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Publications (40)
Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and Scanning electron microscopy (SEM) were used to study the effects of heat treatments and water removal by freeze-drying after different time intervals (6, 12, 24, 48, and 72 h) on the molecular structure of potato tubers. SEM images show structural differences between raw...
Colloidal matrices of native and oxidized pectin were developed to improve iron bioavailability through the digestive tract. Ferrous bisglycinate (Gly-Fe), obtained by precipitation of glycine chelation to Fe2+, was mixed with native and peroxide-oxidized citrus pectin, and subsequently lyophilized. Controls included matrices with iron and glycine...
The creation of 3D printed food with programmed texture has the ambition of getting personalized properties through novel texture perceptions with many different ingredients and is helping the swallowing or mastication problems of vulnerable people. This study is done to determine the correlation between the instrumental and sensory evaluation of 3...
Abstract: Although mineral chelates are widely produced to be used as food fortifiers, the proof that these complexes are chelates is still missing. In our present work, iron II complexes using citric acid in different ratios are produced, and the occurrence of chelation is investigated along with its behavior according to a molar ratio between the...
Recently, personalized meals and customized food design by means of 3D printing technology have been considered over traditional food manufacturing methods. This study examined the effects of different proteins (soy, cricket, and egg albumin protein) in two concentrations (3% and 5%) on rheological, textural, and 3D printing characteristics. The te...
Dysphagia affects a person's ability to swallow, and it causes health problems by directly limiting nutritional intake, being the elderly the most at-risk group and also likely to be deficient in nutrition. Diets for patients with dysphagia require textural modifications to offer soft and safe food to swallow. Puree is easily consumed by the elderl...
The aim of this study was to evaluate the effect of three Lebanese wild plant extracts on acrylamide (AA) content in French fries, and to investigate the impact of air frying (AF) and deep frying (DF) techniques against AA formation. HPLC showed higher level of AA in DF (1384.79 ng/g) than in AF (163.1 ng/g). Indeed, the plant extracts of ginger, b...
The effects of agar, alginate, butter, olive oil, and carrots on the mechanical and rheological properties of potato puree prepared by two different cooking methods (microwave heating (MP) and boiling (BP)) were investigated and interpreted in terms of starch microstructural changes. Microscopic observations revealed more aggregated and densely con...
Constitutive or regulated membrane protein trafficking is a key cell biology process. Transient receptor potential channels are somatosensory proteins in charge of detecting several physical and chemical stimuli, thus requiring fine vesicular trafficking. The membrane proximal or pre-S1 domain (MPD) is a highly conserved domain in transient recepto...
This paper studies the applicability of extrusion-based 3D printing for constructing novel shapes from potato puree and the effects of four additives (agar, alginate, lecithin, and glycerol) added separately at three concentrations (0.5, 1, 1.5%) on the internal strength, mechanical properties, microstructure, and color of potato puree. The printab...
Background: Digitalizing food using 3-Dimensional (3D) printing is an incipient sector that has a great potential of producing customized food with complex geometries, tailored texture and nutritional content. Yet, its application is still limited and the process utility is under the investigation of many researchers. Scope and approach: The main o...
Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) techniques were used to study the effect of four food additives, agar, alginate, lecithin and glycerol, at three different concentrations, 0.5, 1 and 1.5%, on the molecular structure of potato puree prepared from commercial potato powder. Vibrational spectra revealed that th...
The effects of agar, alginate, lecithin and glycerol on the rheological properties of commercial potato puree were investigated and interpreted in terms of starch microstructural changes, and the applicability of the Cox-Merz rule was evaluated. Each additive was applied separately at two concentrations (0.5 and 1%). Microscopic observations reveal...
In this work, a comparative study between Aloe vera, chitosan (formulated with acetic (-AC) or citric acid (-C)) and sodium alginate edible coatings was conducted to evaluate the effects on the quality and shelf life of minimally processed kiwifruit. The pH, soluble solids content, titratable acidity, ascorbic acid, color, texture properties, gas c...
This work investigates the effectiveness of alginate and chitosan edible coatings and ascorbate and lactate calcium salts combined with a low permeable film to maintain the quality of fresh‐cut pineapple through 15 days at 4 C . Respiration rate, color, firmness, pH , ripening index, juice leakage, total soluble solids in juice leakage and ascorbic...
The effect of temperature on the respiration rate and texture of fresh cut pineapple was studied over the course of 10 days of storage. The thermal exchange between the pineapple trays and the cooling environment was simulated using the finite element method and tested at 6 °C. The temperatures on pineapple wedges differed between the cold point an...
Crystallization of honey is a common process of the honey industry. Liquid honey is preferred by most of the consumers and by food companies for ease of handling. A better method compared to expensive and time-consuming heating is desirable to accelerate the liquefaction and retard the crystallization process in honey. In this work, samples of crys...
