title: One-Pot Procedure for Recovery of Gallic Acid from Wastewater and Encapsulation within Protein Particles.
abstract: A whey protein isolate solution was heat-denatured and treated with the enzyme transglutaminase, which cross-linked ≈26% of the amino groups and increased the magnitude of the ζ-potential value. The protein solution was microemulsified, and then the resulting water-in-oil microemulsion was dispersed within a gallic acid-rich model wastewater. Gallic acid extraction by the outlined microemulsion liquid membrane (MLM) from the exterior aqueous phase (wastewater) and accumulation within the internal aqueous nanodroplets induced protein cold-set gelation and resulted in the formation of gallic acid-enveloping nanoparticles. Measurements with a strain-controlled rheometer indicated a progressive increase in the MLM viscosity during gallic acid recovery corresponding to particle formation. The mean hydrodynamic size of the nanoparticles made from the heat-denatured and preheated enzymatically cross-linked proteins was 137 and 122 nm, respectively. The enzymatic cross-linking of whey proteins led to a higher gallic acid recovery yield and increased the glass transition enthalpy and temperature. A similar impact on glass transition indices was observed by the gallic acid-induced nanoparticulation of proteins. Scanning electron microscopy showed the existence of numerous jammed/fused nanoparticles. It was suggested on the basis of the results of Fourier transform infrared spectroscopy that the in situ nanoparticulation of proteins shifted the C-N stretching and C-H bending peaks to higher wavenumbers. X-ray diffraction results proposed a decreased β-sheet content for proteins because of the acid-induced particulation. The nanoparticles made from the enzymatically cross-linked protein were more stable against the in vitro gastrointestinal digestion and retained almost 19% of the entrapped gallic acid after 300 min sequential gastric and intestinal digestions.
authors: Department of Food Science and Engineering, University College of Agriculture and Natural Resources, University of Tehran , Karaj, Iran.
authors: Himan
authors: H
authors: Nourbakhsh
authors: Department of Food Science and Engineering, University College of Agriculture and Natural Resources, University of Tehran , Karaj, Iran.
authors: Ashkan
authors: A
authors: Madadlou
authors: Department of Food Science and Engineering, University College of Agriculture and Natural Resources, University of Tehran , Karaj, Iran.
authors: Zahra
authors: Z
authors: Emam-Djomeh
authors: Department of Biological Systems Engineering, College of Agricultural and Life Sciences, University of Wisconsin-Madison , Madison, Wisconsin, United States.
authors: Yi-Cheng
authors: YC
authors: Wang
authors: Department of Biological Systems Engineering, College of Agricultural and Life Sciences, University of Wisconsin-Madison , Madison, Wisconsin, United States.
authors: Sundaram
authors: S
authors: Gunasekaran
authors: Department of Food Science and Engineering, University College of Agriculture and Natural Resources, University of Tehran , Karaj, Iran.
authors: Mohammad E
authors: ME
authors: Mousavi
mesh_terms: D005707:Gallic Acid / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry; D010316:Particle Size; D017550:Spectroscopy, Fourier Transform Infrared; D014866:Waste Products / Q000032:analysis; D062065:Wastewater / Q000737:chemistry*; D000067816:Whey Proteins / Q000737:chemistry*
chemical_list: D005707:Gallic Acid; D014866:Waste Products; D062065:Wastewater; D000067816:Whey Proteins
keywords: FTIR; X-ray diffraction; digestion; in vitro gastrointestinal digestibility; morphology