Status and Breeding Requirements for Sorghum Utilization in Beverages in Nigeria

D.S. Murty*, S.A. Bello, and C.C. Nwasike

Abstract

Sorghum /Sorghum bicolor (L.) Moench] grain has traditionally been used in Nigeria for malting and brewing opaque beers such as pito and burukutu on a domestic scale, while the beverage industries depended completely On imported barley malt. Since the imposition o f a ban on imported barley and other cereals in 1988, beverage industries have successfully substituted barley malt with sorghum grain as1 malt and adjunct in the production o f lager beer and non-alcoholic malt drinks. Industrial use o f sorghum as adjunct requires cultivars with uniform grain size and shape (round or oval), hard endosperm, higher extract and soluble proteins, lower polyphenol or tannin and fa t contents, and low gelatinization temperatures. Grains required by the malting industry should possessfast water uptake and high germinability, higher malt extract and enzyme (]3-amylasej activities, soft endosperm, low polyphenol/tannin content, and less mold and rootlet activity during germination. Choice o f appropriate cultivars, locations, and growing conditions could improve the quality o f industrial raw material. Increased collaboration between research and industry is required.

Nigeria is the foremost country in Af­ During the 1980s, the government of rica in both total area cultivated with sor­ Nigeria introduced a Structural Adjust­ ghum and sorghum production (4 million ment Program (SAP) with emphasis on t; FAO, 1994). Commonly called dawa, the local sourcing of raw materials to save sorghum is the staple cereal in northern foreign exchange and increase self-reli­ Nigeria and is consumed in traditional ance. Earlier research and development foods such as tuwo (thick porridge), ogi efforts in Nigeria on the prospective use (thin fermented porridge), kunu tsamia of local cereals such as sorghum came to and massa. Traditionally, sorghum is also light, and the Nigerian beverage indus­ used in some parts of Nigeria in the pro­ tries made a strong and successful effort duction of opaque beers such as burukutu, to substitute imported barley malt with' pito and otika by the small cottage indus­ local sorghum. It has been estimated try; Until the 1970s, however, the food through specific surveys in Nigeria that and beverage industries in Nigeria totally about 120,000 metric tons of sorghum depended on imported barley malt, wheat, were used per year by the industries (For- maize, and other cereal products as raw son and Ajayi, 1995). The objective of this materials (ICRISAT, 1990). paper is to summarize the current use of sorghum by the various Nigerian food and beverage industries, review the grain D.S. Murty, ICRISAT, B.P. 320, Bamako, Mali; S.A. Bello, Guinness (Nig.) PLC, PMB 21071, Ikeja, Lagos, Nigeria; and C.C. Nwasike, Department of quality requirements for such end uses, Plant Science, Institute for Agricultural Research PMB 1044, Zaria, Nigeria. ^Corresponding author. and discuss their implication in breeding.

