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1.
The present study applied indicator value analysis as a novel approach to estimate honey authenticity: microscopic indicators of honey origin were identified based on the distinct fungal content of honeys from different sources. The abundance and the IndVal index of 34 selected fungal spore types were quantified in 82 melissopalynological honey samples originating from various honeydew (Pinus, Abies) or nectar sources using multivariate statistical approaches. A dissimilarity matrix of honey samples was obtained by computing Bray-Curtis coefficients, and the distances were visualized using non-metric multidimensional scaling. K-means clustering was applied to sample coordinates to create a classification based on the frequency of selected fungal taxa. Strikingly, the resulting clusters were on a high level of agreement with the melissopalynological or geographical classification of samples. Various fungal taxa were shown to characterize groups of honey samples with a significant indicator value: floral honeys (Metschnikowia reukaufii), Pinus honeydew honeys (Capnobotrys sp., Antennatula sp.), Abies honeydew honeys from Greece (staurospore and scolecospore types) and honeydew honeys from Italy (Tripospermum spp. and Excipularia fusispora). Having revealed that the mere presence of distinct fungal taxa can indicate differences in the botanical and geographical source of honeys, the present findings encourage the confirmation of honey origin also by recording the occurrence of given honeydew elements during routine melissopalynological analysis.  相似文献   

2.
The present study reveals the utility of high-performance thin-layer chromatographic (HPTLC) fingerprinting of phenolic constituents for the authentication of monofloral honeys. The obtained data enables a more complete assessment of honey quality and the identification of emerging threats to honey quality. The developed procedure facilitates differentiation of varietal honeys and detection of honey adulterations. We used an HPTLC fingerprint analysis to determine the characteristic patterns of different honey types (willow, buckwheat, heather, pine honeydew, and manuka honey). The HPTLC chromatograms were used to determine the differences in the botanical origin of the honey samples on the basis of the band profiles, which are characteristic for each honey type. Identification of 11 polyphenols was performed by comparison of the color and Rf of the bands with available standards. Additionally, the results were confirmed by an HPLC analysis.  相似文献   

3.
Differential scanning calorimetry (DSC) was used to study the thermal behavior of Colombian honeys produced by the honey-bee Apis mellifera and by three species of stingless bees: Melipona fuscipes, Melipona favosa favosa, and Melipona compressipes. The honey samples were collected every 2 months over the course of year (August 2014 to August 2015). Up to four thermal transitions (trs1–trs4a, trs4b) were found in the honey samples: M. fuscipes (trs1–trs4a), M. favosa (trs1–trs4a, trs4b), M. compressipes (trs1, trs3, trs4a), and A. mellifera (trs1, trs3, trs4a). Statistical analyses showed significant differences in enthalpies of each transition between species; therefore, DSC analysis can be used as a finger-print to differentiate the honeys of species.  相似文献   

4.
The aim of the present work was to investigate whether honeys of various botanical characteristics could be discriminated and identified on the basis of the isotopic data. For this purpose, 45 commercial honey samples of various botanical types were analyzed using isotope ratio mass spectrometry (IRMS) coupled to element analyzer (EA) and liquid chromatography (LC). δ 13C values of honey; corresponding extracted protein and individual sugars (sucrose, glucose, and fructose) of honey; reducing sugar; and sucrose contents were determined and utilized to demonstrate the authenticity of commercial honeys of different botanical types. Results indicated that a very strong correlation (δ 13Cprotein = 0.862δ 13Choney + 0.800, R 2 = 0.944) was observed between δ 13C honey values and δ 13C protein values of real honey samples. δ 13Choney and δ 13Cprotein should range from ?27.2 to ?23.5 and ?26.9 to ?23.6‰ for pure honeys of various botanical types investigated in this study. The use of isotopic compositions and some systematic differences as authenticity criterion permits the honey samples of various botanical types to be reliably detected.  相似文献   

