• International Journal of Human Ecology
• /
• v.4 no.1
• /
• pp.25-34
• /
• 2003

High dietary phytate is a known factor in reducing the bioavailability of minerals such as zinc and calcium which are already chronically low in the Korean diet. This study was conducted to develop methods for reducing dietary phytate through the addition of phytate and/or the substitution of high phytate foods with low phytate foods. Ten units of phytase per 100g of uncooked brown rice were added to brown rice gruel resulted in a 16.2% phytate reduction after a 3-hour incubation period; an 18.2% reduction was produced after a 6-hour incubation period. The addition of ten units of phytase per 100g of soybean curd residue at 45$^{\circ}C$, followed by refrigeration for 3 hours, resulted in a 19.1% phytate reduction. The addition of 20 units of phytase under the same conditions reduced phytate content by 24.6%. In this study, two typical Korean meals consisting of legumes and unrefined cereals were prepared as high phytate meals; these were then compared to low phytate meals that had been prepared by treating the foods with phytase and substituting unrefined with refined cereals (i.e., brown rice with white rice, whole wheat bread with white bread). The phytate content of the two high phytate meals was 1878.2mg and 1811.8mg. After the addition of phytase and the food substitution, the phytate content of the low phytate meals was reduced to 788.9mg and 606.0mg. The phytate to zinc molar ratio of high phytate diets was 22.4 and 21.3 and 9.4 and 7.9 for the low phytate meals. These results indicate that the nutritional status of Koreans in terms zinc and other minerals can be improved by phytate reduction. This can be accomplished through the change of milling process for some cereals and/or the enzyme treatment of some high phytate food items.

• Journal of Nutrition and Health
• /
• v.28 no.10
• /
• pp.986-994
• /
• 1995

This study was to examine the effect of phytate on the protein digestibility and calcium, iron and zinc availability in phytase treated soymilks digested with pepsin and pepsin-pancreatin in vitro. Also, the bending between phytate and protein in soymilks was investigated by means of SDS-PAGE. The content of phytate in soymilk was reduced by phytase treatment. As the content of phytate decreased, the protein digestibility increased in soymilk treated with the digest enzymes in vitro. The reduction of phytate content in soymilk improved the availability of all calcium, iron and zinc. Although the availability of calcium increased, the amount of change was small. The phytate reduction increased most the availability of iron. A number of bands of high molecular weight protein in soymilk disappleared in SDS-PAGE by lowering the phytate content with phytase treatement on soymilk.

• Journal of Nutrition and Health
• /
• v.26 no.2
• /
• pp.154-154
• /
• 1993

A factorial experiment was conducted to determine the influence of phytate(0 or 10g/kg diet) and calcium (Ca)(3 or 10g/kg diet) intakes on Ca, P and Zn metabolism by growing female rats. Food intake and weight were similar for the all groups, however, phytate ingestion for six weeks depressed femur growth. The low Ca plus phytate group showed the lowest Ca content of total femur and this was related to a significant decrease of Ca retention. Phytate intake depressed zinc(Zn) absorption in the first metabolic collection. This inhibitory effect of phytate on Zn absorption was improved in the low Ca plus phytate group after several weeks. Impared Zn absorption however remained in the high Ca plus phytate group which was reflected in the lowest Zn content of femur, phytate intake with high Ca also depressed phosphorous(P) absorption and serum and urinary P. These adverse effects of phytate on Zn and P absorption when the dietary Ca was high could explain reduced femur weight despite the highest concentration of femur Ca(mg/g ash) in this group. Results suggest that phytate can adversely affect not only Ca metabolism but Zn and P utilization. Thus, for the normal bone growth when phytate intake is high, the ingesion of Ca, P, Zn and other minerals should be enhanced.

