Irwin A. Taub

Textural stability of intermediate-moisture extrudates : Effects of formulation

ABSTRACT Effects of formulation on the textural stability of intermediate-moisture, flour-based, “jerky”-type extrudates were assessed. Potato-based extrudates containing various particulate-meat concentrations and different plasticizers (sucrose, fructose, glycerol, and glucose) were produced and subjected to accelerated storage for three weeks. The elastic modulus of the samples was measured before storage and then weekly. The relative fluidity and moisture mobility of the specimens were assessed by dynamic mechanical spectrometry (DMS), electron spin resonance (ESR), and nuclear magnetic resonance (NMR). Samples were also evaluated by fluorometry and X-ray diffraction to determine the extent of browning reaction and degree of molecular ordering, respectively. While elastic modulus increased appreciably during storage, firming was progressively reduced by entrained meat content and also by plasticizers, especially glycerol; plasticized and meat-containing samples had correspondingly lower tan δ peak tem...

Textural Optimization of Shelf-Stable Bread: Effects of Glycerol Content and Dough-Forming Technique

ABSTRACT The effects of glycerol content and dough-forming method on the physical, textural, and sensory characteristics of shelf-stable bread were determined. Bread dough was produced with 0, 2, 4, and 6% nominal glycerol content, and formed into rolls by either dough-dividing or extrusion-forming methodologies. Baked products were evaluated by uniaxial compression and fitting of stress-strain data to a three-parameter mathematical model. A trained sensory panel quantified textural attributes using magnitude estimation methodology. Selected characteristics were also judged by an untrained consumer panel. Sensoryinstrumental relationships were determined. Products were tested instrumentally after different storage intervals to determine effects of glycerol level and dough-forming process on degree of firming. Results showed that extrusion-forming produced, on average, relatively more dense and less deformable products than did the dough-dividing method; extrusionformed samples also had greater sensory fir...

Formation of a steady state in the radiolysis of ferrimyoglobin in aqueous solution

Abstract The interaction of radiation-generated · OH radicals with ferrimyoglobin in deaerated aqueous solution at neutral pH has been quantitatively studied. Changes in the visible absorption spectrum have been analyzed on the basis of composition changes of the ferri, deoxy, and ferriperoxide forms of the metalloprotein. A postirradiation thermal process must be considered in order to evaluate the radical-induced composition changes. Initially, ·OH induces reduction of ferrimyoglobin to the deoxy form with a G value (molecular yield/100 eV of absorbed energy) in the zero-dose limit of 1.4 (±0.2). Radiation-generated H 2 O 2 reacts with the ferrimyoglobin substrate to produce ferrimyoglobin peroxide with a G value of 0.7 (±0.1) in the zero-dose limit. At doses of >1 krad μ m −1 of myoglobin present, the composition of the three myoglobin derivatives reaches a radiolysis steady state. In this moderate-dose plateau region, this composition is 44% ferri, 18% deoxy, and 38% ferri peroxide. The · OH-induced hemoprotein radicals that do not initiate 1-eq redox conversions undergo reactions that generate dimer and other globin-modified material.