Se realizo un estudio sobre el efecto de la temperatura (25, 35 y 45 grados C) en la cinetica de perdida de agua durante la deshidratacion osmotica de manzana en jarabe de sacarosa a 70 grados Brix. Para este proceso se utilizaron rodajas con geometria placa y en condiciones de minima resistencia difusional externa. Se aplico el modelo difusional de Fick para el ajuste de los resultados experimentales, completandose con la metodologia de Azuara para el calculo de las condiciones de equilibrio

O objetivo desta pesquisa foi estudar os efeitos da secagem sobre o comportamento fisiológico das sementes de tangerina (Citrus reticulata Blanco var. Cleópatra) durante o armazenamento. Assim, sementes extraídas manualmente de frutos maduros foram lavadas em água corrente e o excesso de água drenado à sombra. Em seguida, uma amostra representativa de sementes foi removida a fim de constituir a porção com o maior grau de umidade, 48%, a ser estudado. As sementes remanescentes foram submetidas a secagem em equipamento com circulação forçada de ar a 28±2°C, visando à obtenção dos percentuais de 39, 31, 24, 14, 10 e 7 referentes aos demais graus de umidade. As sementes, embaladas em sacos de polietileno, foram armazenadas em câmaras com temperatura controlada de 10 e 20°C. No início do armazenamento, e a intervalos de quatro semanas até 48 semanas, as sementes foram submetidas às seguintes avaliações: umidade, germinação, emergência de plântulas, índice de velocidade de emergência e comprimento de plântula. Concluiu-se que, considerando o intervalo de 39 a 7% de grau de umidade e a temperatura de 10ºC, o desempenho fisiológico de sementes de tangerina 'Cleopatra' durante o armazenamento, é favorecido pela desidratação até graus de umidade de, no mínimo, 24%. | The objective of this research was to study the effects of dehydration on the physiological performance of 'Cleopatra' tangerine (Citrus reticulata Blanco) seeds during storage. Thus hand extracted seeds from mature fruits were washed in running water and the excess water was drained in the shade. Thereafter, a representative sample of seeds was removed to constitute the portion with the highest water content (48%) to be studied. The remaining seeds were submitted to dehydration in a forced air circulation chamber at 28º±2ºC in order to obtain the other levels of 39, 31, 24, 14, 10 and 7% water contents. The seeds, packed in polyethylene bags, were stored in chambers maintained at temperatures of 10 and 20ºC. At the beginning of storage and then at four-weekly intervals, the seeds were submitted to the following evaluations: water content, germination, seedling emergence, speed of emergence index and seedling length. It was concluded that, considering the water content interval of 39 and 7% and the temperature of 10ºC, the physiological performance of 'Cleopatra' tangerine seeds during storage was favored by dehydration to water contents of at least, 24%.

RESUMEN Propósito: evaluar la efectividad, tolerancia y aceptación de dos bebidas ricas en potasio, comparadas con una bebida deportiva y agua, durante la rehidratación post-ejercicio. Metodología: en cuatro días diferentes, separados entre sí por una semana, 12 voluntarios (10 hombres y 2 mujeres), físicamente activos, con 24.4±3.2 años, 74.75±11.36 kg de masa corporal (promedio±D.E), fueron deshidratados al 2.01%±0.24 de la masa corporal, mediante ejercicio en un laboratorio de clima controlado (32.01±0.41 ºC bs, 53.83±5.15% hr). Cada día ellos fueron rehidratados con una de cuatro bebidas, en orden aleatorio: agua de coco (AC), agua comercial embotellada (AE), una bebida deportiva (BD) o una bebida modificada (BM), utilizando un volumen equivalente al 120% del peso perdido durante el ejercicio, distribuido en 4 porciones iguales consumidas cada 15 minutos. Antes del ejercicio, durante la rehidratación y al final de la sesión se interrogó sobre la percepción de sed, náuseas, llenura, dolor de estómago y urgencia de defecación. Se evaluó además el agrado del sabor, el nivel de dulzura y aceptación general de la bebida, antes del ejercicio y después de cada porción. Posteriormente, los participantes fueron monitoreados por 3 horas, recolectando orina cada 30 minutos. Resultados: los volúmenes de orina fueron mayores (p<0.05) con AE (894±178 mL), que con BD (605±297 mL) y BM (599±254 mL). Por su parte AC (686 ±250 mL), no fue diferente a las demás bebidas (p>.05). La única bebida que fue superior a la AE en el porcentaje de conservación de líquido fue la BD (51.3±% vs. 68.2±% respectivamente, p=.013), ya que al comparar el AC y BM (62.54±15% vs. 65.89±15% respectivamente) con el agua no se hallaron diferencias (p>.05). Ninguna de las bebidas logró la recuperación del peso perdido durante el ejercicio, pero AE produjo un mayor déficit (p=.001) al compararla con BD. No hubo interacción entre las bebidas y el tiempo sobre las percepciones de tolerancia y aceptación medidas en diferentes momentos (p>.05). Conclusiones: ni el agua de coco, ni la bebida modificada, ambas con alto contenido de potasio, pudieron superar los resultados encontrados con la bebida deportiva. Esto demuestra que el potasio en altas concentraciones no produce ventajas adicionales en el proceso de rehidratación, comparado con las ya obtenidas por una bebida que contiene sodio, incluso cuando los dos electrolitos se encuentran juntos en la misma bebida. | ABSTRACT Purpose: To evaluate effectiveness, tolerance and acceptance of two drinks rich in potassium, compared with a sports drinks and bottled water during post-exercise rehydration. Methodology: On four different days, one week apart, 12 healthy students, female (2) and male (10), physically active, young (24.4±3.2 years old) 74.75±11.36 kg of body mass (mean±S.D) students were dehydrated to 2.01±0.24% body mass by exercising in a climate-controlled laboratory (32.01±0.41 ºC dry bulb, 53.83±5.15% rh). Each day they were rehydrated with one of four beverages, in random order: fresh coconut water (CW), bottled water (BW), a sports drink (SD) and sports drink rich in potassium (SDK+) using a volume equivalent to 120% of weight lost during exercise, distributed in 4 equal aliquots, one every 15 minutes. After exercise, after rehydration, before drinking each volume and at the end of the session participants were asked about perception of thirst, nausea, fullness, stomach ache, and urge to defecate; after exercise and after completing each volume, they reported the level of satisfaction of flavor and sweetness, and general acceptability of the drink. Participants were then monitored for three hours, collecting urine every 30 minutes. Comparisons were made with repeated-measures ANOVAs for fluid retention, total urine, and partial times subjective measures and urine production. Results: Urine volumes were higher (p<0.05) for BW (894±178 mL) than SD (605±297 mL) and SDK+ (599±254 mL). On the other hand CW (686 ±250 mL) was not significantly different from the other beverages (p>0.05). The only beverage that was better than BW from the percentage of fluid retained was SD (51.3±% vs. 68.2±% respectively, p=.013), because the comparison between AC y SDK+ (62.54±15% vs. 65.89±15% respectively) with BW did not show significant differences (p>.05). None of the drinks maintained recovery of weight lost during exercise, but BW produced a greater deficit of fluids when that was compared with SD. There was no interaction between beverages and time over tolerance perceptions or acceptability of beverages evaluated in different moments (p>.05). Conclusions: neither CW nor SD, both with high concentrations of potassium, were able to overcome the results found for SD. This shows that potassium in high quantity in some beverages does not produce additional benefits in the rehydration process when these are compared to a SD with sodium, even when both electrolytes are together in the same beverage.

