Pakistan Journal of Nutrition 4 (6): 396-401, 2005ISSN 1680-5194 Asian Network for Scientific Information, 2005

396

Effect of Malt Pretreatment on Antinutritional Factors and HCl Extractability of Minerals of Sorghum Cultivars

Wisal H. Idris, Amro B. Hassan, Elfadil E. Babiker* and Abdullahi H. El TinayDepartment of Food Science and Technology, Faculty of Agriculture,

University of Khartoum, Khartoum North 13314, Shambat, Sudan

Abstract: Sorghum grains of cultivars Wad Ahmed and Tabat were germinated for 1, 2 and 4 days to obtain1-, 2- and 4- day-old malts. About 1% of sorghum malt was added to sorghum flour. The mixtures wereincubated at 30 C with shaking for 30, 60, 90 and 120 min. Phytic acid and tannin contents and mineralso

extractability (as an index for minerals bioavaliability) were assayed for all treatments. The results revealedthat phytate and tannin contents were significantly (P = 0.05) reduced when sorghum flour was pretreatedwith malt. When a mixture containing 4-days-old malt was incubated for 120 min significantly (P < 0.05)reduced phytate and tannin contents by 39.9% and 26.7%, respectively for Wad Ahmed cultivar while for Tabatcultivar they were reduced by 36.6% and 23.8%, respectively. HCl extractability of both major and traceminerals was also significantly (P = 0.05) improved as a result of malt pretreatment especially whensorghum flour was mixed with 4-days malt and incubated for 120 min.

Key words: Malt, phytate, tannin, sorghum, minerals, extractability

IntroductionMalting of cereals is a processing procedure traditionallyused in many African countries for the manufacture ofalcoholic and soft drinks (Taylor, 1983). Malting is aprocess involving germination and drying of cerealseeds, the prime objective being to promote thedevelopment of hydrolytic enzymes that are not active inraw seeds (Dewar et al., 1997). The methods employedto improve the nutritional quality and organolepticproperties of cereal-based foods include geneticimprovement, amino acid fortification, supplementationor complementation with protein rich sources andprocessing technologies which include milling, malting,fermentation or sprouting (Chavan and Kadam, 1989).Cereals and legumes are rich in minerals but thebioavailability of these minerals is usually low due to thepresence of antinutritional factors such as phytate andpolyphenols (Valencia et al., 1999). An adequate mineralabsorption is important especially for infants, children,elderly people and people in clinical situation (Bergmanet al., 1999). It is evident that the nutritional importanceof a given food/ feed stuff depends not only on nutrientcomposition of raw foodstuff but also on the amountutilized (Vijayakumari et al., 1998). In the Sudansorghum comes first in volume of cereals produced andis the staple food for people in rural areas, particularlythe low-income groups as food or sometimesprocessed to produce alcoholic or soft beverages or asfeed for livestock (Brudevold and Southern, 1994). Manyattempts to reduce phytate have been made. It isreported that phytate is reduced in malted oats by 99%(Larrson and Sandberg, 1995) and malted pea by 75% Materials and Methods(Beal and Mehta, 1985). Marfo et al. (1990) found that 72 Source and germination of seeds: Two sorghum

h fermentation significantly decreased phytate content infoodstuffs, (80-98% for rice, cassava, and cocoyam and52-65% for sorghum, maize, soybean, cowpea, andyam). Other attempts to reduce the phytate content suchas fertilization (Elsheikh et al., 2000) and activation of theindigenous enzyme phytase and/or addition of microbialphytase (Barrier et al., 1996) have been tried. Moreover,vigorous efforts are directed towards coupling thebeneficial effects of tannins in sorghum as a field cropwith methods for overcoming the anti-nutritional effectsof tannins in seeds by direct removal of seed testa,inactivation, or by extraction. Extractable tannin contentwas markedly reduced when grains were soaked inwater and stored under a carbon dioxide atmosphere(Reichert et al., 1980). In feeding trials with rats(Yasaman et al., 1990) and chicks (Teeter et al., 1986),tannins reduced weight gain and feed conversion.Sorghum is rich in minerals content but its nutritionalquality is dictated mainly by its chemical composition;presence of considerable amounts of anti-nutritionalfactors such as tannin, phytic acid, polyphenol andtrypsin inhibitors that are undesirable (El Sheikh et al.,2000). Hence elimination or inactivation of such anti-nutritional compounds is absolutely necessary toimprove the nutritional quality of sorghum, and effectivelyutilize its full potential as human food. In the presentstudy we would like to evaluate the efficiency of maltpretreatment on antinutritional factors contents and HClextractability of minerals (in vitro availability) of sorghumcultivars.

