CLSM and TIRF images from lignocellulosic materials: garlic skin and agave fibers study (original) (raw)
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Confocal Laser Staining Microscopy for Microstructure Observation on Starch-Based Food Systems
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T he research on starch-based food products using CLSM remains limited. Therefore, this paper provides the basic principles of CLSM coloring methods which is the development of a conventional confocal microscope, and its application in the starch-based food field. The principle of CLSM reflects on certain light to produce 3D images, which uses flouroscents probes with the right wavelength to clearly visualize objects. Some flouroscents probes often used to color starch are APTS and FITC. Aside from its function in observing the structure of starch, CLSM tends to provide changes in starch granules due to the processing, storage and presence of other components such as protein, fat, and hydrocolloids. Furthermore, in a complex system consisting of various constituent materials, it requires modifications in its coloring technique to assure that the structure of the system is clear and intact. Therefore, CLSM is an excellent microscopy approach to observe the microstructure of starch-ba...
Confocal imaging to reveal the microstructure of soybean processing materials
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Sustainable production of food products for human consumption is required to reduce negative impacts on the environment and to consumer's health. Soybeans are an excellent source of nutritive plant proteins; aqueous extraction yields part of the available oil and protein from the legume. Many studies have been conducted which detail the various processing parameters and their effects on the extraction yields, yet there is little data on the localisation of nutritive components such as oil and protein in the fibrous unextracted by-product. Here we show a novel confocal laser scanning microscopy investigation of soybean processing materials and the physical effects of thermal treatment on the materials microstructure upon aqueous extraction. Various features, more specifically oil, protein (including protein aggregation) and cell wall structures, are visualised in the fibrous by-product, soy slurry and soy extract, with their presence both in the continuous phase and within intact cotyledon cells. Thermal treatment reduced the protein extraction yield; this is shown to be a result of aggregated protein bodies in the continuous phase and within intact cotyledons cells. Knowledge of the processing material microstructures can be applied to improve extraction yields and reduce waste production.
Fotonic and Electron Microscopy Images for Quality Evaluation of Delignification of Agave Fibers
Lecture Notes in Computer Science, 2014
The present work is aimed to study the microstructural changes that occurred during the delignification process of agave fibers using microscopy techniques and image analysis (AI). Acetosolv kinetic was followed by chemical analysis and by light (LM), confocal laser scanning (CLSM), and scanning electron (SEM) microscopies, evaluating the micrographs by image analysis (IA). Kinetic studies showed that delignification process followed three stages: initial, bulk and residual; these stages kept a relation with the microstructural changes occurring in the fibers. The data obtained integrate numerical information that could be valuable for study of pulping of lignocellulosic materials and these techniques can be used as useful non-destructive methods for the evaluation of the delignification process.
Food Research International, 2010
Observations of raw, fried and air-dried potato parenchyma samples were made with a UV-VIS confocal laser scanning microscope in reflective and fluorescence modes. Distinction between oil and cells was made possible by the addition of a fluorescent probe in the frying oil and the use of the natural fluorescence of cells. Observations were recorded at different depths and were treated to make volumetric reconstructions at different product scales. The results showed that after frying, the cellular structures were well conserved in terms of shape and size. Oil was shown to be mainly located in the first cell layer occupying around 50% of its volume. Oil remained in the cut cells emptied during the washing or the frying operation or in the damaged cells partially filled with starch. Cell detachment, because of starch swelling and dehydration, seemed to be the preferential connection between cell layers. The positive effect of air-drying toward oil uptake reduction could be the restriction of these connections.
Food Surface Texture Measurement Using Reflective Confocal Laser Scanning Microscopy
Journal of Food Science, 2008
Confocal laser scanning microscopy (CLSM) was used in the reflection mode to characterize the surface texture (roughness) of sliced food surfaces. Sandpapers with grit size between 150 and 600 were used as height references to standardize the CLSM hardware settings. Sandpaper particle sizes were verified by scanning electron microscopy (SEM). The mean amplitude (in micrometers) of surface variation along line segments of the scanned sandpaper topographical image sets showed very close agreement between the measured result and the grit particle size (based on the U.S. Coated Abrasive Manufactures Inst. {CAMI], standard). The verified instrument settings were then used to measure the surface texture of mechanically sliced food surfaces, including cooked ham, salami, and cheese. Sliced food surface texture parameters of Ra (average height of a line segment), Rs (surface area ratio), Pa (average height on a region of interest), and Pq (root-mean-square height on a region of interest) were evaluated by this method. Values of the surface roughness of sliced ham, salami, and cheese were found to be comparable to the range of dimensions of selected sandpapers. The CLSM method may be useful for other surface texture measurements, and to investigate the impact of food surface texture on microbial adhesion or attachment, which might play a significant role in microbial transfer from one surface to another.
Evaluation of Agave Fiber Delignification by Means of Microscopy Techniques and Image Analysis
Microscopy and Microanalysis, 2014
Recently, the use of different types of natural fibers to produce paper and textiles from agave plants has been proposed. Agave atrovirens can be a good source of cellulose and lignin; nevertheless, the microstructural changes that happen during delignification have scarcely been studied. The aim of this work was to study the microstructural changes that occur during the delignification of agave fibers by means of microscopy techniques and image analysis. The fibers of A. atrovirens were obtained from leaves using convective drying, milling, and sieving. Fibers were processed using the Acetosolv pulping method at different concentrations of acetic acid; increasing acid concentration promoted higher levels of delignification, structural damage, and the breakdown of fiber clumps. Delignification followed by spectrometric analysis and microstructural studies were carried out by light, confocal laser scanning and scanning electron microscopy and showed that the delignification process f...
Istituto Lombardo - Accademia di Scienze e Lettere - Incontri di Studio
This review focuses on the combination of optical microscopy (OM) and Environmental Scanning Electron Microscopy-Energy Dispersive Spectroscopy (ESEM-EDS) in the anatomical and functional characterization of the cereal caryopsis in order to drive the technology of transformation as well as to save the nutrients in the flours and their derived products. With OM, we analyzed caryopsis sections stained with Azan Trichrome, Periodic Acid Shiff (PAS) and Toluidine blue staining. These techniques allowed the characterization of the aleuronic layers with their protein globoids and starch granules of variable dimensions in the endosperm. Fluorescence OM allowed to evidence phenolic compounds and soluble fibers, in particolar the β-glucan of oat and barley, with the aid of the dye Calcoflour white. ESEM-EDS does not require fixation or embedding of the samples, and the structures are visualized under natural conditions. By means of ESEM-EDS, we localized protein globoids, the germ with the d...
Cryo-laser scanning confocal microscopy of diffusible plant compounds
Plant Methods, 2018
Background: The in vivo observation of diffusible components, such as ions and small phenolic compounds, remains a challenge in turgid plant organs. The analytical techniques used to localize such components in water-rich tissue with a large field of view are lacking. It remains an issue to limit compound diffusion during sample preparation and observation processes. Results: An experimental setup involving the infusion staining of plant tissue and the cryo-fixation and cryo-sectioning of tissue samples followed by fluorescence cryo-observation by laser scanning confocal microscopy (LSCM) was developed. This setup was successfully applied to investigate the structure of the apple fruit cortex and table grape berry and was shown to be relevant for localizing calcium, potassium and flavonoid compounds. Conclusion: The cryo-approach was well adapted and opens new opportunities for imaging other diffusible components in hydrated tissues.