5.
Pyrrolizidine alkaloids (PAs) are secondary plant compounds, which may be carried into honey by honey bees (Apis mellifera) and thus enter the human food chain. Depending on the quantity consumed, PAs are considered harmful to human health. At present, however, there is no statutory limit for PAs in foodstuffs. Because of several hints that larger occurrences of PA-containing tansy ragwort (Senecio jacobaea) may be responsible for PAs in summer honeys, honey samples from regions with and without tansy ragwort from all across Schleswig-Holstein were tested for their PA content (28 individual PAs) by LC-MS/MS analysis in 2014. By including honey samples from surroundings of flower plots established on arable land, it was tested if the carry-over of PAs into honey can be reduced by “distraction feed”. Samples from regions with tansy ragwort showed significantly higher PA contents than those from regions without tansy ragwort. Flower plots had no significant influence on the PA content. PAs were detected in 53.5 % of the 86 honey samples investigated. The mean PA value of PA-positive honeys was much higher than the median value since the sample comprised only few high and many low values. 28.6 % of the detected PAs were not from Senecio species, but from the Borage family (Boraginaceae) or Hemp Agrimony (Eupatorium cannabinum). In 2.3–15.1 % of the samples the limit value recommended by the BfR (Analytik und Toxizität von Pyrrolizidinalkaloiden sowie eine Einschätzung des gesundheitlichen Risikos durch deren Vorkommen in Honig. Stellungnahme Nr. 038/2011 des BfR vom 11. August 2011, ergänzt am 21. Januar 2013. Bundesinstitut für Risikobewertung [Hrsg.], Berlin: 37 S, 2013a) for different eating habits was exceeded. Because of the potential risk to human health, beekeepers and users of land with larger occurrences of tansy ragwort should take joint measures to keep the PA load in summer honeys as low as possible.  相似文献   

6.
The aim of the present study was to differentiate Greek thyme honeys according to geographical origin, based on phenolic compound content and conventional physicochemical parameters using MANOVA and Linear Discriminant Analysis. Thirty-five thyme honey samples were collected during the harvesting period 2011 from four different regions in Greece (Irakleio, Hania, Kefalonia and Lakonia) known to produce thyme honey of good quality. The analysis of phenolic compounds (quercetin, myricetin, kaempferol, chrysin, and syringic acid) was performed by high pressure liquid chromatography. Conventional quality parameter analysis included the determination of the following: pH, free, lactonic and total acidity, electrical conductivity, moisture, ash, as well as lactonic/free acidity ratio and colour parameters L*, a*, b*. Using five phenolic compounds and 11 conventional quality parameters, thyme honey samples were satisfactorily classified (91.2 % correct prediction) according to geographical origin.  相似文献   

7.
This work determines the radical scavenging activity of antioxidants and berry extracts based on the heat generated during their reaction with hydrogen peroxide, under isothermal condition (25 °C). After addition of H2O2 to a water solution containing antioxidants, an exothermic heat flow appeared. After an initial damping time, the signal decayed exponentially, following a first-order kinetic. Through an iterative fitting routine, both thermodynamic (ΔH) and kinetic (k) information were achieved. Such approach was applied toward relevant food antioxidants, revealing that the fastest reactivity (k) was for tannic acid > gallic acid > caffeic acid > ascorbic acid. Interestingly, k was inversely correlated with ΔH (r = ?0.96) and with the DPPH test (r = ?0.98). Apparently, strong radical scavengers show faster kinetics and lower ΔH-values, as expected, respectively, from a high reactivity toward peroxyl radical and efficient delocalization capacity. Such approach was finally applied to berry extracts (mixed grape seed and skin; chokeberries; grape seed; goji berries). The resulting ΔH-values were correlated with three indices, namely, total phenol, amperometry, and DPPH test. However, k-values largely deviated from these indices. Such discrepancy was explained considering that none of these indices is a “true” measure of the kinetic of the reaction, but only express an apparent concentration. Conversely, reaction calorimetry provides directly and simultaneously both thermodynamic and kinetic properties of the radical scavenging reactivity of antioxidants or natural extracts.  相似文献   