558 Current Status of Utilization complete saccharification and wort clari­ fication during the brewing process Lager Beer (Aisien, 1990). Bogunjoko (1992) esti­ mated that one ton of sorghum grain could The potential use of sorghum as grain produce 70 hL of lager that would require and/or malt in lager beer production was 4 kg of exogenous enzymes. Hallgren under investigation by researchers in Ni­ (1995) described the clear beer brewing geria during the 1970s and early 1980s procedures required for sorghum substitu­ (Aisien, 1982; FIIRO, 1976; Okafor and tion mixtures and their associated prob­ Aniche, 1980; Okon and Uwaifo, 1985; lems. Olaniyi, 1984; Skinner, 1976). Encourag­ ing results led to pilot production trials in During the early . 1980s, the sorghum 1984 (Koleoso and Olatunji, 1992). How­ cultivar SK5912, developed at the Insti­ ever, the brewing industry was not tute for Agricultural Research (IAR), was obliged to use sorghum grain and malt in identified as suitable for brewing and lager beer production until January, 1988, malting (Andrews, 1970; Curtis, 1967; when the ban on barley imports became Koleoso and Olatunji, 1992; Obilana, effective. The breweries have sub­ 1985). Due to insufficient supply of this sequently modified their brewing proc­ grain, however, brewers have been using esses and equipment to a considerable local Kaura and Farafara grains procured extent to suit sorghum processing and from the markets. The grains of SK5912 brewing. and Kaura have yellow endosperm while Farafara has normal white endosperm. Currently several brands of lager beer The brewers are not satisfied with the and stout, such as Star, Gulder, Satzen- grain lots available in the local market brau, Harp, 33 Export, Trophy, Rock and because they frequently represent a mix­ Kronenburg, are being produced and mar­ ture of different cultivars with similar keted with a major proportion of their grain color, and impurities are high. Some cereal extract derived from sorghum. Sev­ breweries have invested in large agricul­ eral of these are produced by using 50- tural farms, where they could grow sor­ 80% sorghum and 50-20% maize as the ghum and maize cultivars of their choice cereal source. Preferences for the form of and obtain uniform and dependable raw sorghum used in lager beer production material. Guinness (Nig.) PLC has under­ vary with brewers. It is used either as raw taken a contract grower scheme for grain grain (broken pieces or fine grits) or malt. procurement of another recently bred Different brewers use different propor­ early maturing white grain sorghum cul­ tions of sorghum malt, sorghum grits, and tivar, ICSV400. maize grits. For example some brewers use 40% sorghum malt, 40% sorghum The qualities of sorghum malt avail­ grits, and 20% maize grits. However, all able to brewers in the Nigerian market the breweries are using significant quan­ vary from lot to lot, and non-uniform tities of external enzymes such as a-amy- grain lots and malt affect their milling and lase, neutral protease, p-glucanase, cellu- brew house performance (ICRI SAT, lase, and amylo-glucosidase to obtain 1990). The sorghum, malting technology

559 in Nigeria is in its infancy and undergoing wort separation stage; alcoholic fermen­ constant improvement. Only a few com­ tation is avoided. The wort is further panies can supply sorghum malt in com­ boiled; flavor and coloring agents are mercial quantities; some breweries have added before bottling. Since the ban on acquired their own malting facilities. imported barley came into effect, the Floor malting is still widely used, while breweries have successfully substituted box malting and various other locally sorghum grain and malt for barley malt modified methods are upcoming. Prob­ and other adjuncts used in malt drinks. lems encountered during industrial The use of sorghum malt for production malting in Nigeria include molds, cyano- of non-alcoholic malt drinks and other genesis, high malting losses (up to 20%), food drinks appears to be much more insufficient modification, and non-uni- widespread than for production of lager form germination (Ikediobi, 1990). There beer. There seem to be no major problems also is a shortage of good quality brewers’ in consumer acceptance and marketing of grits in the market, and some brewers use these malt drinks, which are highly popu­ a coarse meal of whole sorghum grain lar and liked across various religious com­ obtained by hammer milling. The milling munities. However, problems related to quality of the grain available in the market the acquisition of good quality sorghum and the milling process are not satisfac­ malt and adjunct by the breweries are the tory; as a result, millers are able to achieve same as those mentioned for lager beer only a maximum of 50% extraction of production. grits after dehulling (Hallgren, 1995). Weaning Food Drinks Non-Alcoholic Malt Drinks Malt cocoa-based weaning food drinks The production of lager beer by the are highly popular in Nigeria. The indus­ brewing industry in Nigeria has declined tries in this sector traditionally used bar­ considerably over the years (ICRISAT, ley malt extract as the base material. How­ 1990). In 1995, most breweries operated ever, since 1988, these industries also at 50% of their installed capacity and un­ have successfully substituted sorghum official estimates of total beer produced malt or grain extract for barley. The pro­ that year are around only 4 million hL, duction process involves the preparation compared to the original installed produc­ of a clear wort,7 concentration of the wort ^ tion capacity of 18 million hL in 1988 to a syrup, addition of cocoa, whey, and (Bogunjoko, 1992). However, the produc­ other nutritive ingredients, and prepara­ tion of non-alcoholic malt drinks by the tion of a dry cake followed by packaging same breweries is apparently increasing. in a granulated form. Several malt cocoa A variety of malt drinks with brand names drinks, such as Milo and Bournvita, are such as Malta, Maltina, Amstel Malta and being marketed with considerable sor­ Evamalt are being increasingly and suc­ ghum extract contents. The quality of sor­ cessfully marketed. ghum malt extract is, in general, similar to that of barley malt extract; therefore, lo­ The production process for malt drinks cally sourced sorghum malt extract can is similar to that for lager beer until the substitute for imported barley malt in a