• Journal of Nutrition and Health
• /
• v.30 no.4
• /
• pp.406-414
• /
• 1997

It has been known that dietary phytate decreases the absorption of body zinc pool which is composed of the dietary and endogenous zinc in the body. The purpose of this study was to examine the effect of phytate on the absorption of total bodyzinc in Zn-depleted rats. Rats were Zn-depleted with either low(0.8%) or high(1.6%) Ca diet containing sodium phytate for 4 weeks. After zinc depletion, rats were assigned into phytate or non-phytate dietary groups within each low-or high-Ca dietary group. ant feces were collected for 2 weeks of the initial collection and 1 week after dietary crossover, during which the phytate and the non-phytate diet was switched over within the same Ca group. The content of Zn and Ca measured by atomic absorption spectrophotometer and phytate content was analyzed. food intake was higher in the high Ca group than in the low Ca group(p <0.0001), and was also higher in the non-phytate group than in the phytate group(p <0.0001). Food intake and phytate level affected body weight gain in rats(p <0.0001). Zinc excretion in the total feces was higher in the phytate group than in the non-phytate group at both low and high Ca level(p <0.0001), except during the crossover collection period in high Ca group. Calcium, however, didn't show any synergistic effect on phytate effect(p <0.05). This study showed that phytate decreased the absorption of total body zinc at both low and high Ca levels in Zn-depleted rats. A large portion of total body zinc originated from the endogenous zinc pool in these rats. The results of the present study showed the same effect of phytate on the endogenous zinc in Zn-depleted rats as in a previous study, confirming that phytate adversely affects zinc bioavailability, especially under marginal and poor zinc nutrition.

• International Journal of Human Ecology
• /
• v.4 no.1
• /
• pp.35-44
• /
• 2003

This study investigated the effects of dietary phyate reduction on the apparent absorption and biochemical parameters of iron status in young Korean women. Fourteen healthy, young women consumed low and high phytate diets for ten days of each experimental period. Duplicate diet samples, a fasting blood sample on day 9, and complete fecal samples for five consecutive days starting from day 5 of each diet period were collected. The iron content of diet and fecal samples were analyzed to calculate apparent absorption. Serum samples were analyzed for iron, ferritin, transferrin receptor and TIBC; transferrin saturation was also calculated. The apparent absorption of iron tended to increase in the low phytate period (32.51%) compared to the high phytate period (17.91%), but the difference was not significant (p=0.06). Serum ferritin decreased and serum transferrin receptor increased significantly during the low phytate diet although the mean values were within the normal range. Serum iron and transferrin saturation did not change significantly. In conclusion, the results indicated that reducing dietary phytate for ten days negatively affected iron nutritional parameters, but it moderately and positively affected apparent iron absorption in young Korean women. Further research on the long-term effects of a low phytate diet with an adequate iron content for vows Korean women is necessary.

• Journal of Nutrition and Health
• /
• v.26 no.2
• /
• pp.145-155
• /
• 1993

A factorial experiment was conducted to determine the influence of phytate(0 or 10g/kg diet) and calcium (Ca)(3 or 10g/kg diet) intakes on Ca, P and Zn metabolism by growing female rats. Food intake and weight were similar for the all groups, however, phytate ingestion for six weeks depressed femur growth. The low Ca plus phytate group showed the lowest Ca content of total femur and this was related to a significant decrease of Ca retention. Phytate intake depressed zinc(Zn) absorption in the first metabolic collection. This inhibitory effect of phytate on Zn absorption was improved in the low Ca plus phytate group after several weeks. Impared Zn absorption however remained in the high Ca plus phytate group which was reflected in the lowest Zn content of femur, phytate intake with high Ca also depressed phosphorous(P) absorption and serum and urinary P. These adverse effects of phytate on Zn and P absorption when the dietary Ca was high could explain reduced femur weight despite the highest concentration of femur Ca(mg/g ash) in this group. Results suggest that phytate can adversely affect not only Ca metabolism but Zn and P utilization. Thus, for the normal bone growth when phytate intake is high, the ingesion of Ca, P, Zn and other minerals should be enhanced.

