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Energy use reduction and recovery from food dryers
THE USE OF TROPICAL ROOT STARCHES IN BREADMAKING. Keya*, Erastus and D. Hadziyev, Department of Food Science, University of Alberta, Edmonton, Alberta T6G 2P5. Starches from tubers of arrowroot, cassava, sweet potato, taro, and yam were studied for their affinity for vital gluten in formulation systems representing dough, early, and fully-baked stages of breadmaking. Water absorption, dough rheological properties and dough hydration capacities of composite flours were determined. Structure of dough and bread crumb, emphasizing starch grain spacing in protein matrix, was revealed by TEM and SEM. Bread volumes and crumb hydration capacity were also assayed. Retrogradation of crumb was followed by compressibility and X-ray crystallography measurements. Influence of monoglycerides on firming properties of crumb was also followed. Dough and bread from Neepawa (HRSW) and Fielder (SWSW) flours were used for comparison. Results proved the possible use of root starches in breadmaking formulations close in quality to that of a wheat bread.
DEHYDRATED POTATOES: IMPROVEMENT OF DRYING RATE AND RECONSTITUTION CHARACTERISTICS BY PHYSICAL AND CHEMICAL PRETREATMENTS. Nargal*, M. Sadiq and B. Ooraikul, Dept. of Food Science, University of Alberta, Edmonton, Alberta, T6G 2P5. Slow rehydration rate, brown discoloration and excessive breakage on handling are common problems associated with dehydrated potatoes such as hash browns. However, if drying rate could be increased, case-hardening, shrinkage and browning of the product may be minimized. This presentation will show that when hash brown potatoes were precooked in CaCI2 solution, steam-cooked, dipped in glycerol/surfactant emulsion then dried in a fluid bed dryer, the following improvements were obtained. Drying time was only I h. The product was less dense (0.15 g/c.c. vs 0.23 g/c.c.) and fully rehydrated after 20 min in hot water as compared to > 35 min for commercial product. Its color was lighter (L = 74 vs L = 69) and breakage on handling was also reduced.
VENTING OF VERTICAL RETORTS - ENERGY USE AND EFFECT OF CONDENSATE BUILD-UP. Smith, Trudi* and Marvin A. Tung, Department of Food Science, University of British Columbia, Vancouver, British Columbia, and Lee V. Bennett, T.J. Lipton Inc., Richmond, and Dan B. Cumming, Agriculture Canada, Summerland, British Columbia. Venting losses accounted for 17070 of retort energy use. Other major energy losses included 15070 in condensate, 10070 to heat the retort shell and baskets, 7070 loss through bleeders, and 4070 loss through radiation and convection. Only about 40070 of input energy was used to heat the product. It was observed that normal condensate buildup can interfere with retort venting. When condensate was purged, vent time could be significantly reduced with greater assurance of temperature uniformity in the retort. Energy savings of up to 15070 could also be realized.
COMPUTERIZED IMAGE ANALYSIS AND PROTEIN QUALITY OF SIMULATED PIZZA CRUSTS. Heyne*, L., N. Unklesbay, K. Unklesbay, J. Keller, Depts. of Food Science and Electrical Engineering, University of Missouri-Columbia, Columbia, MO 65211. Computerized image analysis was investigated as an automated quality control technique for determining the protein quality of simulated pizza crusts (SPC). A mini-computer with a digitizer and camera analyzed the surface of 12 groups of SPC, ranging from raw dough to visually black. Composite intensity numbers (CIN), represented the average gray level for the pixels or picture elements of the SPC. Cubic functions provided the best fits for lysine and DC-PER and C-PER, indicating lysine predicted protein quality. Quadratic and cubic functions of CIN with DC-PER and C-PER, respectively, indicated CIN gave a precise estimate of both DC-PER and C-PER.