560 range of weaning foods at a cheaper price, Clean and Mold-Free Grains and some Nigerian companies are selling sorghum malt extract (Solabi, 1990). Re­ Sorghum grains for malting should be cently baby food formulations also have generally clean and free from molds and been supplemented with sorghum malt bacteria. Grain molds are the major prob­ extract. lem in sorghum malting, and, in spite of treatment with formaldehyde, fungi lo­ Sorghum for Malting cated in the endosperm could create mold problems on the malting floor under high Sorghum has traditionally been malted humidity and warm temperatures. Sor­ for centuries in Africa to make alcoholic ghum grains produced under hot and hu­ and non-alcoholic beverages. Industrial mid conditions are ideal for development of fungi such as Aspergillus flavus and malting of sorghum based on scientific Fusarium spp on the grain surface and can principles and modem technology has pose mycotoxin problems in the malt been well established in South Africa, but (Dufour and Melotte, 1992). Although is only a recent enterprise in Nigeria grain mold-resistant cultivars are desir­ (Daiber and Taylor, 1995;Ikediobi, 1990; able, molded grain can be avoided by Novellie, 1968 ). Sorghum can be malted choosing production environments less by soaking clean grain in water at 25-30°C prone to mold attack. for 24-48 hours, then draining the excess water, and allowing germination and High Germinability (95%) growth for about 5 to 6 days at 25-30°C (Palmer, 1992). The moisture level of the The importance of good germinability grain is kept high (>40%) by frequent of grains used for malting should not be sprinkling of water. The germinating overemphasized. Germinability must be grains are frequently turned and aerated, assured by harvesting grain at complete and a high level of humidity is main­ maturity and appropriate moisture content tained. Microbial infection can be reduced (<12%) and storing it under clean and dry by using 0.1% formaldehyde during the conditions to protect the grain from insect steeping process. The malted grain is and microbial attack. dried rapidly at 50°C for about 24 hours to a moisture level of about 10%. In Nige­ Uniform Grain Size and ria, the dried malt is agitated and derooted Fast Water Uptake by screening. Unlike barley, the applica­ tion of gibberillic acid during steeping of Uniform grain size is desired in malts sorghum doesn’t trigger enzyme synthe­ for lager brewing because the undersized sis (Palmer, 1989). Sorghum grain used grains potentially yield lower extract, al­ for malting must meet more stringent and beit relatively more protein due to the specific requirements than that used for improved embryo to endosperm ratio. food, feed, or adjunct. However, no offi­ Fast water uptake by the grain is also cial standards of sorghum malt quality desired for rapid mobilization of enzyme have been established in Nigeria, but the activity, increased soluble protein, and following grain and malt characters are endosperm modification (Dufour and desired by the maltsters and brewers. Melotte, 1992; Ikediobf 1990).

