Alejandro Fernandez

Differentiation between Cooking Bananas and Dessert Bananas. 1. Morphological and Compositional Characterization of Cultivated Colombian Musaceae (Musa sp.) in Relation to Consumer Preferences

The morphological, physical, and chemical characteristics of 23 unripe cultivated varieties of Colombian Musaceae were assessed. Fresh pulp dry matter helped to discriminate the following consumption subgroups: FHIA dessert hybrids (hydes: 24.6%) < dessert bananas (des: 29.4%) < nonplantain cooking bananas (cook: 32.0%) < FHIA cooking hybrids (hycook: 34.2%) < plantains (pl: 41.1%). Banana flour starch content on dry basis (db) varied from 74.2 to 88.2% among the varieties, with: pl: 86.5% > cook and hycook: 84% > des: 81.9% > hydes: 79.7% (p <or= 0.01). Flour pH varied in the range 4.8 to 6.2, with the highest pH for the plantain subgroup (5.6), which also had lower titratable acidity than those of the cooking banana and FHIA groups with 7.9, 13.6, and 15.6 mEq H(+)/100 g db, respectively (p <or= 0.05). pl and hycook presented the highest glucose and fructose contents at 0.8% and 1.5% (p <or= 0.05). No significant differences were observed between the groups in proteins (3.2%), total soluble sugars (1.7%), and crude fibers (3%). pl had lower ash, calcium, and magnesium contents (2.7%; 8.4 and 90.7 mg/100 g db) than des (3.2%; 9.3 and 117.9 mg/100 g db) and hydes (3.9%; 23.7 and 125 mg/100 g db) (p <or= 0.05). pl and des had significantly lower peel percentages (38%) than the other subgroups (42-45%). The principal components analysis (PCA) highlights the strong relationship between some of the varietal characteristics and the consumption pattern, which is especially marked for the plantain subgroup in relation to stakeholder and the consumer preferences.

Differentiation between Cooking Bananas and Dessert Bananas. 2. Thermal and Functional Characterization of Cultivated Colombian Musaceae (Musa sp.)

The starch and flour thermal and functional characteristics of 23 cultivated varieties of bananas in Colombia were assessed. Onset temperature for gelatinization of starches measured by differential scanning calorimetry (DSC) varied from 59.7 to 67.8 degrees C, thereby significantly differentiating dessert bananas (63.2 degrees C) from nonplantain cooking bananas (65.7 degrees C) from FHIA hybrids (66.6 degrees C) and plantains (67.1 degrees C). FHIA hybrids are significantly discriminated from dessert banana landraces but not from the cooking group. The starch amylose contents varied from 15.4 to 24.9%; most dessert banana starch amylose contents were below 19%, whereas in cooking banana starches the contents were over 21%. Flour functional properties were assessed by Rapid ViscoAnalyser (RVA) using silver nitrate as alpha-amylase inhibitor. The flour pasting temperature was relevant to differentiate dessert bananas (69.5 degrees C) from FHIA dessert hybrids and nonplantain cooking bananas (72.8 degrees C) from cooking hybrids and plantains (75.8 degrees C). Among other criteria, the cooking ability also helped to differentiate dessert bananas and FHIA hybrids from cooking bananas. A close relation between cultivar genotypes and uses with the thermal and pasting properties were revealed.

Efecto de las Variables de Proceso sobre la Cinética de Acidificación, la Viabilidad y la Sinéresis del Suero Costeño Colombiano

In the present study the simultaneous effect of fermentation temperature, milk total solid level and total inoculums concentration on the acidification process, syneresis and viability of Colombian coastal whey, a fermented milk product, traditional of Colombia. For this the response surface methodology with three variables and five levels was employed. Fermentation was done using the bacteria Lactococcus lactis Subs. Lactis (ATCC29146) and Lactobacillus Paracasei Subs paracasei (ATCC 334). The statistical analysis allowed generating mathematical models that were used to determine that the total solids significantly decreased the maximum rate of acidification and syneresis of costal whey, while the temperature significantly affects the viability of lactic acid bacteria.

Parámetros de Calidad y Metodologías para Determinar las Propiedades Físicas de Alimentos Extruidos para Peces

espanolEl presente trabajo relaciona los metodos tradicionales usados para analizar la calidad fisica de un alimento extruido para peces, como dureza, durabilidad, estabilidad en agua, velocidad de hundimiento, densidad aparente, capacidad de absorcion-perdida de aceite y porosidad como metodos para en el control de su produccion a nivel industrial. Las propiedades fisicas de los pellets son relevantes para la toma de decisiones relacionadas con las condiciones de procesamiento, transporte, almacenamiento, aprovechamiento biologico del animal y evaluacion de nuevas materias primas y aditivos. Existen diversos metodos para determinar la calidad fisica de los pellets. Sin embargo, en su mayoria se relacionan con alimentacion de animales terrestres, los cuales no son apropiados para la alimentacion de peces. Estos requieren condiciones de resistencia al estres mecanico y al mismo tiempo presentar una textura y tamano que facilite la ingesta adecuada del alimento en el agua. EnglishThe present work relates the traditional methods used to analyze the physical quality of fish extruded food, such as hardness, durability, water stability, sinking speed, bulk density, oil absorption and loss capacity and porosity as methods for the control of Its production at an industrial level. The physical properties of the pellets are relevant for decision making related to the conditions of processing, transport, storage, biological use of the animal and evaluation of new raw materials and additives. There are several methods for determining the physical quality of the pellets. However, they are mostly related to feeding of terrestrial animals, which are not suitable for feeding fish. These require conditions of resistance to mechanical stress and at the same time should have a texture and size that facilitates the adequate intake of food in the water.