EFFECTS OF CHEMICAL MODIFICATIONS ON THE PHYSICOCHEMICAL AND CAKE-BAKING PROPERTIES OF EGG WHITE PROTEINS. Ching-Yung Ma*, Linda Poste and Carol Patterson, Food Research Institute, Agriculture Canada, Ottawa, Ontario KIA OC6 and John Holme, Griffith Laboratories, Scarborough, Ontario, MIL 3J8. Egg white solids (EWS) were modified with succinic anhydride and a water-soluble carbodiimide. Both succinylation and carboxyl modification caused a change in net charge but no marked change in surface hydrophobicity or SH content. Succinylated EWS had poor performance in angel food cake system, probably due to poor foaming properties and low heat coagulability. The layer cake baking performance, however, was improved by succinylation which may be attributed to an increase in emulsifying capacity. Carboxyl modification did not cause marked changes in functional and baking properties of EWS, suggesting that ionic interaction is not a major factor in cake baking. ENERGY USE REDUCTION AND RECOVERY FROM FOOD DRYERS. Husain*, H., W.L. Wardrop & Associates Ltd. 77 Main Street, Winnipeg, Manitoba and L.D. Barker, Woodstone Foods, Portage la Prairie, Manitoba. Woodstone Foods processes field peas into protein, starch and fibre products. Wet processing is employed and protein fraction is dried in a spray dryer, and fibre and starch fractions dried in flash dryers. These dryers use over 75 percent of the plant's natural gas consumption and efficiency improvements can substantially reduce costs. This paper presents detailed investigations into energy use reduction for these dryers. A computer model has been used to perform complete mass and energy balances for each dryer. Recycling of part of the exhaust gases offers substantial energy savings, and the model determines the fuel savings and exhaust humidities for a range of recycle rates. Using data on drying rates, optimum recycle rates have been determined, and recycling systems designed for each dryer. Further energy use reductions are possible through preheating combustion air and alternative methods of recovery are discussed. Application of exhaust gas recycling and heat recovery techniques are discussed for various types of dryers used by the food industry. Can. Inst. Food Sei. Techno/. J. Vol. 17, No. 3, 1984
EFFECT OF OIL BLENDING ON THE UTILIZATION OF CANOLA OIL IN THE GROWING CHICK. Crick", D.C., D.B.Bragg and J .S. Sim, Department of Poultry Science, University of British Columbia, Vancouver, British Columbia V6T 2A2. It has been shown that improving the fatty acid balance of canola oil by blending with other fats produced a synergistic effect on energy utilization in experimental animals. A study was designed to investigate the influence of balancing the fatty acid profile of Canola oil by blending with other fats (sunflower oil and animal lard) on the nutritional quality of Canola oil utilized in chick diets. Canbra oil (CBO) containing 5.1070 erucic acid was blended with sunflower oil (SFO) or animal lard (AL) at 50:50 ratio. Canola oil (CAO) containing 0.5070 erucic acid was blended with SFO to various ratios (90: 10; 70:30 and 50:50). Two feeding trials were carried out with day-old single comb White Leghorn cockerels fed at a level of 8070 in the diet during a 4-week growing period. Results show that CBO is significantly inferior to SFO in promoting chick growth, whereas CAO is superior to either SFO or SBO in supporting chick growth. However, both oils were significantly improved by oil blending. Oil blending also improved digestibility of individual fatty acids.
COMPARISON OF PROTEOLYTIC PSYCHROTROPH COUNTS AND PROTEINASE ACTIVITY IN RAW MILK. Yan, Dan, * Nancy Baillie & Craig Maishment, Fraser Valley Milk Producers Co-op Assoc., Vancouver, British Coumbia V6B 4G4 and Brent J. Skura, Department of Food Science, University of British Columbia, Vancouver, British Columbia V6T 2A2. Proteolytic psychrotrophic bacteria in raw milk were enumerated by surface plating on skim milk agar (8 and 10 d, 4°C; 24 and 48 h, 21°C). Total non-casein nitrogen (NCN) soluble in 12070 tricWoracetic acid and NCN released by proteolytic enzymes in milk (40°C, 4 h) were determined for each milk sample. There was a a poor correlation between proteolytic psychrotroph counts (4°C or 21°C) and proteinase activity. It is recommended that estimation of proteinase activity (by measuring release of NCN from milk proteins) be evaluated as a quick (5 h) quality assurance procedure to determine suitability of milk for processing.
Institute Affairs I xxxi
DEHYDRATED POTATOES: IMPROVEMENT OF DRYING RATE AND RECONSTITUTION CHARACTERISTICS BY PHYSICAL AND CHEMICAL PRETREATMENTS. Nargal*, M. Sadiq and B. Ooraikul, Dept. of Food Science, University of Alberta, Edmonton, Alberta, T6G 2P5. Slow rehydration rate, brown discoloration and excessive breakage on handling are common problems associated with dehydrated potatoes such as hash browns. However, if drying rate could be increased, case-hardening, shrinkage and browning of the product may be minimized. This presentation will show that when hash brown potatoes were precooked in CaCI2 solution, steam-cooked, dipped in glycerol/surfactant emulsion then dried in a fluid bed dryer, the following improvements were obtained. Drying time was only I h. The product was less dense (0.15 g/c.c. vs 0.23 g/c.c.) and fully rehydrated after 20 min in hot water as compared to > 35 min for commercial product. Its color was lighter (L = 74 vs L = 69) and breakage on handling was also reduced.
VENTING OF VERTICAL RETORTS - ENERGY USE AND EFFECT OF CONDENSATE BUILD-UP. Smith, Trudi* and Marvin A. Tung, Department of Food Science, University of British Columbia, Vancouver, British Columbia, and Lee V. Bennett, T.J. Lipton Inc., Richmond, and Dan B. Cumming, Agriculture Canada, Summerland, British Columbia. Venting losses accounted for 17070 of retort energy use. Other major energy losses included 15070 in condensate, 10070 to heat the retort shell and baskets, 7070 loss through bleeders, and 4070 loss through radiation and convection. Only about 40070 of input energy was used to heat the product. It was observed that normal condensate buildup can interfere with retort venting. When condensate was purged, vent time could be significantly reduced with greater assurance of temperature uniformity in the retort. Energy savings of up to 15070 could also be realized.