561 Low Malting Loss lower than that of barley malt. Also in contrast to barley, in sorghum malt a- One disadvantage of sorghum as a amylase is the major component (60- source of malt is the relatively higher 80%) and p-amylase is the minor. The malting loss compared to barley. Malting methods employed to measure and ex­ losses of about 18 to 28% were reported press diastatic power by various workers by different researchers after 96 hours of have varied. The joint activity of the two germination, and there were significant enzymes has frequently been measured differences between cultivars (Illori et al., and expressed in Sorghum Diastase Units 1990; Jayatissa et al., 1980; Subramanian (SDU/g-dry malt); one SDU is roughly et al., 1995). Average malting losses of equivalent to 0.5° Lintner. 20% may have to be tolerated in sorghum while selection for relatively lower The diastatic power of sorghum is malting loss continues. widely recognized to vary between culti­ vars (Novellie, 1984; Daiber, 1988; Jaya­ High Malt Extract (80%) tissa et al., 1980; Subramanian et al., 1995). The activity of one amylase could Percentage of total malt extract is the be determined by the inactivation of the most important trait considered by lager other. Munck and Mundy (1984) identi­ brewers since it is the net result of enzyme fied two a-amylase isozymes and a homo­ activity, endosperm modification, and geneous a-amylase. The saccharification solubilization. In opaque beer production, power of malted sorghum is restricted complete solubilization is not required, so mainly because of limited P-amylase percentage of total extract is of secondary (Nout and Davies, 1982). However, some importance to diastatic enzyme activity. cultivars can develop significantly higher Palmer (1989) and Dufour and Melotte levels of p-amylase during germination (1992) suggested improved three-step (Palmer, 1989). Munck and Mundy mashing procedures to obtain higher per­ (1984), Swanston et al. (1992), and centage of malt extracts in sorghum. Dufour and Melotte (1992) analysed sor­ Swanston et al. (1992 and 1993) observed ghum grains from a large number of cul­ wide differences between sorghum culti­ tivars and found highly significant differ­ vars for percentage of total extract. Large ences for P-amylase activity. The a-amy­ grain size is important for obtaining a lase activity levels were found to be higher percentage of total malt extract. generally acceptable for brewing and sometimes even higher than those found High Diastatic Power in barley. It is therefore important to select sorghum cultivars with relatively higher Diastatic power is the inherent ability levels of P-amylase or a higher ratio of of the malt to enzymatically hydrolyze P-amylase to a-amylase. carbohydrates. Diastatic power of sor­ ghum malt is due to the joint activity of High Free Alpha-Amino a-amylase and P-amylase, both of which Nitrogen (Fan) Content are synthesized de novo during germina­ tion in the embryo and scutellum (Daiber During malting, the grain proteins are and Taylor 1995; Novellie, 1984). The hydrolysed by the proteolytic enzymes to diastatic power of sorghum malt is much yield soluble peptides and free a-amino

562 nitrogen (FAN). The ratio of FAN to total process, which leads to wort clarification nitrogen of the malt naturally indicates the and separation problems in lager brewing proteolytic activity. In germinating (Palmer, 1992). During the malting of grains, FAN supports the growing seed­ barley, endogenous p-glucanases degrade ling, while in brewing, FAN is critical for the cell walls rapidly, while in the malting rapid multiplication of the yeast followed of sorghum, endosperm cell walls do not by normal fermentation of the wort (Pick- break down, but develop portals through erell, 1986; Taylor, 1983; Taylor and which starch and protein-degrading en­ Boyd, 1986). Normally an optimal level zymes pass to access the cell reserves (Palmer, 1991). It has been suggested that of 130-150 mg/L of FAN is required for sorghum endosperm cell walls might re­ satisfactory growth of yeast (Hallgren, quire application of P-glucanases and cel- 1995). Variation due to cultivars and en­ lulases to obtain improved modification vironments has been recognized to be and wort separation (Etok Akpan, 1993). equally important for FAN of malted sor­ ghum (Daiber, 1988 ; Daiber and Taylor, Since the peripheral corneous en­ 1995; Chitsika and Mudimbu 1992; dosperm resists complete modification, Subramanian et al., 1995). Good monitor­ Ikediobi (1990) identified loosely packed ing and selection of sorghum cultivars starch granules and easily accessible pro­ with a favorable FAN ratio and optimal tein bodies as desired properties for im­ fertilization of production fields is re­ proved malting. Swanston et al. (1992) quired. found a close relationship between malt milling energy and percentage of total Low Polyphenol or Tannin Content extract. Rooney et al. (1986) suggested that sorghum grains with intermediate In clear or lager beer production, only texture could be suitable for beer prod­ white or cream colored grains free from ucts. Palmer (1989) felt that grains with tannins or polyphenols are used for malt mealy endosperm may be required by and adjunct. Grains of local white grain maltsters. Since soft and floury en­ cultivars procured from Nigerian markets dosperm types are generally known to be exhibit impurities with brown grains con­ vulnerable to molds and storage insects, taining testa. White grains with red or medium endosperm texture types with a purple spots on the pericarp could leach limited peripheral corneous layer and a pigment into the endosperm. The relatively large central floury area might polyphenolic compounds not only inhibit be suitable for malting. enzyme activity, but also lead to color problems in the wort. White grains from Sorghum as Adjunct tan plant types cause the least color prob­ lems of the wort. Sorghum is used by the lager beer in­ dustry, as well as the non-alcoholic bev­ Medium to Soft Endosperm Texture erage and baby food industries in Nigeria, as an adjunct or a source of cereal extract. Sorghum malt is relatively hard and It is used either as a coarse meal or uni­ less friable than barley malt; therefore form grits, depending upon availability endosperm cell wall breakdown is rela­ and price. Because of either the lack of tively poor and slow during the malting well-established industrial sorghum mill­

