Cultivos lácticos como potenciadores de compuestos bioactivos de avena / Lactic starter cultures to improve the oat bioactive compounds

RESUMEN El objetivo de este trabajo fue estudiar la fermentación láctica como bioestrategia para potenciar la actividad antioxidante de la avena. Se evaluó la capacidad de 31 cepas de bacterias lácticas (BL) para adaptarse a un sistema de avena/agua (SAA) mediante la determinación del crecimiento, la acidificación y la actividad fermentativa (método impedimétrico; tiempo de detección [DT], velocidad máxima de cambio de conductabilidad [VMCC] y porcentaje de cambio de conductabilidad [PCC]). Además, se determinó el contenido de compuestos fenólicos (CF) mediante el método de Folin-Ciocalteu (equivalentes de ácido gálico [EAG]), así como de péptidos, de aminoácidos libres y de actividad antirradicalaria (métodos DPPH•y ABTS•+) de los extractos metanólicos y acuosos obtenidos a partir de los SAA fermentados (SAAf). Seis cepas mostraron la mejor adaptabilidad al SAA y produjeron altos valores de VMCC (0,34-0,47 μS/min) y PCC (53,6-66,6%), con bajos valores de DT (≤ 3 h). Estos cambios fueron acompañados por modificaciones en la concentración de CF, péptidos y aminoácidos libres, los cuales fueron dependientes de la cepa. Se evidenció un incremento de la concentración de CF en los SAAf de las seis cepas (29,1-39,85 μg EAG/ml) con respecto al SAA control (17,1 μg EAG/ml). Además, hubo un incremento (9-25,5%) en la actividad antioxidante de los extractos metanólicos de SAAf medida por ambos métodos. Respecto del contenido en péptidos/aminoácidos libres de los SAAf y de su actividad antioxidante, se encontraron modificaciones de menor magnitud. Los resultados muestran que las BL son capaces de adaptarse a la avena como sustrato de fermentación e incrementar su contenido de compuestos antioxidantes.

ABSTRACT The objective of this work was to study lactic fermentation as a biostrategy to enhance the antioxidant activity of oats. The adaptability of 31 strains of lactic bacteria (LB) in an oats/water system (OWS/SAA) was evaluated, measuring growth, acidification and fermentation activity (impedimetric method; detection time [DT], maximum rate of conductance change [MRCC/VMCC] and percentage of conductance change [PCC]). Moreover, the content of phenolic compounds (PC) was determined using the Folin-Ciocalteu method (gallic acid equivalents [GAE]), free peptides and amino acids and free radical scavenging activity (DPPH•and ABTS•+methods) of methanolic and aqueous extracts obtained from fermented OWS/SAAs (fOWS/SAAf) were determined. Six strains have shown the best adaptability to SAA, with high values of VMCC (0.34-0.47 μS/min) and PCC (53.6-66.6%), and low values of DT (≤ 3 h). In these f/OWS/SAAf the chemical composition was also modified (PC concentration, peptides and free amino acids) with strain-dependent behavior. The PC content in f/OWS/SAAf using these six strains (29.1-36.9 μg GAE/ml) was higher than the control content in OWS/SAA control (17.1 ± 1.9 μg GAE/ml). An increase (9-25.5%) in antioxidant activity in f/OWS/SAAf methanolic extracts was detected using both methods. Minor modifications were observed in the peptide and free amino acid content of SAA and their antioxidant activity. Our results show LB ability to adapt to oat as fermentation substrate and increase the content of its antioxidant compounds.

Consumo, desempenho e análise econômica da alimentação de cordeiros terminados em confinamento com o uso de dietas de alto grão / Consumption, performance and economic analysis of the feeding of lambs finished in feedlot as the use of high-grain diets

