No abstract

Dry beans (Phaseolus vulgaris L.) are a nutrient dense food produced globally as a major pulse crop for direct human consumption. Despite being rich in protein and micronutrients, long cooking times limit the use of dry beans worldwide, especially in regions relying on wood and charcoal as the primary sources of fuel for cooking, such as Sub‐Sahara Africa and the Caribbean. These same regions also have populations at risk for iron deficiency. There is need for a fast cooking bean, which can positively impact consumers by reducing fuel cost and preparation time. To help accelerate a reliable increase in dry bean production for Sub‐Saharan Africa, the Andean Bean Diversity Panel (ADP) was assembled as a genetic resource in the development of fast cooking, nutritional improved, biotic/abiotic resistant varieties (http://arsftfbean.uprm.edu/bean/). Six genotypes were identified as fast cooking (<25 min @ 100°C) from a germplasm screening for atmospheric cooking time of over 200 bean genotypes from the ADP. Three of these genotypes had a pale ‘Manteca’ yellow seed color (Entry name: Ervilha; Cebo Cela; Mantega, Kibala). Yellow beans of various shades are important in Eastern and Southern Africa. Their popularity has increased in recent years and they often fetch the highest prices at the marketplace. There is evidence to suggest that Manteca yellow beans have a unique nutritional profile when compared to other yellow seed types; with more soluble dietary fiber, less indigestible protein and starch and are free of condensed tannins. The hypothesis was tested that this unique composition would also have a positive influence on the bioavailability of iron in an in vitro digestion/Caco‐2 cell culture bioassay. A subset of 16 yellow bean genotypes entries selected from ADP that varied in color, appearance and cooking time (named the Yellow Bean Collection; YBC) were planted in a Randomized‐Complete‐Block Design with 2 field replicates at the Michigan State University, Montcalm Research Farm near Entrican, MI for 2 field seasons and evaluated 3 months after harvest for iron concentration and bioavailability (Figure 1). Significant variation (P < 0.0001) in iron bioavailability was measured in cooked/lyophilized/milled seed of the YBC, when expressed as the percentage of Caco‐2 cell ferritin formation (ng ferritin/mg total cell protein) relative to a high bioavailable Fe white navy bean (cv. Merlin) control with each assay (Table 1). Significantly greater Fe uptake was observed from the fast cooking Manteca yellow genotypes (17–23 min; 90 – 110% of control) when compared to slower cooking (38 – 48 min) Njano and Canary yellow genotypes (32 – 42% of control). These data suggest that genotypes within the Manteca yellow market class have enhanced nutritional quality (ie. more absorbable Fe) and fast cooking properties. Such traits can be promoted to increase bean consumption and improve Fe status of those who rely on beans as a major component of their diet.Support or Funding InformationThis research funded by USDA‐ARS. Iron concentrations, iron bioavailability, phytate to iron molar ratios and cooking times among yellow genotypes of the Andean Diversity Panel. Entry/Seed TypeParameter1 ErvilhaManteca Uyole 98Yellow Brown CanarioCanary PI527538Njano Iron (ppm) 74a 70b 79a 79a Iron bioavailability (%)2 106a 62b 47b 32c Phytate:iron ratio3 16a 15a 12b 14ab Cooking time (min) 22d 35c 38b 48a Values are presented as means of two field replicates per entry measured over 2 field seasons at Montcalm Research Farm, MI. Means sharing the same letter in each row are not significantly different at P ≤ 0.05. To compare between field seasons in vitro iron bioavailability is expressed as the percentage of Caco‐2 cell ferritin formation (ng ferritin/mg total cell protein) relative to a navy bean control with each assay. The molar ratio between concentrations of phytate and iron in lyophilized cooked whole seed (dry weight).

Objectives The common dry bean (Phaseolus vulgaris L.) is a globally produced pulse crop and an important source of protein and micronutrients for millions of people across Latin America and Africa. In these regions, energy for cooking is expensive or scarce and long cooking times deter consumers from purchasing beans. In addition, many of the preferred black and red seed types have phytate and polyphenols that limit the absorption of trace minerals. Yellow beans are unique because their seed coats are rich in kaempferol 3-glucoside, a recently discovered promoter of iron absorption. Several market classes of yellow beans are sold throughout Latin America and Africa, where they are marketed at premium prices for their fast cooking tendencies. Exploring the yellow bean's unique heritage to develop new fast cooking varieties that deliver more absorbable iron would be useful for regions where inhabitants have limited access to fuelwood for cooking. This study compared the iron bioavailability of three fast cooking yellow beans from Africa with contrasting seed coat colors (Manteca, Amarillo, Njano) to slower cooking white and red kidney commercial varieties from North America (Table 1). Methods Cooked beans were formulated into diets with the complementary food crops of potato, rice and cabbage. Iron bioavailability was measured as ferritin formation in an in vitro digestion Caco-2 bioassay and the ability to maintain total body iron hemoglobin (Hb-Fe) during a 6 week in vivo (Gallus gallus) feeding trial. Results Animals fed yellow bean diets had faster growth rates, accumulated more dietary iron and had higher Hb-Fe than animals fed either kidney bean diet (Figure 1). In contrast to yellow beans, the kidney beans had almost no kaempferol 3-glucoside (Table 2). When compared to the other four bean based diets, the fast cooking Manteca yellow bean diet had the highest Caco-2 ferritin formation in vitro (Table 3) and delivered the largest increase in Hb-Fe in vivo (Figure 1). Conclusions Through the added benefit of fast preparation times and improved iron quality after cooking, this study provides evidence that the Manteca market class is worthy of germplasm enhancement as a new convenience food to help alleviate trace mineral deficiencies in regions where beans are widely accepted as a dietary staple. Funding Sources USDA-NIFA. Supporting Tables, Images and/or Graphs