563 ing technologies or insufficient supply of (Hallgren and Murty, 1983; Pomeranz, grain of uniform and consistent quality, 1986). All these methods are useful to there is a shortage of sorghum brewers’ breeders, although flotation in sodium ni­ grits in the market. Hallgren (1995) dis­ trate and Stenvert hardness tests require cussed the problems associated with small sample size and simple equipment. brewing a sorghum meal of non-uniform A combination of the Stenvert hardness particles, particularly when the flour con­ test with psi determination of the milled tent is high. Therefore, for sorghum grain product might yield complete information to be used as an adjunct, the dehulling and to select for grain hardness. Hallgren milling qualities are most important. (1995) suggested particle size index de­ Various grain quality characters that af­ termination to evaluate the quality of fect milling quality and brewers’ grits are grits. considered below. Higher Extract (90%) and Uniform Size and Shape Soluble Nitrogen

It is now well established that uniform High starch content in the sorghum size and symmetrical (oval or round) grits is important for yielding the desired shape of the sorghum grain are important extract (90% on dry basis). The protein for mechanical dehulling and processing content of the grits should be around 8- to grits with minimum milling losses 9%, but more importantly, the grits should (Murty, 1992). possess a favorable ratio of soluble to insoluble nitrogen. Low Phenols and Tannin Content Low Fat Content Polyphenols and tannins in the adjunct impart an off color and astringency prob­ The oil content of sorghum grits used lems to the extract, in addition to causing as adjunct in lager beer should be less than enzyme inhibition. In general, grains with 1%, because oil reduces the shelf life of testa exhibit poor milling qualities. There­ the grits and leads to poor foam stability fore grains with white or yellow pericarp of the beer (Hallgren, 1995). Normally (and endosperm) free from colored spots oil, ash, and fiber contents of the grits and are preferred for milling. other flour products are routinely evalu­ ated. Efficient degermination and milling Hard Endosperm Texture techniques applied to hard grain sorghum should yield grits with acceptable low fat Grains with hard endosperm texture are content. suitable for dehulling and gritting. Hard­ ness of the grain could be evaluated Low Gelatinization Temperature through various tests: resistance to abra­ sive dehulling or pearling, flotation, mill­ The gelatinization temperature (GT) of ing energy determination, particle size in­ sorghum starch can be observed by the dex (psi) of milled products, milling loss of birefringence in the hot stage mi­ time/Stenvert hardness measurement, etc. croscope. Normally the GTs in sorghum

