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Cereal and nut bars, nutritional quality and storage stability

Six snack-type bars were manufactured, to contain oat and wheat germ and two different walnut levels, agglutinated with natural sweeteners and fats. Two bars also contained toasted amaranth with brown sugar cover and wheat extrudate, while two others, contained puffed instead of toasted amaranth. Water activity (Aw) and moisture were determined in the manufactured products. Quality and sensory evaluation and proximate analysis were carried out on the bars containing highest levels of walnuts (18%). The caloric contribution of the bars was computed by Atwater methods. The nutritional quality of the bars was determined by means of the Protein Efficiency Ratio (PER) and Net Protein Ratio (NPR), and the results were used to obtain relative PER and relative NPR. Samples of the latter bars were kept under accelerated storage for 15 days at 37 °C and analyzed every 5 days to determine their Aw, moisture, peroxide and sensory acceptability. The drying time for the cereal — and walnut — based bars was 45 min at 120 °C. All bars presented a good fiber supply and the CN1 bar, containing only oat, wheat germ and walnut, had the greatest protein content. In the sensory evaluation, the walnut level with the greatest preference was 18%. PER and NPR values of the bars did not differ significantly showing values approximately 86% that of the casein value. During storage, the moisture and Aw decreased in all the bars. Peroxides remained within the acceptable ranges; acceptability based on sensory evaluation remained best in the bar with toasted amaranth. Walnuts can successfully be used in the manufacture of snack bars as these offer good nutritional and sensory quality and remain stable in storage.

Physical and rheological characterization of seeds of three legume trees

El algarrobo chileno (Prosopis chilensis (Mol) Stuntz), la tara (Caesalpinea spinosa (Mol) Kuntze) y la acacia de las tres espinas (Gleditsia triacanthos L) ofrecen un interesante potencial para promover el desarrollo de las zonas aridas. En el endosperma de sus semillas existe una goma del tipo galactomanano que posee propiedades viscosantes y estabilizadoras de emulsiones. Se realizo una investigacion para evaluar las caracteristicas fisicas de las vainas y semillas y las propiedades reologicas de las gomas de estas especies. Se estudiaron frutos de cinco ecotipos de algarrobo (Region de Coquimbo y Region Metropolitana), de tara (Region de Coquimbo) y de acacia de las tres espinas (Region Metropolitana). Se midieron las dimensiones de las vainas, numero de semillas/ vaina, peso de semillas, rendimiento y parametros de color de cotiledon y goma y las propiedades reologicas de las gomas extraidas. Las gomas se extrajeron manualmente y se secaron a 50 oQ En algarrobo, las semillas pesaron 0,04 g y el rendimiento de goma vario entre 25,5 y 31,5%. Las semillas de tara pesaron 0,14 g y las de acacia de las tres espinas 0,16 g, con un rendimiento de goma 31,0 y de 40,1% y respectivamente. Las gomas presentaron una alta luminosidad y contribucion del amarillo y baja contribucion de rojo. Las dispersiones, en todas las gomas estudiadas, presentaron un comportamiento no newtoniano del tipo Herschel-Bulkley, correspondiendo a un fluido inelastico, independiente del tiempo. La viscosidad aparente de la goma de algarrobo fluctuo entre 0,020 y 0,12, la de tara entre 0,06 y 1,3, y la de acacia de las tres espinas entre 0,034 y 0,08 Pa*s. Las gomas de estas especies tienen caracteristicas reologicas que permitirian su aplicacion en alimentos.