"Gowé", a Sprouted Or Non Sprouted Sorghum Beverage from West-Africa

African Journal of Biotechnology Vol. 4 (6), pp. 487-496, June 2005 Available online at http://www.academicjournals.org/AJB ISSN 1684–5315 © 2005 Academic Journals Full Length Research Paper Physical, chemical and microbiological changes during natural fermentation of "gowé", a sprouted or non sprouted sorghum beverage from West-Africa Michodjèhoun-Mestres Laetitia1, Hounhouigan D. Joseph1*, Dossou Joseph1, Mestres Christian2 1Département de Nutrition et Sciences alimentaires, Faculté des Sciences Agronomiques, Université d’Abomey-Calavi, 01 BP 526 Cotonou, Benin. 2 CIRAD, TA 40/16, 73 rue JF Breton, 34398 Montpellier Cedex 5, France. Accepted 22 March, 2005 Gowé is a traditional Beninese fermented beverage prepared from sprouted and non-sprouted cereals. Due to urbanization, a new technique without any malting step has appeared in Southern Benin and is now widely used. The two techniques were compared using sorghum as the raw material. The physical, chemical and microbiological changes that occurred during a 72 h fermentation period were studied in both techniques. The dominant microflora was a mixed population of lactic acid bacteria and yeasts. The lactic acid bacteria population was higher in the traditional product at the start of fermentation (6.1 log cfu/g wet basis versus 4.5 in the modified process) because of the malting step. It then increased to 9.3 log cfu/g after 48 h fermentation. Enterobacteriaceae counts increased slightly during the first stage of fermentation but fell below the detectable level after 24 h in the traditional raw gowé and after 48 h in the modified raw gowé. The pH decreased from 6.3 to 3.4 in the traditional process and from 6.6 to 3.8 in the modified process, while the titratable acidity increased from 0.4 to 6.4% (w/w, lactic acid) and from 0.4 to 4.2%, respectively. Total soluble and reducing sugar content first increased, and then decreased with a concomitant increase in organic acids. The major organic acids were lactic acid and acetic acid. The fermentation process was thus more intense and faster in the traditional process, giving a significantly lower level of crude fat. Key words: Traditional technology, beverage, sorghum, malting, fermentation, organic acids. INTRODUCTION Sorghum (Sorghum bicolor L. Moench) is a staple food in Asia and East Africa and steamed foods (couscous), most parts of Africa, where it is the main source of fermented and unfermented porridges and pastes (ugali, carbohydrates and proteins for millions of people, mostly akamu, tô, eko, kamu, koko, ogi, etc.) and alcoholic and in the Southern Sahara. Various types of foods are non-alcoholic beverages in Africa generally (Chilkunda prepared from sorghum whole kernels, for instance and Paramahans, 2001). unfermented and fermented breads (chapati, roti, kisra) in Like other cereal products, sorghum products have poor nutritional value. This is due to their deficiency in lysine, threonine and tryptophan and to the presence of anti-nutritional factors (Salunkhe et al., 1977) such as tannins and phytates that interact with proteins, vitamins and minerals, thus restricting their bio-availability *Corresponding Author. E-mail: [email protected]. (Harland and Oberleas, 1986; Bhise et al., 1988). The 488 Afr. J. Biotechnol. above factors contribute to anemia and other nutritional most urban producers do not have. Recent surveys in diseases in developing countries where the consumption Cotonou showed that most producers use a modified of sorghum products is high. Furthermore, sorghum technique, which consists of fermenting non-malted proteins are less digestible than those of other cereals sorghum flour and adding commercial sugar to obtain the (Klopfenstein and Hoseney, 1995). Various simple naturally sweet taste provided in the traditional process techniques have been investigated to improve the protein by malting. The time required to produce gowé using the digestibility and mineral availability of sorghum by modified technique (Figure 2) is 3 days, as against 6-8 reducing its tannin and phytate content. These include days with the traditional process. malting, fermentation (Kazanas and Fields, 1981; Chavan No information is available on the processing of et al., 1988) and cooking (Khan et al., 1986). sorghum to produce gowé, as this takes place in Benin. Fermentation is widely used traditionally for processing The present study deals with the physical, chemical and sorghum, and fermented products are well accepted and microbiological changes that occur during processing, widely used as complementary foods (Tomkins et al., using the traditional and the modified techniques as 1988). Their low pH confers the advantage of applied in small-scale urban production. microbiological safety (Hamad and Fields, 1979). The malting of sorghum grains has been reported (Au and Fields, 1981; Ahmed et al., 1996; Lasekan et al., 1997) MATERIALS AND METHODS and is used to increase