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Thermal Softening Kinetics Of Vegetables
The effect of temperature and pH on the stability of th~ sweetener sucralose has been investigated in order to determine its acceptability in beverages and under various heat processing conditions. Heat processes studied include pasteurization, sterilization, U.H.T. treatment and extrusion. It is demonstrated using HPLC analysis with Refractive Index detection that sucralose is an effective sweetener in heat processed foods and is particularly stable, even under the acidic conditions typically found in beverages.
tion of 0.7fr7o and ethanol of 1fr70 were achieved within 24 h of fermentation as compared to several months required by the traditional fermentation process.
41. A TECHNIQUE FOR CENTERPOINT NUTRIENT DEGRADATION IN CANS SUBJECTED TO THERMAL PROCESSING. H. Ramaswamy and S. Ghazala, Departments of Pood Science and Agricultural Engineering, Macdonald College of McGill University, Ste. Anne de Bellevue, P.Q. H9X 1CO. In the present studies, a technique was developed for the evaluation of centerpoint nutrient degradation in cans subjected to thermal processing. The methodology involved sealing of a 50-75 mL aliquote of test solution in a leakproof pressure-stable stainless steel capsule, placing the capsule at the geometric center of the can prior to closure, and recovering the capsule and analysing the contents following a given thermal process treatment. In these studics, temperature measurements at the geometric centers were obtained from several simultaneously processed cans and were assumed to represent the temperature response at the center of the test can. Experiments carried out using aqueous solutions of ascorbic acid analysed by a HPLC technique indicated good repeatability and reproducibility of results between replicate test samples and test runs. This technique provides a simple means, based on nutrient destruction, for the verification of several models currently used for thermal process calculations. 42.
KINETICS OF NUTRIENT DEGRADATION. S. Ghazala, H. Ramaswamy, F.R. van de Voort, S. Barrington and S. Prasher, Departments of Agricultural Engineering and Food Science,. Macdonald College of McGill University, Ste. Anne de Bellevue, P.Q. H9X 1CO. Degradation kinetics of ascorbic acid and thiamine were studied by heating aqueous solutions of these nutrients in sealed glass ampoules for known periods at 110 to 150°C. Both ascorbic acid and thiamine were estimated using HPLC techniques. The results showed that destruction kinetics of both nutrients obeyed a first order reaction and that the temperature dependence of rate constants could be described equally well by both Arrhenius and TDT concepts. The following kinetic data were obtained using TDT concept: (1) Ascorbic acid, D121.1 = 455 min; z = 39.4 QC. (2) Thiamine, D 121.1 = 394 min; z = 26.4°C.
43. THERMAL SOFTENING KINETICS OF VEGETABLES. G.S. Mittal, School of Engineering, University of Guelph, Guelph, Ont. N1G 2W1. Vegetables soften when heated in part due to the loss of turgor, but also due to complex chemical changes in the cell wall matrix polysaccharides. Kinetics parameters of potato and carrot were determined in the range of 30 to 90°C by monitoring the changes in texture profile analysis (TPA) parameters, stress relaxation properties, water holding capacity during thermal processing. The effect of temperature on the quality attributes were described by these kinetics parameters. Knowledge regarding the softening phenomena is useful in improving the design of processing schedules.
44.
45.
RELATIONSHIP BETWEEN COOKING KINETICS AND MEAT BATTER FILLER SELECTION. L. R. Correia*, Agricultural Engineering Department, Technical University of Nova Scotia B31 2X4 and G.S. Mittal, School of Engineering,University of Guelph, Guelph, Ont. NI G 2W l. Various textural and functional properties of the meat batter with or without fillers were determined in the raw state at product temperatures of 30, 40, 50, 60, 65 and 70°C, and after showering. Reaction kinetics modelled the cooking process, and based on the properties changes during cooking, the kinetics parameters were calculated. Regression models of enthalpy change of activation and fully cooked meat batter properties as a function of the filler properties were developed. The filler selection criteria were then developed. STABILITY OF THE SWEETENER SUCRALOSE IN AQUEOUS SOLUTION AT VARYING TEMPERATURES. I. Knight, M.R. Jenner and C. Heath, Redpath Sugars, 95 Queen's Quay E., Toronto, Ont. M5E 1A3.
