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1.
Spectrochim Acta A Mol Biomol Spectrosc ; 283: 121766, 2022 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-35988468

RESUMEN

Essential oil distilled from Melaleuca alternifolialeaves, commonly known as tea tree oil, is well known for its biological activity, principally its antimicrobial properties. However, many samples are adulterated with other, cheaper essential oils such as eucalyptus oil. Current methods of detecting such adulteration are costly and time-consuming, making them unsuitable for rapid authentication screening. This study investigated the use of mid-infrared (MIR) spectroscopy for detecting and quantifying the level of eucalyptus oil adulteration in spiked samples of pure Australian tea tree oil. To confirm the authenticity of the tea tree oil samples, GC-MS analysis was used to profile 37 of the main volatile constituents present, demonstrating that the samples conformed to ISO specifications. Three chemometric regression techniques (PLSR, PCR and SVR) were trialled on the MIR spectra, along with a variety of pre-processing techniques. The best-performing full-wavelength PLSR model showed excellent prediction of eucalyptus oil content, with an R2CV of 0.999 and RMSECV of 1.08 % v/v. The RMSECV could be further improved to 0.82 % v/v through a moving window wavenumber optimisation process. The results suggest that MIR spectroscopy combined with PLSR can be used to predict eucalyptus oil adulteration in Australian tea tree oil samples with a high level of accuracy.


Asunto(s)
Melaleuca , Aceites Volátiles , Aceite de Árbol de Té , Australia , Aceite de Eucalipto , Melaleuca/química , Aceites Volátiles/química , Espectrofotometría Infrarroja , Aceite de Árbol de Té/química
2.
Molecules ; 27(10)2022 May 19.
Artículo en Inglés | MEDLINE | ID: mdl-35630725

RESUMEN

The number of food frauds in coconut-based products is increasing due to higher consumer demands for these products. Rising health consciousness, public awareness and increased concerns about food safety and quality have made authorities and various other certifying agencies focus more on the authentication of coconut products. As the conventional techniques for determining the quality attributes of coconut are destructive and time-consuming, non-destructive testing methods which are accurate, rapid, and easy to perform with no detrimental sampling methods are currently gaining importance. Spectroscopic methods such as nuclear magnetic resonance (NMR), infrared (IR)spectroscopy, mid-infrared (MIR)spectroscopy, near-infrared (NIR) spectroscopy, ultraviolet-visible (UV-VIS) spectroscopy, fluorescence spectroscopy, Fourier-transform infrared spectroscopy (FTIR), and Raman spectroscopy (RS) are gaining in importance for determining the oxidative stability of coconut oil, the adulteration of oils, and the detection of harmful additives, pathogens, and toxins in coconut products and are also employed in deducing the interactions in food constituents, and microbial contaminations. The objective of this review is to provide a comprehensive analysis on the various spectroscopic techniques along with different chemometric approaches for the successful authentication and quality determination of coconut products. The manuscript was prepared by analyzing and compiling the articles that were collected from various databases such as PubMed, Google Scholar, Scopus and ScienceDirect. The spectroscopic techniques in combination with chemometrics were shown to be successful in the authentication of coconut products. RS and NMR spectroscopy techniques proved their utility and accuracy in assessing the changes in coconut oil's chemical and viscosity profile. FTIR spectroscopy was successfully utilized to analyze the oxidation levels and determine the authenticity of coconut oils. An FT-NIR-based analysis of various coconut samples confirmed the acceptable levels of accuracy in prediction. These non-destructive methods of spectroscopy offer a broad spectrum of applications in food processing industries to detect adulterants. Moreover, the combined chemometrics and spectroscopy detection method is a versatile and accurate measurement for adulterant identification.


Asunto(s)
Cocos , Espectrometría Raman , Aceite de Coco , Aceites de Plantas/análisis , Espectroscopía Infrarroja por Transformada de Fourier/métodos
3.
Food Chem ; 358: 129833, 2021 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-33933967

