Availability of Zinc from Pea Seeds to Rats

Abstract
Experiments were conducted to determine the effects of endogenous phytic acid in pea seeds (Pisum sativa, var. ‘Early Market’) on the availability of 65Zn in the seeds to Zn-depleted rats. Seeds were harvested at two stages of maturation from plants supplied with either 0.066 or 0.262 ppm Zn. Increasing Zn supply to growing plants increased the amount of Zn in the seeds. The phytic acid content of immature and mature seeds was 0.17 and 1.23% dry weight, respectively. Most of the Zn in the seeds was in the form of a soluble, small anionic complex (<1,000 mol wt) and did not appear to be present as a Zn-phytate complex. When rats were fed seeds at the same stage of development, the efficiency of Zn absorption by rats was not influenced significantly by the level of Zn in the seeds. Although the absorption by rats of Zn from mature seeds was significantly lower than that from immature seeds, both seed types appeared to be good dietary sources of Zn. In addition, cooking the seeds did not affect the availability of Zn to rats. It was concluded that phytic acid in mature pea seeds was not solely responsible for the decreased availability of Zn in seeds to Zn-depleted rats. Moreover, it is suggested that the nutritional value of legume seeds with respect to Zn content can be increased by applying Zn fertilizers possibly in excess of requirements for optimum plant yields.