408 / Abstract
46.
MODELISATION DU COMPORTEMENT OSMOTIQUE DE LA POMME DE TERRE EN PRESENCE DE SOLUTIONS SUCREES. M. Marcotte* et M. LeMaguer, Department of Food Science, University of Alberta, Edmonton, Alta. T6G 2P5. L' etude du comportement osmotique de pommes de terre en presence de solutions, variant de 5fr7o it 60fr7o (w /w) sucrose, a demontre, qu'it l'equilibre, le sucre ne penetre pas dans le protoplaste et que l'espace extracellulaire se remplit de solution sucree. L'approche thermodynamique a permis d'expIiquer le comportement du protoplaste en tenant compte de la structure et de la composition de la cellule. Le modele, developpe par Toupin (1986), a ete modifie pour decrire la cinetique du transfert de sucrose dans la pomme de terre. La comparaison des courbes experimentale et predite de penetration de sucre pour un traitement d'une heure dans une solution it 60fr7o indique que le modele explique adequatement les changements survenant dans la pomme de terre, lors du traitement osmotique.
47. DEVELOPMENT AND EVALUATION OFA CARROT LEATHER SNACK PRODUCT. N. L. Crowe*, M. Dench and J. Hironaka, Alberta Special Crops and Horticultural Research Centre, Brooks, Alta. TOl 010. The development of a carrot leather snack was initiated as a potential use for cull carrots. Carrots (mixed cvs) were finely ground, retaining both the pulp and the juice. Various acidulants (citric, malic acids) and texture-modifying agents (pectin, starch, applesauce) were used in the formulations. The resultant purees were dehydrated (55 C; 6-8 h) on trays (1 cm depth) and the finished products evaluated for color, texture, flavor, degree of splitting and separation. A formulation containing carrot, rhubarb juice, pectin, and sugar was selected based on in-house sensory tests. Nutritional and shelf-life studies examined the retention of nutrients (B-carotene, vitamin C) and product quality (color, texture). 48.
LA QUALITE NUTRITIONNELLE DU POLLEN A L'ETAT NATUREL ET TRANSFORME. J.A. Zee*, R. Breton, L. Lacroix et L Savoie, Departement de Nutrition humaine et de Consommation, Universite Laval, Quebec, P.Q. GIK 7P4. Le pollen contient plusieurs nutriments interessants., Afin d' ameliorer leur disponibilite, nous avons fait subir un traitement acide et un traitement enzymatique au pollen dans le but d'hydrolyser la paroi cellulaire. Les resultats indiquent que ces traitements n'affectent que peu la valeur nutritionnelle du pollen, it l'exception des fibres insolubles, Na et Pe. Le traitement acide diminue quelque peu la digestibilite proteique du pollen (52 au lieu de 57fr7o). Ainsi, le pollen it l'etat naturel est de qualite nutritionnelle equivalente aux pollens transformes.
49.
SWEET POTATO CHIPS: A CULTIVAR EVALUATION. J.I. 1 Vliegenthart1 R.Y. Yada2 *, R.H. Coffin 3 and E.C. Lougheed Departments of 1Horticultural Science and 2 pood Science, University of Guelph, Guelph, Ont. N1G 2Wl; and 3Agriculture Canada. Seven orange and two white-flesh sweet potato cultivars were assessed for chip quality in relation to sugar content. Three of the orange-flesh cultivars, which contained relatively low amounts of glucose and fructose, produced chips with acceptable colour. The white-flesh cultivars contained low levels of glucose and fructose but did not produce chips with acceptable colour. Minimal darkening appeared to be associated with low glucose and low fructose concentrations but unrelated to sucrose levels. Chilling increased the levels of sucrose but chip colour was not affected. J. Inst. Can. Sci. Technol. Aliment. Vol. 22, No. 4, 1989
tion of 0.7fr7o and ethanol of 1fr70 were achieved within 24 h of fermentation as compared to several months required by the traditional fermentation process.