564 vary between 68-76°C and are higher than quate and not a serious limitation for in­ those of barley (Hallgren, 1995). Brewers dustrial use, provided the production en­ need to follow modified mashing proce­ vironments are properly managed. It dures for sorghum and thus incur extra might therefore be practical to choose energy costs. Therefore, sorghum grains suitable cultivars and environments less with lower GTs and better cooking prop­ prone to molds for producing grain for erties are desired by brewers, although the malting. problems are not insurmountable. Except for grain color and shape, most Breeding Implications of the quality traits desired for malting and brewing are affected by genotype x envi­ For millers to produce a good adjunct ronment interactions. On the other hand, and for maltsters to produce malt required there is a considerable limitation of en­ by the various industries, sorghum grain zyme activity levels in sorghum required quality considerations are generally the for satisfactory conversion and solubiliza­ same except for the relatively soft en­ tion during the malting and brewing of dosperm texture and higher diastatic lager beer. In view of reports on signifi­ power needs of maltsters. Laboratory cant genetic variation for a- and P-amy­ methods to evaluate the various physical lase activities in sorghum, breeders and chemical parameters desired by the should pursue selection for ‘a higher P- industries are straightforward and simple amylase component in germplasm and except for the enzyme assays. Sorghum breeding collections. The need for sor­ cultivars suitable for producing adjunct ghum grains with low gelatinization tem­ must have white or yellow grains (no testa peratures and lack of endosperm cell wall- or phenols) of an optimum size degrading enzymes has been mentioned. (30g/1000) and shape (round or oval) and It is suggested that mutation breeding a highly corneous texture to permit higher techniques could possibly be applied to extraction of pearled and gritted products. search for such desired sorghum mutants. These traits can be achieved by selecting for increased density and hardness of the Future grain and high recovery from pearling. Sorghum utilization by the industries in In view of the positive correlation of Nigeria is currently less than 5% of total endosperm hardness and mold resistance sorghum production, but is widespread in among white grain types (Jambunathan et various beverage, food drink, and baby al., 1992), simultaneous progress could be food industries. Observed market prices made for improved mold resistance. How­ in the last decade have generally shown ever, maltsters’ requirements suggest se­ sorghum to be marginally cheaper than lection of medium or soft endosperm maize. If this trend continues into the fu­ types, which are unfortunately known to ture, it is expected that sorghum utiliza­ be vulnerable to grain molds in wet and tion by industries in Nigeria will increase. humid environments. In general, the grain The problems of procuring sorghum grain protein content of sorghum is fairly ade­ of consistent quality would be resolved by

