In countries such as Brazil and Mexico, common beans are an important part of the human diet because they are the primary source of daily proteins and minerals. ...when the grains are subjected to improper post-harvest storage conditions, such as high temperature (30-40 °C) and high humidity (>75%), the grains can be altered in their color, texture, flavor and time required for cooking.[3-5] These alterations have been associated with the 'hard-to-cook' phenomenon (HTC) and a reduction in the quality of the grains.
Adapted from Figure 2 of Medeiros Coelho et al. (2007). Phytate content of the bean genotypes Peruano and Paraiso stored at 29 °C (C) and at 5 °C ( D), both at 75% relative humidity (RH) for 135 days.
Why the post on beans? Threats to fellow bloggers who comply with fair use of material published in scientific journals are "hard-to-swallow" and don't amount to a hill of beans1.
1 For a fascinating look at bean biopiracy, read Danielle Goldberg's excellent report, JACK AND THE ENOLA BEAN, which describes how an American bean industry executive patented a yellow bean originally obtained from Mexico.
Cileide Maria Medeiros Coelho, Cláudia de Mattos Bellato, Julio Cesar Pires Santos, Edwin Moises Marcos Ortega, Siu Mui Tsai (2007). Effect of phytate and storage conditions on the development of the 'hard-to-cook' phenomenon in common beans. Journal of the Science of Food and Agriculture 87:1237-1243.