Adaptabilidad de granos de híbridos de maíz super dulce sh2 al procesamiento industrial. II Enlatado / Super sweet corn hybrid sh2 adaptability for industrial canning process

The super sweet corns Krispy king, Victor and 324 (sh2 hybrids) were evaluated to determine their adaptabilities to the industrial canning process as whole kernels. All these hybrids and Bonanza (control) were sown in San Joaquín (Carabobo, Venezuela), harvested and canned. After 110 days storage at room temperature they were analyzed to be compared physically, chemically and sensorially with Bonanza hybrid. Results did not show significant differences among most of the physical characteristics, except for percentage of broken kernels which was higher in 324 hybrid. Chemical parameters showed significant differences (P < 0.05) comparing each super sweet hybrid with Bonanza. The super sweet hybrids presented a higher sugar content and soluble solid of the brine than Bonanza, also a lower pH. The super sweet whole kernel presented a lower soluble solids content than Bonanza but they were not significant (Krispy king and 324). Appearance, odor and overall quality were the same for super sweet hybrids and Bonanza (su). Color, flavor and sweetness were better for 324 than all the other hybrids. Super sweet hybrids presented a very good adaptation to the canning process, having as an advantage that doesn't require sugar addition in the brine and a very good texture (firm and crispy).

[Suitability study for super sweet corn on the ears hybrids under refrigerated conditions evaluating chemicals microbiological and sensorial characteristics]. / Estudio de la estabilidad de las características químicas, microbiológicas y sensoriales de mazorcas refrigeradas de híbridos de maíz super dulce.

Krispy King, Víctor and 324, super sweet hybrids (sh2) were cultivated in San Joaquín, estado Carabobo, Venezuela. The scheme was stablished to produce refrigerated fresh ears to be commercialized. The chemistry, microbiology and sensorial characteristics were evaluated at 0; 7; 14; 21 and 28 days of storage. One hundred ears of each hybrid were picked at the ripe fresh stage and packed in polystyrene trays covered with polyethylene. The storage temperature was 4 degrees C +/- 1 degree C. The scheme used was well adapted, allowing a good stability of the ears until 28 days of storing. The plastic cover avoid the lost of humidity. The soluble solids, total sugars and pH went down during the storage. The acidity and the microorganisms increased as expected. The sensorial variables kept the same for Krispy king and Víctor, while the hybrid 324 shown the lowest humidity content, the highest count of microorganisms and the poorest sensorial quality.

The effect of the omission of perfusate orthophospahate on lactate gluconeogenesis and Pi exchange in the perfused fasted rat liver

En la estandardización de un método para la perfusión del hígado de la rata. Hems et al., observaron que al omitir el fosfato del medio tenía lugar una reducción de la neoglucogénesis a partir de lactado, en un 50%. Con el propósito de utilizar esta técnica para producir deplección aguda de fosfato en el hígado, se realizaron experimentos similares con un perfusado que sólo difería por contener aproximadamente el doble de eritrocitos humanos (20-22%). Los glóbulos rojos humanos usados habían sido envejecidos 4-5 semanas en condiciones de banco de sangre. Hems y colaboradores encontraron que en estas condiciones los hematíes pierden su poder glicolítico y mantienen su capacidad para transportar oxígeno. Con el fin de acentuar la depleción de Pi, los hígados de las ratas previamente mantenidas en ayunas por 24 h. fueron perfundidos con medio sin fosfato por 75 min. y luego transferidos a otro aparato de perfusión también privado de Pi en el cual se mantuvo al órgano por 120 min. adicionales. A los 15 min. de haber montado el hígado para la segunda perfusión 1 micronCI de Pi de alta actividad por ml, se añadió al medio y a los 15 min. se tomó la muestra cero, de allí en adelante se obtuvieron muestras adicionales cada 15 min. La omisión de fosfato del medio no redujo la gluconeogenesis a partir del lactado ni aún añadiendo glucagon para estimular ese proceso. En los experimentos de perfusión del hígado y en los blancos en los cuales se hizo circular el perfusado en ausencia del hígado, se observó que el valor inicial de Pi era alrededor de 50% del obtenido con el medio standard, lo que indica que la liberación de fosfato por los hematíes y por el hígado no permitió trabajar con el medio libre del anión. La hemólisis fue mínima y las muestras fueron esfriadas rápidamente para evitar desintegración de compuestos fosforados. Se observó también que los glóbulos rojos humanos envejecidos por 4-5 semanas no pierden su poder glicolítico. En la depleción parcial del fosfato obtenida en nuestros experimentos, el lactado y con mayor intensidad el lactado...

