Effect of several germination conditions on total P, phytate P, phytase, acid phosphatase activities and inositol phosphate esters in spring and winter wheat

Abstract

Changes in the wheat phosphatases (phytase-Phy and acid phosphatase-AcPh) and the degradation of their substrates (inositol phosphates esters) during seed germination have been examined in two studies. Germinated grains with high phytate degrading enzymes are of potential interest in the improvement of phosphorus availability in monogastric animals. In the first study, the seeds were soaked for 1 and 14 h and germinated for 3 and 5 days with and without the addition of gibberellic acid (GA3). In the second study, the seeds were soaked for 1 h and germinated for 1, 3 and 5 days with GA3. Phytase (up to 1800 and 1573 U/kg) and acid phosphatase (up to 13 115 and 10 154 U/g) activities and IP6 (6·96 and 7·67 mg/g), IP5 (0·40 and 0·60 mg/g) and IP4 (0·04 and 0·04 mg/g) were detected in ungerminated spring and winter wheat, respectively. The germination process caused a significant increase of Phy and AcPh activities in spring (up to 275 and 235%) and winter wheat (up to 250 and 329%) and a reduction in the phytate phosphorus content (up to 35 and 64%, respectively). Phytate phosphorus content was affected in both spring and winter wheat by the soaking time. Finally, during the course of germination, IP6 and IP5 were more rapidly degraded in winter wheat (62 and 62%) than in spring wheat (32 and 29%), and IP4 was only a short-living intermediate, which was increased during hydrolysis and degraded to IP3. In conclusion, the germination process caused a significant increase of Phy and AcPh in spring and winter wheat, which was accompanied with a significant reduction of phytate phosphorus content and an increase in the content of lower inositol phosphates.

Combating Mineral Malnutrition through Iron and Zinc Biofortification of Cereals

“…Recently, an interaction between lpa mutations and anthocyanin accumulation and compartmentalization in the kernels of maize lpa mutants was suggested (Badone and others ), which could lead to changes in the attraction of pollinators, signaling with microbes, male fertility, antimicrobial activity, UV protection, and in general the protection from oxidative damage (Winkel‐Shiley ). Phytate are degraded by endogenous phytases which release phosphate and other minerals during seed germination that supports the growth and development of the seedling (Centeno and others ; Hemalatha and others ). Thus, it is anticipated that breeding lpa crops using mutation breeding may seriously hamper seed germination and plant performance, which will ultimately affect yields.…”

Phytase activity in brown rice during steeping and sprouting

“…Phytase activity increases significantly during seed germination. In spring and winter wheats, phytase activities increased by 275% and 250%, respectively after germination (Centeno et al 2003). Phytase activity in lentils, broad beans and runner beans reached maximum levels after 8 days of germination, around 10-fold (Kyriakidis et al 1998).…”

Identification of a Phytase Gene in Barley (Hordeum vulgare L.)

“…It is suggested that phytases with broad substrate specificity are better suited for animal nutrition purposes than phytases with narrow substrate specificity [39] . A widely used method for estimation of phytase activity is to incubate the sample with phytate and estimate the phytase activity by determining released inorganic phosphorus, which can also be performed on crude extracted phytases [8] , [27] , [30] , [40] . This method was employed in all the experiments in the current study.…”