Processing white or yellow dry beans (phaseolus vulgaris L.) into a heat treated flour enhances the iron bioavailability of bean-based pastas

Authors: Wiesinger, Jason; Cichy, Karen; HOOPER, SHARON - Michigan State University; Hart, Jonathan; Glahn, Raymond

Submitted to: Journal of Functional Foods
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/10/2020
Publication Date: 5/23/2020
Citation: Wiesinger, J.A., Cichy, K.A., Hooper, S., Hart, J.J., Glahn, R.P. 2020. Processing white or yellow dry beans (phaseolus vulgaris L.) into a heat treated flour enhances the iron bioavailability of bean-based pastas. Journal of Functional Foods. 71:104018.
DOI: https://doi.org/10.1016/j.jff.2020.104018

Interpretive Summary: Dry beans (Phaseolus vulgaris L.) are a rich source of micronutrients and are traditionally available to consumers as whole seed products. The interest in using beans as a flour ingredient is growing among food manufactures. Milling beans into flour breaks open the cotyledon cell walls of beans, allowing digestive enzymes greater access to their intercellular stores of micronutrients such as iron during digestion. The research presented in this manuscript compared the iron bioavailability of different colored bean varieties (white, yellow, cranberry, red kidney and black) prepared either as traditional boiled whole beans or processed into spaghetti pasta. The results of this study reveal that breaking cotyledon cell walls during processing can lead to more bioavailable iron when compared to boiled beans with intact cotyledon cells. The improved iron bioavailability, however, depended on seed coat color. Despite the broken cell walls and iron concentrations similar to their boiled beans counterparts, the iron bioavailability of cranberry, red kidney and black beans did not improve after formulation into pasta. Our data indicate that the polyphenol profiles of the different colored beans is an underlying factor contributing to these differences.

Technical Abstract: Dry beans (Phaseolus vulgaris L.) are traditionally available to consumers as either uncooked or canned whole seed products. As more consumers learn about the health benefits of eating beans, food manufacturers are responding by processing beans into flour for new food products. Processing techniques can disrupt the cotyledon cell walls of raw beans, allowing digestive enzymes greater access to their intercellular stores of micronutrients such as iron during digestion. This study evaluated the iron bioavailability of seven bean varieties with different seed coat colors (white, yellow, cranberry, red, black) either boiled or processed into spaghetti pastas formulated form heat treated bean flour as the major ingredient (90% bean flour). Iron bioavailability was significantly (p = 0.05) higher in spaghetti made from white or yellow bean varieties Snowdon, Alpena, Samurai and Canario when compared to boiled beans. Although cotyledon cells were broken and the phytate to iron molar ratios were significantly (p = 0.05) lower, the iron bioavailability of the cranberry (Etna), red kidney (Red Hawk) and black (Zenith) bean varieties did not improve after processing into spaghetti. Low iron bioavailability of the dark colored bean varieties and their bean-based pastas were associated with seed coat color compounds such as proanthocyanidins that have a negative impact on the absorption of iron.