8.
Raw honeys from four different bee species, namely the honey bees and stingless bees, were classified based on its chemical profiles, mineral contents and heavy metals. Chemical profiles including proximate composition, predominant sugars, hydroxymethylfurfural content, and diastase activity were determined following official methods while mineral and heavy metals contents were obtained from atomic adsorption spectrometry (AAS) and inductively coupled plasma-mass spectrometry (ICP-MS) measurements, respectively. Both hierarchical cluster analysis and principal component analysis show high possibility of distinguishing honey by its bee species of honey bees (Apis spp.) and stingless bees (Heterotrigona itama) based on distinctive differences in chemical compositions and mineral contents. Potassium and sodium were the major elements in raw honey samples at average of 904.9 and 617.6 mg/kg, respectively. Honey from stingless bee contained more protein, 0.85 g/100 g and less total sugar of fructose and glucose at 24.99 g/100 g. The information of bee speciation origin of honey bees and stingless bees enhances the identity of honey on the product labelling.  相似文献   

9.
Summary In connection with investigations on flavour-related carbonyl compounds and the chemical classification of the geographical and floral origin of honey, the compound (S)-(+)-dehydrovomi folio [4-cyclohexene-3-one-6-hydroxy-1,1,5-trimethyl-6-(3oxo-l-butenyl)] was isolated from heather honey by HPLC and identified for the first time in honey by ultraviolet, infrared and nuclear-magnetic-resonance spectroscopy, mass spectrometry and polarimetry. After the isolation of the carbonyl compounds by derivatisation with Girard-T reagent and gas chromatography, heather honeys showed an (S)-(+)-dehy-drovomifoliol content of 56–264 mg/kg, whereas honeys from eight other floral origins contained only 0.033 to 6 mg/kg of this compound. The isolated compound was odourless, but the great difference in the (S)-(+)-dehydrovomifoliol content between heather honey and the honeys of other floral origin may offer the possibility of determining adulterations of heather honey.
Isolierung, Identifizierung und quantitative Bestimmung des NorisoprenoidsS-(+)-Dehydrovomifoliol im Honig
Zusammenfassung Im Zusammenhang mit Untersuchungen auf aromarelevante Carbonylverbindungen und der chemischen Charakterisierung der geographischen und floralen Herkunft von Honigen wurde die VerbindungS-(+)-Dehydrovomifoliol [6-Hydroxy-1, 1,5-trimethyl-6-(3-oxo-l-butenyl)-4-cyclohexen-3-on] hochdruckfüssigchromatographisch aus Heidehonig isoliert und mittels UV-, IR-, NMR-Spektroskopie, Massenspektrometrie und Polarimetrie erstmals in Honig identifiziert. Nach der Isolierung der Carbonylverbindungen mit Girard-T-Reagens and Gaschromatographie zeigten Heidehonige einenS-(+)-Dehy-drovomifoliolgehalt von 56–264 mg/kg, während Honige acht anderer Trachten lediglich Gehalte im Bereich von 33 g/kg bis 6 mg/kg aufwiesen. Die isolierte Verbindung war geruchslos. Der große Gehaltsunterschied zwischen Heidehonigen and Honigen anderer Trachten gestattet aber möglicherweise, Verfälschun-gen von Heidehonigen festzustellen.
  相似文献   

