Reduced Phytate Content Research Articles

Moderate Decrease of pH by Sourdough Fermentation Is Sufficient To Reduce Phytate Content of Whole Wheat Flour through Endogenous Phytase Activity

Whole wheat bread is an important source of minerals but also contains considerable amounts of phytic acid, which is known to impair their absorption. An in vitro trial was performed to assess the effect of a moderate drop of the dough pH (around 5.5) by way of sourdough fermentation or by exogenous organic acid addition on phytate hydrolysis. It was shown that a slight acidification of the dough (pH 5.5) with either sourdough or lactic acid addition allowed a significant phytate breakdown (70% of the initial flour content compared to 40% without any leavening agent or acidification). This result highlights the predominance of wheat phytase activity over sourdough microflora phytase activity during moderate sourdough fermentation and shows that a slight drop of the pH (pH value around 5.5) is sufficient to reduce significantly the phytate content of a wholemeal flour. Mg "bioaccessibility"of whole wheat dough was improved by direct solubilization of the cation and by phytate hydrolysis.

Ectopic expression of a soybean phytase in developing seeds of Glycine max to improve phosphorus availability

A transgenic approach was used to alter soybean seed phytate content by expressing a soybean phytase gene (GmPhy) during seed development to degrade accumulating phytic acid (IP6). An expression vector containing the soybean phytase cDNA controlled by the seed-specific beta-conglycinin promoter (alpha'-subunit) was used to transform embryogenic soybean cultures. Plants from four independent transgenic lines were analyzed for transgene integration and seed IP6 levels. The reduction in IP6 levels in transgenic seeds compared to control 'Jack' soybeans ranged from 12.6 to 24.8 as determined by HPLC. A low copy transformant was propagated to the T4 generation and examined in more detail for phytase expression and enzyme activity during seed development. Expression of phytase mRNA and phytase activity increased during seed development, consistent with the use of an embryo-specific promoter. Ectopic phytase expression during seed development offers potential as an effective strategy for reducing phytate content in soybean seed.

Bacterial phytase: potential application, in vivo function and regulation of its synthesis

The stepwise release of phosphate from phytate, the major storage form of phosphate in plant seeds and pollen, is initiated by a class of enzymes that have been collectively called phytases. The classification is solely due to the in vitro capability of these enzymes to accept phytate as a substrate. Phytases have been studied intensively in recent years because of the great interest in such enzymes for reducing phytate content in animal feed and food for human consumption. They have a wide distribution in plants, microorganisms, and in some animal tissues. Due to several biological characteristics, such as substrate specificity, resistance to proteolysis and catalytic efficiency, bacterial phytases have considerable potential in commercial applications. In bacteria, phytase is an inducible enzyme and its expression is subjected to a complex regulation, but phytase formation is not controlled uniformly among different bacteria. It was suggested that phytase is not required for balanced growth of bacterial cells, but may be synthesised in response to a nutrient or energy limitation.

Effect of culture conditions on the biosynthesis of Aspergillus niger phytase and acid phosphatase

The reduction of phytate content in plant feeds is advisable for increasing of their nutritional values. The dephosphorylation of phytates is believed to be mainly effected by phytase. A strain of Aspergillus niger shows a high potential for phytase production. In this study the possibilities to increase the enzyme production by alteration of the growth conditions of Aspergillus niger 307 are investigated. The effect of the type, age and quantity of the inoculum was established. The strain showed maximal productivity when about 50-day-old spores were used as inoculum and the augmentation of phytase and acid phosphatase activities was 3.29-fold and 2.17-fold, respectively. Two-fold increase of the phytase activity was observed when the inorganic phosphorus concentration in the media was 10 mg%. The highest level of acid phosphatase activity was produced at 17.5 mg% P i. The unpurified phytase from Aspergillus niger 307 shows two pH optima—at 2.5 and 5.0 and temperature optimum ( T opt) is 56 and 58 °C, respectively. The pH optimum for acid phosphatase action is 2.1 and T opt is 73 °C.

Molecular and catalytic properties of phytate‐degrading enzymes (phytases)

SummaryPhytate‐degrading enzymes catalyse the step‐wise release of phosphate from phytate, the principle storage form of phosphorus in plant seeds and pollen. They are widespread in nature, occurring in plants and micro‐organisms, as well as in some animal tissues. Phytate‐degrading enzymes have been studied intensively in recent years because of the great interest in such enzymes for reducing phytate content in animal feed and food for human consumption. Phytate‐degrading enzymes are also of interest for producing defined breakdown products of phytate for kinetic and physiological studies. Certain myo‐inositol phosphates have been proposed to have novel metabolic effects and therefore, the physiological role of different myo‐inositol phosphates is presently undergoing extensive research. Generally, phytase behaves like a monomeric enzyme with molecular masses between 40 and 70 kDa. Up to now, two main types of phytate‐degrading enzymes have been identified; acid phytate‐degrading enzymes with an pH optimum around pH 5 and alkaline phytate‐degrading enzymes with an pH optimum around pH 8. Most of the so far described phytate‐degrading enzymes belong to the acidic type, and their optimal pH ranges from 4.5 to 6.0. This review summarises the molecular features as well as catalytic properties of phytate‐degrading enzymes and also discusses enzymatic phytate degradation.