41. A TECHNIQUE FOR CENTERPOINT NUTRIENT DEGRADATION IN CANS SUBJECTED TO THERMAL PROCESSING. H. Ramaswamy and S. Ghazala, Departments of Pood Science and Agricultural Engineering, Macdonald College of McGill University, Ste. Anne de Bellevue, P.Q. H9X 1CO. In the present studies, a technique was developed for the evaluation of centerpoint nutrient degradation in cans subjected to thermal processing. The methodology involved sealing of a 50-75 mL aliquote of test solution in a leakproof pressure-stable stainless steel capsule, placing the capsule at the geometric center of the can prior to closure, and recovering the capsule and analysing the contents following a given thermal process treatment. In these studics, temperature measurements at the geometric centers were obtained from several simultaneously processed cans and were assumed to represent the temperature response at the center of the test can. Experiments carried out using aqueous solutions of ascorbic acid analysed by a HPLC technique indicated good repeatability and reproducibility of results between replicate test samples and test runs. This technique provides a simple means, based on nutrient destruction, for the verification of several models currently used for thermal process calculations. 42.
KINETICS OF NUTRIENT DEGRADATION. S. Ghazala, H. Ramaswamy, F.R. van de Voort, S. Barrington and S. Prasher, Departments of Agricultural Engineering and Food Science,. Macdonald College of McGill University, Ste. Anne de Bellevue, P.Q. H9X 1CO. Degradation kinetics of ascorbic acid and thiamine were studied by heating aqueous solutions of these nutrients in sealed glass ampoules for known periods at 110 to 150°C. Both ascorbic acid and thiamine were estimated using HPLC techniques. The results showed that destruction kinetics of both nutrients obeyed a first order reaction and that the temperature dependence of rate constants could be described equally well by both Arrhenius and TDT concepts. The following kinetic data were obtained using TDT concept: (1) Ascorbic acid, D121.1 = 455 min; z = 39.4 QC. (2) Thiamine, D 121.1 = 394 min; z = 26.4°C.
43. THERMAL SOFTENING KINETICS OF VEGETABLES. G.S. Mittal, School of Engineering, University of Guelph, Guelph, Ont. N1G 2W1. Vegetables soften when heated in part due to the loss of turgor, but also due to complex chemical changes in the cell wall matrix polysaccharides. Kinetics parameters of potato and carrot were determined in the range of 30 to 90°C by monitoring the changes in texture profile analysis (TPA) parameters, stress relaxation properties, water holding capacity during thermal processing. The effect of temperature on the quality attributes were described by these kinetics parameters. Knowledge regarding the softening phenomena is useful in improving the design of processing schedules.
44.
45.
RELATIONSHIP BETWEEN COOKING KINETICS AND MEAT BATTER FILLER SELECTION. L. R. Correia*, Agricultural Engineering Department, Technical University of Nova Scotia B31 2X4 and G.S. Mittal, School of Engineering,University of Guelph, Guelph, Ont. NI G 2W l. Various textural and functional properties of the meat batter with or without fillers were determined in the raw state at product temperatures of 30, 40, 50, 60, 65 and 70°C, and after showering. Reaction kinetics modelled the cooking process, and based on the properties changes during cooking, the kinetics parameters were calculated. Regression models of enthalpy change of activation and fully cooked meat batter properties as a function of the filler properties were developed. The filler selection criteria were then developed. STABILITY OF THE SWEETENER SUCRALOSE IN AQUEOUS SOLUTION AT VARYING TEMPERATURES. I. Knight, M.R. Jenner and C. Heath, Redpath Sugars, 95 Queen's Quay E., Toronto, Ont. M5E 1A3.