Inhibition of the glucagon induced incorporation of orthophosphate into the liver by gluconeogenic blockers

Hígados aislados de ratas alimentadas, fueron perfundidos con un medio preparado a partir de solución KRB a la cual se añadieron: seroalbúmina bovina, 3g/dl; glucosa, 90 mg/dl; ortofosfato para obtener una concentración en el plasma de 1 mg/dl; 18 por ciento de glóbulos rojos de rata lavados; pH, 7.40, fase gaseosa O2 95%-CO2 5%. Flujo 36 ml/min. Temperatura, 37-C. Volumen del perfusado 70 ml. 0,5 micronCi de 32P-ortofosfato por ml. fueron añadidos al perfusado diez minutos antes de montar el hígado: el tiempo, 15 minutos después de montar el órgano, se tomó como punto cero. En los experimentos en los cuales se emplearon los bloqueadores de la neoglucogénesis ( quinolinato 1,68 mM o aminoóxi-acetato 0.2 mM) éstos fueron añadidos al perfusado al tiempo 15 min. el glucagon, cuando fue administrado, se empleó en inyección continua entre 45 y 90 min. (20 microngm). Se tomaron muestras cada 15 minutos hasta 120 minutos, que se recogieron en tubos enfriados en hielo. Glucosa en el perfusado, Pi en el plasma, 32Pi en perfusado y actividad específica del Pi plasmático fueron los parámetros determinados. Se calcularon Deltas a partir de 45 min. Los valores de glucosa y de Pi plasmático se corrigieron a partir de blancos obtenidos, haciendo circular el perfusado en ausencia del hígado y los resultados se expresaron por 10g de hígado fresco

Glucose and orthophosphate incorporation and lactate release in the perfused hind limb of the rat during lactic acidemia.

A perfused preparation of the hind limb of normal and diabetic rats was used to study the effects of lactic acidosis, alone or associated with hypoinsulinemic diabetes, on the incorporation of glucose and inorganic orthophosphate (Pi) into the skeletal muscle. A well oxygenated perfusate was recirculated for ninety minutes during which the lactic acid accumulated into the medium with the ensuing pH drop. The perfusions were practiced in the hind limb of alloxanized diabetic rats, in the hind limb of diabetic rats with perfusate containing 200 microU of insulin/ml, in the hind limb of 24 hour fasted rats, and on the hind limb of fed rats, and they were compared to similar groups with normalized pH perfusate with a sodium bicarbonate infusion. In the diabetic perfusions with lactic acidemia, it was observed that the addition of insulin increased the uptake of Pi and of glucose, and reduced the release of Pi by the muscular tissues. A smaller release of Pi by the preparations obtained from fed rats was observed when compared to the hind limb preparations of fasted rats. The diabetic preparations showed an increased glucose uptake when the pH was normalized, and a decrease of Pi released by the muscles, even in the absence of insulin, and at the same time, the administration of insulin associated with the normalization of pH increased the uptake of Pi and of glucose, and decreased the Pi released by the muscles. In all the groups, the administration of sodium bicarbonate significantly increased the lactate release into the medium. It was also found that the lactic acidosis reduced the uptake of Pi by the preparations inducing hyperphosphatemia. According to these results, muscular tissue plays a role in the hypophosphatemia that has been reported in the insulin treated diabetic ketoacidosis by increasing the incorporation of Pi and reducing its release by the same tissue.

Glucose and orthophosphate incorporation and lactate release in the perfused hind limb of the rat during lactic acidemia.

A perfused preparation of the hind limb of normal and diabetic rats was used to study the effects of lactic acidosis, alone or associated with hypoinsulinemic diabetes, on the incorporation of glucose and inorganic orthophosphate (Pi) into the skeletal muscle. A well oxygenated perfusate was recirculated for ninety minutes during which the lactic acid accumulated into the medium with the ensuing pH drop. The perfusions were practiced in the hind limb of alloxanized diabetic rats, in the hind limb of diabetic rats with perfusate containing 200 microU of insulin/ml, in the hind limb of 24 hour fasted rats, and on the hind limb of fed rats, and they were compared to similar groups with normalized pH perfusate with a sodium bicarbonate infusion. In the diabetic perfusions with lactic acidemia, it was observed that the addition of insulin increased the uptake of Pi and of glucose, and reduced the release of Pi by the muscular tissues. A smaller release of Pi by the preparations obtained from fed rats was observed when compared to the hind limb preparations of fasted rats. The diabetic preparations showed an increased glucose uptake when the pH was normalized, and a decrease of Pi released by the muscles, even in the absence of insulin, and at the same time, the administration of insulin associated with the normalization of pH increased the uptake of Pi and of glucose, and decreased the Pi released by the muscles. In all the groups, the administration of sodium bicarbonate significantly increased the lactate release into the medium. It was also found that the lactic acidosis reduced the uptake of Pi by the preparations inducing hyperphosphatemia. According to these results, muscular tissue plays a role in the hypophosphatemia that has been reported in the insulin treated diabetic ketoacidosis by increasing the incorporation of Pi and reducing its release by the same tissue.

Effect of fasting and insulin on the glucagon-induced orthophosphate incorporation to the isolated perfused rat liver.

Isolated perfused fed rat livers spontaneously liberated glucose and orthophosphate to the medium; 24-hr fasted rat livers did not exhibit these phenomena. In perfused fed rat livers, glucagon (2 mug) increased glucose output and promoted orthophosphate incorporation. In perfused fed rat livers, insulin (250 or 500 mU) inhibited the spontaneous liberation of glucose and orthophosphate. Comparable doses of insulin significantly reduced the glucagon (2 mug)-induced increase in glucose output from perfused fed rat liver, but did not affect orthophosphate uptake by the organ.