Extrusion Crystallinity and its Effect on Enzyme Digestibility

ENZYMATIC HYDROL YSIS OF INULIN AND ITS RELATED FRUCTOSANS. McKay, e., E. Hoehn and R. Bacchus, Department of Food Science, University of Manitoba, Winnipeg, Manitoba R3T 2N2. Current research at our department has been directed towards the utilization of Jerusalem Artichoke (JA) (Helianthus tuberosus L.) as a source of high fructose syrup. The degradation of inulin both by tuber enzymes and a number of enzymes from other sources was investigated in view of storage of and to application in processing of JA tubers. Enzyme activities were evaluated based on assays involving measurement of reducing sugars and formation of oligomers by GLC techniques. Results indicated that tuber enzymes were relatively heat labile and thus (I) easily controlled during tuber storage but (2) not utilizable in processing of tubers. Inulin degrading enzymes showed variability in activity depending on the degree of inulin polymerization. This and other characteristics indicated that for processing purposes a mixture of several inulases may result in most efficient hydrolysis of inulin to high fructose syrup. MOLECULAR WEIGHT DISTRIBUTION OF OVOMUCIN FROM THINNED EGG WHITE. Miller, S.M., A. Kato and S. Nakai, Department of Food Science, University of British Columbia, Vancouver, British Columbia V6T 2A2. It was intended to further prove the involvement of ovomucin alone in egg white thinning. Sedimentation equilibrium ultracentrifugation was used for determining the molecular weight distribution (MWD) of a soluble ovomucin separated from blended egg white by gel filtration. The apparent molecular weight offresh ovomucin was 5.64 . 10 6 at pH 6.95 and an ionic strength of O. 13. Ovomucin from naturally thinned white showed similar MWD patterns without signs of degradation. Treatment of fresh white with .02% 2mercaptoethanol decreased mol wt,pp to 309,500 and 726,200. These results support the previous finding that J3-elimination of O-glycosidically linked carbohydrates could be a cause of egg white thinning, but not disulfide linkage splitting. COMPARISON OF THE DIRECT AND INDIRECT WIDELINE NMR METHODS FOR DETERMINING SOLID FAT CONTENT. Mills, B.L. and F.R. van de Voort, Department of Food Science, University of Guelph, Guelph, Ontario NI G 2W I. A "direct" method of measuring the solid fat content by wide-line NMR was compared to the conventional indirect wide-line NMR procedure. The direct method is based on the combined use of a narrow (1.5 gauss) and a wide (10 gauss) gate to admit resonances from the liquid and liquid plus solid portions of the fat respectively. The results obtained for four different fats using the direct method did not differ significantly from those of the indirect method. Since the direct method requires additional measurements, is somewhat more complex theoretically, and inherently has the potential to provide more variable results due to the weaker additional signal being measured at the wide gate, no real advantage could be found for its use. INTERACTION OF MEAT AND VEGETABLE PROTEINS IN EXTENDED MEAT PRODUCTS. Morrissey, P.J., M. Enriquez, D. Mayers, Diversified Research Laboratories, Toronto, Ontario M4W 2L3 and J. R. Quinn and D. Wood, Food Research Institute, Agriculture Canada, Ottawa, Ontario K IA OC6. Varied effects of vegetable protein substitute in a sausage matrix were examined by monitoring textural attributes. Formulations prepared using several proteins and an inert material were immersion cooked to several internal temperatures. Physical appearance and yields were recorded and textural characteristics measured using the Instron Compression Tester. Results indicate the larger the replacement value the greater the effect on texture. Textural measurements were generally found to increase with increased internal temperatures at a constant replacement value. Interaction levels of the proteins are exhibited in the amount of change in textural characteristics. APPLICATION OF MODIFIED SUPER-SIMPLEX OPTIMIZATION TO FOOD PROCESSING. Nakai, S. and T. Kuwata, Department of Food Science, University of British Columbia, Vancouver, British Columbia V6T 2A2.

170 {Affaires de I'Institut

A computing program for optimizing 2-5 factor experiments was written for a Monroe 1880 calculator. The program includes the weighted centroid method of Ryan (1980) for calculating the reflection conditions. For new processes, it is recommended to perform fractional factorial designs to select influential factors before applying the optimization technique. The optimization can be flexible using stepwise multiple regression analyses for discarding nonsignificant factors or introducing new factors during optimization procedure. It was found that the method was quite efficient for optimizing food analysis and processing. Conversely, it was difficult to optimize them without using similar techniques especially when factors were interacting. A NOVEL, MULTI-SAMPLE, TANGENTIAL ABRASIVE DEHULLING DEVICE (TA DD). Oomah, B.D., R.D. Reichert and e.G. Youngs, Food Research Institute, Agriculture Canada, Ottawa, Ontario KIA OC6. The design and testing of a novel, laboratory tangential abrasive dehulling device (TADD) is described. The unit can process eight 10 g samples at a time to provide a measure of grain hardness and an extraction rate based on flour colour. Using barley and grain sorghum as test materials, coefficients of variation range from 1.0 to 3.8 for the percent kernel removed at a given time. For thirty-one samples of sorghum the abrasive hardness index ranged from 5.0 to 12.7 and extraction rates from 71 to 98%. One operator can process sixteen samples in duplicate per day. EXTRUSION CRYSTALLINITY AND ITS EFFECT ON ENZYME DIGESTIBILITY. Owusu-Ansah, J., F.R. van de Voort and D.W. Stanley, Department of Food Science, University of Guelph, Guelph, Ontario NI G 2W I. The use of extruders in cereal processing, especially in the production of precooked and modified starches, ready-to-eat cereals, infant formulae and snack foods, has increased in the last few years. However, the formation of extrusion crystallinity in extruded cereals is currently raising much concern with regard to the possible undesirable effects of this change in products such as infant formulae. The effect of primary extrusion variables, temperature, feed moisture and screw speed on extrusion crystallinity in corn starch was studied using response surface methodology. Extrusion crystallinity was quadratically related to these variables, accounting for 84.5% (P
J. InS!. Can. So'. Technol. Aliment. Vol. 14. No. 3. Juillet 1981