the water-soluble protein, lysine, methionine and soluble sugar content, diastasic activity Pilot-scale experiments for processing sorghum into gowé were carried out using the skills of a local producer. and iron, calcium and phosphorus availability (Bhise et al., 1988). It should be noted, however, that sorghum plants contain appreciable amounts of dhurrin (a Materials cyanogenic glycoside that yields hydrocyanic acid when hydrolyzed), and that immature plants contain A local red variety of sorghum (Sorghum vulgare (L.) Moench) was purchased from a market in Southern Benin. The grains were exceptionally high levels of this cyanogen (Panasiuk and cleaned by removing foreign objects and broken kernels. They were Bills, 1984). immediately washed in water and sun-dried. The grains were then Most Beninese households consume sorghum foods as divided in two parts. One part was milled into flour to pass through unfermented paste (tô), fermented paste (akassa), and a 0.5 mm sieve, using a community plate disc mill. The flour was fermented beverages from sprouted grains (chakpalo, stored at ambient temperature (28-30°C). The second part, stored tchoucoutou and gowé). Gowé is a homogenous at ambient temperature (28-30°C), was used for malting. gelatinized, malted, fermented and cooked paste prepared from sorghum, millet or maize. It is consumed Malting as a beverage after dilution in water and the addition of ice, sugar and sometimes milk. It is the preferred The dried grains were steeped overnight in a plastic container in 3 beverage of children, pregnant women, sick and old volumes of tap-water at room temperature (28-30°C), without people. All types of sorghum, millet and white maize can changing the water. The soaked grains were washed and drained. They were uniformly spread on a wet piece of thin cloth placed in a be used to make acceptable gowé but colored sweet traditional wicker basket, then covered with another piece of cloth to gowé is preferred. Raw gowé is cooked into a thin gel, reduce dehydration. The grains were kept wet by frequent spraying the texture of which is between that of a thick and a stiff with tap-water. Germination was done at room temperature (28- porridge. The texture is in fact a critical sensory attribute. 30°C), over a 48-h period. The germinated grains were sun-dried (4 Consumers want a gowé of intermediate texture, one that days) but the roots were not removed, in accordance with local practice. The malt was milled in the community plate disc mill to get holds together but yields easily to finger pressure. When a fine flour, passing through a 0.5 mm sieve. consumed, the gowé should not stick to the fingers, the teeth or the roof of the mouth, it should simply melt in the mouth. Gowé can be stored for two to three days at ambient temperature (and up to one week at +4°C) Preparation of fermented malted raw gowé without reheating. A survey conducted in the Cotonou area showed that The traditional process was reproduced by a local gowé producer at pilot scale (Figure 1). 1 kg of malted sorghum flour was mixed with gowé was traditionally produced in central Benin. The 2 kg of non-malted sorghum flour and 3 L of water. The sample was technique was introduced to Cotonou (Southern Benin) divided between 7 lidded plastic buckets marked with different by small-scale producers. The traditional process (Figure fermentation times (0, 4, 8, 12, 24, 48 and 72 h). The first 1) consists of three stages: malting (6 days), first fermentation was carried out at room temperature (28-30°C). After fermentation (12 h) and second fermentation (24-48 h). 12 h fermentation, non-acid thick porridge (prepared by mixing 1 kg The malting improves the nutritional quality of the product of whole sorghum flour and 10 L of water and cooking at 100°C for 10 min) was added to the samples in the buckets marked 12, 24, 48 while the fermentation improves its safety. The major and 72 h. The temperature of the mixture was 50-60°C when added constraints of the traditional process are the time needed to the samples and decreased to room temperature (28-30°C) for malting and the skill required to carry it out, one that during the following (or second) fermentation period. Michodjèhoun-Mestres et al. 489 Sorghum grains Cleaning Steeping, overnight Germination, 482h d ays Sun-drying, 4 days Milling Milling Raw sorghum flour MMaltaeltde ds osurgrghhuumm Water Water dispersion Mixing Water, 3l Cooking 100°C, 10 min FirsFti rfsetr fmeremnetantaiotino n1 2h 12h Mixing and Non-acid porridge homogenization SeconSde cFoenrdm feernmtaetnitoanti o2n4 -48h 24-60h Raw gowé Cooking 100°C 30 min Packing in leaves Cooked gowé Figure 1. Flow sheet for the production of traditional gowé. 490 Afr. J. Biotechnol. Sorg hum grains C leaning Milling Raw sorghum flour WWaateterr, 10 l Mixing Homogenization Fermentation 72 h Raw gowé Coooking 100°C Sugar Cooking 100 C 30 min 30 min Packin g in leaves Cooked gowé Figure 2.

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