Content of phytic acid and HCl-extractability of calcium, phosphorus and iron as affected by various domestic processing and cooking methods

ICPL-87, the high yielding cultivar of pigeon pea (Cajanus cajan) released by ICRISAT (International Crop Research Institute for Semi-Arid Tropics), India was subjected to various domestic processing and cooking methods, i.e. soaking (6, 12, 18 h, 30°C), soaking (12 h) and dehulling, ordinary as well as pressure cooking and germination (24, 36 and 48 h, 30°C). The unprocessed seeds of this variety contained considerable amounts of phytic acid, (857 mg per 100 g). This was reduced significantly (P<0.05) by 6–28%, 30%, 4–32%, 4–36%, 35–45% in soaked, soaked-dehulled, ordinary as well as pressure cooked and germinated seeds, respectively. Except for soaking and dehulling, the remaining processing and cooking methods did not lower the contents of total calcium, phosphorus and iron. HCl-extractability of these dietary essential minerals, an index of their bioavailability, was enhanced significantly when the pigeon pea seeds were processed and cooked, possibly due to reduction in phytate content, which is known to chelate the minerals. A significant and negative correlation between the phytic acid and HCl-extractability of minerals further strengthens these findings.

A home-based method to reduce phytate content and increase zinc bioavailability in maize-based complementary diets

A home-based method to reduce phytate content and increase zinc bioavailability in maize-based complementary diets

A home-based method to reduce phytate content and increase zinc bioavailability in maize-based complementary diets

This study aimed to develop and assess the feasibility of a home-based method to reduce the phytate content of maize and improve zinc bioavailability from maizebased complementary diets in rural Malawi. A method of extracting phytate through the soaking of pounded maize was developed, and found to reduce phytate content to 49% of unrefined maize. An educational program was used to teach the processing method to mothers of children receiving complementary foods in rural Malawian communities. Samples of maize flour prepared by this process by participants were collected and analysed for phytate and zinc content. Of these, 70% of samples were found to be adequately prepared; mean phytate content of these samples was 48% of unprocessed, unrefined maize flour controls. Most participants found the cooked product to have an acceptable taste (99%) and texture (68%), and felt the processing method took little or no extra time (86%) and was culturally acceptable (96%). The phytate and zinc content of the processed maize flour samples analysed from community prepared samples was substituted into the dietary analysis of complementary foods for 9- to 11-month-old children (n = 31). The bioavailability of zinc from the complementary diet would predict an increase from low (24%) to moderate (33%) levels.

ENDOGENOUS PHYTATE-DEGRADING ENZYMES ARE RESPONSIBLE FOR PHYTATE REDUCTION WHILE PREPARING BEANS (PHASEOLUS VULGARIS)

The three dry nonprocessed bean varieties contain high amounts of phytate ranging from 9.3 to 15.9 μmol g-1 dry basis, representing 85 to 89% of total myo-inositol phosphates, while the other myo-inositol phosphates were found only in small or trace amounts. Myo-inositol phosphate concentrations were not affected by soaking in water for 15h at 25C, whereas cooking resulted in a significant reduction in phytate content (16 to 24%) with a concomitant increase in the concentrations of the lower myo-inositol phosphates. The sum of phytate and myo-inositol pentakisphosphate after soaking and cooking represents about 93% of the amount in raw beans. Therefore, preparing of beans has only a limited effect on the content of myo-inositol phosphates with inhibitory effects on mineral absorption. Phytate-degrading enzymes (phytases) were identified as responsible for phytate removal during cooking, since a good correlation between phytase activity and phytate hydrolysis was observed.

Fermentation of soybean flour with Aspergillus usamii improves availabilities of zinc and iron in rats.

Soybean flour was fermented with Aspergillus usamii to improve the availabilities of dietary zinc and iron through the degradation of phytate. Three kinds of experimental diets that differed in protein sources were prepared: one consisting of 40% fermented soybean flour (RS diet), one consisting of 40% fermented soybean flour (FS diet), and one consisting of 20% regular soybean flour and 20% fermented soybean flour (RF diet). Zinc solubilities in the upper and the lower segments of the small intestine were higher in rats fed the FS diet than in rats fed the RS diet. The FS group showed higher solubility of iron in the lower small intestine than the RS group did. Zinc concentrations in the femur and plasma and iron concentrations in the liver and plasma were higher in the FS group than in the RS group. These results suggested that the fermentation of soybean flour improved the availabilities of dietary zinc and iron, which may be induced by increasing the solubilities of these minerals in the small intestine through the reduction of phytate content. Femoral and plasma zinc concentrations in the RF group were higher than in the RS group, but lower than in the FS group. No difference was noted in liver and plasma iron concentrations between the RF group and the FS group. Although phytase activity in FS degrades phytate in the RF diet, higher activity may be needed to degrade phytate completely.