Objetivo: comparar la efectividad rehidratante del agua de coco fresca, con el agua embotellada y una bebida deportiva. Metodología: once participantes de 22,0 ± 1,9 años y 65,6 ± 13,0 kg de masa corporal (promedio ± D.E), asistieron al laboratorio en tres ocasiones, separadas entre sí por una semana. En cada sesión se deshidrataron por ejercicio en el calor hasta perder 1,84 ± 0,2% de la masa corporal. Luego fueron rehidratados en una hora, con agua comercial embotellada (AE), una bebida deportiva (BD) o agua de coco (AC), utilizando un volumen equivalente al 120% del peso perdido. Se evaluaron las sensaciones percibidas relacionadas con la tolerancia y la aceptación de las bebidas. Se recolectó la orina eliminada durante tres horas post-rehidratación. Resultados: Hubo interacción entre las bebidas y el tiempo sobre la orina excretada (p=0,003), siendo el AE estadísticamente diferente al AC y la BD a los 30 y 60 min post-rehidratación (p<0,05). El volumen total de orina fue mayor con agua embotellada (625 ± 183 mL), en comparación con AC y BD (390 ± 73 mL y 416 ± 200 mL, respectivamente, p<0,002); AC y BD no fueron distintas entre sí (p>0,05). Esto produjo porcentajes de conservación de líquido diferentes para AE (56%),con respecto a BD (71%) y AC (71%) (p<0,001). No hubo interacción entre las bebidas y el tiempo sobre las sensaciones percibidas de tolerancia (p>0,05). La percepción de la dulzura fue menor para AE (p= 0,024). BD obtuvo mejores puntajes de sabor y aceptación general (p<0,05). Conclusiones: el agua de coco fresca resulta tan efectiva como una bebida deportiva para conservar el líquido consumido, teniendo una buena tolerancia y aceptación. Podría ser usada como una bebida rehidratante, cuando la persona la tenga disponible y le agrade su sabor. | Objective: To compare the effectiveness of fresh coconut water as a rehydration beverage with bottled water and a sports drink. Method: eleven participants, 22.0±1.9 years of age and 65.6±13.0 kg body mass (average ± S.D.), reported to the laboratory on three separate occasions, each one week apart. Each time they exercised in the heat until they were dehydrated by 1.84 ± 0.2% of initial body mass. They were then rehydrated for one hour with commercial bottled water (BW), a sports drink (SD), or coconut water (CW), using a volume equivalent to 120% of weight loss. Perceived beverage acceptance and tolerance ratings were evaluated, and urine was collected over three hours following rehydration. Results: Urine volumes showed an interaction between beverage and time (p=0.003); BW was statistically different from CW and SD, 30 and 60 minutes after rehydration (p<0.05). Total urine volume was higher for BW (625 ± 183 mL) compared with both CW and SD (390 ± 73 mL and 416 ± 200 mL, respectively, p<0.002); CW and SD were not different from each other (p>0.05). This resulted in a different fluid conservation percentage for BW (56%) compared with CW (71%) and SD (71%) (p<0.001). Perceived tolerance ratings showed no interaction between beverage and time (p>0.05). Perceived sweetness was lower for BW (p= 0.024); SD had higher scores for flavor and overall acceptance (p<0.05). Conclusions: fresh coconut water is as effective as a sports drink in terms of fluid retained following consumption, and it has good tolerance and acceptance; it could be used for rehydration provided it is accessible to the individual and the person finds the flavor pleasing.