RESUMEN

This work evaluated the application of organic acids (acetic and peracetic acid) and ultrasound as alternative sanitization methods for improving the microbiological and physicochemical qualities of strawberries. A reduction of up to 2.48 log CFU/g aerobic mesophiles and between 0.89 and 1.45 log CFU/g coliforms at 35 °C was found. For molds and yeasts, significant differences occurred with different treatments and storage time (p < 0.05). Ultrasound treatments in combination with peracetic acid and acetic acid allowed a decimal reduction in molds and yeasts (p < 0.05). All evaluated treatments promoted a significant reduction in the Escherichia coli count (p < 0.05). Scanning electron microscopy revealed fragmented E. coli cells due to treatment with acetic acid and ultrasound. Storage time significantly affected pH, total titratable acidity, total soluble solids and the ratio of the total titratable acidity to the total soluble solids (p < 0.05). Anthocyanin content did not change with treatment or time and generally averaged 13.47 mg anthocyanin/100 g of strawberries on fresh matter. Mass loss was not significantly affected by the applied treatments (p > 0.05). The combination of ultrasound and peracetic acid may be an alternative to chlorine-based compounds to ensure microbiological safety without causing significant changes in the physicochemical characteristics of strawberries.

Asunto(s)

RESUMEN

Yacon flour has been used in several food products due to its high fructooligosaccharides and inulin contents, compounds that present health promoting properties. In this study, yacon flour was used as an ingredient in light yogurt in the following concentrations: 1.58; 2.56; 3.00 and 3.86%. Centesimal composition, pH, soluble solids, acidity and apparent viscosity of the yogurt supplemented with yacon were determined. Results were evaluated through analyses of variance and regression. Centesimal composition of the yogurts allowed for their classification as low-fat foods, presenting low carbohydrate content and containing dietary fiber, especially those supplemented with more than 2.56% yacon flour, which may be considered as sources of fiber and, consequently, prebiotics. Physicochemical analysis revealed significant (p<0.05) changes in analysis of color, soluble solids, acidity and viscosity at the temperatures of 10 and 25 °C with the increase in yacon flour.

La harina de yacón se ha utilizado en muchos productos alimenticios, debido a su alto contenido de fructooligosacáridos y inulina, compuestos que tienen propiedades promotoras de la salud. En este estudio, la harina de yacón fue utilizada como ingrediente en yogur "light" en las siguientes concentraciones: 1,58, 2,56, 3,00 y 3,86%. Se determinaron la composición centesimal, pH, sólidos solubles, acidez y la viscosidad del yogur suplementado con yacón se determinaron. Los resultados fueron evaluados mediante un análisis de varianza y de regresión. La composición centesimal de los yogures permite que los clasifiquen como alimentos bajos en grasa, con bajo contenido de carbohidratos y que contenga fibra dietética, particularmente aquellos suplementados con más de 2,56% de harina de yacón, que puede considerarse como fuente de fibra y, en consecuencia, prebióticos. El análisis físico-químico reveló cambios significativos (p <0,05) en el análisis de color, sólidos solubles, viscosidad y acidez a temperaturas de 10 y 25 °C con la harina de yacón en aumento.

Asunto(s)

RESUMEN

This study aimed to evaluate the physical-chemical, microbiological and sensory characteristics of four formulations of yacon jams. The following characteristics were analyzed: chemical composition, soluble solids, pH, microbiological presence of total coliforms and salmonella at 45 °C, and presence of fungi and yeasts. The yacon jams exhibited high moisture content (> 62%) as well as high concentrations of carbohydrates (> 28%) and total dietary fiber (2.5%), mainly fructooligosaccharides (> 0.9%). The average energy value was 124.6 kcal/100 g. The average pH was 3.8 and the soluble solids measured 27.6 °Brix. All yacon jams complied with standard microbiological requirements and received high acceptance scores, especially the yacon jam and yacon jam with cinnamon. Yacon jam products may offer an excellent alternative to more common jams due to their lower concentrations of simple sugar, lower calorie value, increased presence of dietary fibers, and desirable sensory characteristics.