408 / Abstract
46.
MODELISATION DU COMPORTEMENT OSMOTIQUE DE LA POMME DE TERRE EN PRESENCE DE SOLUTIONS SUCREES. M. Marcotte* et M. LeMaguer, Department of Food Science, University of Alberta, Edmonton, Alta. T6G 2P5. L' etude du comportement osmotique de pommes de terre en presence de solutions, variant de 5fr7o it 60fr7o (w /w) sucrose, a demontre, qu'it l'equilibre, le sucre ne penetre pas dans le protoplaste et que l'espace extracellulaire se remplit de solution sucree. L'approche thermodynamique a permis d'expIiquer le comportement du protoplaste en tenant compte de la structure et de la composition de la cellule. Le modele, developpe par Toupin (1986), a ete modifie pour decrire la cinetique du transfert de sucrose dans la pomme de terre. La comparaison des courbes experimentale et predite de penetration de sucre pour un traitement d'une heure dans une solution it 60fr7o indique que le modele explique adequatement les changements survenant dans la pomme de terre, lors du traitement osmotique.
47. DEVELOPMENT AND EVALUATION OFA CARROT LEATHER SNACK PRODUCT. N. L. Crowe*, M. Dench and J. Hironaka, Alberta Special Crops and Horticultural Research Centre, Brooks, Alta. TOl 010. The development of a carrot leather snack was initiated as a potential use for cull carrots. Carrots (mixed cvs) were finely ground, retaining both the pulp and the juice. Various acidulants (citric, malic acids) and texture-modifying agents (pectin, starch, applesauce) were used in the formulations. The resultant purees were dehydrated (55 C; 6-8 h) on trays (1 cm depth) and the finished products evaluated for color, texture, flavor, degree of splitting and separation. A formulation containing carrot, rhubarb juice, pectin, and sugar was selected based on in-house sensory tests. Nutritional and shelf-life studies examined the retention of nutrients (B-carotene, vitamin C) and product quality (color, texture). 48.
LA QUALITE NUTRITIONNELLE DU POLLEN A L'ETAT NATUREL ET TRANSFORME. J.A. Zee*, R. Breton, L. Lacroix et L Savoie, Departement de Nutrition humaine et de Consommation, Universite Laval, Quebec, P.Q. GIK 7P4. Le pollen contient plusieurs nutriments interessants., Afin d' ameliorer leur disponibilite, nous avons fait subir un traitement acide et un traitement enzymatique au pollen dans le but d'hydrolyser la paroi cellulaire. Les resultats indiquent que ces traitements n'affectent que peu la valeur nutritionnelle du pollen, it l'exception des fibres insolubles, Na et Pe. Le traitement acide diminue quelque peu la digestibilite proteique du pollen (52 au lieu de 57fr7o). Ainsi, le pollen it l'etat naturel est de qualite nutritionnelle equivalente aux pollens transformes.
49.
SWEET POTATO CHIPS: A CULTIVAR EVALUATION. J.I. 1 Vliegenthart1 R.Y. Yada2 *, R.H. Coffin 3 and E.C. Lougheed Departments of 1Horticultural Science and 2 pood Science, University of Guelph, Guelph, Ont. N1G 2Wl; and 3Agriculture Canada. Seven orange and two white-flesh sweet potato cultivars were assessed for chip quality in relation to sugar content. Three of the orange-flesh cultivars, which contained relatively low amounts of glucose and fructose, produced chips with acceptable colour. The white-flesh cultivars contained low levels of glucose and fructose but did not produce chips with acceptable colour. Minimal darkening appeared to be associated with low glucose and low fructose concentrations but unrelated to sucrose levels. Chilling increased the levels of sucrose but chip colour was not affected. J. Inst. Can. Sci. Technol. Aliment. Vol. 22, No. 4, 1989