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Table 1: Percent reduction in Phytate* and tannin** content of sorghum flour incubated with malt of different age at different periodof time

Cultivars Incubation 1st day malt 2nd day malt 4th day maltperiod ------------------------------------------ ----------------------------------------- -------------------------------------------(min) Phytate Tannin Phytate Tannin Phytate Tannin

Wad Ahmed 0 0.0 0.0 0.0 0.0 0.0 0.0 30 3.90.15 2.40.93 6.40.10 3.80.19 9.92.10 6.60.59dc c c d bc

60 9.80.02 4.50.70 13.10.76 8.00.23 17.84.01 13.50.92b b bc c b c

90 13.10.52 7.60.51 22.21.80 11.80.91 32.08.40 19.80.90b ab ab b a b

120 17.81.81 9.740.51 28.91.77 16.70.82 39.96.60 26.71.66a a a a a a

Tabat 0 0.0 0.0 0.0 0.0 0.0 0.0 30 3.80.97 2.90.08 6.10.61 4.30.80 8.81.56 6.20.70cd b d c d d

60 7.00.75 3.80.93 11.51.12 7.50.21 17.81.55 12.41.03bc b c c c bc

90 10.10.41 7.60.20 16.40.60 13.80.64 27.61.08 18.61.59ab a b b b ab

120 15.10.53 9.40.97 24.00.81 18.10.96 36.60.70 23.82.19a a a a a a

Values are means of three replicates SD. Means not sharing a common superscript letter in a column for each cultivar aresignificantly different at P ? 0.05 as assessed by Duncans multiple range test. *Phytate content of Wad Ahmed and Tabat cultivarswas 265 and 233 mg/100g respectively. **Tannin content of the cultivars was 0.96 and 0.35% respectively.

(Sorghum biocolor) cultivars, locally known as Wad Phytic acid determination: Phytic acid content wasAhmed (high tannin) and Tabat (low tannin) wereobtained from Pioneer Company, Khartoum, Sudan. Theseeds were carefully cleaned and freed from broken andextraneous matter. Seeds were germinated according tothe method described by Bhise et al. (1988) for differentperiods to obtain 1-, 2- and 4-days old malt. Thegerminated seeds were sun-dried and the root portionswere manually removed. The seeds were milled into fineflour to pass a 0.4 mm sieve and kept at 4 C before use.o

Addition and incubation of malt to sorghum flour: About1% of 1-, 2- or 4-days-old malt was added to sorghumflour in triplicate. Samples were shaken for 30 min andthen mixed with water 1:2 (w/v) and incubated at 30 C ino

a shaker for 30, 60, 90 and 120 min, thereafter dried at65 C and ground to pass a 0.4 mm sieve and kept ato

4 C before use. o

Total minerals determination: Minerals were extractedfrom the samples by dry ashing method that describedby Chapman and Pratt (1961). The amount of iron, zinc,manganese, cobalt and copper were determined usingAtomic Absorption Spectroscopy (Perkin-Elmer 2380).Ammonium Vandate was used to determinephosphorus along with Ammonium Molybdate methodof Chapman and Pratt (1982). Calcium and magnesiumwere determined by titration method that described byChapman and Pratt (1961). Sodium and potassiumwere determined by flame photometer (CORNIG EEL)according to AOAC (1984).