10.
Starch availability has been implicated in unripe matured banana (Musa species), which when processed yields flour suitable for application in low gluten and composite wheat formulations. Unripe Musa species: Williams, Luvhele, Mabonde and Muomva-red obtained from fruit bunch were pretreated with ascorbic, citric and lactic acids, processed into 50 g of flour and characterised for their functional and thermal properties. Scanning electron microscope of unripe banana flour (UBF) showed varying micrographs of flour, with polygonal for Luvhele, oval for Mabonde, elongated for Muomva-red and between polygonal and spherical for Williams. The bulk density of UBF samples was within the range of 0.66–0.84 g/mL for all organic acid pretreatment while citric acid pretreated UBF had the least browning index. Significant difference (p < 0.05) was recorded in swelling power with no significant difference in water solubility index except for Mabonde UBF. Thermal properties showed single endothermic transition for all UBF samples at various pretreatment concentration. The onset temperature (To) of UBF ranges from 49.82 to 65.59 °C, peak temperature (Tp) from 60.11 to 76.71 °C, conclusion temperature (Tc) from 70.36 to 94.16 °C and enthalpy of gelatinization (ΔH) from 2.61 to 32.24 J/g. Short amylopectin chains present in starch of UBF was attributed to low To, Tp, Tc and ΔH values recorded for Mabonde cultivar, while the contribution of heat-moisture treatment rather than organic acid pretreatment of UBF samples was attributed to different gelatinization and transition temperatures recorded for all cultivars examined.  相似文献   

11.
The objective of this study was to investigate the potential use of protein hydrolysate from yellow stripe trevally as a nitrogen source for the growth of different microorganisms. Protein hydrolysates from yellow stripe trevally with different degrees of hydrolysis (5, 15 and 25%) prepared using Alcalase (HA) or Flavourzyme (HF) were determined in comparison with commercial Bacto Peptone. For bacteria, Staphylococcus aureus and Escherichia coli, HF with 25% DH (HF25) yielded the highest cell density and specific growth rate (μ max) and the lowest generation time (t d) (p?Saccharomyces cerevisiae and Candida albicans, Bacto Peptone yielded the higher growth rate than did HA and HF (p?μ max and t d were observed for fungus, Aspergillus oryzae (p?>?0.05). The pH of culture broth containing HF25 decreased markedly during the first 8 hours of cultivation of S. aureus and E. coli (p?S. aureus (p?25 rendered the similar growth and colony size of S. aureus (p?>?0.05), compared with that containing Bacto Peptone. Scanning electron microscopic study revealed no differences in size and shape of microorganisms cultured in HF25 and Bacto Peptone (p?>?0.05).  相似文献   

12.
During come-up time (CUT), the time to reach a desired processing pressure, isobaric-isothermal conditions cannot be assumed in the estimation of kinetic parameters for the design of commercial high-pressure processing (HPP) treatments. Since CUT effects on microbial population, enzyme activity, and chemical concentration are often ignored, kinetic models incorporating the non-isobaric and non-isothermal conditions prevailing during CUT were the objective of this work. The analysis of peer-reviewed data on the HPP inactivation of bacteria (counts observations n = 919, 60 survival curves) and bacterial spores (n = 273, 12 curves) showed that a Gompertz model (GMPZ) approach is an effective alternative. The GMPZ parameter A was fixed as the difference between the initial population (log10 N o ) and the lower quantification limit of microbial counts (log10 N lim), while exponential equations were used to describe pressure effects on the lag time (λ) and the maximum inactivation rate (μmax). In low-acid media (pH > 4.5), λ decreased exponentially with pressure, allowing the identification of a theoretical pressure level (P λ) sufficient to initiate microbial inactivation during CUT. The parameter μmax exponentially increased with pressure for all evaluated datasets. Dynamic pressure effects during CUT were simplified by assuming isobaric conditions during CUT (t CUT), allowing to obtain GMPZ parameter estimates using only nonlinear regression (R 2 ~ 0.938, σ 2 = 0.030–0.604). The proposed approach is a simpler, promising tool for a more informative analysis of the kinetics of microbial inactivation by HPP and should be further validated with additional experimental data.  相似文献   