RESUMEN

This study identified and quantified hydrolysable tannins (HTs) in Terminalia ferdinandiana Exell (Kakadu plum) fruit, freeze dried powder extracted with 80% aqueous acetone (AA) and 80% aqueous acidified ethanol (AAE), using UHPLC-Q/Orbitrap/MS/MS. The vitamin C and ellagic acid were quantified by UHPLC-PDA. A total of seven HTs were identified: corilagin, 3,4,6-tri-O-galloyl-ß-d-glucose, elaeocarpusin, chebulinic acid, chebulagic acid, helioscopin B, and punicalagin, with five classified as ellagitannins. The two extracts AA and AAE, comprised of gallic acid (2.5 and 2.2 mg/g DW), punicalagins α and ß (2.8 and 1.3 mg/g DW), respectively, and both contained ellagic acid (~4 g/100 g DW). These extracts showed high antioxidant properties and strong antimicrobial effects against methicillin-resistant Staphylococcus aureus clinical isolate, Staphylococcus aureus, and Shewanella putrefaciens. These results suggest that Kakadu plum fruit is a rich, edible source of ellagitannins, ellagic acid and vitamin C with potential applications in food, cosmetic and nutraceutical industries.


Asunto(s)
Antibacterianos/farmacología , Antioxidantes/farmacología , Taninos Hidrolizables/química , Taninos Hidrolizables/farmacología , Terminalia/química , Antibacterianos/química , Antioxidantes/química , Etanol/química , Liofilización , Frutas/química , Glucósidos/análisis , Glucósidos/química , Taninos Hidrolizables/análisis , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Extractos Vegetales/química , Polvos , Solventes , Espectrometría de Masas en Tándem
4.
Sensors (Basel) ; 21(4)2021 Feb 18.
Artículo en Inglés | MEDLINE | ID: mdl-33670523

RESUMEN

Kakadu plum (KP; Terminalia ferdinandiana Exell, Combretaceae) is an emergent indigenous fruit originating from Northern Australia, with valuable health and nutritional characteristics and properties (e.g., high levels of vitamin C and ellagic acid). In recent years, the utilization of handheld NIR instruments has allowed for the in situ quantification of a wide range of bioactive compounds in fruit and vegetables. The objective of this study was to evaluate the ability of a handheld NIR spectrophotometer to measure vitamin C and ellagic acid in wild harvested KP fruit samples. Whole and pureed fruit samples were collected from two locations in the Kimberley region (Western Australia, Australia) and were analysed using both reference and NIR methods. The standard error in cross validation (SECV) and the residual predictive deviation (RPD) values were 1.81% dry matter (DM) with an RPD of 2.1, and 3.8 mg g-1 DM with an RPD of 1.9 for the prediction of vitamin C and ellagic acid, respectively, in whole KP fruit. The SECV and RPD values were 1.73% DM with an RPD of 2.2, and 5.6 mg g-1 DM with an RPD of 1.3 for the prediction of vitamin C and ellagic acid, respectively, in powdered KP samples. The results of this study demonstrated the ability of a handheld NIR instrument to predict vitamin C and ellagic acid in whole and pureed KP fruit samples. Although the RPD values obtained were not considered adequate to quantify these bioactive compounds (e.g., analytical quantification), this technique can be used as a rapid tool to screen vitamin C in KP fruit samples for high and low quality vitamin C.


Asunto(s)
Prunus domestica , Terminalia , Ácido Ascórbico , Australia , Frutas
5.
J Microbiol Methods ; 182: 106169, 2021 03.
Artículo en Inglés | MEDLINE | ID: mdl-33596404

RESUMEN

Different types of susceptibility tests are available to identify antimicrobial activity, including the disc agar diffusion and broth micro-dilution methods. In recent years, high throughput screening (HTS) methods have been considered and evaluated as an efficient method to rapidly monitor the antimicrobial potential of a wide range of plant products. The objective of this study was to test the ability of a 96-well plate reader as HTS method to evaluate the antimicrobial potential of extracts of Terminalia ferdinandiana (Kakadu plum). The main changes observed in the UV-VIS spectra of the bacteria samples were related to the biochemical and chemical compounds that might originate from the effect of the T. ferdinandiana extracts and the bacteria. Partial least squares discriminant analysis (PLS-DA) allowed the correct classification of samples according to the concentration of extract added to the culture (e.g. high, medium and low). The results of this study indicated that might be possible to record changes in the UV-VIS spectra associated with the interactions between bacteria and T. ferdinandiana extracts using a 96-well plate reader. The method was able to detect or differentiate between live and dead bacteria based on the UV-VIS spectra as a function of the addition of the T. ferdinandiana extracts.


