In the process of isolating sialic acid from bovine isoelectric casein a hydrolytic product (CBF) was obtained, possessing growth promoting activity for Bifidobacterium bifidum var. pennsylvanicus. Growth was measured turbidimetrically by addition of CBF (250 ppm) to ATCC Medium 76. Stimulation by CBF was comparable to that obtained with N-acetylglucosamine. Whole casein, sialic acid-free casein and k-casein failed -to stimulate the growth of -the organism to the level achieved with CBI? The CBF fraction contained 0.15% nhosohorus. 7% free lactose and various peptides. No sialic acid or other amino sugars were detected. On the basis of phosphorus content and amino acid analysis it was concluded that CBF was likely a degradation product of k-casein.

Effects of moisture level, temperature and shear rate on the rheological properties of defatted soy dough during extrusion were studied on a Brabender laboratory extruder. Entrance pressure loss through the extruder capillary die as well as viscosity of the cooked and compressed soy dough were expressed as a function of added moisture, shear rate and temperature through multiple regression analysis. Process conditions involved in this study were (a) temperature from 100 to 160°C; (b) added moisture from 22 to 32% and (c) shear rate from 50 to 10,500 sec−1. Data were collected at steady state. It was found that in the shear rate range of 50 to 1,000 sec−1 and temperature range of 100 to 160°C the viscosity of the cooked and compressed soy dough with 32%, 25% and 22% added moisture ranged from 10,000 to 500 poise and 20,000 to 200 poise and 20,000 to 1,000 poise respectively.

A viscosity model of defatted soy dough under various conditions of shear rate, temperature and moisture level in the extrusion process is reported The model represents the data well within the shear rate rangeof 50 to 1,000 s-l, the temperature range of 100°C to 16OoC, 4nd the added moisture range of 22% to 32%. The flow index is determined to be 0.127, and response surfaces of the viscosity are also presented.

Growth stimulation of B. bifidum var. pennsylvanicus by filtersterilized, unheated amino sugars was studied utilizing an ATCC medium 76 assay system. The order of stimulatory effect was N-acetylglucosamine (GlcNAc) > N-acetylgalactosamine > N-acetylmannosamine > N-acetylneuraminic acid. When GlcNAc was heated at 121°C for 15, 30 and 45 min, depression of growth occurred and was directly related to the heat treatment applied. The presence of E. coli B organisms in the assay system did not influence the growth stimulatory effect of the amino sugars on B. bijidum. Spent broth, prepared by growth of E. coli B in the assay medium followed by filter sterilization, was found to stimulate the subsequent growth of B. bifidum. The spent broth contained small quantities of amino sugars. E. coli B failed to grow in spent broth prepared from B. bifidum without pH adjustment. Growth of E. coli B was observed when this spent medium was neutralized and fortified with amino sugars, however, without any specific stimulatory pattern attributable to the type of amino sugar.

Functional properties of corn protein concentrate were evaluated after extrusion with a laboratory Brabender and a Wenger X-25 extruder. Bulk density, water content and hardness after rehydration were used as criteria for textural comparison among extrudates. Results indicated that corn protein concentrates resulting from either aqueous (CPC-A) or ethyl acetate (CPC-E) extraction were more suitable for extrusion applications than the one resulting from hexane extraction. A blend containing corn protein concentrate and soy flour at the ratio of IS:85 was good for chunks and granules extrusion in the pH range 7.0 -7.3. In a dry spinning process which requires a dough with high cohesiveness for fiber formation, a blend containing 21% of corn protein concentrate, 20% soy isolate, and 59% soy concentrate at a natural pH was satisfactory.

The effects of p H (5.0 to 7.0), salt content (0 to 3%), cooking time (15 to 75 min at 10OoC), soy isolate and egg white level (both from 1 to 5%) on the gel strength of a model meat loaf analog system are investigated. An Instron Universal tester is used for evaluating the analog's strength of oarious compositions. The study indicates an insignificant influence of p H and soy isolate content on the analog's strength. Effects of egg white content, salt content, and cookittg time are expressed in terms of a second order polynomial, where linear effects and interactions are shown to be significant. Egg white content and cooking time are exponentially related to the hardness, whereas, salt content is linearly proportional to the logarithm of hardness. Response surface analysis reveals that egg white usage can be greatly reduced if salt content and cooking time are manipulated.This study provides a model that can be used to optimize a process for producing meat loaf analogs.

The rheological pr jperties of commercial enzyme modified cheese products (Dariteen B, Miles Laboratories, Inc.) are investigated with a micro-rheolog type of viscometer with cone-and-plate geometry. These products ex ribit thixotropic shear-thinning behavior, where viscosity changes !vith the duration and the rate of the applied shear. A viscosity jnodel invoking gradually increasing and decreasing shear rate is inrestigated. The model.involves expression of viscosity as a function of shear rate in the range 1.92-384 see-r for the case of Increasing shear rate and 384-1.92 set-r for the case of decreasing shear ra' e. In these investigations, temperature and moisture content rangt: from 24-72°C and 42.3-59.3%, respectively.Hysteresis curves representative of the phenomena are also illustrated.

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