HCl extractability of minerals (in vitro availability):Minerals in the samples were extracted by the methoddescribed by Chauhan and Mahjan (1988). One gram ofthe sample was shaken with 10 ml of 0.03 M HCl for 3 hat 37 C and then filtered. The clear extract obtained waso

oven dried at 100 C and then dry acid digested. Theo

amount of the extractable minerals was determined bythe methods described above.

determined by the method described by Wheeler andFerrel (1971) using two grams of a dried sample. Astandard curve was prepared expressing the results asFe (NO ) equivalent. Phytate phosphorus was3 3calculated from the standard curve assuming 4:6 iron tophosphorus molar ratio.

Tannin determination: Quantitative estimation of tanninswas carried out using the modified vanillinHCl methodby Price et al. (1978). A standard curve was preparedexpressing the result as catechin equivalent i.e. amountof catechin (mg/100g) which gives a color intensityequivalent to that given by tannin after correction forblank.

Statistical analysis: Each determination was carried outon three separate samples and analyzed in triplicate, thefigures were then averaged. Data was assessed by theanalysis of variance (ANOVA) (Snedecor and Cochran,1987). Means comparisons for treatments were madeby using Duncan's multiple range test (Duncan, 1955).Significance was accepted at P = 0.05.

Results and Discussion Effect of malt pretreatment on phytate and tannincontents: Table 1 shows the effect of malt pretreatmenton phytate (percent reduction) during incubation ofsorghum flour with 1% malt (1-, 2-, or 4-days old) fordifferent period of time (30, 60, 90 or 120 min). Phyticacid content of untreated sorghum cultivars was 265 and233 mg/100g for Wad Ahmed and Tabat cultivars,respectively. For each cultivar and for each malt age,percent reduction in phytate increased significantly (P =0.05) with increasing time of incubation. When the flourwas mixed with 1%, 1-day old malt, percent phytatereduction varied from 3.9 to 17.8% for Wad Ahmedcultivar while for Tabat varied from 3.8 to 15.1% dependon the incubation time. For 1%, 4-days old malt percent

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Table 2: Total mg/100g) and available %) major and trace minerals of untreated sorghum cultivarsMinerals Cultivars

------------------------------------------------------------------------------------------------------------------------------------WadAhmed Tabat-------------------------------------------------------- -------------------------------------------------------Total Available Total Available

Na 6.30.20 66.702.80 7.00.60 64.32.20K 450.02.00 46.36.40 441.72.40 51.06.70Ca 10.81.50 3.30.95 12.50.77 35.71.20Mg 59.35.70 46.41.06 63.01.00 55.61.60P 303.02.00 43.41.40 283.32.30 44.91.50Fe 3.800.10 4.200.40 4.500.12 6.000.45Zn 3.210.11 47.70.60 3.53 0.18 53.85.70Mn 3.900.30 40.82.36 3.500.10 46.24.70Co 0.210.010 66.72.80 0.180.02 72.25.60Cu 0.00 0.00 0.00 0.00Values are means of three replicates SD.