565 intervention of the agrobased industries in Chitsika, J.M., andM.W. Mudimbu. 1992. Quality seed multiplication of sorghum and con­ criteria for opaque beer in Zimbabwe, p. 151- 155. In Utilization of sorghum and millets. tract farming in suitable agroecological ICRISAT, Patancheru, 502 324 (A.P.), India. production zones. The Nigerian experi­ Curtis, D.L. 1967. A review o f the sorghum breed­ ence during the last decade in the indus­ ing programme in Nigeria. Samaru Miscellane­ ous Paper No. 18, p. 14. ABU, Samaru, Nigeria. trial application of locally produced cere­ Daiber, K.H. 1988. Malted and treated sorghum for als is remarkable and could set the trend the industrial production o f beer, feed and food, in other countries of the continent. p. 15-30. In Proceedings 4th quadrennial sym­ posium on sorghum and millet. Lausanne, Swit­ zerland, ICC, International Association of Sorghum is probably the only tropical Cereal Science and Technology. Daiber, K.H., and J.R.N. Taylor. 1995. Opaque cereal with increased potential for use in beers, p: 299-323. In D.A.V. Dendy (ed.) Sor­ malt-based products in the future. There­ ghum and millets: Chemistry and technology. fore research should focus on improved AACC. Minn. USA Dufour, J.P., and L. Melotte. 1992. Sorghum malts knowledge of sorghum malting, assess­ for the production of a lager beer. ASBC Journal ment and use, and methods to reduce local 50:3, 110-119. production costs. It would be profitable to Etbk Akpan, O.U. 1993. Enzyme degradation and nature o f the endosperm cell walls o f germinat­ fully explore the sorghum germplasm for ing sorghums and barley. J. Sci. Food Agric. malting traits. Further advances in tech­ 61:389-393. nology for malting and brewing of sor­ FAO. 1994. Agrostat data base. Food and Agricul­ tural Organization o f the UN., Rome ghum, coupled with genetic enhance­ FIIRO (Federal Institute of Industrial Research, ment, could brighten the prospects for Oshodi). 1976. Production o f malt from Nige­ industrial use of sorghum. More intensive rian sorghum. Technical Information Bulletin for Industries (FIIRO). 1976 (5) 1-4. collaboration between research and in­ Forson, J.B., and O. Ajayi. 1995. Industrial utiliza­ dustry is called for. tion o f sorghum in Nigeria: Implication o f evi­ dence and distributive impacts for research, p. 7-18. In Processing and industrial utilization of References sorghum and related cereals in Africa. OAU/STRC-SAFGRAD, Ouagadougou, Burk­ Aisien, A .0 .1982. Enzymatic modification of sor­ ina Faso. ghum endosperm duringgrowth and malting. J. Glennie, C W. 1984. Endosperm cell wall modifi­ Sci. Food Agric. 33:754-759. cation in sorghum grain during germination. Aisien, A .0 .1990. Utilization o f sorghum in brew­ Cereal Chem. 61:285-289. ing lager beer in Nigeria, p. 24. In Industrial Hallgren, L. 1995. Lager beers from sorghum, p. utilization o f sorghum. Summary proceedings 283-297. In Sorghum and millets: Chemistry o f a symposium on the current status and poten­ and technology, AACC. Minn. USA. tial o f industrial uses o f sorghum in Nigeria, 4-6 Hallgren, L., and D.S. Murty. 1983. A screening Dec, 1989, Kano, Nigeria. ICRISAT, test for grain hardness in sorghum employing Patancheru, 502 324 (A.P.), India. density grading in sodium nitrate solution. J. Aisien, A.O., and G.C.J. Muts. 1987. Microscale Cereal Sci. 1:265-274. malting and brewing studies o f some sorghum Ikediobi, C.O. 1990. Industrial production o f sor­ varieties. J. Inst. Brew. 93:328-331. ghum malt in Nigeria, p. 32. In Industrial utili­ Aisien, A.O., G.H. Palmer, and J.R. Stark. 1983. zation of sorghum. ICRISAT, Patancheru, 502 The development of enzymes during germina­ 324, (A.P.) India. tion and seedling growth in Nigerian sorghum. Illori, M.O. 1991. The use o f sorghum for beer Starch/Staerke 35:316-320. brewing in Nigeria. Technovation 11:1,27-37. Andrews, D.J. 1970. Breeding and testing dwarf Illori, M.O., J.O. Akingbala, G.B. Oguntimein, and sorghums in Nigeria. Expl. Agric. 6:41-50. J.O. Ogundiwin. 1990. Effect of grain bed thick­ Bogunjoko. J.S.T. 1992. Industrial uses of sorghum ness, duration of steeping and germination on in Nigeria, p. 115-119. In Utilization o f sor­ the malting properties o f improved Nigerian ghum and millets. ICRISAT, Patancheru, 502 sorghum varieties. Lebensm. Wiss.U. Technol. 324 (A.P.) India. 23, 505-512.

