Anthony U. Osagie

Determination of phytate and lower inositol phosphates in Spanish legumes by HPLC methodology

Abstract The separation and quantitative determination of phytic acid (inositol hexaphosphate) and lower inositol phosphates (tri-, tetra- and penta-phosphates) was carried out using a HPLC method that included purification by anion-exchange chromatography, and analysis by ion-pair chromatography on a C18 reverse phase column. Samples of the most important legumes in the Mediterranean diet were analysed using this system. The different samples presented a variable content of phytic acid and different relative proportions of lower inositol phosphates.

Effect of germination, under different environmental conditions, on saponins, phytic acid and tannins in lentils (Lens culinaris)

The effect of germination conditions on some antinutrients of Lens culinaris var Magda 20 seeds were studied. The seeds were germinated at 20°C under variable conditions of time, water and light. Quantitative analyses of the soyasapogenols, inositol phosphates and tannins were carried out by capillary gas chromatography, high-performance liquid chromatography and spectrophotometric techniques respectively. Germinated seeds at day 6 contained higher levels soyasapogenol B than the controls, whereas in general the tannin content was reduced. Total phytic acid amounts did not decrease after 3 days of germination but was greatly reduced after 6 days. This work shows that the optimal conditions to reduce some antinutritional factors (tannins and phytic acid) in lentils were 6 days of seed germination in dark and with alternate watering. Therefore, germination conditions offer a good opportunity to improve the nutritional quality of lentils.

Effect of soaking, cooking and germination on the oligosaccharide content of selected Nigerian legume seeds

The identity and quantity of and effect ofprocessing on raffinose oligosaccharides in raw,mature seeds of lima beans (Phaseolus lunatus),pigeon peas (Cajanus cajan), African yam beans(Sphenostylis sternocarpa) and jackbeans (Canavalia ensiformis) were investigated. Sucrose,raffinose, stachyose and verbascose were identified byHPLC in all the legume seeds. The totalα-galactoside contents of the seeds in decreasing order were African yam beans3.84 mg/100 mg; white lima beans 3.62 mg/100 mg; creampigeon peas 3.51 mg/100 mg; red lima beans3.37 mg/100 mg; jackbeans 2.83 mg/100 mg and brownpigeon peas 2.34 mg/100 mg. The predominantoligosaccharide was verbascose in pigeon peas andstachyose in the other three legumes. Cooking unsoakedseeds brought about a greater reduction in the totalα-galactoside content than soaking for ninehours. The removal of oligosaccharides was higher inlegumes cooked in alkaline solution than in water.Germination quantitatively reduced raffinose,stachyose and verbascose while sucrose was increasedin all seeds except red lima beans and jackbeans.

Anti-nutritional constituents of six underutilized legumes grown in Nigeria

Six underutilized legume seeds grown in Nigeria namely, red and white lima beans, brown and cream pigeon pea, African yam bean and jackbean were analysed for different anti-nutritional factors Sojasapogenol B was identified as the predominant sapogenol in lima beans and jackbeans by capillary gas chromatography. The content of total inositol phosphates and individual inositol phosphates (IP6, IP5, IP4 and IP3) were analysed by ion-pair HPLC, being in the range of other legumes. Trace quantities of lupanine were identified as the alkaloid in jackbean. alpha-Galactosides were present in all the legume seeds, stachyose being the predominant galactoside in lima beans, African yam bean and jackbean, and verbascose in pigeon pea. The haemagglutinating activity was estimated as a measure of the lectin content of the samples. African yam bean was found to have the highest heamagglutinating activity. Tannins were found to be in low quantities. The presence of these anti-nutrients in relation to the nutritional value of the legume is discussed.

Effect of malting on protein metabolism in two varieties of sorghum

The metabolism of albumin, globulin, glutelin and prolamin in two varieties of sorghum recommended as alternatives to barley malt for brewing in Nigeria has been studied. There was a continuous degradation of prolamin and glutelin (storage proteins) with a concomitant rise in albumin and globulin (enzyme proteins) resulting in a synchronous rise in free amino nitrogen (FAN) during malting of SK 5912. On the other hand, all the major proteins in farafara increased at the peak of malting without a synchronous increase in FAN. When compared to the unmalted sorghum digested with external enzymes, only a quarter to half of the groups of amino acids required for yeast nutrition were obtained with malted sorghum. The production of FAN in SK 5912 malt is higher than farafara malt. FAN produced in SK 5912 malt is high enough for lager beer production therefore its recommendation as a local substitute is supported, in part, by this study.

Effect of local food processing on the inositol phosphate contents in lima bean (Phaseolus lunatus L.); pigeon pea (Cajanus cajan); African yam bean (Sphenostylis sternocarpa) and jackbean (Canavalia ensiformis)

The effects of cooking in water or alkaline solution, soaking and germination on the individual inositol phosphates (IP3 to IP6), and total inositol phosphates (IP) content of lima bean, pigeon pea, African yam bean, and jackbean were investigated. Inositol triphosphate was not detected in any of the legumes studied. The predominant inositol phosphate in all the legumes was inositol hexaphosphate (IP6). Raw white lima bean contained the highest quantity of IP6, 0.350 mg/100 mg. Pigeon pea contained 0.289 mg/100 mg IP6 in the brown and cream varieties. Jackbean contained 0.242 mg/100 mg IP6 while African yam bean had the lowest IP6 content of 0.139 mg/100 mg. All processing methods reduced the total IP to various extents. Germination led to a reduction of 85% of total IP in white lima bean. Cooking reduced IP6 by 39–65% in all the grain legumes while cooking in alkaline solution reduced total IP up to 80% in cream pigeon pea.