Gelation Properties of Ovalbumin as Affected by Fatty Acid Salts

The physicochemical properties of heat-induced ovalbumin (OVA) gels containing fatty acid salts (FAS) were investigated. Water-holding ability and transparency markedly increased in the presence of sodium caprate or sodium laurate. At 9% of the protein concentration transparent and hard gels formed; at 7%, transparent and soft gels formed. Scanning electron microscopy showed that the transparent gels had a more homogeneous structure than turbid gels without FAS. Differential scanning calorimetry indicated that denaturation temperature of OVA was decreased and the peaks became broader after addition of FAS.     

11B and 27Al Nuclear Quadrupole Interactions in SiO2-B2O3-Al2O3-R2O Glass Systems

Quadrupole interactions of ¹¹B and ²⁷Al in SiO₂-B₂O₃-Al₂O₃-R₂O glass systems were investigated to determine the structure of these glasses, which should be amenable to chemical strengthening. The ratio of BO₄ units to BO₃ units approached unity as the R₂O/Al₂O₃ ratio for compounds having fixed B₂O₃ contents approached unity. Nuclear quadrupole coupling constants ( e²Qq/h =2.73 to 2.93 MHz) were measured for the NMR spectra of ¹¹B triangles. The line shapes of ²⁷Al spectra varied with chemical composition, but a few glasses exhibited ²⁷Al line shapes similar to those of the AlO₄ triclusters in SiO₂-Al₂O₃-Na₂O glasses. Compositional trends in the formation of BO₄ and AlO₄ were deduced from the NMR spectra.     

Comment on the equivalence condition of optimal control problems

Given a general non-linear plant, a method is presented for designing model reference feedback controllers for the plant. It is shown that the feedback controllers produced will guarantee prespecified closed-loop properties if the error between the plant and model lies within computable bounds. In particular, an upper bound on the tracking error is established and conditions are given that ensure closed-loop stability.     

Relationships Between Hydrophobicity and Foaming Characteristics of Food Proteins

Hydrophobocity measured fluorometrically for food proteins and pure proteins using cis-parinaric acid as a hydrophobic probe had significant correlations to foaming capacity when the proteins in solution were unfolded by heating in boiling water in the presence of 1.5% dodecyl sulphate prior to fluorometric measurement. Hydrophobicity measured without unfolding, which had previously shown a significant correlation to emulsification, was not significantly correlated with foaming capacity. Two highly significant regression equations were generated: one included hydrophobicity and dispersibility and the other, hydrophobicity and viscosity as the independent variables. High hydrophobicity and viscosity and moderate dispersibility were associated with optimum foaming capacity. There was a significant negative relationship between foam stability and charge density. Hydrophobicity and viscosity were also important in foam stability.     

DETERMINATION OF REACTION ORDER BY LINEARIZATION AND ITS APPLICATION TO ESTIMATION OF MICHAELIS-MENTON PARAMETERS

A simple Basic program was tested with the aid of mathematical models for its reliability for the determination of reaction orders of chemical and enzymatic reactions. Accurate determination of reaction order in hypothetical models was achieved with 5–10 data points, provided that data were available for approximately 80% completion of the reaction. If the maximum extent of completion of the reaction was 60%, then even 20 data points were insufficient for accurate determination. The procedure was also combined with a linearization method and applied to experimental data for the determination of Michaelis-Menten parameters. Mathematically derived V₀'s (initial velocities) allowed calculation of K_m and V_mx with reduced standard errors.     

A New Mapping Super-Simplex Optimization for Food Product and Process Development

Graphic illustration of response surface is difficult to carry out for cases with more than two factors as the graphs are of higher orders than three dimensions. An approximation was made by dividing the level values of each factor into four groups of equal intervals, and then the response values plotted were linked to each other when all other factor levels were “in the same groups” of experimental conditions, instead of “under the same conditions” in the case of two or three dimensional graphics. When applied to mathematical models, this new mapping simplex optimization significantly (p < 0.01) reduced the number of experiments required for reaching the optimum as compared to the Morgan-Deming simplex optimization. Most experiments on food analysis and processing have been optimized within 25 – 35 iterative experiments depending on the number of factors. Computer-directed optimization in conjunction with the mapping technique followed by a simultaneous shift of factor levels greatly facilitated research supervision.     

Ultrasonication, Lyophilization, Freezing and Storage Effects on Fat Loss during Mechanical Infusion of Expressed Human Milk

Ultrasonic homogenization was extended to situations where expressed human milk needs to be stored before being administered. We investigated whether the effect of ultrasonication would persist during storage in the frozen or lyophilized form. Recovery of fat was higher in ultrasonicated and frozen milk (stored for both 1 and 4 mo), than in milk stored following ultrasonication and lyophilization. The low fat recovery from stored lyophilized milk was increased by ultrasonicating the milk after storage and reconstitution (instead of prior to storage). Protein recovery was virtually complete with both methods.