13.
Seeds from fruits such as Citrullus (C.) lanatus (watermelon) and Limonia (L.) acidissima (wood apple) are not commonly utilized but could be suitable in numerous food formulations. It was shown that the protein content of defatted seed flours was 71.38 and 49.51 % and that these contained considerable amounts of minerals such as Na, Mn, Mg, K, Cu, Fe and Zn. The defatted L. acidissima seed flour was superior to C. lanatus in essential amino acids. The flours obtained from both seeds were also evaluated for functional properties and characterized by X-ray diffraction, differential scanning calorimeter and scanning electron microscope (SEM). Amorphous nature was observed in defatted C. lanatus and L. acidissima flours due to the low percentage of degree of crystallinity. Spherical morphologies were observed through SEM. The exothermic peak was recorded in defatted C. lanatus and L. acidissima flour.  相似文献   

14.
This study aimed to understand the micromechanism of thermosonic pretreatment and microwave vacuum drying on Agaricus bisporus. The water state and glass transition temperature (T g ) of fresh and thermosonically treated Agaricus bisporus slices during microwave vacuum drying were studied using differential scanning calorimetry (DSC), low-field nuclear magnetic resonance (LF-NMR), and magnetic resonance imaging (MRI). Results showed that four population groups were contained in the initial distribution of transverse relaxation time (T 2) data of fresh A. bisporus slices: T 21 (0.38–7.05 ms), T 22 (9.33–32.75 ms), T 231 (37.65–265.61 ms), and T 232 (305.39–811.13 ms). Thermosonic pretreatment significantly decreased the initial free water content of A. bisporus sample but was accompanied by a sharp increase in its immobilized water. “Semi-bound water transfer” appeared during microwave vacuum drying (MVD) at moisture contents (X w ) of 0.70 and 0.60 g/g (wet basis (w.b.)) for untreated and thermosonically treated samples, respectively. MVD caused dramatic changes in the water state and enhanced the T g by decreasing the content and mobility of immobilized water in A. bisporus tissues. The mobility of semi-bound water for thermosonically and MVD-treated samples was higher than for MVD-untreated samples, resulting in T g values decreasing by approximately 2–11.5 °C, but the uniformity of water distribution in thermosonic-treated and MVD-treated samples was better at X w  ≤ 0.52 g/g (w.b.).  相似文献   

15.
A preliminary study revealed that a 10 µg/mL n-BuOH fraction of Malva verticillata aerial parts significantly enhanced splenocyte proliferation and induced significant enhancement of natural-killer (NK) cell activity against tumor cells (YAC-1). This study was initiated to identify the principal components that exhibited these activities, and four glycerides were isolated through repeated SiO2 and ODS column chromatography. Structures of compounds 14 were determined to be (2S)-1-O-palmitoyl glyceride, (2S)-1-O-stearoyl glyceride, (2S)-1-O-linolenoyl glyceride, and (2S)-1,2-di-O-linoleoyl glyceride, respectively. Compounds 13 showed potential immune-enhancing activity in murine splenocyte and natural-killer (NK) cells at 10 µM. In contrast, compound 4 showed weak activity, indicating the monoacyl glycerides (13) are more effective than diacyl glyceride (4). Also, the longer the carbon number of the fatty acid in monoacyl glyceride, the better the activity, and the monoacyl glyceride including an unsaturated fatty acid (3) is more effective than the glycerides including the saturated fatty acids (12).  相似文献   

16.
A modified diffusion-based mathematical model is proposed to describe the moisture movement during continuous and intermittent drying of Eucalyptus saligna. This model includes the temperature change, the surface drying coefficient (β n ) and 2 diffusion coefficients [from green to FSP (D f ) and from FSP to dry condition (D o )] as important parameters. The final model expression obtained was M?=?exp (??25 β n 2 D t /l2) with the β n used was 1.5807 kg m?2 s?1, the D f was 2.26?×?10?11 m2 s?1, and the D o was 5.85?×?10?12 m2 s?1. The range of temperature change between heating and non-heating phases in the intermittent drying regimes was from 24.9 to 31.8 °C. The R2 values obtained when the model was fitted into the drying data of different intermittent regimes ranged from 71.5 to 85.9%. The R2 value was 87.4% when the model was fitted into continuous trial data. The high values of R2 indicate that the model can be used to understand the moisture reduction both in intermittent and continuous regimes.  相似文献   