566 Jambunathan, R., N.S. Kherdekar, and J.W. Sten- Palmer, G.H. 1989. Cereals in malting and brew­ house. 1992. Sorghum grain hardness and its ing. p. 61-242. In G.H. Palmer (ed.) Cereal relationship to mold susceptibility and mold science and technology. Aberdeen, Aberdeen resistance. J. Agric. FoodChem. 40:1403-1408. University Press. Koleoso, O.A., and O. Olatunji, 1992. Sorghum Palmer, G.H. 1991. Enzymatic degradation o f the and millet adjunct replacement in clear (lager) endosperm cell walls of germinated sorghum. beer: Policy and practice in Nigeria, p. 41-46. In World Journal o f Microbiology and Biotechnol­ M.I. Gomez, L.R. House, L.W. Rooney, and ogy 7:17-21. D. A. V. Dendy (eds.) Utilization o f sorghum and Palmer, G.H. 1992. Sorghum and food beverage millets. ICRISAT, Patancheru (AP) 502 324, and brewing potentials. Process Biochemistry India. 27:145-153. ' . Munck, L., and J. Mundy, 1984. Sorghum malting Pickerell, A.T.W. 1986. The influence o f free al- studies, p. 56-58. In Proceedings of the sympo­ pha-amino nitrogen in sorghum beer fermenta­ sium, the processing o f sorghum and millets: tions. J. Inst. Brew. 92:568-571. Criteria for quality o f grains and products for Pomeranz, Y. 1986. Comparison of screening human food. ICC. Vienna, Austria, 4-5 June methods for indirect determination o f sorghum 1984. hardness. Cereal Chem. 63:36-38. Murty, D.S. 1992. The breeder’s role in crop utili­ Rooney, L.W., Kirleis, A.W., and D.S. Murty, zation. A perspective, p. 157-163. In Utilization 1986. Traditional foods from sorghum: Their o f sorghum and millets. ICRISAT, Patancheru production, evaluation and nutritional value, p. 502 324 (A.P.), India. 317-353. In Y. Pomeranz (ed.) Advances in Murty, D.S. (ed.). 1990. Industrial utilization of cereal science and technology. AACC. St. Paul, sorghum: Summary of proceedings of a sympo­ Minn., U.S. sium on the current status and potential of in­ Skinner, K. 1976. Tropical lager beer brewing with dustrial use o f sorghum in Nigeria, 4-6 Dec., sorghum malt. Brewing and Distilling Interna­ 1989, Kano, Nigeria. ICRISAT, Patancheru tional 6, 26-27. (A.P.) India. Solabi, G.A. 1990. Uses of sorghum in malted and Nout, M.J.R., and B.J. Davies. 1982. Malting char­ fermented foods and drinks, p. 37. In Industrial acteristics o f finger millet, sorghum and barley. utilization of sorghum. ICRISAT, Patancheru, I. Inst. Brew. 88:157-163. 502 324 (A.P.), India. Novellie, L. 1968. Kaffir beer brewing, ancient art Subramanian, V., Murty, D.S., Rao, N.S., and R. and modem industry. Wallerstein Lab. Com- Jambunathan, 1992. Chemical changes, and di­ mum. 31:17-32. astatic activity in grains o f sorghum (Sorghum Novellie, L. 1984. Sorghum quality for malting and bicolor) cultivars during germination. J Sci. brewing. In Proceedings o f the symposium, the Food Agric. 58:35-40. processing o f sorghum and millets: Criteria for Subramanian, N. Sambasiva Rao, R. Jambu­ quality o f grains and products for human food. nathan, D.S. Murty, and B.V.S. Reddy. 1995. ICC. Vienna^ Austria. 4-5 June 1984. The effect of malting on the extractability of Obilana, A.B. 1985. Sorghum breeding and selec- proteins and its relationship to diastatic activity • tion for brewing industry in Nigeria. National in sorghum. Journal of Cereal Sci. 21:283-289. Symposium on the brewing industry: Now and Swanston, J.S., K. Taylor, and D.S. Murty, 1992. in the 21st century. Problems-challenges and Grain and malt milling energies in sorghum and prospect 29 May-1st June, 1985, Owerri, Nige­ their relationships with extract and diastatic ria. power. J. Inst. Brew. 98(2): 129-131. Okafor, N., and Aniche. 1980. Brewing a lager beer Swanston, J.S., K. Taylor, N.S. Rao, V. Subrama­ from Nigerian sorghum. Brewing and Distilla­ nian, and -D.S. Murty. 1993. The use o f rapid tion International 10:3 2-3 5. screening tests to compare changes during Okon, E.U., and A.O. Uwaifo.1985. Evaluation of malting in sorghum. J. Inst. Brew. 99:(G) 483- malting sorghums. I. The malting potential of 486. Nigerian varieties o f sorghum. Brewers Digest Taylor, J.R.N. 1983. The effect o f malting on the 24-29. protein and free amino nitrogen composition of Olaniyi, O.A. 1984. Cereal in brewing industry. A sorghum. J. Sci Food Agric. 34:885-892. paper presented at the 8th Annual Conference Taylor, J.R.N., and H.K. Boyd. 1986. Free amino o f the Nigerian Institute o f Food Technology. nitrogen production in sorghum beer mashing. Obafemi Awolowo University. lie Ife, Novem­ J. Inst Brew. J. Sci Food Agric. 37:1109-1117. ber, 1984.

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