reduction in phytate was significantly increased and was The data obtained for trace minerals studied showedfound to be varied from 9.9 to 39.9% and from 8.8 to that Mn and Fe were the major mineral constituents36.6% for Wad Ahmed and Tabat cultivars, respectively. (3.90 and 3.80 mg/100g) followed by Zn (3.21 mg/100g)Results showed that as the age of malt and incubation while Co was the least constituents (0.21 mg/100g) andtime increased, percent reduction in phytate was no Cu was detected in the untreated grain of the cultivarsignificantly increased. The results indicated that phytic Wad Ahmed. For Tabat, Fe and Zn were the majoracid reduction was significantly affected by addition of minerals constituent (4.50 and 3.53 mg/100g) followedsorghum malt because the germination stage had a by Mn and Co (3.50 and 0.18 mg/100g) and the grainssubstantial effect on the reduction in phytate content due were lacking Cu. For both cultivars HCl-extractability ofto the action of endogenous phytases obtained during trace minerals revealed that Co and Zn were the mostgermination that degrade the phytate into inorganic available minerals and Fe was the least available onephosphorus and inositol and its intermediate forms. (Table 2). Malt pretreatment of the flour greatly affectsThe rate of reduction depends upon the age as well as extractability of major minerals (Table 3). Major mineralsthe amount of malt. Valverde et al. (1994) reported that content increased significantly (P = 0.05) specially Pgermination of lentils greatly reduced phytate content (data not shown) when the flour of the cultivars wascompared to soaking or cooking. Similar results were pretreated with malt. The increment in P content is likelyalso reported when sorghum flour was treated with malt due to the release of phytate P by the action of theand incubated for different time intervals (Elkhalil et al., enzyme phytase produced during germination of the2001). Percent reduction in tannin content was similar to grains and also due solubilization of phytate P duringthat obtained for phytate. However, the rate of reduction incubation as reported by Khetarpaul and Chauhanin tannin was less than that of phytate due the fact that (1990). The HCl extractability of the minerals wasphytate can be degraded by the malt enzymes but significantly (P=0.05) increased with the age andtannins only washed out. incubation time. Addition of malt to the flour of the

Effect of malt pretreatment on minerals extractability increase in malt age and incubation time (Table 3).(availability): The data obtained for the cultivars showed Sodium and phosphorus were the most available (87that among major minerals studied, K and P were the and 76%) minerals when a mixture of a 4-days old maltmajor constituents (450 and 303 mg/100g) followed by and sorghum flour were incubated for 120 min for WadMg (59.3 mg/100g) while Na and Ca were the least Ahmed cultivar. However, for Tabat cultivar, Na and Kconstituents (6.3 and 10.8 mg/100g) in the untreated were the most available minerals (84 and 81%) followedgrain of the cultivar Wad Ahmed. For Tabat cultivar, K and by Mg (76%) and finally P and Ca (72%). ResultsP were the major constituents (441.7 and 283.3 indicated that addition of sorghum malt to sorghum flourmg/100g) followed by Mg (63.0 mg/100g) while Na and greatly improved the availability of minerals. TheCa were also the least constituents (7.0 and 12.5 improvement in minerals availability is likely due themg/100g) in the untreated grain (Table 2). For both reduction in phytate and tannin content of the flour. Rakhicultivars HCl-extractability of major minerals of untreated and Khetarpau (1995) reported that, the HCl-grains revealed that Na and Mg were the most available extractabilities of calcium, iron, zinc, copper andminerals and Ca and P were the least available ones. manganese from the rice-defatted soy flour blend greatly

cultivars increased major minerals extractability with an

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Table 3: Effect of malt pretreatment and incubation for different period of time on major minerals availability (%) of sorghum flour oftwo cultivars

Minerals Malt Cultivarage -----------------------------------------------------------------------------------------------------------------------------------------------------------------(days) Wad Ahmed Tabat

------------------------------------------------------------------------------- ------------------------------------------------------------------------------Incubation period (min.)------------------------------------------------------------------------------- ------------------------------------------------------------------------------0 30 60 90 120 0 30 60 90 120

Na 1 672.8 691.9 712.3 751.5 761.8 640.0 69 0.5 712.1 732.7 732.4d cd bc ab a c bc ab ab a

2 670.0 711.3 741.1 782.5 811.6 651.9 711.4 730.8 760.3 78 2.3c b b a a c b b a a

4 672.7 731.5 761.5 821.1 871.1 651.9 732.4 760.6 812.3 841.3e d c b a e d c b a

K 1 466.4 501.3 532.4 561.6 591.8 510.7 550.8 591.4 632.7 662.3c bc ab ab s d cd bc ab a