Asunto(s)
Antibacterianos , Bacterias/efectos de los fármacos , Frutas/química , Extractos Vegetales , Terminalia/química , Antibacterianos/química , Antibacterianos/farmacología , Extractos Vegetales/química , Extractos Vegetales/farmacología , Prueba de Estudio Conceptual
6.
Appl Spectrosc ; 75(7): 834-838, 2021 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-33464155

RESUMEN

In recent years, the native food industry in Australia has increased in both value and volume due to the discovery of a wide range of phytochemicals (e.g., vitamin C, polyphenols) that have potential health benefits. Thus, plant organs and tissues of these native plants are used in a wide range of applications. In particular, the kernel of a native plum, the Kakadu plum (Terminalia ferdinandiana, Combretaceae) is considered to be rich in lipids and other phytochemical compounds. The aim of this study was to evaluate the use of NIR spectroscopy to analyze and characterize kernel samples and tissues of wild harvest fruit samples. The Fourier transform near-infrared reflectance spectra of cracked kernels, seeds cover tissues, and dry powder Kakadu plum kernels were acquired. Both principal component analysis and partial least squares discriminant analysis were used to analyze and interpret the spectral data. A correct classification rate of 93%, 86%, and 80% was achieved for the identification of kernel provenance using all tissues, seed coats, and the whole nuts, respectively. The results of this study reported for the first time the analysis of Kakadu plum kernels and their tissues using NIR spectroscopy.


Asunto(s)
Prunus domestica , Terminalia , Ácido Ascórbico , Frutas , Espectroscopía Infrarroja Corta
7.
J Sci Food Agric ; 101(8): 3208-3213, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33215708

RESUMEN

BACKGROUND: The objective of this study was to evaluate the feasibility of using either mid-infrared (MIR) or near-infrared (NIR) spectroscopy to predict the vitamin C content in Kakadu plum (Terminalia ferdinandiana Exell, Combretaceae) powder samples. Vitamin C is the main and quality-determining bioactive compound in Kakadu plum (KP). Kakadu plum powder samples were analyzed by ultra-performance liquid chromatography coupled to a photodiode array detector (UPLC-PDA) and scanned using both MIR and NIR spectroscopy. RESULTS: The coefficient of determination (R2 ) and the standard error in cross validation (SECV) for vitamin C were 0.93 and 1811 mg 100 g dry weight (DW) and 0.91 and 1839 mg 100 g DW using MIR and NIR spectroscopy, respectively. The coefficient of correlation and the standard error of prediction (SEP) obtained using the independent set (n = 5) were 0.65 (SEP: 2367 mg 100 g DW) and 0.73 (SEP: 4773 mg 100 g DW) using MIR and NIR spectroscopy, respectively. CONCLUSIONS: The results obtained in this study clearly showed that it is possible to calibrate IR spectroscopic instruments for the measurement of vitamin C in KP plum powder samples. Mid-infrared spectroscopy showed the most promising results; however, Fourier transform near-infrared (FTNIR) spectroscopy also produced models capable of good quantification of this important bioactive compound and vitamin. These findings are promising in terms of using high-throughput IR spectroscopy as a routine technology to determine vitamin C in plant-based foods and derived products. © 2020 Society of Chemical Industry.


Asunto(s)
Ácido Ascórbico/análisis , Análisis de los Alimentos/métodos , Extractos Vegetales/análisis , Terminalia/química , Polvos/química , Espectroscopía Infrarroja Corta/métodos
8.
Spectrochim Acta A Mol Biomol Spectrosc ; 247: 119121, 2021 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-33160133

RESUMEN

The effect of drying (oven and freeze-drying) and the addition of maltodextrin as a carrier to Kakadu plum (Terminalia ferdinandiana) puree powder samples were evaluated using a combination of two dimensional (2DCOS) and near infrared (NIR) spectroscopy. Fruit powder samples were obtained from an experiment where oven and freeze-drying methods were compared together with the addition of seven levels of maltodextrin to the samples (control, 5, 7.5, 10, 15, 20 and 25% w/w). Samples were scanned using a FT-NIR instrument (Tango, Bruker, Germany) and data analysed using 2DCOS. Asynchronous and synchronous 2DCOS spectroscopy were used to analyse and interpret the effects of the method of drying and the addition of maltodextrin on the NIR spectra of the fruit samples. The utilization of 2DCOS combined with NIR spectroscopy showed how the drying method affect the NIR spectra and thus the main implications of developing an effective, quick, and easy to use protocol for determining the drying method.