O presente experimento, conduzido no Laboratório de Ovinocultura da Universidade Federal de Santa Maria, teve como objetivo avaliar o efeito do uso de diferentes dietas de alto grão sobre o consumo de nutrientes e o desempenho de cordeiros terminados em confinamento, bem como realizar uma análise econômica da alimentação utilizada para terminação dos animais. Foram utilizados 32 cordeiros machos, castrados, da raça Texel, nascidos de parto simples e desmamados com aproximadamente 50 dias de idade. Os tratamentos foram constituídos por diferentes tipos de grãos, não processados, sendo: grão de milho, grão de aveia branca, grão de aveia preta ou grão de arroz com casca. Os animais foram abatidos quando atingiram o peso vivo de abate pré-estabelecido de 32kg, que corresponde a 60% do peso adulto de suas mães. Cordeiros alimentados com dietas de alto grão de milho apresentam maiores consumos de matéria seca, matéria orgânica, proteína bruta, carboidratos totais e de nutrientes digestíveis totais, menor consumo de fibra em detergente neutro, melhor escore de condição corporal, ganho de peso e conversão alimentar, o que leva à redução do número de dias no confinamento necessários para atingir o peso de abate. Além disso, cordeiros terminados com o uso de dieta de alto grão à base de grão de milho proporcionam melhor resultado econômico quando comparados com cordeiros terminados com as demais dietas de alto grão utilizadas neste experimento. O uso de dietas de alto grão de milho, aveia branca, aveia preta ou arroz com casca para terminação de cordeiros em sistema de confinamento é uma alternativa viável do ponto de vista produtivo. Porém, o uso de grão de milho proporciona melhores resultados produtivos e econômicos.

This experiment was conducted at the Laboratory of Sheep, Federal University of Santa Maria, and aimed to evaluate the effect of using different high-grain diets on nutrient intake and performance of lambs in a feedlot, as well as conduct an economic analysis of feeding used for termination of the animals. A total of 32 Texel breed castrated male lambs, born from a simple birth and weaned at approximately 50 days of age were used. The treatments consisted of different types of grains, unprocessed, as follows: corn grain, white oat grain, black oat grain or grain of rice in the husk. The animals were slaughtered when they reached a pre-established body weight of 32kg for slaughter, which corresponds to 60% of the mature weight of their mothers. Lambs fed diets with high corn grain have higher intakes of dry matter, organic matter, crude protein, total digestible nutrients and total carbohydrate, lower consumption of neutral detergent fiber and better body condition score, weight gain and feed conversion, which leads to reduction in the number of days in confinement needed to reach slaughter weight. In addition, lambs using high-grain diet based grain corn provide better economic results when compared with lambs with other high-grain diets used in this experiment. The use of diets high in grain corn, white oat grain, black oat grain or grain of rice in the husk for finishing lambs in feedlot is a viable alternative from a productive point of view. However, the use of corn grain provides better performance and economic results.

Respuesta glicémica al consumo de una barra de cereales-leguminosa (Phaseolus vulgaris) en individuos sanos / Glycemic response to consumption of a cereals and legume (Phaseolus vulgaris) bar on healthy individuals

El objetivo de la presente investigación fue formular una barra de cereales y leguminosa (Phaseolus vulgaris) y evaluar su impacto sobre la respuesta glicémica de individuos sanos, a fin de contribuir con la oferta de alimentos beneficiosos para la salud del consumidor. Para esto se formuló una barra con una mezcla de cereales (maíz y avena) y dos porcentajes (20% y 30%) de Phaseolus vulgaris. Adicionalmente, se preparó una barra de cereales sin leguminosa (barra control). Mediante evaluación sensorial, se seleccionó la barra con 30% de Phaseolus vulgaris, por ser evaluada con mejor sabor y textura, además esa combinación de cereales y leguminosas favorece la complementación aminoacídica y los criterios de formulación previamente establecidos. La caracterización química indicó un contenido de proteínas mayor en la barra con 30% de Phaseolus vulgaris (13,55%), en relación a la barra control (8,5%). Los contenidos de grasa, cenizas y fibra dietética no presentaron diferencias (p>0,05) entre ambas barras evaluadas. Sin embargo, el contenido de fibra soluble y de almidón resistente de la barra seleccionada resultó un 32,05% y 18,67% mayor, respectivamente, que en la barra control, con lo cual se podría contribuir con la disminución de la velocidad de absorción de la glucosa. La barra seleccionada presentó un índice glicémico bajo (49) y carga glicémica intermedia (12,0) en voluntarios sanos, lo que podría traducirse en una posible reducción de la tasa de absorción de glucosa al torrente sanguíneo, asociada a un contenido de carbohidratos de absorción lenta. La barra formulada representa una propuesta de merienda saludable para el consumidor.

