1
ITICALE FLOURS: THE EFFECT OF PARTICLE SIZE AND ACTIVITY ON THE TEXTURE OF BAKED PRODUCTS. Stranger*, Anita c., Food Advisory Division, Agricul- ture Canada, Ottawa, Ontario KIA OC5. . .. Three triticale flour samples havmg different particle sizes and alpha-amylase activities were used in the preparation of baked products. Samples were then presented to a taste panel for sensory evaluation. The differences in particle size in the flour were not noticeable in baked products. The triticale flour with the highest alpha-amylase activ- ity of I 000 IDC units did produce muffins and yeast bread that were drier. This dryness did not occur in the coffeecake. It is speculated that an acid ingredient, such as the sour cream used in the coffeecake, may aid in producing moister baked products. A SIMPLE HPLC ANALYSIS OF VITAMIN D IN FORTIFIED MILK. Jang*, Michael B., Department of Food Science, University of British Columbia, Vancouver, B.C. V6T 2A2. To simplify the time-consuming HPLC procedures for vitamin D analysis (one or two samples a day) a programmed ternary solvent delivery system was introduced to eliminate cleanup column pretreat- ments or dual column processes. A simplex optimization technique was used to find the best combination of five factors, these being: the initial proportions (%) of water and acetonitrile, the final proportions of water and acetonitrile, and the time (lOin) required for the solvent gradient to be achieved. The optimal conditions found were a composition of eluant with acetonitrile and water 73.0%: 18.0% (methanol 9.0%) changing to 53.1%:9.1% (methanol 37.8%) over a period of 22.2 min. Vitamin D was eluted after 20.1 lOin with a recovery of92%. Contaminating sterols were eliminated before application to the HPLC column by filtering the precipate produced upon cooling of a methanol suspension of dried extract. The simplex optimization technique used was found to be very efficient in selecting the best conditions of the programmed ternary solvent delivery system. The HPLC method thus found considerably simplifed the vitamin D analysis making it suitable for routine quality control. FERMENTATION OF WHEY FILTRATE BY SACCHAROMYCES FRAGILIS FOR THE PRODUCTION OF SINGLE CELL PROTEIN. AI-Shabibi, M.M.A. and Vian A. Mohammed, Dept. of Food Science, University of Baghdad, Iraq. School of Food Science, Macdonald College of McGill University, Dept. of Food Science, University of British Columbia. S. Sragilis was used in the fermentation of cheese whey which was enriched with ammonium and other salts to produce a biomass rich in protein. Rapid fermentation rate and lactose utilization was achieved as indicated by the percentage of consumed lactose which varied from 58 to 100 per cent and chemical oxygen demand of the whey was reduced by 40 to 82 per cent depending on the treatment. Cellular protein was found to range between 5 and 14 per cent and the nucleic acid content of the yeast cells based on dry basis ranged between 6.5 to 40.8 fLg and 1.4 to I 1.4 fLg for DND and RNA respectively. Amino acids profile for the protein isolate was also determined. MOLECULAR SIZE DISTRIBUTION PATTERN OF THERMALLY PRODUCED WHEY PROTEIN AGGREGATE BY SEPHACRYL S-IOOO. Toma, S.J., T. Beveridge and S. Nakai. The potential use of sephacryl S-I000 as a gel filtration media for the separation of thermally produced whey protein aggregate was in- vestigated. Results obtained clearly indicated the presence of aggregates and showed their relative size distribution. An intermediate peak appeared upon heating to 85 ± C at PH7 and ionic strength of 0.05 phosphate buffer. The peak disappeared when the PR of the medium was decreased to 6.0 or the ionic strength was increased to 0.2. Detailed studies of the effect of PH and ionic strength were performed and compared to polyacrylamide electrophoretic results. RESIDUE LEVELS OF THE BEE REPELLENT, PHENOL, FOUND IN HONEY. Daharu*, Patricia and Peter Sporns, Department of Food Science, University of Alberta, Edmonton, Alberta T6G 2P5. Many beekeepers, especially large commercial beekeepers, rely on bee repellents such as phenol, benzaldehyde and butyric anhydride to repel bees when collecting honey. The low cost and efficacy of phenol have resulted in the use of this chemical by many beekeepers. At high concentrations phenol residues will impart an undesirable "medicinal" f1avor to the honey. Data on phenol residue levels in Canadian and some Can. Insl. Food Sci. Techno!. J. Vol. 16. No. 3. 