House, L R

Murty, D S

Patil, H D

ICRISAT Open Access Repository

NUTRITIONAL AND 3OCESSING QUALITY OF SORGHUM D.K. SALUNKHE J.K. CHAVAN S . J .  JADHAV OXFORD & IBH P U B L l S H l N G  CO. New Delhi Bombay Ca Icu t ln  - Processitig and Cooking Quality Characters in Sorgltum 157 Processing and Cooking Quality Characters in Sorghum D.S. Murty, 11. D. Patil and L. Re House 'I 1.w processing and food quality characters of the cultivar are of' gre:it importance to the farmers who grow sorghum for their o w n  consumption (Pushpamma and Vogel, 1982). The accept- al>ility and extension of high-yielding cultivars of sorghum are i1112cted by their consumer quality characters (Rooney and hl urty, 1982). Over the past few years, a systematic evaluation 01' genetic variability for processing and food quality characters 01' sorghum has been attempted at ICRJSAT and some of ~ h e s c  studies are reported in  this chapter. Results from these invrbtigations would be useful in formulating selection criteria for breeders and could be applied in the development of lsbora- tory techniques necessary to rapidly screen large number of brccciing stocks. 2. PROCESSING O F  SORGHUM 2.1 Traditional Dehalling In several countries of Africa and some regions of South India sorghum is consumed after removing the pericarp of the grain by traditional methods with a mortar and pestle (Vogel and Graham, 1979). Moist grain is placed in a mortar and pounded with a pestle until the pericarp is separated from the endosperm. In this process, variable quantities of germ are removed from the grain. The pounded material is winnowed and the bran is separated. The endosperm recovered is either pounded again to obtain flour or is cleaned in water and cooked depending upon the food product. Although mechanical methods of dehulling have been designed and some pilot plants are in operation (Riechert, 1982), currently most of the dehulling of sorghum in the rural areas is done by traditional methods. Preliminary reports from Upper Volta and Mali indicated that sorghum grain from local cultivars of West Africa was relatively easier to dehull by traditional methods (Murty and House, 1980), than introduced cultivars from USA and India. These reports have prompted the undertaking of controlled evaluations of sorghum samples from diverse origin for their traditional dehulling quality. 2.2 Dehulling Quality of Sorghum Cultivars Fifty-five sorghum cultivars representing different taxonomic groups of the world collection, improved cultivars of recent origin and diverse breeding stocks were included in the dehull- ing studies. These cultivars exhibited variation for size, shape, weight, breaking strength, presence of testa, endosperm texture and pericarp thickness of the grain. The samples were grown during the rabi seasons of 1978, 1979 and 1980 at the ICRISAT Centre. A standard quantity of 400 g of grain was used for each dehulling quality observation. A stone mortar and a wooden pestle with a steel ring a t  the end were used as dehul- ling equipment. Each sample was placed in the mortar and adequate quantity of water was added. A skilled woman pound- ed the grain samples with the pestle and the number of pound- ed strokes necessary to satisfactorily dehull the grain were recorded. Three grain samples of each cultivar were dehulled by three different women and the three observations were averaged. The dehulled material was dried at  70°C for half an hour and winnowed to separate the bran. The endosperm was washed and dried again at  70°C until the moisture per writ decreased to 10. The weight of dehulled endosperm and broken ProcessLtg IM Cooking Quality C/raracfers in Sorghum I 59 I v r , t i , :  \:'CI.LI I C C C ) T ~ ~ C ~  i l f ~ e ~  sifting the endosperm with a US 41311~1.irrl  biz\. t of 111c"sh 1.70 mm. The dehvlled endosperrn Was \ i \ i r ; i I f >  bcorcd for the extent of pericarp ren~oval on it scale 1 I 0  5 .  '1-l:e ph>sical properties of the grdirl samples with respect to PI.:\ III  s i ~ c ,  grain shape, weight per 100 grains and breaking strength 01' I \ : C  gritin exhibitrd a broad range (Table 12.1). Pericarp ~Ilicb,ncss of the cultibars varied from thin to very thick while the ~ndospet'ln texlure varied from floury to completely ~ o r n c o ~ ~ s .  Alllong the 30 cultivars studied, the number of poun- dinp ..trokes necessary to dehuil 400 g grain varied from 336 to 644 wiib ;1 mean of' 473 (Table 12.1). The extent of pericary re~~lo\. i l  r:ur~ed fr.om complete to very poor removal. Further pt~trn~ttng of' samples \tllich had poor initial pericarp removal ~.rc\ulteJ in Inore broken endosperm. The per cent endosperm I t.co\ cry ranged from 69 to 88 with n mean of 80 (Table 12. I ) .  