Comparison between steeping and pelleting a mixed diet at different calcium levels on phytate degradation in pigs

The degradation of phytate (inositol hexaphosphate) in the stomach, small intestine and colon was studied in 36 female pigs. A comparison was made between steeped (9 h, room temperature, feed:water 1:2.5) and pelleted diets with or without calcium carbonate supplementation (12.5 g kg−1). The diet was composed of barley, rapeseed cake and peas in the proportion 70:15:15. Dietary and intestinal content of phytate and its hydrolysis products (inositol penta-, tetra- and triphosphates) were determined using HPLC ion-pair chromatography. Steeping the feed for 9 h at room temperature reduced the phytate content by 45% and increased the amount of free phosphorus threefold. Pelleting the diet reduced phytate content by 7%. Supplementation with Ca decreased dietary phytate reduction. Steeping of the diet reduced ileal phytate content by 40% compared with pelleting. Apparent phosphorus absorption from ileal digesta was 10% lower when pigs were fed the pelleted diet, as compared to the steeped diet. Calcium carbonate supplementation impared inositol hexaphosphate degradation in the colon of pigs, but did not affect phytate degradation in the stomach and small intestine. Calcium carbonate supplementation, moreover, depressed apparent P uptake in the stomach/small intestinal region, as well as in the total gastrointestinal tract, for all feed treatments. Key words: Phytate degradation, inositol phosphates, steeping, pelleting, calcium, pigs

Phytate Reduction in Whole Grains of Wheat, Rye, Barley and Oats after Hydrothermal Treatment

Whole grains of different cereals have traditionally been prepared with water and heat prior to dehulling, but knowledge of the effect on nutritional properties is limited. The aim of the present study was to investigate if phytate reduction occurred during hydrothermal treatment of whole grains. Wheat, rye, hulled and dehulled barley, hulled oats and naked oats were incubated with either water or acetate buffer (pH 4·8) at 55 °C for 24 h with the exception of oats, which were incubated at 37 °C. Phytate in wheat, rye and barley was reduced by 46–77% when water was used and by 84–99% when acetate buffer was used. The phytate reduction in oats was considerably less, 8–26%, but, after grinding and soaking, phytate was reduced by 72–77% in dehulled oats and by 88–94% in naked oats. Citric acid and citrate buffer was used for pH adjustment in some experiments, and their use resulted in less phytate reduction than when acetate and lactic acid were used. Wet-steeping of naked oats and naked barley in water at 53–57 °C for 20–30 min reduced the bacterial counts by 99·97%, and the addition of acid prevented bacterial growth during the incubations. It was concluded that cereals with reduced phytate content and good hygienic quality can be developed and produced using hydrothermal treatment of whole grains.

Effect of domestic processing on the cooking time, nutrients, antinutrients and in vitro protein digestibility of the African yambean (Sphenostylis stenocarpa).

The effects of processing (soaking, dehulling, fermentation and heat treatment) on the cooking time, protein, mineral, tannin, phytate and in vitro protein digestibility (IVPD) of the African yambean (AYB) were examined. The cooking time ranged from 90-155 minutes. Soaking reduced cooking time by about 50 percent. Soaking for 12 hours was the most appropriate to reduce cooking time, tannin and phytate levels. It improved in vitro protein digestibility (IVPD). Prolonged soaking (24 hours) decreased calcium (Ca) and iron (Fe) values by 19 percent and 35 percent, respectively. Dehulling showed that Ca, Fe, magnesium (Mg) and zinc (Zn) were concentrated in the seed coat of the AYB. The seeds soaked and dehulled retained Mg and Zn. Dehulling reduced tannin but had no significant effect on phytate and the IVPD of the AYB except for seeds soaked for 12 hours before dehulling. Soaking for 24 hours before dehulling significantly increased crude protein content by 16 percent (p < 0.05). Blanching and roasting increased the IVPD by 8-11 percent. Fermentation had no effect on the crude protein, Ca, Fe, Mg and Zn but significantly reduced phytate content of the AYB. Fermentation had no advantage over heat treatment with respect to improving the in vitro protein digestibility of the AYB.

Reduction of phytate content in wheat bran and glandless cotton flour by Schwanniomyces castellii

ADVERTISEMENT RETURN TO ISSUEPREVArticleReduction of phytate content in wheat bran and glandless cotton flour by Schwanniomyces castelliiLaurent. Segueilha, Guy. Moulin, and Pierre. GalzyCite this: J. Agric. Food Chem. 1993, 41, 12, 2451–2454Publication Date (Print):December 1, 1993Publication History Published online1 May 2002Published inissue 1 December 1993https://doi.org/10.1021/jf00036a046RIGHTS & PERMISSIONSArticle Views97Altmetric-Citations24LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (2 MB) Get e-Alerts Get e-Alerts