cis9) and linolenic acid (C18:3). With regard to the volatile profile, both in fresh and yogurt samples stored for 7 days, the OL supplementation induced an increase in free fatty acids, probably due to an increase in lipolysis carried out by microbial and endogenous milk enzymes. Specifically, the largest variations were found for C6, C7, C8 and C10 free fatty acids. In the same samples, a significant decrease in aldehydes, mainly heptanal and nonanal, was also detected, supporting-at least in part-an improvement in the oxidative stability. Moreover, alcohols, esters and ketones appeared lower in OLG samples, while no significant variations were observed for lactones. These findings suggest the positive role of dietary OL supplementation in the production of goats' milk yogurt, with characteristics potentially indicative of an improvement in nutritional properties and flavor.

Influence of Harvest Time and Malaxation Conditions on the Concentration of Individual Phenols in Extra Virgin Olive Oil Related to Its Healthy Properties.

The phenolic fraction of the extra virgin olive oil (EVOO) has been studied over the past two decades because of its important health protective properties. Numerous studies have been performed in order to clarify the most crucial factors that affect the concentration of the EVOO's phenolic fraction and many contradictory results have been reported. Having as target to maximize the phenolic content of EVOO and its healthy properties we investigated the impact of harvest time, malaxation temperature, and malaxation duration on the concentration of individual phenols in extra virgin olive oil. Olive oil was prepared in a lab-scale olive mill from different varieties in Greece. The extraction process for cultivar (cv) Koroneiki samples was performed at five different harvest periods from the same trees with three different malaxation temperatures and five different malaxation duration times (N = 75). Similar types of experiments were also performed for other varieties: cv Athenolia (N = 20), cv Olympia (N = 3), cv Kalamata (N = 3), and cv Throubolia Aegean (N=3) in order to compare the changes in the phenolic profile during malaxation. The quantitative analysis of the olive oil samples with NMR showed that the total phenolic content has a negative correlation with the ripening degree and the malaxation time. The NMR data we collected helped us to quantitate not only the total phenolic content but also the concentration of the major phenolic compounds such as oleocanthal, oleacein, oleokoronal, and oleomissional. We noticed different trends for the concentration of these phenols during malaxation process and for different malaxation temperatures. The different trends of the concentration of the individual phenols during malaxation and the completely different behavior of each variety revealed possible biosynthetic formation steps for oleocanthal and oleacein and may explain the discrepancies reported from previous studies.

Effect of fruit maturity on volatiles and sensory descriptors of four mandarin hybrids.

Mandarins (or tangerines) are mainly consumed as fresh fruits due to the ease of peeling and desirable flavor. Sweetness, acidity, and flavor of mandarin are the most important criteria for consumer preference. The objective of this study was to evaluate the effects of harvest date on sensory and chemical components of four mandarin cultivars (Murcott, 411, Temple, and 'LB8-9' Sugar Belle®). Volatiles were extracted from the headspace of juice samples with solid phase microextraction (SPME) and analyzed using gas chromatography-mass spectrometry (GC-MS). The optimum harvest window for eating quality of 411 was late January to mid-February (soluble solids content [SSC]/titratable acidity [TA]: 11.3 to 14.0), Sugar Belle® fruits were best tasted when harvested from mid- to end of January (SSC/TA: 14.1 to 16.1), and February was the best month for harvesting Murcott (SSC/TA: 13.10 to 18.0) and Temple (SSC/TA:10.3 to 12.50). Sensory perception of sweetness, ripeness, and juiciness increased as SSC/TA increased while sourness and bitterness decreased. Pumpkin flavor, an indicator of overripe fruit, was mainly noticed late in the season. Tangerine flavor tended to decrease, whereas fruity-noncitrus flavor tended to increase with fruit maturity. Monoterpenes were the most abundant volatiles and tended to decrease with fruit maturity, whereas alcohols, esters, and aldehydes increase. Aldehydes, esters, and alcohols were positively correlated with sweetness, ripeness, juiciness, and fruity characteristics, and negatively with sourness and bitterness. On the other hand, monoterpenes were positively correlated with bitterness and tangerine flavor, and negatively correlated with sweetness and fruity-noncitrus flavor. The highest number of esters was found in Temple, whereas Murcott and 411 were high in aldehydes.