2 471.6 520.7 551.9 581.7 622.2 511.5 571.9 631.3 681.8 7 3 2 . 0d cd bc ab a d c b ab

4 470.8 520.6 581.9 642.1 701.7 520.6 591.6 632.6 742.5 811.8 Cac c b a a c c b a a

1 330.9 382.9 411.1 453.0 491.9 351.2 412.0 461.6 512.6 562.6c b b a a e d c b a

2 341.6 402.4 451.4 522.9 573.1 361.4 421.7 491.6 552.9 611.9e d c b a e d c b a

4 34.6 431.7 511.0 591.8 672.1 361.1 452.3 541.0 631.9 720.7e d c b a e d c b a

Mg 1 460.6 410.9 52 0.9 540.9 581.5 551.5 591.0 611.0 641.2 671.7e d c b a e d c b a

2 46.0 511.8 551.4 591.6 691.1 562.2 591.1 631.1 671.7 701.5e d c b a e d c b a

4 471.1 522.1 581.9 631.8 691.9 562.1 611.9 661.5 711.3 762.9e d c b a e d c b s

P 1 431.4 463.0 512.5 550.9 581.8 451.4 472.7 501.5 520.7 563.3c c b a a d cd bc ab a

2 441.2 48 2.3 540.9 591.8 641.8 453.0 491.3 531.1 570.5 611.1e d c b a e d c b a

4 442.3 510.8 601.9 681.6 76 3.4 453.0 521.6 591.4 642.3 720.9e d c b a e d c b a

Values are mean of three replicates ( SD). Means not sharing a common superscript letter in a row for each cultivar are significantlydifferent at P < 0.05 as assessed by Duncans multiple range test.

Table 4: Effect of malt pretreatment and incubation for different period of time on trace minerals availability (%) of sorghum flour oftwo cultivars

Minerals Malt Cultivarage -----------------------------------------------------------------------------------------------------------------------------------------------------------------(days) Wad Ahmed Tabat

------------------------------------------------------------------------------- -------------------------------------------------------------------------------Incubation period (min.)------------------------------------------------------------------------------- -------------------------------------------------------------------------------0 30 60 90 120 0 30 60 90 120

Fe 1 4 0.4 70.2 90.9 121.5 150.5 60.4 90.9 121.3 151.7 171.3c d c b a e d c b a

2 41.7 70.5 110.8 141.5 181.7 60.5 100.9 121.8 161.7 19 1.7e d c b a c b b a a

4 4 0.5 80.7 121.1 151.5 191.6 70.2 111.2 141.6 181.8 212.3e d c b a d c b a a

Zn 1 472.0 511.5 55 2.4 581.7 621.9 543.8 611.2 641.1 681.9 721.3d c b a a d c bc ab a

2 480.9 520.5 572.3 632.1 690.9 541.8 621.4 671.7 701.8 751.7e d c b a d c bc ab a

4 481.5 551.8 621.1 681.9 75 1.4 542.1 642.3 70.1.7 761.9 811.5e d c b a d c b b a

Mn 1 411.9 441.3 462.4 493.2 512.6 462.5 492.3 510.5 532.4 551.9d d c ab a c bc ab a a

2 420.4 461.9 501.1 551.9 591.8 462.5 510.9 54 1.1 581.6 622.1e d c b a e d c b a

4 410.9 481.5 561.8 611.0 702.2 462.1 552.4 611.6 671.7 742.2e d c b a d d c b a

Co 1 674.7 692.1 701.8 723.4 731.2 720.3 752.0 771.8 801.6 811.7a a a a a c bc abc ab a

2 674.7 701.8 742.4 762.0 791.7 730.5 750.8 781.9 822.2 851.1c bc abc ab a d cd bc ab a

4 672.2 733.4 7706 802.1 851.8 73 0.5 773.1 841.1 881.9 933.1c bc b ab a c c b ab a

Cu 1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.002 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.004 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

