2004 Annual Report
1.What major problem or issue is being resolved and how are you resolving it (summarize project aims and objectives)? How serious is the problem? What does it matter?
Dry bean has been used as the primary source of protein and calories for many populations lacking meat in the diet, particularly in the lesser developed countries of Africa and Latin America. However, in the U.S. where dry bean is not a staple, beans are eaten mainly to provide variety to the diet. However, heightened consumer awareness of the link between food consumption and health has led to the promotion of less saturated fat, cholesterol, sugar, and sodium (salt),in the diet, and a preference for complex carbohydrates such as fiber. Hence, dry bean has been promoted as a health food because of its superior nutritional quality, especially dietary fiber and low fat, compared to other plant foods. The food guide pyramid designed by the U.S. Department of Agriculture in 1992, recommends a serving of one-half cup of cooked beans under the vegetable group, which calls for 3-5 servings of food legumes per day. Dry bean consumption in the U.S. is expected to grow steadily over the next 5 to 10 years. In addition to the accrued health benefits, an increase in dry bean consumption will benefit "cash-starved" farmers. Beans are an excellent local source of cash and contribute significantly to the incomes of many growers who are struggling with today's stressed agriculture. Beans also provide a significant source of supplementary family income for part-time growers, whose major occupations are in the factories of many industrial areas of the U.S.
Gastrointestinal discomfort, including flatulence and diarrhea, is the single most important factor limiting the consumption of dry beans in the diets of American consumers. Moreover, the gastrointestinal discomfort from eating beans is often the result of the poor digestibility of bean carbohydrates and protein. We do not have a clear understanding as to why bean protein and starch is less digestible than other plant foods, but, in regards to starch, this macromolecule is stored in bean vesicles called starch granules. As beans cook, the starch granules melt, hydrate, and swell. Swelling of the granules causes starch to become viscous and absorb more water. This sequence of events is known as starch gelatinization. The degree of gelatinization that occurs as beans cook largely determines the completeness of digestion of starch. Dietary starch that does not digest is known as "resistant" starch. Cooking beans beyond 10 minutes apparently reduces starch gelatinization. Ungelatinized starch is a large contributor to flatulence and other gastrointestinal discomfort because starch that does not gelatinize is not absorbed in the small intestine, and, thus, freely enters the colon where it is fermented by colonic bacteria. Ungelatinized starch is associated with large clumps of starch containing cells. The suppression of gelatinization may be caused by a limited supply of water to hydrate starch inside the cell because of insufficient space inside the cell associated with the physical strength of the cell wall. The cooking of beans may cause cell walls to crystalize; thus, entrapping starch granules within the cell and preventing them from hydrating. We will determine if cell walls crystallize during cooking by observing optical changes that occur with a light microscope. The loss of birefringence, as the optical changes that occur are called, under polarized light microscopy is used as an indicator of crystallization.
2.List the milestones (indicators of progress) from your Project Plan.
1. Identification of cell structural factors:
a. Determine resistant starch (FY03/04)
b. Determine influence of mechanisms that entrap starch in cells (FY05/06)
c. Determine the effect of cell wall crystallization on cellular breakdown and cooking time (FY07/08)
2. Determine the genetic basis of food quality traits:
a. Determine the inheritance of starch digestibility (FY07/08)
b. Determine the inheritance of protein digestibility (FY07/08)
c. Determine the inheritance of phytic acid (FY04/05)
d. Identify major genes affecting culinary quality traits (FY04/05)
e. Identify markers associated with seed coat microstructural traits (FY04/05)
f. Determine the role of the seed coat microstructure in water imbibition and color loss due to leaching in black beans (FY05/06)
3. Enhance and release germplasm
a. Improved food quality (FY07/08)
b. Improved disease resistance (FY07/08)
c. Development of germplasm with shorter cooking times (FY07/08)
4. Isolate, identify, and characterize seed coat flavonoids and determine the relationship between seed coat color determining genes and the flavonoids they control
a. Isolate, identify, and characterize seed coat flavonoids from selected genetic stocks (FY07/08)
b. Determine the function of P and B genes (FY07/08)
c. Determine the antioxidant potential of flavonoids (FY04/05)
A. List the milestones that were scheduled to be addressed in FY 2004. How many milestones did you fully or substantially meet in FY2004 and indicate which ones were not fully or substantially met, briefly explain why not, and your plans to do so.
The milestones listed below were scheduled to be completed during FY 2004:
Determine antioxidant potential of flavonoids
Determine resistant starch
Both milestones were completed. The antioxidant work was published in the Journal of Agricultural and Food Chemistry (see publications below). The resistant starch of 41 bean lines was determined and results will be submitted for publication in FY 2005.
B. List the milestones that you expect to address over the next 3 years (FY 2005, 2006, & 2007). What do you expect to accomplish, year by year, over the next 3 years under each milestone?