COMPUTERIZED IMAGE ANALYSIS AND PROTEIN QUALITY OF SIMULATED PIZZA CRUSTS. Heyne*, L., N. Unklesbay, K. Unklesbay, J. Keller, Depts. of Food Science and Electrical Engineering, University of Missouri-Columbia, Columbia, MO 65211. Computerized image analysis was investigated as an automated quality control technique for determining the protein quality of simulated pizza crusts (SPC). A mini-computer with a digitizer and camera analyzed the surface of 12 groups of SPC, ranging from raw dough to visually black. Composite intensity numbers (CIN), represented the average gray level for the pixels or picture elements of the SPC. Cubic functions provided the best fits for lysine and DC-PER and C-PER, indicating lysine predicted protein quality. Quadratic and cubic functions of CIN with DC-PER and C-PER, respectively, indicated CIN gave a precise estimate of both DC-PER and C-PER.
EFFECTS OF CHEMICAL MODIFICATIONS ON THE PHYSICOCHEMICAL AND CAKE-BAKING PROPERTIES OF EGG WHITE PROTEINS. Ching-Yung Ma*, Linda Poste and Carol Patterson, Food Research Institute, Agriculture Canada, Ottawa, Ontario KIA OC6 and John Holme, Griffith Laboratories, Scarborough, Ontario, MIL 3J8. Egg white solids (EWS) were modified with succinic anhydride and a water-soluble carbodiimide. Both succinylation and carboxyl modification caused a change in net charge but no marked change in surface hydrophobicity or SH content. Succinylated EWS had poor performance in angel food cake system, probably due to poor foaming properties and low heat coagulability. The layer cake baking performance, however, was improved by succinylation which may be attributed to an increase in emulsifying capacity. Carboxyl modification did not cause marked changes in functional and baking properties of EWS, suggesting that ionic interaction is not a major factor in cake baking. ENERGY USE REDUCTION AND RECOVERY FROM FOOD DRYERS. Husain*, H., W.L. Wardrop & Associates Ltd. 77 Main Street, Winnipeg, Manitoba and L.D. Barker, Woodstone Foods, Portage la Prairie, Manitoba. Woodstone Foods processes field peas into protein, starch and fibre products. Wet processing is employed and protein fraction is dried in a spray dryer, and fibre and starch fractions dried in flash dryers. These dryers use over 75 percent of the plant's natural gas consumption and efficiency improvements can substantially reduce costs. This paper presents detailed investigations into energy use reduction for these dryers. A computer model has been used to perform complete mass and energy balances for each dryer. Recycling of part of the exhaust gases offers substantial energy savings, and the model determines the fuel savings and exhaust humidities for a range of recycle rates. Using data on drying rates, optimum recycle rates have been determined, and recycling systems designed for each dryer. Further energy use reductions are possible through preheating combustion air and alternative methods of recovery are discussed. Application of exhaust gas recycling and heat recovery techniques are discussed for various types of dryers used by the food industry. Can. Inst. Food Sei. Techno/. J. Vol. 17, No. 3, 1984
EFFECT OF OIL BLENDING ON THE UTILIZATION OF CANOLA OIL IN THE GROWING CHICK. Crick", D.C., D.B.Bragg and J .S. Sim, Department of Poultry Science, University of British Columbia, Vancouver, British Columbia V6T 2A2. It has been shown that improving the fatty acid balance of canola oil by blending with other fats produced a synergistic effect on energy utilization in experimental animals. A study was designed to investigate the influence of balancing the fatty acid profile of Canola oil by blending with other fats (sunflower oil and animal lard) on the nutritional quality of Canola oil utilized in chick diets. Canbra oil (CBO) containing 5.1070 erucic acid was blended with sunflower oil (SFO) or animal lard (AL) at 50:50 ratio. Canola oil (CAO) containing 0.5070 erucic acid was blended with SFO to various ratios (90: 10; 70:30 and 50:50). Two feeding trials were carried out with day-old single comb White Leghorn cockerels fed at a level of 8070 in the diet during a 4-week growing period. Results show that CBO is significantly inferior to SFO in promoting chick growth, whereas CAO is superior to either SFO or SBO in supporting chick growth. However, both oils were significantly improved by oil blending. Oil blending also improved digestibility of individual fatty acids.
COMPARISON OF PROTEOLYTIC PSYCHROTROPH COUNTS AND PROTEINASE ACTIVITY IN RAW MILK. Yan, Dan, * Nancy Baillie & Craig Maishment, Fraser Valley Milk Producers Co-op Assoc., Vancouver, British Coumbia V6B 4G4 and Brent J. Skura, Department of Food Science, University of British Columbia, Vancouver, British Columbia V6T 2A2. Proteolytic psychrotrophic bacteria in raw milk were enumerated by surface plating on skim milk agar (8 and 10 d, 4°C; 24 and 48 h, 21°C). Total non-casein nitrogen (NCN) soluble in 12070 tricWoracetic acid and NCN released by proteolytic enzymes in milk (40°C, 4 h) were determined for each milk sample. There was a a poor correlation between proteolytic psychrotroph counts (4°C or 21°C) and proteinase activity. It is recommended that estimation of proteinase activity (by measuring release of NCN from milk proteins) be evaluated as a quick (5 h) quality assurance procedure to determine suitability of milk for processing.
Institute Affairs I xxxi