ABSTRACT
Biological macromolecules such as starches of different amylaceous sources have been used in the formulation of edible films. However, there are few studies aimed at evaluating edible and intelligent films with response to pH changes from natural pigments, this despite the importance of these materials. In this context, films from native and modified plantain flour, plasticized with glycerol, with or without the addition of beet flour were developed. The chemical and structural composition of the flours, and its incidence on thickness, water solubility, contact angle, and mechanical and microstructural properties were evaluated, thus as its response to pH changes of the developed films. The observations showed that the incorporation of beet flour allowed to obtain intelligent films front to pH changes alkaline. Likewise, the betalains that were found in beet flour interacted more efficiently with the phosphated plantain flour, limiting well its immediate response to pH changes. In the same way, proteins and sugars of beet flour allowed to obtain more flexible films, due to the hydrogen bond interactions between these constituents and the plantain flours. This latter could justify the decrease of contact angle, and the increase on thickness and solubility of these films.
Subject(s)
Flour , Macromolecular Substances/chemistry , Plantago/chemistry , Hydrogen-Ion Concentration , Macromolecular Substances/ultrastructure , Mechanical Phenomena , SolubilityABSTRACT
Los errores innatos del metabolismo se definen como trastornos genéticos que ocurren en la estructura y/o función de las moléculas proteicas. Uno de estos trastornos, es la fenilcetonuria (PKU, por sus siglas en inglés), la cual se presenta debido a la alteración en la reacción enzimática de la hidroxilación de fenilalanina (F). El tratamiento de la PKU es básicamente nutricional, por lo cual, en Venezuela, se están evaluando nuevas materias primas con bajo contenido de F, de manera que puedan ser incluidas en dietas de niños fenilcetonúricos. Estas materias primas, deben ser validadas a través de pruebas biológicas in vivo usando animales experimentales, antes de suministralos a los humanos. En el presente estudio se evaluó la harina de plátano Musa paradisíaca (como ingrediente único) como coadyudante en el manejo nutricional de ratones fenilcetonuricos inducidos experimentalmente utilizando un bloqueante de la enzima a-metilfenilalanina a una dosis de 24 µM/10 g peso vivo (PV) y el aminoácido D-fenilalanina a una dosis de 52µM/10 g p.v. Se observó que los ratones presentaron solo una elevación de los niveles de F (P≤0,05) alcanzando una hiperfenilalaninemia leve (4-10mg/dL de sangre) durante la etapa predestete. Sin embargo, al ser sometidos a una alimentación postdestete con la harina de plátano, como única fuente nutritiva, se pudo observar una diferencia en el desarrollo del animal (P≤0,05), evidenciándose un marcado deterioro y desnutrición. Se recomienda realizar estudios adicionales, que incorporen junto con la harina de plátano, un glicomacropéptido que supla los requerimientos mínimos nutricionales de los ratones en crecimiento y mantenga bajo los niveles de F.
Inborn errors of metabolism are defined as genetic disturbances that occur in the structure and/or function of protein molecules. Phenylketonuria (PKU) is a good example of this type of disturbance, which is due to an alteration in the enzymatic reaction responsible for phenylalanine (Phe) hydroxylation. Treatment of this disease is basically nutritional. In Venezuela, new raw materials with a low content of Phe are being tested, so that they can be included in the diets of children suffering from PKU. Previous administration to humans, these raw materials should be validated by in vivo biological tests, using laboratory animals. Therefore, the purpose of this study was to assess the plantain (Musa paradisíaca) meal, as the only ingredient, in the nutritional management of experimentally induced PKU in laboratory mice, using a-methyphenylalanine, as the agent responsible for blocking phenylalanine hydroxylase, at a dose of 24 µM/10 of body weight (BW). To help blockade, a dose of D-phenylalanine (52 µM/10g of BW), was also administered. The results of the investigation showed that during the pre-weaning stage, mice exhibited a slight elevation in Phe levels that was statistically significant (P≤0.05), reaching a hyperphenylalalinemia level of 4-10 mg/dL of blood. In contrast, when mice were subjected to a post-weaning diet with plantain meal as the only nutritional source, a difference (P≤0.05) in their development could be observed, which evidenced marked deterioration and malnutrition. It is recommended that additional studies be performed that include a glycomacropeptid along with the plantain meal, so that minimum nutritional requirements can be supplied, keeping low levels of Phe in PKU patients.
ABSTRACT
This work aimed to characterize the molecular structure and functional properties of starches isolated from wild Dioscorea yams grown at the Amazons, using conventional and up-to-date methodologies. Among the high purity starches isolated (≥99%), the chain lengths were similar, whereas variations in gelatinization profile were observed. Starches have shown varied-shaped granules with monomodal distribution, and B-type crystallinity. Variations in amylose contents found by three analyses were hypothesized being related to intermediate material. Linear chain lengths were similar, and their amylopectins showed a dense, spherical conformation and similar molecular characteristics. The average molar mass and the radius of gyration of the chromatograms of the yam amylopectin, M¯W and R¯G were ranging between 174×10(6) g mol(-1) and 237×10(6) g mol(-1), and 201 nm and 233 nm, respectively. The white yams starches were more sensible to enzymes than the other two. All starches have shown a wide range of functional and nutritional properties.