The objective of this work was to formulate a cereals and legume (Phaseolus vulgaris) bar and assess its impact on the glycemic response of healthy individuals, in order to contribute to the healthy food supply beneficial to consumers. A mixture of cereals (corn and oats) and different percentages (20 and 30%) of Phaseolus vulgaris was used to formulate the bar. Additionally, a legume cereal bar without legumes (bar control) was prepared. The bar with 30% of Phaseolus vulgaris was selected through sensory evaluation, being scored with better flavor and texture. This combination of cereals and legumes aminoacid improves complementation and reaches the formulation criteria previously established. Chemical characterization indicated a higher protein content in the bar with 30% of Phaseolus vulgaris (13,55%) relative to the bar control (8,5%). The contents of fat, ash and dietary fiber did not differ between the two bars evaluated. However, the soluble fiber and resistant starch of the selected bar was a 32,05% and 18,67%, respectively, than in the control bar; this may contribute to decreasing the rate of glucose uptake. The selected bar presented a low glycemic index (49) and intermediate glycemic load (12,0) in healthy volunteers, which could lead to a possible reduction in the rate of absorption of glucose into the bloodstream, associated with a carbohydrate content of slow absorption. This bar represents a proposal of a healthy snack for the consumer.

Efecto del consumo de dietas con avena y caraotas negras sobre el perfil lipídico en un modelo experimental en rata / Effect of consumption of diets with oats and black beans on the lipid profile of an experimental model in rat

El consumo de alimentos ricos en fibra dietética (FD) soluble e insoluble, afecta favorablemente el perfil de lípidos séricos al reducir las concentraciones de colesterol total, colesterol- LDL y triglicéridos (TG). El objetivo de este trabajo, fue comparar el efecto del consumo de dietas con avena (Avena sa tiva) y con caraotas negras (Phaseolus vulgaris ) sobre el perfil lipídico de ratas. Quince ratas machos, cepa Sprague Dawley, fueron alimentadas ad libitum por 18 días, con tres tipos de dietas: un con trol, una conteniendo caraotas negras (15% p/p) y otra con avena (15% p/p). La concentración del colesterol total sérico disminuyo 50,56% en el grupo alimentado con avena y 40,52% en el alimentado con caraotas. Así mismo, se observó una disminución de colesterol-LDL de 49,21% en el grupo alimentado con avena y un 42,93% en el grupo alimentado con caraotas. Hubo una reducción de 52,47% del colesterol-HDL en el grupo alimentado con avena y 31,29% para el grupo alimentado con caraotas; esta reducción no es beneficiosa. La concentración de TG séricos fue significativamente menor, un 50,20% para el grupo alimentado con avena y de 51,8% para el grupo alimentado con caraota. La disminución de los lípidos séricos debido a la dieta, con avena o con caraotas, mostró diferencias significativas respecto al control, pero, no entre ellas. La consideración de estos resultados en el caso de la salud humana es bien importante, particularmente en la disminución de la prevalencia de enfermedades cardiovasculares. El efecto de FD sobre los niveles de colesterol-HDL, son hasta los momentos, contradictorios.

The consumption of foods rich in soluble and insoluble dietary fiber (DF) favorably affects the serum lipid profile by lowering total cholesterol, LDL-cholesterol and triglycerides (TG). The objective of this work was to compare the effect of consumption of diets with oats (Avena sativa) and black beans (Pha seo lus vulgaris) on the lipid profile of rats. Fifteen male rats, Spra gue Dawley strain were fed ad libitum for 18 days, with three different diets: a control, one containing black beans (15% w / w) and another with oats (15% w / w). The serum total cholesterol concentration decreased 50.56% in the group fed with oats and 40.52% in the group fed with beans. Also a de crease of LDL-cholesterol 49.21% in the group fed with oats and 42.93% in the group fed with beans was observed. There was 52.47% reduction of HDLcho lesterol in the group fed with oats and 31.29% for the group fed with beans, this is not a be neficial reduction. The serum TG concentration was significantly lower, 50.20% for the group fed with oats and 51.8% for the group fed with beans. The decrease of these lipids due to diet containing oats or beans, was significantly different from control but not between them. Consideration of these results for human health is very important, particularly in reducing the prevalence of cardiovascular disease. The FD effect on HDL-cholesterol levels, are until now contradictory.