Values are mean of three replicates SD. Means not sharing a common superscript letter in a row for each cultivar are significantlydifferent at P < 0.05 as assessed by Duncans multiple range test.

improved. Further they reported that higher HCl- It was observed that HCl extractability of trace mineralsextractability of minerals may be partly ascribed to the was significantly (P=0.05) increased with the age anddecreased content of phytic acid, as a significant incubation time. Addition of 1% malt to the flour of thenegative correlation between the phytic acid and HCl- cultivars increased trace minerals extractability with anextractability of dietary essential minerals was obtained. increase in malt age and incubation time (Table 4).Malt pretreatment of the flour greatly affects and When a mixture of 1%, 4-days old malt and the flour ofextractability of trace minerals (Table 4). Trace minerals Wad Ahmed cultivar were incubated for 120 min, Co andcontent increased significantly (P = 0.05) when the flour Zn became the most available minerals (85 and 75%)of the cultivars pretreated with 1% malt (data not shown). and Fe was the least available (19%). For Tabat cultivar,

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also Co and Zn were the most available minerals (93 Chauhan, B.M. and L. Mahjan, 1988. Effect of naturaland 81%) followed by Mn (74%) and Fe was the leastavailable mineral (21%). It is clear from the dataobtained that the percent availability of Co and Zn aregreater in Tabat compared to Wad Ahmed. Resultsindicated that addition of sorghum malt to sorghum flourgreatly improved the availability of trace minerals. Theimprovement in the availability is likely due the reductionin phytate and tannin content of the flour as reported byRakhi and Khetarpau (1995). Moreover, results revealedthat as the age of the malt and the incubation time wereincreased, both major and trace minerals availabilityincreased this basically due to the fact that more phytasewill be available which solubilize phytate of the flour.

Conclusion: Utilization of sorghum malt to lower phyticacid and tannin contents and to improve the extractabilityof major and trace minerals is a promising and simplemethod. The rate of reduction of phytate and tannincontents with a concomitant increment of mineralsavailability depends on the age and incubation period ofthe malt.

ReferencesAOAC, 1984 Official methods of analysis. (14th ed.).

Association of Official Analytical Chemists:Washington, DC.

Barrier, G.B., P. Casado, C. Jondreville, F. Gatel andM.R. Larbier, 1996. Wheat phosphorus availability:In vivo study in broiler and pigs; relationship withindigenous phytase activity and phytic phosphoruscontent in wheat. J. Sci. Food Agri., 70: 69-74.

Beal, L. and T. Mehta, 1985. Zinc and phytate distributionin peas. Influence of heat treatment, germination,pH, substrate and phosphorus on pea phytate andphytase. J. Food Sci., 50: 96-100.

Bergman, E.L., K. Fredhund, P. Reinikainent and A.S.Sandberg, 1999. Hydrothermal processing of barley(cv. Blenheim): Optimization of phytate degradationand increase of free myo-inositol. J. Cereal Sci., 29:261-271.

Bhise, V.J., J.K. Chavan and S.S. Kadam, 1988. Effect ofmalting on proximate composition and in vitroprotein and starch digestibilities of grain sorghum.J. Food Sci. Tec., 25: 327-329.

Brudevold, A.B. and L.L. Southern, 1994. Low proteincrystalline amino acidsupplemented, sorghum-soybean meal diet for the 10 to 20 Kilogram pig. J.Anim. Sci., 72: 635-641.

Chapman, H.D. and F.P. Pratt, 1982. Determination ofminerals by titration method. Methods of Analysis forSoils, Plants and Water, 2 edn, Californiand

University, Agriculture Division, U.S.A., pp: 169-170.Chapman, H.D. and F.P. Pratt, 1961. Ammonium

vandate-molybdate method for determination ofphosphorus. Methods of Analysis for Soils, Plantsand Water, 1 edn, California University. Agriculturest

Division, U.S.A., pp: 184-203. hydrolysis. Int. J. Food Sci. Nutr., 50: 203-208.

fermentation on the extractability of minerals frompearl millet flour. J. Food Sci., 53: 1576-1577.