We have performed a quantitative X-ray absorption fine structure analysis of bacteriorhodopsin in purple membrane patches and in lipidic cubic phases regenerated with Mn(2+). Lipidic cubic phases and purple membrane results have been compared, demonstrating that the lipidic cubic phase process does not introduce relevant distortions in the local ge...
For the first time to our knowledge, X-ray absorption spectroscopy (XAS) has been used to investigate the environment of putative Zn(2+) binding sites in rhodopsin. We studied native purified nondeionized rhodopsin without any further addition of Zn(2+), as well as with 1.5 mol of Zn(2+)-as zinc chloride-per mole of protein. Three different binding...
Cell adhesion and proliferation in poly(3,4-ethylenedioxythiophene), an electroactive polythiophene derivative generated by anodic polymerization, has been investigated. Results show that epithelial cells Hep-2 present significant activity on the surface of poly(3,4-ethylenedioxythiophene) electrodeposited on stainless steel electrodes, no sign of...
The present work describes the results of a study aimed at identifying candidate cation binding sites on the extracellular region of bacteriorhodopsin, including a site near the retinal pocket. The approach used is a combined effort involving computational chemistry methods (computation of cation affinity maps and molecular dynamics) together with...
Copolymers of 3,4‐ethylenedioxythiophene and 3‐methylthiophene have been prepared by recurrent potential pulses using monomer mixtures with various concentration ratios, their properties being compared with those of the corresponding homopolymers. In addition, different technological applications have been tested for the generated copolymers. Resul...
X-ray absorption measurements were performed on Ca2+ and 5 Mn2+ regenerated purple membrane in order to obtain structural information about the cation environment. For the regenerated membrane with 5 Mn2+, EXAFS analysis shows a first six-coordination sphere with two Mn-O distances (2.18 Å and 2.49 Å), whereas for the 5 Mn2+ regenerated bleached me...
In this article we report x-ray absorption measurements of Ca(2+)-substituted bacteriorhodopsin. We present a detailed study of the absorption spectrum close to the absorption edge that is very sensitive to the site geometry. We combined ab initio calculations of the x-ray absorption cross section based on a full multiple scattering approach, with...
Low-temperature Fourier transform infrared spectroscopy has been used to study mutants of Glu194 and Glu204, two amino acids that are involved in proton release to the extracellular side of bacteriorhodopsin. Difference spectra of films of E194Q, E204Q, E194Q/E204Q, E9Q/E194Q/E204Q, and E9Q/E74Q/E194Q/E204Q at 243, 277, and 293 K and several pH val...
Single and multiple mutants of extracellular Glu side chains of bacteriorhodopsin were analyzed by acid and calcium titration, differential scanning calorimetry, and thermal difference spectrophotometry. Acid titration spectra show that the second group protonating with Asp(85) is revealed in E204Q in the absence of Cl(-) but is not observed in the...
The following multiple Glu extracellular mutants of bacteriorhodopsin have been studied, with respect to their possible use in bioelectronic applications: the quadruple E9Q+E74Q+E194Q+E204Q, the triple E9Q+E194Q+E204Q and the double E194Q+E204Q. The wavelength of the absorption maximum of the quadruple mutant is very sensitive to pH and salts, cove...
The quadruple bacteriorhodopsin (BR) mutant E9Q+E74Q+E194Q+E204Q shows a lambda(max) of about 500 nm in water at neutral pH and a great influence of pH and salts on the visible absorption spectrum. Accessibility to the Schiff base is strongly increased, as detected by the rapid bleaching effect of hydroxylamine in the dark as well as in light. Both...
Binding of Mn2+ or Mg2+ to the high-affinity site of the purple membrane from Halobacterium salinarium has been studied by superconducting quantum interference device magnetometry or by ab initio quantum mechanical calculations, respectively. The binding of Mn2+ cation, in a low-spin state, to the high-affinity site occurs through a major octahedra...
Differential scanning calorimetry and Fourier-transform infrared spectroscopy have been used to characterize the thermal stability of bacteriorhodopsin (BR) cleaved within different loops connecting the helical rods. The results are compared to those of the native protein. We show that the denaturation temperature and enthalpy of BR cleaved at pept...
The structure of the high-affinity cation-binding site of bacteriorhodopsin was studied using extended x-ray absorption fine structure techniques. The results obtained for Mn2+ in aqueous solution and for the complex BR-Mn2+ (1:1 molar ratio) show great similarities, suggesting that Mn2+, when bound to this site, is coordinated with six atoms of ox...
Fourier transform infrared spectra of bacteriorhodopsin samples were obtained in conditions in which the aggregation state of the protein (i.e., monomeric or trimeric) was modified by different treatments, Two approaches were followed: (1) renaturation of bacteriorhodopsin starting from bacterioopsin dissolved in SDS and (2) reconstitution of bacte...