1983 foreign honeys will be presented. Also, the results of sensory evaluation to establish a threshold value for the detection of phenol residues in honey will be given. LACTOSE HYDROLYSIS IN WHEY AND MODEL SYSTEMS. Bernal*, V. and P. Jelen, Department of Food Science, University of Alberta, Edmonton, Alberta T6G 2P5. The effectiveness of lactose hydrolysis by a free 13-galactosidase enzyme was compared in neutralized cottage cheese whey, ultrafiltra- tion whey permeate, heated whey, whole milk and buffered lactose solution. The highest 13-galactosidase activity was observed in heated and unheated wheys followed by the activity in the permeate and lactose solution. The enzyme activity in whole milk was only about 50% of that found in whey. Heating the cottage cheese whey at 72° C for 15 seconds prior to neutralization by KOH had no effect on the hydrolysis rate. Comparison between NaOH and KOH adjusted whey confirmed the inhibitory effect of Na on the 13-galactosidase enzyme used. USE OF NISIN AS AN ADJUNCT TO NITRITE ON THE SHELF LIFE OF BACON. Calderon*, C. and D.L. Collins-Thompson, Uni- versity of Guelph, Guelph, Ontario. The effects of various concentrations of nisin (250, 500 or 750 TU/g) combined with 50 ppm of nitrite on the shelf life of vacuum- packed bacon was evaluated. Control packages were included. Total numbers of lactic bacteria and organoleptic assessment were used as criteria quality. Bacon samples were stored at 30° C, 16° C and 5° C for four days, two weeks and six weeks respectively. At the end of the storage period the numbers of lactic acid bacteria were similar in all packages. The combination of nisin and nitrite resulted in a shelf life period comparable to that of bacon treated with 150 ppm of nitrite. In both cases, lactic acid bacteria were not inhibited. The bacon treated with 50 ppm of nitrite had a shorter life. RAPID DIRECT ENUMERATION OF ENTEROTOXIGENIC STAPHYLOCOCCUS AUREUS COLONIES ON MEMBRANE FIL- TERS BY ENZYME IMMUNOSORBENT TECHNIQUE. Peterkin*, Pearl I. and Anthony N. Shape, Bureau of Microbial Hazards, Food Directorate, Health Protection Branch, Health and Welfare Canada, Ottawa, Ontario. A method utilizing enzyme-linked immunosorbent assay (ELlS A) for the demonstration of staphylococcal enterotoxin (SE) production by S. aureus colonies on membrane filters (MF) was devised. When class IgM monoclonal antibodies of mouse origin were used, no cross reaction was observed between SEB producers and strains producing other SE. The method requires 4 h to complete and yields an insoluble colored products at the site of SEB-producing colonies thus allowing direct enumeration of enterotoxigenic S. aureus within 24 h. This work was carried out as part of a continuing program for the development of manual or automated MF techniques for use in food microbiology. LACTOBACILLI SPOILAGE OF VACUUM- OR NITROGEN- PACKAGED MEATS. Lee*, B.H., Agriculture Canada Research Sta- tion, St. Jean Quebec BB 6Z8 and R.E. Simard, Departement de Sciences et technologie des aliments, Universite Laval, Quebec GIK 7P4. Fifty lactobacilli isolates from anaerobically spoiled meats were compared with 24 authentic lactobacilli for their ability to produce hydrogen sulphide from different media. Four isolates indicated the presence of hydrogen sulfide, while some became yellow-brown and others caused no discoloration or died after growth. In addition, lactoba- cilli isolates from the greenish exudate and meat indicated that most greening lactobacilli are not hydrogen sulfide producers. A variety of morphological and biochemical characteristics of the isolates were com- pared with authentic lactobacilli by the methods of VPI anaerobe, Minitek and API-ZYM systems and results of this study will be pre- sented. CROISSANCE BACTERIENNE ET ACTIVITE DE LA CATALASE. Bourassa, Michel, Fran<;ois Pelletier et Alexandre Strachan, Universite du Quebec a Rimouski. Le dosage de la catalase a deja ete propose comme methode de controle de la qualite bacteriologique et d'estimation du temps de cuis- son de la saucisse. Utilisant des souches pures de differentes especes de bacteries, nous pouvons demontrer une correlation entre les comptes bacteriens (CFu/ml) et la concentration de catalase. Institute Affairs / xv