Chavan, J.K. and S.S. Kadam, 1989. Nutritionalimprovement of cereals by sprouting. Cr. Rev. FoodSci. Nutr., 28: 401-408.

Dewar, J., J.R.N. Taylor and P. Berjak, 1997.Determination of improved steeping conditions forsorghum malting. J. Cereal Sci., 26: 129-136.

Duncan, D.M., 1955. Multiple range and multiple F-test,Biometric, 11:1 42.

Elkhalil, E.A.I., A.H. El Tinay, B.E. Mohamed and E.A.E.Elsheikh, 2001. Effect of malt pretreatment on phyticacid and in vitro protein digestibility of sorghumflour. Food Chem., 72: 29-32.

Elsheikh, E.A.E., I.A. Fadul and A.H. El Tinay, 2000. Effectof cooking on antinutritional factors and in vitroprotein digestibility of faba bean grown with differentnutritional regimes. Food Chem., 68: 211-212.

Khetarpaul, N. and B.M. Chauhan, 1990. Improvement inHCl-extractability of minerals from pearl millet bynatural fermentation. Food Chem., 37: 69-75.

Larrson, M. and A. Sandberg, 1995. Malting of oats inpilot plant process. Effect of heat treatment, storageand soaking conditions on phytate reduction. J.Cereal Sci., 21: 8795.

Marfo, E.K., B.K. Simpson, J.S. Idowu and O.L. Oke,1990. Effect of local food processing on phytatelevels in cassava and soybean. J. Agri. Food Chem.,38: 15801585.

Price, M.L., S. Van Scoyoc and L.G. Butler, 1978. A criticalevaluation of the vanillin reactions as an assay fortannin in sorghum grain. J. Agri. and Food Chem.,26: 1214-1218.

Rakhi, G. and N. Khetarpau, 1995. Effect of fermentationon HCl-extractability of minerals from rice-defattedsoy flour blend. Food Chem., 50: 419-422.

Reichert, R.D., S.E. Fleming and D.J. Schwab, 1980.Tannin deactivation and nutritional improvement ofsorghum by anaerobic storage of H O-, HCl-, or2NaOH-treated grain. J. Agri. Food Chem., 28: 824-829.

Snedecor, G.W. and W.G. Cochran, 1987. StatisticalMethods, 17 ed. The Iowa State University Press,th

Ames, IA, U.S.A., pp: 221-222.Taylor, J.R.N., 1983. Effect of malting on the protein and

free amino nitrogen composition of sorghum. J. Sci.Food Agri., 34: 885892.

Teeter, R.G., Sarani, M.O. Smith and C.A. Hibberd, 1986.Detoxification of high-tannin sorghum grains. J.Poult. Sci., 65: 6771.

Valencia, S., U. Svanberg, A.S. Sanberg and J. Ruals,1999. Processing of quinoa (Chenopodium quinoa,Willd). Effects on in vitro iron availability and phytae

Idris et al.: Malting of cereals

401

Valverde, C.V., J. Frias, I. Estrella, M.J. Gorope, R. Ruize, Wheeler, E.L. and R.E. Ferrel, 1971. A method for phyticand J. Bacon, 1994. Effect of processing on some acid determination in wheat and wheat fractions.antinutritional factors of lentils. J. Agri. Food Chem., Cereal Chem., 28:313-320.42: 2291-2295. Yasaman, S., A.F. Paul, H. Richard and F. Edward, 1990.

Vijayakumari, K., P. Siddhuraju, M. Pugalenthi and K. Effect of foods rich in polyphenols on nitrogenJanardhanan, 1998. Effect of soaking and heat excretion in rats. J. Nutr., 120: 346-352.processing on the levels of anti-nutrients anddigestible proteins in seeds of vigna, aconitifoliaand vigna sinensis. Food Chem., 63: 259-263.