ABSTRACT
Frambuesas (Rubus idaeus) se deshidrataron osmóticamente a través de un tratamiento convencional bajo el supuesto de solución homogénea, utilizando como medio una solución de glucosa al 62% a una temperatura de 50ºC. También se deshidrataron osmóticamente por medio de calentamiento óhmico, utilizando como medio una solución de glucosa al 57%, con voltaje variable (para mantener una temperatura entre 40-50ºC) y unaintensidad del campo eléctrico <100 V/cm. Al comparar los resultados se observa una evidente disminución en el tiempo de proceso al utilizar el calentamiento óhmico. En algunos casos, ésta reducción alcanzó hasta un 50%. Esto se explica por el efecto adicional al daño térmico que se genera en un proceso óhmico, denominado electroporación.
Acceleration of osmotic dehydration process through ohmic heating of foods: raspberries (Rubus idaeus). Raspberries (Rubus idaeus) were osmotically dehydrated by applying a conventional method under the supposition of a homogeneous solution, all in a 62% glucose solution at 50ºC. Raspberries (Rubus idaeus) were also osmotically dehydrated by using ohmic heating in a 57% glucose solution at a variable voltage (to maintain temperaturebetween 40 and 50ºC) and an electric field intensity <100 V/cm. When comparing the results from both experiments it was evident that processing time is reduced when ohmic heating technique wasused. In some cases this reduction reached even 50%. This is explained by the additional effect to the thermal damage that is generated in an ohmic process, denominated electroporation.
Subject(s)
Desiccation/methods , Fruit , Food Handling/methods , Hot Temperature , Rosaceae , Osmosis , Time FactorsABSTRACT
Se estudió el efecto de distintos tratamientos de esterilización sobre la calidad nutricional expresada como retención de tiamina y sobre la pérdida de color en conservas de salmón (Salmo salar). En la materia prima y en las conservas se determinó el contenido de tiamina mediante HPLC y la variación de color mediante colorímetro triestímulo Hunter. Las conservas se elaboraron en envase salmonero y se esterilizaron hasta alcanzar el valor Fo = 6 min. El valor nutricional representado por la tiamina se vio afectado por las altas temperaturas y por el tiempo de exposición al calor. La mayor retención de tiamina fue de 19,2% y se obtuvo en las conservas que se procesaron a 114°C por 89 min. El color de las conservas de salmón varió significativamente respecto a la materia prima, se produjo pérdida de coloración roja y mayor claridad de la carne.
The present work studied the effect of different treatments at high temperatures on the nutritional properties of thiamine retention and color measurement experimentally. Canned salmon (Salmo salar) was processed under different temperatures and time conditions (110°C for 135 minutes; 114°C for 89 minutes; 118°C for 69 minutes and 121°C for 62 minutes). Thiamine was determined by HPLC before and after the process. Color changes, due to processing conditions, were also measured utilizing a Hunter colorimeter. The canning was prepared in 300 x 407 cans and sterilized until Fo value reached 6 min. The nutritional value or index represented by the B1 vitamin or thiamine was affected by high temperature and time exposition. The lowest loss of thiamine of 19.2% was obtained in the canned salmon sterilized at 114°C for 89 minutes. The color in canned salmon was different from the raw material, with a severe loss of red color and a greater clarity of the meat.
Subject(s)
Animals , Color , Food Preservation/methods , Hot Temperature , Salmon , Thiamine/analogs & derivatives , Chromatography, High Pressure Liquid , Nutritive ValueABSTRACT
En este estudio se obtuvieron harinas a partir de la manaca o acai (Euterpe oleracea Mart), de la batata (Ipomea batatas), y del ñame (Dioscorea spp.), especies vegetales cultivadas en el Amazonas venezolano. A dichas harinas se les determinó su composición proximal, actividad de agua (aw), contenido de Fe, Ca, Zn, Mg, Cu, Na y K y se usaron como ingredientes de productos destinados a dos etnias del Amazonas Venezolano (Piaroa y Hiwi). Se formularon dos tipos de productos que tradicionalmente contienen harina de trigo en su formulación (ingrediente que ellos conocen por la transculturización), a los fines de sustituirla total o parcialmente por las harinas de manaca, batata y/o ñame. Para seleccionar los productos a formular se consideraron los gustos y hábitos alimentarios de las dos etnias, la facilidad y sencillez de las preparaciones. Los productos que se formularon fueron galletas y "torticas". Para decidir la(s) formulación(es) definitiva(s) se realizaron evaluaciones sensoriales a nivel de laboratorio y en las comunidades indígenas Piaroa y Hiwi. Destaca el alto contenido de grasa (16%), fibra dietética (59,7%) y hierro (73,7mg/100g) de la harina de manaca. Dos tipos de galletas y dos de "torticas" fueron igualmente aceptadas por las comunidades indígenas Las galletas aportan un alta cantidad de hierro (aproximadamente 24mg/100g). Se demostró la factibilidad de sustituir la harina de trigo por harina de manaca, batata y ñame en productos aceptados por dos etnias del amazonas venezolano.
In this study, flours from manaca or acai (Euterpe oleracea Mart), sweet potato (Ipomea batatas), and yam (Dioscorea spp.), species grown in the Venezuelan Amazon, were obtained. The proximal composition, water activity (aw), Fe, Ca, Zn, Mg, Cu, Na and K content were determined for the flours of manaca, sweet potato and yam. These flours were used as ingredients of products for the inhabitants of the indigenous populations of the Venezuelan Amazon (Piaroa and Hiwi). Two types of products that traditionally contain wheat flour in their formulation (ingredient they know by transculturation) were formulated; an attempt to substitute it totally or partially by the manaca, sweet potato and/or yam flours was made. For the selection of the products to be formulated, the preferences and eating habits of the indigenous communities and ease and simplicity of the preparations to be developed, were considered. The two products formulated were cookies and "small cakes". To decide on the formulation(s) of the final product(s), sensorial evaluations were made in the laboratory and in the indigenous communities Piaroa and Hiwi. High fat content (16%), dietetic fiber (59.7 %) and iron (25mg/100g) in manaca or acai flour were remarkable. Two types of cookies and two of "small cakes" were equally accepted by the indigenous communities. Cookies supply a high iron amount (about 24%). The feasibility of substituting the wheat flour by manaca, sweet potato and yam flour in products accepted by two ethnic populations of the Venezuelan Amazon was demonstrated.