FY2005: The major cellular starch entrapment mechanism, 'cotyledon cell wall crystallization,' will be studied to elucidate how heat causes crystallization and what cell wall compounds are involved in the crystallization mechanism. This is critical to developing segregating populations for determining the genetic control of the trait and for designing appropriate breeding strategies for its amelioration; Genetically defined populations segregating for major traits [e.g., recombinant inbred lines (RILs)], will be developed and used for genetic analyses of digestibility, cookability, and nutrient bioavailability; ARS will continue releasing germplasm with improved agronomic, food quality, and consumer acceptability traits.
FY2006: Genetic markers for starch digestibility and mineral bioavailability will be made available to partners, customers, and stakeholders; Seed coat flavonoids (seed coat pigments) will be isolated and identified and the health benefits as antioxidants of these compounds will be determined; the continued release of germplasm with improved agronomic, food quality, and consumer acceptability traits will improve the image of dry bean as a healthy component of the diet.
FY2007: The identity and function of the P (seed coat color 'Ground Factor') and B (a color modifying factor) genes in the seed coat flavonoid biosynthetic pathway will be determined; the continued release of germplasm with improved agronomic, food quality, and consumer acceptability traits will further improve the image of dry bean as a healthy component of the diet.
4.What were the most significant accomplishments this past year?
A. Single Most Significant Accomplishment During FY 2004: Merlot small red dry bean was developed and released cooperatively by the USDA-ARS Sugarbeet and Bean Research Unit, East Lansing, Michigan and the Michigan Agricultural Experiment Station. Merlot is an upright, short-vine (Type IIA), full season cultivar with consistent and desirable canning quality, and the first small red commercial cultivar with resistance to bean rust disease. The release of Merlot improves the seed characteristics, canning quality, and disease resistance of the small red market class; grower interest in Merlot is considerable as determined by the quantity of foundation seed ordered through commercial channels.
B. Other significant accomplishment(s), if any: Results of antioxidant activity were published. This research shows that flavonoid compounds found in bean seed coats have high levels of antioxidant activity, promoting the consumption of dry beans as a healthy component of the diet.
C. Significant activities that support special target populations:
5.Describe the major accomplishments over the life of the project, including their predicted or actual impact.
i.) Ten dry bean cultivars in seven market (commercial) classes and three small red germplasm breeding lines were cooperative releases between the Michigan Agricultural Experiment Stations and/or the Washington Agricultural Research Center and USDA-ARS Sugarbeet and Bean research Unit, East Lansing, Michigan. 'Kodiak' and 'Burke' pinto beans, 'Beluga' alubia bean, 'Chinook' light red kidney bean, 'Glacier' great northern bean, 'Phantom' and 'Jaguar' black beans all have high yields, acceptable to excellent canning quality, and multiple disease resistance. The high yields of these varieties may increase profits for small farmers who generally rely on a good production to offset profit risk because of a reduced farm size compared to large scale operations. The multiple disease resistance of these cultivars reduces the need to use chemicals, thus reducing production costs and protecting the environment. 'LeBaron' small red bean is early maturing and very upright in growth habit. Its attractive vegetative appearance and uniform "dry down" and early maturity has attracted growers to plant 'LeBaron' as a second crop in a double-crop production system. 'Rojo Chiquito' Central American Red market class is the first small red with the dominant I gene form of resistance to bean common mosaic virus, and it has excellent canning quality with good firmness, and a very attractive bright red color after cooking. 'Rojo Chiquito' is becoming popular among Central American bean brokers and may represent a niche market for beans that are exported from the U.S. to this Region. The erect, upright germplasm lines, ARS-R93344, ARS-R93346, and ARS-R93349 all have excellent dry seed appearance and good to excellent canning quality. Impact: These germplasms represent a significant improvement in the adaptation of small red beans for the humid Great Lakes region of the U.S. Midwest and likely will be valuable as parental lines in bean breeding programs. Cultivar and germplasm enhancement and release are linked to National Program 301 Problem Areas I d-Expanding Germplasm evaluations and characterizations and II b-Genetic Improvement.
ii.) We developed new and fundamental knowledge of cellular changes in dry bean during cooking that leads to their ability to be digested. Heat induces cell walls to crystallize during the cooking process of dry beans. The cell wall crystallization forms a barrier that keeps water and digestive enzymes from solubilizing and breaking down starch. The indigestible starch passes through the gastrointestinal tract to the lower gut where microorganisms there metabolize it, thus, producing gas, which is subsequently expelled. Impact: This research provided the important knowledge base needed to develop strategies for improving dry bean digestibility. Studies on genes differentially expressed during cell wall crystallization will aid in identifying and manipulating the genes controlling crystallization.
iii.) Research showed that both the genotype and processing method affect the digestibility of dry beans. There were significant differences among a select sample of 41 dry bean genetic stocks for total dietary fiber, indigestible starch, and indigestible protein. Canned beans contained less total dietary fiber, and indigestible starch and protein than beans cooked in a pot on a stovetop. Impact: This research provides plant breeders with the knowledge needed to develop selection strategies to lower the indigestible residue in cooked beans. The finding than canned beans contained less indigestible starch and protein than beans cooked in a pot on a stovetop may influence a larger consumption of canned beans; thus, leading to higher profits for industry and increased nutrition for consumers.