f'cr cScrlt brokens ranged fro111 1 to 30, In general, grains with hi;kly co~.nttous endospel-rn produced the least number of b r o L c n ~  and yielded more endosper~n while floury endospern~ j ~ a d  to ~ l l e  highest per cent brokens. These results are in agree- ment \ v ~ t l ~  t h ~ s e  obtained by Maxon et al., (1971) who, using a scot1 b,trley prarler studied the pearling quality of sorghum grain> having diff'erent endosperm textural properties. However, grains with a thin pericarp and highly corneous endosperm ( ~ u l h  2, IS 3813) resulted in a relatively poor pericarp removal cornpiired to grains with a very thick pericirrp and highly corneous endosperm (IS 5758). Pericarp removal of the turtle beaked caudatum type of graiqs (E 15-5, SPV 35, Bulk 3, EC 64734) wa$ sl~wer qnd incomplete. The pericarp around the byhr miqn of caudatum grain types was particularly difficult lo remove. Another set of 25 cultivgrs were evaluated from grain samples grown in two copsecutive years, 1980 and 1981 for their traditional dehulling quality (Table 1.2).  In geqerd, the results cpnfjrmed the obsesyation$ made on the 30 cultivars in 1979. 7he ayqyge cndopp~rq~ recovery of the 25 cultivars in the year 1S)ISO Was 80.g per pent while io 1981 it was 73.4 per cent. The p c ~  eqnt of brokqns were also relatively higber in 19k I .  Cul$yar# S 29 a84 Market 1 (origiwtiqg frqq West Africa) with ;l thick pcricarp gnd highly yitre.ous e n d ~ $ ~ r m  u! YI - 0 z -? z 2 t- C! N 09 - DQ 00 v, I- - m Pi N N r-4 N t-i z 2 w 09 CJ tn 0: c') d 9: cV 00 z m d s 8 Proces~itigand'L~okin~ Quality Clmcters inSurghum 165 4 ic l~lvci  1 1 1 i  clcancst endosperm and produced the least brokens. I low*cvcr, corneous grains like CSH 5 and S 13 also showed good dcl~ullir~g quality. Grain with a subcoat (IS 2317, WS 1297 arid IS 7635) and grain with a brown pericarp (Dobbs and IS 7055) exhibited very poor dehulling quality. Grain with pigmentation and pink coloured spotting on the pericarp geaeriilly yielded endosperm with a similar coloured spotting, althougl~ to a lesser extent than brown grains. Pericarp removal 01' tlre rctl and yellow pericarp types from South lndia (CO 4 and I'atche Jonna) was satisfi~ctory. However, their less corneous endosperm contributed to more brokens and consequ- ently poor endospernl recovcry. Significant differences were ob5crvt.d between 1980 and 1981 for the number of pounding strokes, pcr cent endospernl recovery and per cent brokens for illin prricarp types (CSH 5) and soft endosperm lypes (WS 1297 and 1' 721). Probably initial poor pericarp removal led the wornen lo continue pounding which made a negative contribu- tion to per cent endosperm recovery and brokens. Highly cc~rneous endosperm types with a very thick pericarp possessed 1 he most desirable traditional dehulling quai it ies, as evidenced by a complete pericarp removal, less broken endosperm and Icsh rrianual eflbrt. Thick pericarp is governed by single reces- hive gene (Ayyangar et ai., 1934) and cat1 be visually selected. 3. C'OOKING QUALITY In several regions of the Indian semi-arid tropics, sorghum is consumed in the form of boiled rice-like products after remov- ing the pericarp (Subramanian and Jambunathan, 1980). Cook- ing time, volume and texture of the cooked product are important quality criteria for rice-like products. In order to assess the variability for these cooking quality characters, small grain samples (20 g) from 112 diverse sorghum cultivars. (including the 25 from dehulling experiments) were evaluated under controlled laboratory conditions. Whole/pearled grain samples were used for cooking quality evaluation. Graia samples were boikd in excess of water on an electric hot plate. The time taken for satisfactory cooking of the grain Gudged by exorminatiw of 2 or 3 kernels after cutting them longitudinally with a scalpel) and the final volume and weight of the cooked product obtained by filtering the cooking water were recorded. The texture of the cooked grain was subjectively scored. Vari- ability observed for cooking quality characteristics of the 112 cultivars is summarised in Table 12.3. Water absorption of Table 12.3. Variability for Boiled Grain Attributes Among 1 12 Cultirars of SorghumU Attribute Mean +s.c. Range -- -- - Minimum Maximum Corneousness 2.73 0.10 1 .00  5.00 Grain weight (g1100) 3.3 1 0.09 0.76 6.80 Water absorption capacity of grain (%)b 24.97 0.49 15.71 40.23 Breaking strength (kg) 7.58 0.22 1.80 15.03 Grain density Cooking time (min) Weight of cooked grain (g) 48.9 0.30 41.5 57.2 Volume of cooked grain (cc) 44.0 0.31 36.0 52.5 Per cent increase in weight 143.5 1.52 107.4 186.2 Per cent increase in volume 182.9 2.71 100.0 273.5 Cooked grain texturee 3.2 0 07 1.1 4.7 aWholc grain samples were used. water absorption of the grain was determined by soaking 100 whole grainsin water for 5 hours at room temperature and observing the increase of weight. ~Cookcd grai~r texture was rated by pressing individual grains by the thumb and fore finger on a scale of 1 to 5 wbtre 1 = very soft and 5 =hard. whole grain varied from 15.7 to 40.2 per cent while cooking time varied from 54 to 114 minutes. Increase in the weight and volume of the grains as a result of cooking varied from 107 to 186 per cent and 100 to 273 per cent respectively. The cooking quality of whole grain and pearled grain samples were studied comparatively for only the 25 cultivars of the I oo .i 1 1 i o t ~ i 1  tltlil f'rocessitzg Quality of Sorgl~urrt ,- Processing and Cookitlg Quality Characters in Sorgl~urn 167 clcl~ttll~~r:!, exj)eri~uents ('Table 12.4). As a result of dehulling, tllc c , o o l \ i ~ ~ g  ~ i n w  was ~.etluced by half and the volume and ' I ' ~ l b c .  12.4. Variability f ~ r  Some Cooking Quality Attributes of Whole (;rain and Del~ulled Grain from 25 Sorghum Cultivars" Mean f s.e. Range A111 ibulr: Minimum Maximum . " - - .-- -- -- - -- U I , , W ~ ~ C I  al)surption of grain 37.95 0.93 30.62 48.52 (24.704) (0.99) (I 7.4) (40.23) \Vc:ght o f  cooked grain (g) 74.80 1.24 62.20 88.1 S (50.26) (0.60) (44.04) (52.5) Volun~c of cooked grain (cc) 70.18 1.285 57.50 82.00 (45.92) (0.60) (40.0) (52.5) I'cr ccnt increase in weight 273.60 6.167 212.00 340.00 (151.2) (2.82) (130.5) (181.5) I'er cent incressc in voli~me 362.40 8.786 283 00 465.50 (1 97.0) (4.94) (1 42.5) (273 5 )  Cooked grain texture 2.33 0.11 1.00 3.57 (2.55) (0.12) (1.12) (3.75) --- -- .-- UValues within parcnthtscs indicate observations on whole grain samples and values without pannthtscs iadjcatc observations on dehulled grains. weight of the cooked product increased by about 80 per cent. Correlation coefficients (r values) between various grain and cooking quality characteristics (Table 12.5) indicated that grain density was positively correlated with per cent increase in the valume af the m k e d  product. Table 12 5. Correlations between Various Physical and Cooking Quality Parameters of Whole Graina - - - - -a - . - - - - - - - - . - - - - - -- - -< Correlations r values - _ _ - _ _ - - -  Corneousness vs % water absorption of graln -0.529 vs Breaking strength 0.557 vs % Increase in cooked volume 0.543 % Water absorption of grain vs. grain density vs "/, Increase in cooked volume Breaking strength (kg) vs Grain density vs Cooking time vs % Increase in volume Grain density vs % Increase in volume 0 662  based on observations on 112 cultivars. The sign and magniludc of thc correlations were in general the same in cooked product from wholt: grain and pearled grain. r value at  1 per cent level for 110 d.f.=0.25. 4. SORU QUALITY EVALUATION Soru, a SoutI~ Indian food, is a boiled rice-like product prep:tr- ed by using pearled sorghum grain. In order to evaluate the sort4 quality characters of sorghum, taste panel studies were conducted at Bhavanisagar (South India). Pearled grain samples from the 25 cultivar set were used. Samples of 125 g were coek- ed in  approximately 800 to 900 n11 of water on an electric stole. The freshly prepared samples of soru were evaluated indepcn- dently for taste, texture and colour by a taste panel of six fiirm women. Duplicate soru samples of each test entry werc prepnr- ed for the taste panel evaluation. The product was submerged in water and stored overnight, as per the local custom, and the keeping quality was evaluated in the morning. A white soru similar to boiled rice in appearance and texture was preferred by the panelists (Table 12.6). Ia general, white grains with a corneous endosperm produced an acceptable pro- duct. The keeping quality of soru from the cultivar CO 4 was 'W Processing arzrr ..