Distribution of Bean and Wheat Inositol Phosphate Esters During Autolysis and Germination

Abstract

Ion-exchange chromatography was used to follow changes in inositol phosphate esters of California small white beans and hard red winter wheat during autolysis and germination. Untreated bean extracts con-,tained appreciable quantities of lower phosphate esters, while wheat extracts contained only inositol hexaphosphate (IHP). Autolysis in beans at both 35 and 55°C was slow (30% of IHP still present after 48 hr). Over 80% of wheat IHP was hydrolyzed in 4 hr at both temperatures. During autolysis bean extracts contained appreciable quantities of lower phosphate esters while wheat chromatograms showed trace amounts. Germination of the seeds for 2,4 and 7 days produced similar patterns of change in the phosphate esters as in autolysis. The use of wheat phytase to rapidly reduce phytic acid in bean preparations is presented.

Effect of Fermentation Time on the Inositol Phosphates of Bread

“…In a previous communication (Ferrel, 1978) only phytic acid was reported as present in wheat flour. Table 1 shows that IPe is the dominant inositol phosphate in both of the unfermented breads analyzed, although whole wheat bread (WWB) contains more than twice the amount of IPe preSent in 70%-extraction bread (70B).…”

Inositol Phosphate Content of Selected Dry Beans, Peas, and Lentils, Raw and Cooked

“…Few literature references are available in which the inositol phosphates in raw, dry legumes are differentiated. Ferrel (1978) determined that 66% of the inositol phosphates in unautolyzed California small white beans was IP 6 , 15% was IP 4 , with smaller amounts of the others, including the mono-and di-phosphate esters. Gustafsson and Sandberg (1995) determined 1.01 and 12.6 mmol/kg, respectively, of IP 5 and IP 6 , IP 6 accounting for 92% of the total, but detected no IP 3 or IP 4 in raw brown beans.…”

“…Consequently, the IP 6 concentration may be overestimated if hydrolysis products of IP 6 are present (Lehrfeld and Morris, 1992). Ferrel (1978) separated inositol phosphates of beans by an anion-exchange procedure and found IP 4 and IP 5 as well as IP 6 in dry beans, especially after autolysis or germination. Only 44% of the total inositol phosphates in canned red kidney beans was determined to be IP 6 .…”

Preparation of High Bran Arabic Bread with Low Phytic Acid Content

“…Preincubation of the bran in a limited volume of water before incorporating it in the bread preparation formula did not cause any noticeable change in the phytic acid levels. Although the soaking process was expected to accelerate the enzymatic hydrolysis of phytic acid (Ferrel, 1978) the temperature and pH of the incubating medium were typical of regular bread preparation procedures, but quite different from the optimal requirements for enzymatic hydrolysis. When larger volumes of water were used as an incubation medium and the bran pressed free of excess water, the phytic acid content of the resulting bread was much lower.…”

“…Enzymatic hydrolysis of phytic acid is known to occur during the preparation of various foods particularly during the leavening of bread (Ranhorta, 1972;Nayini and Markakis, 1983). Phytase, which is the enzyme responsible for phytic acid hydrolysis was reported to be present in yeast and in wheat bran (Ferrel, 1978). This enzyme hydrolyzes phytate to orthophosphate and inositol, (Lopez and Fields, 1983) thereby eliminating the available binding sites.…”