Beans are rich in dietary fiber and polyphenols;however, growing conditions may affect the occurrence of these components. The effect of irrigation and rain fed conditions on dietary fiber, indigestible fraction, poly...Beans are rich in dietary fiber and polyphenols;however, growing conditions may affect the occurrence of these components. The effect of irrigation and rain fed conditions on dietary fiber, indigestible fraction, polyphenols and antioxidant capacity of Black 8025 and Pinto Durango bean cultivars grown in Mexico have been determined. Total dietary fiber decreased in beans grown under rain fed conditions compared to those grown under irrigation. The water regimes had an effect on the total indigestible fraction for Black 8025 bean. The extractable polyphenols were affected by the water regimes, while the antioxidant capacity of extractable and non-extractable polyphenols was dependent on the bean variety. Cooking the beans altered the extractable and non-extractable polyphenols and the antioxidant capacity. Also, the antioxidant properties and some extend, the digestibility of non-digestible carbohydrates of beans were affected by water regimes. This information could be taken into account for dry bean breeding programs to improve the nutritional quality of beans.展开更多
A soil water retention curve (SWRC) is an essential soil physical property for analyzing transport and retention of water in a soil layer. A SWRC is often described as a single-valued function that relates the soil wa...A soil water retention curve (SWRC) is an essential soil physical property for analyzing transport and retention of water in a soil layer. A SWRC is often described as a single-valued function that relates the soil water potential ψ to volumetric water content θ of the soil. However, an in-situ ψ − θ relation should show soil water hysteresis, though this fact is often neglected in analyses of field soil water regimes while long-term in-situ soil water hysteresis is not well characterized. This study aimed at probing and characterizing in-situ ψ − θ relations. The developments of large hysteresis in the in-situ ψ − θ relations were observed only a few times during the study period of 82 months. Any of the large hysteretic behaviors in the ψ − θ relations began with an unusually strong continual reduction in ψ. The completion of a hysteresis loop required a recorded maximum rainfall. Because the study field had very small chances to meet such strong rainfall events, it took multiple years to restore the fraction of soil water depleted by the unusually strong continual reduction in ψ. While wetting-drying cycles had occurred within a certain domain of ψ, hysteretic behaviors tended to be so small that the in-situ ψ − θ relation can be approximated as a single-valued function of θ(ψ). These observed patterns of the in-situ ψ − θ relations were characterized by kinds of difference in dθ/dψ between a drying process and a wetting process at a given ψ. Thus, more amounts of experimental facts about wetting SWRCs in parallel with drying SWRCs should be needed for correct modelling, analyzing, and predicting soil water regimes in fields. It is also necessary to increase our understandings about the long-term trends of occurrences of extreme weather conditions associated with possible change in climate.展开更多
文摘Beans are rich in dietary fiber and polyphenols;however, growing conditions may affect the occurrence of these components. The effect of irrigation and rain fed conditions on dietary fiber, indigestible fraction, polyphenols and antioxidant capacity of Black 8025 and Pinto Durango bean cultivars grown in Mexico have been determined. Total dietary fiber decreased in beans grown under rain fed conditions compared to those grown under irrigation. The water regimes had an effect on the total indigestible fraction for Black 8025 bean. The extractable polyphenols were affected by the water regimes, while the antioxidant capacity of extractable and non-extractable polyphenols was dependent on the bean variety. Cooking the beans altered the extractable and non-extractable polyphenols and the antioxidant capacity. Also, the antioxidant properties and some extend, the digestibility of non-digestible carbohydrates of beans were affected by water regimes. This information could be taken into account for dry bean breeding programs to improve the nutritional quality of beans.
文摘A soil water retention curve (SWRC) is an essential soil physical property for analyzing transport and retention of water in a soil layer. A SWRC is often described as a single-valued function that relates the soil water potential ψ to volumetric water content θ of the soil. However, an in-situ ψ − θ relation should show soil water hysteresis, though this fact is often neglected in analyses of field soil water regimes while long-term in-situ soil water hysteresis is not well characterized. This study aimed at probing and characterizing in-situ ψ − θ relations. The developments of large hysteresis in the in-situ ψ − θ relations were observed only a few times during the study period of 82 months. Any of the large hysteretic behaviors in the ψ − θ relations began with an unusually strong continual reduction in ψ. The completion of a hysteresis loop required a recorded maximum rainfall. Because the study field had very small chances to meet such strong rainfall events, it took multiple years to restore the fraction of soil water depleted by the unusually strong continual reduction in ψ. While wetting-drying cycles had occurred within a certain domain of ψ, hysteretic behaviors tended to be so small that the in-situ ψ − θ relation can be approximated as a single-valued function of θ(ψ). These observed patterns of the in-situ ψ − θ relations were characterized by kinds of difference in dθ/dψ between a drying process and a wetting process at a given ψ. Thus, more amounts of experimental facts about wetting SWRCs in parallel with drying SWRCs should be needed for correct modelling, analyzing, and predicting soil water regimes in fields. It is also necessary to increase our understandings about the long-term trends of occurrences of extreme weather conditions associated with possible change in climate.
