SLow steady shear deformation and small amplitude oscillation measurements have been used to characterize the onset of gelation in high‐methoxyl pectin gels. A simplified technique with a shear modulus threshold criterion is proposed for routine evaluation of the gelpoint with a normalized parameter. Limiting conditions of the three methods are discussed.

The gel-forming abilities of a rapeseed protein isolate, composed of 70% globulin (cruciferin) and 30% albumin (napin), and their individual protein components, were investigated. The influence of acetylation upon the gelation properties was also studied. Highest gel strength (measured as shear modulus) of the isolate was obtained at pH values around 9, which is between the isoelectric points of both major proteins. Purified cruciferin gave the highest shear modulus values, with maxima at pH 6 and 8. Weak and poorly stable gels exhibiting strong hysteresis were obtained with isolated napin. Acetylation resulted in a pH shift of the shear modulus maximum of the protein isolate to about 6. The gelation temperature of the acetylated isolate had the highest pH and concentration dependence compared with the other proteins. JAOCS 75, 83-87 (1998).The ability to form gels is a key functional property in utilizing plant proteins. The gel-forming properties of proteins from soybeans and other legume and oilseed crops have been extensively studied (1-7).Gill and Tung (8) first demonstrated the ability of a highly glycosylated 12S rapeseed protein to form gels on heating at pH > 4. The strongest gels were formed at high pH and ionic strength. The high level of carbohydrate (12.9%) led the authors to assume protein-carbohydrate interaction during gel formation. Thompson et al. (9) observed increased viscosity of a hexametaphosphate-extracted rapeseed protein isolate on heating to 80˚C but did not obtain a gel. Paulson and Tung (10) studied thermally induced gelation of a rapeseed (canola) protein isolate on heating to 72°C. Gels formed only at high pH (>9.5).Léger and Arntfield (11) studied gelation of 12S canola globulin. Gels prepared with 6% protein under alkaline conditions were superior to gels prepared from acidic solutions. The effects of pH, salts, and denaturing and reducing agents on gelation properties led the authors to conclude that hydrophobic forces and electrostatic interactions were responsible for establishing the gel network, while gel stabilization and strengthening were attributed to disulfide bonding, electrostatic interactions, and hydrogen bonding.Succinylation has been used to improve the gel-forming properties of a canola protein isolate by Paulson and Tung (10). In this way, the pH range of gel formation was extended from the alkaline region (pH > 9.5) to 5.0.Comparison of the gel-forming properties of the different rapeseed protein preparations is difficult owing to differences in protein composition and purity. Moreover, data on the protein composition of the isolates studied are scanty.The present paper deals with the influence of the major protein components of rapeseed protein isolate [12S globulin "cruciferin" and 2S protein "napin" (12)] and of acetylation on the gel-forming properties of the isolate. The pH and concentration dependencies on the gelation temperature and the shear modulus of purified cruciferin and napin as well as nonmodified and acetylated isolates containing both proteins...

A sufficient correlation between objective (e.g. eCAP of the auditory nerve) and psychoacoustic data has not yet been possible due to high interindividual variability in cochlear implantees. Therefore, the application of objective data in the evaluation of speech rehabilitation after cochlear implantation was investigated. eCaps of all electrodes were measured intraoperatively. The ‘threshold’ and ‘comfort’ levels, speech recognition and pure tone thresholds were determined at follow-up. The correlation coefficient was calculated between eCap thresholds and psychoacoustic levels. This correlation coefficient was ranked with other individual items in relation to their influence on the development of speech recognition. Only the duration of preimplant deafness, the pure tone hearing threshold and the correlation between eCAP and psychoacoustic levels have a significant influence on the rehabilitation within this selection of variables. Based on these results, an individualized mathematical modeling approach was introduced to predict the development of postoperative speech recognition by incorporating objective data.

A physical characterization of the deformation behavior up to the gel fracture is given for a weak pectin‐saccharose‐water standard gel from high‐methoxyl citrus pectin. The results refer to citrus pectin from different commercial sources and also to high‐methoxyl apple pectin.

A. DAHME und J. DECHANT Akademie der \T'issenschaf teu der DDR, Institut f u r Polymerenchemie ,,Eric11 Correns", DDR-1530 Teltow-Seehof Die Infrarotspektren von linearem Polyethylcri wurden im Temperaturbereich von 120 K bis 420 K gemessen. Die IR-Banden, die den kristallinen Bereichcn des Polymers zugeordnet werdcn, zeigen eine starlre Temperatnrabhangigkeit auch bei Tcrnperaturen unterhalb tliermischer Umwandlungen. Die Tcmperaturabhiingigkeit wird durch thermisch angeregte Bewegungen oder Defekte crklart, die die Phasenbeziehungen zwischen bcnachbarten CH,-Einheiten storen. memnepamypfioii 3a~ucu.~ocmu MR-cnetcmpa nonuwepos. Zlacmb I . Wumepnpemayua memnepamypfioii ~~B U C U M O C~UHHHYIJHPOBaHHhIMH JJBIllKeHHHMH HJIH J(e@eKTaMl'I, HaPJ'lllaH)UlHMR @ a 3 0 B b I e COOTHOUleHHH MeH(8Y COCeAHblMM C112-3BeHbHMH. The temperature dependence of the I R spectrum of polymers. Part 1. Interpretation of the temperature dependence of I R bands of polyethyleneThe I R spectra of linear polyelhylene were measured within the temperature range of 120 K to 430 K. The I R bands assigned to the crystalline region were found to depend strongly on the temperature even below thermal transitions. The temperature-dependence is cxplaincd by thermally stimulated motions or defects disturbing the phase relations between neighbouring CH, units.