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The ability of phytases from fresh fruits and vegetables to degrade phytate in foods was determined in vitro. In contrast to the more consistent presence of phytase in vegetables, only a few fruits contained detectable phytase activity. The highest phytase activities were 121 and 97 nrnol min -1 g -1 in scallion leaves and avocado fruit, respectively. Avocado fruit also contained 0.14% phytate on a wet-weight basis. Crude phytase extracts were incubated with ground corn tortillas or refried beans at 37 °C. Most of the phytate was degraded within 30 min by a 4-fold excess by dry weight of scallion leaves. Avocado extracts incubated alone metabolized most of their endogenous phytate within 2h. La quantite de phytate, considere comme un facteur antinutritionnel en raison de sa capacite a fixer les elements mineraux et l'activite de la phytase est testee dans differents fruits et legumes. L'activite phytase de l'avocat est 97nmol/min/g. La phytase de feuilles d'oignon est extraite et incubee avec des tortillas moulus, ou des haricots pintos cuits, et la biodisponibilite du calcium et du fer est mesuree in vitro.

In northern Mexico, refried beans and corn and flour tortillas are basic foods. Cereals and legumes are high in phytates and affect mineral absorption. The objective of this study was to determine total phytate and Fe, Zn, and Ca content in these foods and their solubility. Refried beans contained 622 ± 95 mg of phytates/100 g, corn tortillas, 448±40 mg/100 g, and flour tortillas, 123±18 mg/100 g. On the basis of the daily intake of these foods, refried beans provide 861 mg/day of phytates, corn tortillas, 650 mg/day, and flour tortillas, 97 mg/day, for a total of 1608 mg/day. The majority of the phytates are in the insoluble fraction. Refried beans contained 6.05±1.19 mg of Fe/100 g, 3.03±0.12 mg of Zn/100 g, and 170.9±33.3 mg of Ca/100 g

Calcium (Ca) is important in bone formation and as aging progresses, bone loss gradually occurs. With the onset of menopause, reduced estrogen levels and insufficient Ca in the diet often create serious problems with fractures. Since little is known about the diet and other factors related to risk factors in postmenopausal women in northern Mexico, it was the objective of this study to determine the effects of dietary Ca and phosphorus (P) and their excretion, anthropometric measurements, and blood serum estradiol on bone density in women aged 45–63 years. No studies are available on the dietary intake of Ca and P and the effects on bone mineral density (BMD) in postmenopausal women in northern Mexico, so this study reports some of the first data on this population. Women with an average age of 55 years showed a positive relation of Ca intake and Ca excretion, however, dietary intake of Ca and P had no relation to bone density. Age, urinary Ca, Ca/creatinine and years of postmenopause had the highest negative correlation. Weight and body mass index had a positive correlation with BMD in the forearm and heel. Only 15% of the women met the recommendation of 1,500 mg/day of Ca. A high Ca/creatinine ratio has been proposed to indicate excess Ca excretion and subsequent bone density loss. Thirty-five percent of the women exceed the Ca/creatinine indicator of >0.16. In this study, 1% of the subjects were classified as osteoporotic and 37% as osteopenic.