17.
18.
Cone yoghurt is a yoghurt variety produced by adding only pine cones to milk without culture in a limited area of Turkey. The present study was conducted to identify and characterize lactic flora in traditional cone yoghurt. Morphological, cultural, physiological, biochemical, and genotypic characteristics were employed to identify lactic acid bacteria isolates from cones and cone yoghurts. Streptococcus salivarius subsp. thermophilus (S. thermophilus) and Lactobacillus delbrueckii subsp. bulgaricus (L. bulgaricus) were obtained from both cones and yoghurts. Among the isolates, L. plantarum was frequently isolated except for these two bacteria (S. thermophilus and L. bulgaricus). The results indicate that the cone yoghurt has a mixed microflora contrary to the yoghurt produced by the addition of a starter culture and S. thermophilus, and L. bulgaricus in cone yoghurt originates from the pine cones.  相似文献   

19.
Storage potential and eating quality of guava (Psidium guajava L.) fruit depend on its maturity. Segregation of guava according to maturity and firmness measured using non-destructive technologies would help the industry to designate ripe fruit to immediate market and less ripe fruit for distant market (e.g., exportation). This research was conducted to evaluate the potential of experimental resonant frequency (f e) and elasticity index (EI) to estimate fruit firmness, which has been reported to be inversely correlated to its maturity. A maturity index (I m) was calculated as the ratio of total soluble solids/titratable acidity (TSS/TA). It was proved that TSS, TA, and I m were significantly correlated (P?<?0.05) to skin firmness (F s), flesh firmness (F f), stiffness (S), and analytical resonant frequency (ω n ), being S the attribute best fitted to I m (R 2?=?0.77). Since it was observed that f e and EI were sensitive to changes in fruit firmness, both of them were explored as alternatives to predict F s, F f, S, and ω n of guava fruit. In some cases, EI improved the models to predict guava firmness traits (e.g., F s vs f e had a coefficient of determination of R 2?=?0.58, whereas for F s vs EI, it was R 2?=?0.62). The best model occurred when plotting ω n vs f e (R 2?=?0.86), followed by S vs EI (R 2?=?0.84), making these promising features for the development of a new practical application using frequency response measurement as a non-destructive method to assess guava maturity.  相似文献   

20.
Biodegradable films of chia by-products (mucilage and protein-rich fraction (PF)) incorporated with clove essential oil (CEO) were obtained and characterized. The effects of polymer concentration (PC; 1.0–3.0 %, w/v) and CEO concentration (0.1–1.0 %, v/v) were evaluated as well as the pH (7–10), using a 23 factorial design with four central points. The films exhibited moisture values between 11.6 and 52.1 % (d.b.), which decreased (p?<?0.05) with increasing PC and CEO. The thickness of the films increased (p?<?0.05) with increasing PC. PC and pH influenced (p?<?0.05) the lightness (L) and variation in color between red and green (a). The orientation of the color to yellow-blue hues (b) decreased significantly (p?<?0.05) with increasing PC. Transparency was significantly lower and higher (p?<?0.05) than PC and CEO, respectively. The film surface morphology was evaluated using atomic force miscrocope images, and thermogravimetric analysis (TGA) was performed to study the thermal stability of the films. The displacement and tensile strength were significantly lower (p?<?0.05) at higher concentrations of CEO, this variable being the only one with a significant effect. The chemical composition of the films was confirmed utilizing Fourier transform infrared (FTIR) spectroscopy. The proportion of CEO added to the films had a significant influence on antimicrobial activity, inhibiting the growth of both Escherichia coli and Staphylococcus aureus.  相似文献   

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