iv.) We have determined that the flavonoids kaempferol 3-0-Beta-D glucoside and kaempferol 3-0-Beta-D-glucopyranoside-2 1-0-Beta-D xylopyranoside are the compounds responsible for yellow color in beans; the anthocyanins, delphinidin-3-o-glucoside, petunidin-3-0-glucoside, and malvidin-3-0-glucoside impart the black color to black beans; and the garnet red color of kidney beans is due primarily to proanthocyanidins which mask the yellow kaempferol flavonoids. Impact: This research was the breakthough needed to determine the function of genes in the biosynthetic pathway leading to the various flavonoid compounds involved in bean seed coat color.
v.) An experiment was conducted in black bean to study water imbibition and its relationship to the thickness and continuity of the waxy cuticular layer of the seed coat. 'Shiny Crow' has a shiny seed coat and 'Raven' and 'Black Magic' both have opaque seed coats. Differences were detected between the three cultivars for thickness and continuity of the waxy epicuticular layer using scanning electron microscopy. In 'Shiny Crow' the epicuticular layer had a uniform thickness over the seed coat. The waxy epicuticular layers of 'Raven' and 'Black Magic' were of uneven thickness over the entire seed coat with areas varying in thickness by more than 1 micrometer. 'Black Magic' had the thickest epicuticular wax layer. Blanching in near boiling water (95ºC) caused a breakdown of the waxy epicuticular layer in all three genotypes. Data from the experiment indicated that breakdown of the waxy epicuticular layer occurred most rapidly in the thinnest regions, allowing water to penetrate the seed coat faster than in the thicker regions. Since water uptake is a key factor in leaching of pigments in thermally processed black beans, the thickness of the waxy epicuticular layer may control the magnitude of pigment loss after canning in black beans. This research on the effect of leaching on product quality of thermally processed black beans is linked to National Program 306, Problem Area I c-Factors and Processes That Affect Quality.
vi.) An experiment was conducted to develop baseline data for cooking time on representative genotypes of several market classes that are of interest to growers who export beans to Central America and the Caribbean. Pinto beans were the fastest cooking among the seven market classes studied and small-red beans were the slowest cooking (110.3 min on average). There was a negative relationship (r=-0.84) between cooking time and water absorption. Since fast-cooking beans imbibed more water than slow-cooking ones, water absorption should be useful to predict cooking time in beans. Impact: Breeders should be able to select fast cooking genotypes from slow cooking ones. Selection based on the water absorption of a breeding line as an indirect estimation of its cooking time is rapid and saves resources. Research on the cookability and cooking rate of beans is linked to National Program 301, Problem Area I d-Expanding Germplasm Evaluations and characterizations.
6.What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end-user (industry, farmer, other scientists)? What are the constraints, if known, to the adoption and durability of the technology products?
We provided new information to the scientific community and bean grower and shipper industries on the importance of beans in a healthy diet and on important findings on the digestibility of beans and methods for improving the bioavailability of nutrients in this crop. New knowledge based on our research provided a basis to improve the health and nutrition of civil society. New cultivars of dry beans in several market classes were released to industry. These new cultivars have the potential of enhancing the profitability to growers and reducing costs for consumers. Cultivar releases in the small red market class have the potential to replace existing varieties grown in the humid Midwest, which will help stabilize production and grower income. In addition, disease resistance in the cultivars reduces the reliance on agricultural chemicals to control diseases and insect pests, thus, protecting the environment and reducing production costs. Several major consultations with the national media led to the publication of major articles publicizing our findings on flavonoids and their antioxidant potential and other health benefits from including beans in the diet. We participated in a "Dry Beans and Health" workshop cosponsored by USDA-ARS and the Dry Bean Industry to assess research needs for the required government approval to make specific health claims on bean product labels. This research establishes USDA-ARS as a leader and visionary in the area of bean consumption and human health.
New and improved cultivars have been released to industry and are currently being used by growers. New knowledge on digestibility and the health benefits from eating beans has been published in the national media and presented at health workshops.
Utility of the knowledge provided to society regarding beans and human health requires a change in attitude by consumers and a commitment to change current culinary habits that lead to unhealthy diets. The new dry bean cultivars released to industry will lose their durability as future germplasm is developed, enhanced, and released. It may be very difficult to improve the digestibility of beans and reduce the flatulence potential while maintaining the inherent qualities, namely fiber and starch, that make beans such a good human food.
Hosfield, G.L., Kelly, J.D., Taylor, J., Varner, G.V. 2004. Notice of Naming and Release of Merlot, a New, Upright, Disease Resistant Small-red Bean (Phaseolus vulgaris L.) cultivar. Crop Science. 44(1):351-352.
Beninger, C.W., Hosfield, G.L. 2003. Antioxidant Activity of Extracts, Condensed Tannin Fractions, and Pure Flavonoids from Phaseolus vulgaris L. Seed Coat Color Genotypes. Journal of Agricultural and Food Chemistry. 51(27):7879-7883.