Este estudio tuvo como objetivo evaluar las características físico-químicas, microbiológicas y sensoriales de cuatro formulaciones de mermeladas de yacón. Las características analizadas fueron: composición química, contenido de sólidos solubles, pH, presencia microbiológica de coliformes totales, coliformes y salmonella a 45 °C, y la presencia de hongos y levaduras. Los atascos de yacón mostraron alto contenido de humedad (> 62%), así como altas concentraciones de hidratos de carbono (> 28%) y fibra dietética total (2, 5%), principalmente fructooligosacáridos (> 0, 9%). El valor energético promedio fue de 124, 6 kcal/100g. El pH promedio fue de 3, 8 y los sólidos solubles mide 27, 6 ° Brix. Todas las mermeladas de yacón cumplido con los requisitos microbiológicos estándar y recibió altos puntajes de aceptación, en especial la mermelada de yacón y mermelada de yacón con canela. Productos de mermelada de yacón pueden ofrecer una excelente alternativa a los atascos más comunes debido a sus concentraciones más bajas de azúcar simple, un valor más bajo de calorías, el aumento de la presencia de fibras dietéticas y las características sensoriales deseadas.

Asunto(s)

RESUMEN

This study aimed at determining the total dietary fiber contents in yacon root pulp (YRP) and yacon flour(YF) by the AOAC enzymatic-gravimetric method, and fructans by high performance liquid chromatography(HPLC). The YF was put through the process of cleaning, sanitizing, bleaching, and YRP was dried at 55 Cfor 48 hours. The chemical composition of the YF and YRP was determined, being the total fiber contentsthe sum of the determinations by enzymatic-gravimetric method and HPLC. High contents of total dietaryfiber were detected in the dry mater of both YRP and YF samples (33.14 and 50.76%, respectively), beingmostly fructooligosaccharides [FOS] (37.97 and 40.97%, respectively), and substantial inulin contents (26.10and 20.75%, respectively). The chromatogram also showed high contents of fructose, glucose and sucroseas the sole source of carbohydrates besides fructans, inulin and FOS. The enzymatic-gravimetric methodsare considered the most suitable for routine analysis of dietary fibers, but are ineffective for determiningoligosaccharides with polymerization degree less than 12, as yacon. Thus, a complementary method, suchas HPLC, needs to be carried out to quantify the exacting dietary fiber contents in this root.

Este trabalho teve como objetivo determinar o teor total de fibras alimentares em polpa da raiz (PRY) e defarinha de yacon (FY) pelo método enzimático-gravimétrico segundo AOAC e os frutanos por cromatografialíquida de alta eficiência (HPLC). A FY foi preparada por meio do processo de limpeza, sanitização,branqueamento e a secagem da PRY a 55C por 48 horas. Foi determinada a composição centesimal da FYe da PRY; o teor de fibras totais correspondeu ao somatório das determinações pelo método enzimáticogravimétricoe HPLC. Encontrou-se elevado teor de fibra alimentar total (matéria seca) nas amostras de PRYe de FY (33,14 e 50,76%, respectivamente), com predomínio de frutooligossacarídeos [FOS] (37,97 e 40,97%respectivamente) e considerável teor de inulina (26,10 e 20,75%, respectivamente). O cromatograma tambémmostrou elevada concentração de frutose, glicose e sacarose como únicas fontes de carboidratos, além dosfrutanos, inulina e FOS. Os métodos enzimático-gravimétricos são considerados os mais apropriados paraanálises rotineiras de fibras alimentares, contudo estes são ineficazes para determinação de oligossacarídeos comgrau de polimerização menor do que 12, como é o yacon. Assim, é necessário efetuar métodos complementares,como HPLC, para quantificar com exatidão o teor total de fibra alimentar dessa raiz.