Asunto(s)
Prunus domestica , Espectroscopía Infrarroja Corta , Desecación , Liofilización , Polisacáridos , Polvos
9.
ACS Nano ; 14(1): 802-817, 2020 01 28.
Artículo en Inglés | MEDLINE | ID: mdl-31922722

RESUMEN

Antibiotic resistance has made the treatment of biofilm-related infections challenging. As such, the quest for next-generation antimicrobial technologies must focus on targeted therapies to which pathogenic bacteria cannot develop resistance. Stimuli-responsive therapies represent an alternative technological focus due to their capability of delivering targeted treatment. This study provides a proof-of-concept investigation into the use of magneto-responsive gallium-based liquid metal (LM) droplets as antibacterial materials, which can physically damage, disintegrate, and kill pathogens within a mature biofilm. Once exposed to a low-intensity rotating magnetic field, the LM droplets become physically actuated and transform their shape, developing sharp edges. When placed in contact with a bacterial biofilm, the movement of the particles resulting from the magnetic field, coupled with the presence of nanosharp edges, physically ruptures the bacterial cells and the dense biofilm matrix is broken down. The antibacterial efficacy of the magnetically activated LM particles was assessed against both Gram-positive and Gram-negative bacterial biofilms. After 90 min over 99% of both bacterial species became nonviable, and the destruction of the biofilms was observed. These results will impact the design of next-generation, LM-based biofilm treatments.


Asunto(s)
Antibacterianos/farmacología , Biopelículas/efectos de los fármacos , Galio/farmacología , Pseudomonas aeruginosa/efectos de los fármacos , Staphylococcus aureus/efectos de los fármacos , Antibacterianos/química , Galio/química , Fenómenos Magnéticos , Pruebas de Sensibilidad Microbiana , Tamaño de la Partícula , Propiedades de Superficie
10.
Appl Microbiol Biotechnol ; 89(5): 1621-8, 2011 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-21076919

RESUMEN

High-throughput methodologies to screen large numbers of microorganisms necessitate the use of small-scale culture vessels. In this context, an increasing number of researchers are turning to microtiter plate (MTP) formats to conduct experiments. MTPs are now widely used as a culturing vessel for phenotypic screening of aerobic laboratory cultures, and their suitability has been assessed for a range of applications. The work presented here extends these previous studies by assessing the metabolic footprint of MTP fermentation. A comparison of Chardonnay grape juice fermentation in MTPs with fermentations performed in air-locked (self-induced anaerobic) and cotton-plugged (aerobic) flasks was made. Maximum growth rates and biomass accumulation of yeast cultures grown in MTPs were indistinguishable from self-induced anaerobic flask cultures. Metabolic profiles measured differed depending on the metabolite. While glycerol and acetate accumulation mirrored that of self-induced anaerobic cultures, ethanol accumulation in MTP ferments was limited by the increased propensity of this volatile metabolite for evaporation in microlitre-scale culture format. The data illustrates that microplate cultures can be used as a replacement for self-induced anaerobic flasks in some instances and provide a useful and economical platform for the screening of industrial strains and culture media.


Asunto(s)
Industria de Alimentos/métodos , Microbiología Industrial/métodos , Vino/microbiología , Levaduras/crecimiento & desarrollo , Levaduras/metabolismo , Etanol/metabolismo , Ensayos Analíticos de Alto Rendimiento/métodos , Extractos Vegetales/metabolismo , Vitis/química
11.
Planta Med ; 75(7): 746-56, 2009 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-19165716

RESUMEN

Several medicinal and herbal plants properties are related to individual compounds such as essential oils, terpenoids, flavonoids, which are present in natural products in low concentrations (e. g., ppm or ppb). For many years, the use of classical separation and chromatographic and spectrometric techniques such as high performance liquid chromatography (HPLC), gas chromatography (GC), liquid chromatography (LC) and mass spectrometry (MS) were initially used for the elucidation of isolated compounds from different plant matrices. Spectroscopic techniques in the infrared (IR) wavelength region of the electromagnetic spectrum have been used in the food industry to monitor and evaluate the composition of foods. Although Herschel discovered light in the near-infrared (NIR) region as early as 1800, most spectroscopists of the first half of the last century ignored it, in the belief that it lacked any analytical interest. However, during the last 40 years NIR spectroscopy has become one of the most attractive and used methods for analysis. This mini-review highlights recent applications of NIR spectroscopy to the qualitative and quantitative analysis of plant natural products.


Asunto(s)
Productos Biológicos/química , Espectroscopía Infrarroja Corta/métodos
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