-ook ing Quality Characters in Sorglt urn 1 69 'I':il)le 12.6. Sufu Quality Scores of 25 Sorghum Cultivarsa Keeping Colour Taste Texture quality Market 1 Mean Range 1.0-3.0 1.0-3.0 1.0-3.0 1.2-3.0 Wean of two Independent observations of six taste panelists from Bhavaaisagar. An characters wcm rated oa a vcale of 1-3 (I-=good). found to be the best. In fact, the texture of soru from white pa in  with testa (IS 2317) was rated better due to its soft and fluffy nature and better keeping quality. Therefore, white grain types with intermediate and soft endosperm might combine rrood cooking and product qklity. * 5 .  CONCLUSIONS Grain samples of 55 sorghum cultivars were studied for various physical characters and traditional dehulling properties. Kernels with a highly corneous endosperm and a very thick pericarp were easier to dehull by hand pounding than those with a thin pericarp and those with a soft endosperm. Corneous grains yielded more pearled endosperm and less broken grains. The dehulling quality of floury grain and those with a testa was poor. Turtle-beaked or cauclatum types of grain posed problems in pericarp removal at the hylar region. Round or oval grain with a hard endosperm and a very thick white pericarp would be ideal for traditional dehulling. Studies on the  cooking quality of 112 cultivars of sorghum indicated a broad range for variation for cooking time, cooked grain texture and vol~~rne and weight of the cooked product. Cooking time of the dehulled grains was reduced by half while the increase in volume and weight of the cooked product was about 80 per cent. Taste panel studies on the soru (boiled rice-like product) quality of 25 sorghum cultivars indicated that kernels with a white thick pericarp and intermediate endo- sperm texture formed a better combination for traditional de- hulling and cooking quality. Soru from soft cndosperm types exhibited the most desirable texture. REFERENCES Ayyangar, G.N.R., C. Vijayaraghavan, and V.P. Rao, 1934, Inheritance of  characters in sorghum-the great millet, VI. Pearly and chalky grains, Indian J. Agric. Sci. 4: 96. hlaxon, E.D., W.B. Fryar, L.W. Rooney, and M.N. Krishnapramd, 1971, Milling propertits of sorghum grain with different proportions of corneous to floury endosperm, Cereal Cbcm. 48: 478490. Murty, D.S., and L.R. House, 1980, Sorghum food quality: Its assessment and improvement, Report submitted to (ha 5th Joint Meeting of the UNDP-CIM MYT-ICRISAT Policy Advisory Ccmmitter. ICRISAT, ~~yderabad,  India, October 14-18, p. 28. I'ushparnma, P., and S.M. Vogel, 1982. Consumer acceptance of sorghum and sorghum food products, In Proc. of an Int. Symp. on Sorghum Grain Quality, ICRISAT, October 28-31, 1981, ICRISAT Centre, Patancheru 502324, India. Jtiechert, R., 1982, Sorghum dry milling. In Sorglrrmr it1 rile Eighties, Proc. of an Int. Symp., Nov. 1-7.1981, ICRISAT Centre, Patancheru 502324, 1 odia. Itooney, 14.W., and D.S. Murty, 1982, Evaluation of sorghum food quality, In Surgtlunz in tile Eighties, Prw. of an Int. Symp. Nov. 1-7, 1981, ICRISAT Centre, Patancheru 502324, India. Subramanian, V., and R. Jambmathan, 1980, Traditional metbods of processing of sorghum (Sorghum biocolor L. Moenclr) and pearl millet (Petmiseturn arnericanum) grains in India, Reports of the International Association of Cereal Chemist. 10: 115-1 18. Vogci, S., and M. Graham, 1979, Sorgbum and millets-Food producticn and use, Published by International Drvelopmtnt Research Centre, l'ublication IDRC 123, E Box 8500, Ottawa, Canada, p. 63. Processing and Culinary Properties of Grain Sorghum A. C/za~~drashekar and H.S.R. Desikachar 1. INTRODUCTION W g h u m  is one of the most important crops that is used by pvanan3s a staple food. However, perhaps because of the stigma dtached to it as a "poor" man's food, very little work on proceqsing and grain quality seems to have been done on this ever, for some time work has been done on the pro- technological and culinary properties of sorgl~um t atfhe Central Food Technological Research Institute, Mysore. A shart account o f  the results is presented here. 2. PROCESSING OF SORGHUM 2.1 Primary Processing Some of the bran from sorghum can be removed after grinding followed by sieving. Conditioning the grain with about 3-5 per cent extra moisture for 5-10 minutes prior to grinding enables the moistened bran to be ground coarse relative to the emdo- sprm and it can therefore be easily removed by sieving (Table 13.1). The endosperm is recovered as  coarse oemdina, fine semolina and as flour. Varietal diffcresrces exist isr respect of Lhc yield of semolina and the completems of brad rrmoved. Softer wr~hums can bc refined in this way but some of the 

Processing and Cooking Quality Characters in Sorghum

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