Physicochemical characterization of ñuña bean (Phaseolus vulgaris L. ) protein extract / Caracterización fisicoquímica de extracto proteico del frijol ñuña (Phaseolus vulgaris L. )

Background: Although legume protein extracts are useful in food preparation and processing as foam stabilizers and as viscosity, palatability and nutrition enhancers, many legume proteins from South America have not been characterized extensively. One such legume is the ñuña bean (Phaseolus vulgaris L.), which is cooked using dry heat until the cotyledons rapidly expand with a pop. The bean is widely cultivated in the Andes, but almost unknown elsewhere. Objective & Methods: In this study, we characterized ten functional properties of a ñuña protein extract using standard food analysis methods. Results: The extract was similar to other legume protein extracts for many properties (amino acid profile, proximate analysis, yield, water absorption, color, isoelectric point, and thermogravimetric analysis). The electrophoretic analysis revealed that the sample was nearly pure phaseolin. Additionally, the ability to form foam and increase solution viscosity were comparatively low when contrasted to other extracts. Conclusion: These properties make ñuña protein extract useful as a nearly pure phaseolin nutrition enhancer in beverages where foaming and high viscosity are undesirable, such as in fortified beverages, drinkable yogurts, or protein supplements. The extract may also have relevance as a weight-loss supplement. Therefore, we expect that incorporating ñuña protein in processed foods would be a straightforward process.

Antecedentes: Los extractos proteicos de leguminosas son muy utilizados en la preparación y procesamiento de alimentos como agentes estabilizadores de espuma y viscosidad, así como potenciadores de palatabilidad y nutrición. Sin embargo, muchas proteínas de leguminosas procedentes de Sudamérica no han sido caracterizadas extensamente. Una de ellas es el frijol ñuña (Phaseolus vulgaris L.), el cual se cocina utilizando calor seco hasta que los cotiledones se expanden rápidamente y explotan. La ñuña se cultiva ampliamente en los Andes, pero es mayormente desconocida en otras partes del mundo. Objetivo y Métodos: En el presente estudio, caracterizamos diez propiedades funcionales de un extracto proteico de ñuña, utilizando métodos estándares para análisis de alimentos. Resultados: Varias propiedades del extracto analizado fueron similares a las de los extractos proteicos de otras leguminosas (perfil de aminoácidos, análisis proximal, rendimiento, absorción de agua, color, punto isoeléctrico y análisis termogravimétrico). El análisis electroforético reveló que la muestra es mayormente faseolina. Además, el extracto analizado presentó baja capacidad para formar espuma e incrementar viscosidad de una solución a comparación de los otros extractos. Conclusión: Los resultados obtenidos indican que el extracto proteico de ñuña, que es casi faseolina pura, puede ser muy útil como potenciador nutricional de bebidas en las que la espuma y alta viscosidad son indeseadas, como es el caso de bebidas fortificadas, yogures bebibles o suplementos proteicos. El extracto podría tener relevancia como suplemento para pérdida de peso. Por lo tanto, esperamos que el uso de proteína de ñuña sea un proceso sencillo en la industria de alimentos procesados.

Macronutrients and Micronutrients Profile of Some Underutilized Beans in South Western Nigeria.

Beans are a rich source of nutrients in human diet. However a number of edible bean varieties are largely underutilized in developing countries due to little or no information on their nutritional composition. The present study investigated the nutritional content of mung beans, African yam beans, soybeans, black eyed peas and pigeon peas from parts of South Western Nigeria. Samples were collected randomly in duplicates across the six South-western states of Nigeria. Common beans was included as a reference for comparison. Standard methods were used to determine the proximate composition of all bean samples. Mineral nutrients and phaseolin protein fractions (albumin, globulin and prolamine) of bean samples (excluding pigeon pea varieties) was also determined. The proximate, mineral and phaseolin protein contents differed significantly (P<.05) between bean types. Highest protein, fat, carbohydrate, crude fibre and ash content was in African yam bean (24.96%), mung beans (6.60%), soybean (62.81%), mung beans (15.24%) and African yam beans (4.30%), respectively. The beans compared fairly with common beans in proximate composition. Mineral nutrients differed significantly (P<.05) between bean types. Calcium, magnesium, phosphorus and potassium (particularly in Mung beans) were in high amounts. Black eyed peas had the lowest total of mineral content while mung beans had the highest. The phaseolin protein fractions were significantly different (P<.05) among bean types. African yam bean had the highest albumin and globulin content (%/mg protein) of 41.89 and 35.70 respectively, while prolamine was highest in soybeans. These results indicated that these underutilized beans compares favourably in terms of nutritional composition with widely consumed common beans in Nigeria. In addition, African yam beans and Mung beans are equally suitable alternatives from a protein-rich standpoint.