Total sugars and protein in beans native to the Triqui Alta region, Oaxaca

Abstract

Sowing bean compounds, which combine sizes and colors, is a cultural tradition in rural Mexico, used primarily for self-consumption. Bean blends have a visual appeal; however, little is known about the characteristics of flavor and nutritional value represented by this way of consuming beans. The objective was to know the content of protein and total sugars in native bean compounds from the Triqui Alta region of Oaxaca. In 2017, the study of three bean seed samples was carried out. Bean color was determined visually and the weight of 100 grains was measured. The total sugar content was determined with the Antrona method, and the protein content with the Kjeltec semi-automated equipment. The analyzes were performed in duplicate. In each sample at least 4 different colors and grain sizes identified as common beans (Phaseolus vulgaris L.) and ayocote (Phaseolus coccineus L.) were identified. The sugar content in medium grains was 6.17 to 6.48%, while, in large grains, -ayocote-, it was from 9.45 to 11.6%. Protein content varied between subsamples from 21.7% in black P. coccineus, to 24.8% in yellow P. vulgaris. Grain color was not associated with protein or total sugar content; however, the grain size does. A larger grain size, higher percentage of sugars (r= 0.88^**) and lower protein content (r= -0.61^*).