• Korean Journal of Food Science and Technology
• /
• v.32 no.2
• /
• pp.231-237
• /
• 2000

A Comparative study was performed among five Korean wheat(Greu, Eunpa, Tapdong, Allgreu, Woori) and three imported wheat(Dark Northern Spring, Austrian Standard Wheat, Western White) to investigate the characteristics of minerals and phytate from Korean wheat varieties. Ash contents of kernel was higher in Korean wheat than in imported wheat and related to ash contents and darkness of flour. More contents of Fe, P, and Mg from Korean wheat grains and Fe from Korean wheat flours were observed in comparison to imported wheat varieties. Fe concentration in Korean flour show high, indicating Fe was distributed at endosperm layer of kernels and not eliminated with milling. In addition, phytate affecting availability of minerals was determined from kernels and flours. Even though Korean wheat kernels had more phytate than that of imported wheat kernels, it is believed that most of phytate was removed with milling and there was no major difference between Korean and imported wheat flours. We also observed that the content of phosphate closely parallels the content of phytate from both the flours and kernels.

• Korean Journal of Food Science and Technology
• /
• v.26 no.5
• /
• pp.603-608
• /
• 1994

This study was undertaken to find out the effect of phytate on the protein digestibility of various soybean foods, including soy milk, bean curd, curd residue, cheongkukjang, soy sauce, and soy paste. The phytate content of soybean was 2.4%, which decreased to 0.2%, 0.7%, and 0.4% in soy milk, bean curd, and curd residue, respectively, and to 0.2% and 1.0% in soy sauce and soy paste, respectively. The phytate/protein ratio was not correlated with protein digestibility by pepsin whereas the ratio was highly correlated with pancreatin digestibility (p<0.01, r= -0.73). According to SDS-PAGE for the soluble protein fractions, soaked bean showed an alteration in soluble components and bean curd residue exihibited newer low molecular weight bands. Fermented soy products showed no protein band, likely due to degradation.

• Korean Journal of Food Science and Technology
• /
• v.24 no.3
• /
• pp.279-283
• /
• 1992

This study was undertaken to investigate the effects of added phytate and pH on the solubility and in vitro digestibility of low-phytate rapeseed protein isolate. Phytate content of low-phytate rapeseed protein isolate was 1.5%, as a result of 66% removal from defatted rapeseed flour and the protein: phytate ratio was 58:1. Solubility of rapeseed protein isolate at pH 2.0 and pH 11.5 was much higher than near the isoelectric point, pH 5.0. It's solubility was lowered by adding an increased amount of phytate especially at pH 2.0. The inhibitory effect of phytate toward pepsin digestibility of rapeseed protein isolate decreased by the increasing amount of phytate added. It is suggested that the production of low-phytate rapeseed protein isolate is necessary to improve the functionality and nutritional value in order to utilize it as food material.

• Applied Biological Chemistry
• /
• v.39 no.1
• /
• pp.32-38
• /
• 1996

Effects of microwave heating on the content of phytic acid and phosphorus of soaked soybean were investigated. Phytic acid content of Danwon, Marly and Amsoy cultivars were found to be 19.19 mg, 18.38 mg, and 16.73 mg/g defatted soybean respectively. Inorganic phosphorus content of soybeans was significantly increased during microwave heating, while phytic acid and phytate phosphorus was gradually decreased. Microwave heating was more effective than autoclaving in reducing the phytate contents. It was also found that microwave heating to soybean of low moisture content was more effective than that of high moisture content for decreasing the phytic acid content. Soaking in 2.5% sodium chloride, 2% sodium bicarbonate, and mixed salt solution for 12 hrs was not effective on reducing the contents of phytic acid and phytate phosphorus, but microwave-heating after soaking in above solutions greatly decreased the contents of phytic acid and phytate phosphorus, whereas significantly increased inorganic phosphorus of soybeans.