Papa nativa variedad Michuñe negra: caracterización, condiciones de fritura y evaluación sensorial.. El presente trabajo tiene por objetivo evaluar la composición química y nutricional de papa Michuñe negro (BM), establecer condiciones de proceso de fritura, determinar el perfil sensorial y aceptabilidad de papas fritas chips. BM presentó un mayor contenido proteico, la mitad de extracto etéreo y extracto libre de nitrógeno, una menor ingesta calórica (70 kcal/100g) y un menor contenido de amilosa (17,5%) comparada con la variedad Desirée (DES). Para establecer condiciones de fritura se utilizó metodología Taguchi empleando una matriz de diseño L9 (32,22). Las variables seleccionadas fueron: temperatura, tiempo, variedad de papa (materia prima) y pretratamiento. Las respuestas evaluadas fueron: diferencia de color, contenido de azúcares reductores y polifenoles totales. Las mejores condiciones de fritura fueron: BM con pretratamiento a 160ºC por 7 min para color, DES sin pretratamiento a 140ºC por 7 min para azúcares reductores y BM sin pretratamiento a 180ºC por 4 min para polifenoles totales. Luego, los perfiles sensoriales de las papas chips de BM, DES y comercial fueron determinados seleccionando los descriptores textura, firmeza, sasbor salado y aceitoso. Se encontraron diferencias significativas en los descriptores color y aceitoso. El color (64%) fue el único atributo que obtuvo un nivel de aceptación más bajo entre los otros como textura (95%), sabor salado (87%) y producto (97.3%). Este estudio demostró que los chips de BM fueron satisfactoriamente aceptados por los consumidores.

The aim of this study was to evaluate the chemical and nutritional composition, to establish frying processing conditions and to determine the sensory profile and acceptability of Black Michuñe (BM) potato chips. BM had a higher protein content, half the ether extract content and nitrogen-free extract, a lower caloric intake (70 kcal/100g) and amylose content (17.5%) than Desirée (DES). To set the frying conditions, the Taguchi method was applied using a matrix design L9 (32,22). The variables studied were: temperature, time, potato variety (raw material) and pretreatment. The responses evaluated were: the color difference as well as the content of reducing sugars and total polyphenols. The best frying conditions were BM with a pretreatment at 160°C for 7 min for color, DES without pretreatment at 140°C for 7 min for reducing sugar content, and BM without pretreatment at 180°C for 4 min for polyphenol content. Then, sensory profiles of potato chips from BM, DES and a commercial package were determined by selecting the descriptors texture, firmness, color, salty taste and oiliness. Significant differences in color and oiliness were found. Finally, the acceptability test was applied to BM potato chips where color (64%) was the only attribute not as accepted as texture (95%), salty taste (87%) and product (97.3%). This study demonstrated that BM potato chips have a satisfactory acceptability by consumers.

Scientific evidence supports flaxseed consumption; however, a large sector of the population is still unaware of the benefits associated to its consumption and its possible applications as functional food ingredient in foodstuffs. Flaxseed is mainly known by its high alpha-linolenic acid content, but it is also a lignan source, soluble fibre and protein, compounds which are biologically active in the prevention of some non-transmissible chronic diseases. Southern Chile has comparative advantages for the cultivation of this crop. Together with its full processing, this crop could strengthen regional industry. The purpose of the present review is to highlight the nutritional properties of flaxseed.

Thraustochytrids are marine protists found throughout the world in estuarine and marine habitats. These microorganisms have attracted interest, because their lipids contain different long chain polyunsaturated fatty acids (PUFAs). Those able to produce docosahexaenoic acid (C22:6 n-3, DHA) are the most studied because of the physiological importance of this PUFA in human beings. Their heterotrophic cultivation offers several challenges since biomass, lipid content, and fatty acid profile are dependent on growth conditions. In this work the effects of C source and its concentration on DHA production by different thraustochytrid strains are reviewed. Results obtained by different investigators on the use of alternative and low cost nutrient sources for production of DHA by thraustochytrids are also presented.

Flax (Linum usitatissimum) has been used for centuries as a source for oil extraction. In recent years it has attracted considerable interest as a result of studies which attribute potential health benefits to its components, including the prevention of chronic non-communicable diseases. Among these compounds presenting biological activity, alpha-linolenic acid, lignans and soluble fibre are of special interest. Southern Chile has comparative advantages for the cultivation of this crop. Together with its full processing, this crop could strengthen regional industry. The purpose of the present work is to learn how the best use can be made of these compounds, by studying flaxseed and flaxseed cake as sources of compounds of interest for food industry. Oil extracted from flaxseed contained 51.86% of linolenic, 16.34% of linoleic and 20.98% of oleic acid. Fractioning of defatted flaxseed cake produced a polyphenol content of 0.73 mg GAEg-1 extract and a protein isolate of considerable purity, 53.15% yield with 0.78 gof albumin equivalent g-1 protein isolate. Additionally, a polysaccharide was isolated with low protein content as impurity, 10.71% yield with 1.37 mg of glucose equivalent per gram of polysaccharide. This information will form the basis for assessing the extraction of products of interest for the food industry from flaxseed cake.

This work presents the design and implementation of a feed-forward proportional fuzzy controller with an adaptation mechanism (CDPP-MA). This controller was designed for temperature feedback control in a fluidized bed reactor. The fuzzy controller algorithm is programmed in Intouch’s Script language. Matlab software was used for the design and configuration of the fuzzy controller’s parameters. Experimental tests were carried out in a pilot plant and included changes of reference of the controller and applications of disturbances to the system. Excellent performance was obtained with the controller, both in following the reference and in attenuation of the disturbances. The results show the implemented controller to be a feasible alternative to for use in control of highly non-linear or strongly disturbed processes

En el presente trabajo, se muestra el diseño e implementación de un controlador difuso proporcional-prealimentado con Mecanismo de Adaptación (CDPP-MA) para regular la temperatura en el interior del de un secador por lecho fluidizado. El algoritmo del controlador difuso se programa en el “Script” de Intouch, mientras que para diseñar y configurar los diferentes parámetros del controlador difuso se utiliza el software Matlab. Las pruebas se llevaron a cabo en una Planta Piloto e incluyeron cambios en la referencia del controlador y la aplicación de perturbaciones al sistema. El controlador presenta buen desempeño, tanto en el seguimiento de la referencia como en la atenuación de las perturbaciones. Los resultados indican que el controlador implementado es una alternativa factible de ser usado en el control de procesos no lineales o fuertemente perturbados.

A hybrid neural network model for simulating the process of enzymatic reduction of fructose to sorbitol process catalyzed by glucose-fructose oxidoreductase in Zymomonas mobilis CP4 is presented. Data used to derive and validate the model was obtained from experiments carried out under different conditions of pH, temperature and concentrations of both substrates (glucose and fructose) involved in the reaction. Sonicated and lyophilized cells were used as source of the enzyme. The optimal pH for sorbitol synthesis at 30º C is 6.5. For a value of pH of 6, the optimal temperature is 35º C. The neural network in the model computes the value of the kinetic relationship. The hybrid neural network model is able to simulate changes in the substrates and product concentrations during sorbitol synthesis under pH and temperature conditions ranging between 5 and 7.5 and 25 and 40º C, respectively. Under these conditions the rate of sorbitol synthesis shows important differences. Values computed using the hybrid neural network model have an average error of 1.7·10-3 mole.