EVALUATION OF YANYANKU PROCESSING, AN ADDITIVE USED AS STARTER CULTURE TO PRODUCE FERMENTED FOOD CONDIMENTS IN BENIN

EVALUATION OF YANYANKU PROCESSING, AN ADDITIVE USEDAS STARTER CULTURE TO PRODUCE FERMENTED FOODCONDIMENTS IN BENINjfpp_534 813..821

PAULIN AZOKPOTA1,4, MÉLAINE S.E. HOUNDENOUKON2, JOSEPH D. HOUNHOUIGAN1,MATHURIN C. NAGO1 and MOGENS JAKOBSEN3

1Département de Nutrition et Sciences Alimentaires, Centre Régional de Nutrition et d’Alimentation Appliquées (CERNA), Faculté des SciencesAgronomiques, Université d’Abomey-Calavi, 01 BP 526, Abomey-Calavi, Bénin2Département de Biologie Végétale, Faculté des Sciences et Techniques, Université d’Abomey- Calavi, 01 BP 526, Abomey-Calavi, Bénin3Department of Food Science, Food Microbiology, Faculty of Life Sciences, University of Copenhagen, Rolighedsvej 30, DR-1958,Frederiksberg C, Denmark

4Corresponding author. TEL: 229-213-60122;FAX: 229-213-60122; EMAIL:[email protected];[email protected]

Accepted for Publication December 22, 2010

doi:10.1111/j.1745-4549.2011.00534.x

ABSTRACT

Yanyanku is an additive produced by natural fermentation of Hibiscus sabdariffabeans. Three variants of yanyanku processing have been identified: the Yanyanku var.1 (pH = 9.95 � 0.06) involved adding of potash to the beans before cooking, twosteps of 72 h and 24 h of fermentation and one step of sun drying; the Yanyanku var.2 (pH = 8.23 � 0.04) required adding of ash solution after cooking the beans, onestep of 72 h of fermentation, and two steps of pounding and sun drying; the Yan-yanku var. 3 (pH = 10.14 � 0.02) involved adding of potash before cooking thebeans and one step of 7 days of fermentation. Bacillus spores dominated in the threevariants. Spore concentrations (log10cfu/g) were 8.95, 8.22 and 9.55 in Yanyanku var.1, Yanyanku var. 2 and Yanyanku var. 3, respectively. Lipid, protein and carbohydratecontents decreased particularly in Yanyanku var. 1 and Yanyanku var. 3.

PRACTICAL APPLICATIONS

Yanyanku is used as inoculum enrichment or a starter culture-like additive for thefermentation of African locust bean seeds (Parkia biglobosa) to produce sonru, whichis one of the most important food condiments consumed by the rural poor as well ashigh-income urban families in Benin. The production of sonru has increased signifi-cantly in recent years, requiring an increase in the daily production of yanyanku,which is also produced commercially by traditional processors. Yanyanku is aproduct with potential for scaling up and industrialization; it could be an alternativeto standard starter culture utilization. The product is traditionally processed at thehousehold level and has a long shelf life (about 10 years). This study has evaluatedthe yanyanku processing, with a view to upgrade the processing technology and toimprove the product quality in future investigations.

INTRODUCTION

Traditional innovations and indigenous technology are rela-tively developed in Benin,particularly in the field of fermentedfoods. In the last 10 years, several scientific studies in Beninhave been focused on the traditional fermented food condi-ments locally called afitin, iru and sonru,which are obtained bythe spontaneous fermentation of African locust bean seeds

(Parkia biglobosa) (Azokpota et al. 2006a,b, 2007, 2008).Similar to soumbala (Diawara et al. 1992; Ouoba et al. 2003),dawadawa (Omafuvbe et al.2000) or netetu (N’Dir et al.1994,1997), sonru is one of the most important fermented foodcondiments which is used for the preparation of sauces, soupsand some main dishes in Benin (Azokpota et al. 2006a).The consumption of sonru, particularly in urban areas,increasesprogressively,as thecondiment isconsideredbymost

Journal of Food Processing and Preservation ISSN 1745-4549

813Journal of Food Processing and Preservation 35 (2011) 813–821 © 2011 Wiley Periodicals, Inc.

consumers as a functional food which can regularize bloodarterial pressure (Azokpota, unpublished data). However, thesonru processing requires the relevant traditional knowledgeor know-how. The condiment is prepared using cookedAfrican locustbeanwhichis fermentedwithatraditionaladdi-tive called yanyanku. In the local language, yanyanku means“product having ability to degrade.” According to the tradi-tional producers, yanyanku accelerates the fermentation ofAfrican locust beans to produce sonru, because untreatedbeans are too hard to be easily fermented spontaneously. Yan-yanku could be a softening agent which probably plays asimilar role as a standard starter culture during the fermenta-tion.Whereas yanyanku is used as an additive to produce foodcondiments in Benin (Azokpota et al. 2006a), similar Africanproducts such as bikalga, dawadawa botso, datou, furundu,mbuja are used directly as condiments for the preparation ofsauces in Burkina Faso,Mali,Niger,Nigeria,Cameroon,Sudan(Yagoub et al. 2004; Mohamadou et al. 2007; Parkouda et al.2008). Amoa-Awua and Jakobsen (1995) reported the use of atraditional additive known as kudeme to produce agbélima, afermented cassava dough in Ghana.

Yanyanku processing is a typical traditional innovativetechnology which needs to be investigated, improved uponand be used for large-scale-industrial processing. However, tothe best of our knowledge, yanyanku has so far not been sub-jected to any scientific investigation. Therefore, the yanyankuprocessing technologies are not well known or understood;research in this field is still very poor. A first variant of yan-yanku process has already been described: the Malvacenebeans (Hibiscus sabdariffa beans) are first soaked in a solutionof ash for 7 days, before sun drying. The dried product isfinally milled into yanyanku as a dried powder which can bestored for many years (Azokpota et al. 2006a). In NorthernBenin, particularly in the Djougou region, it appears that yan-yanku processing varies from locality to locality and proces-sor to processor; however, there are no data on the details ofprocessing procedures and the chemical and microbial char-acteristics of the final product. It is probable that the chemicaland microbial composition of yanyanku depends on thevariant of yanyanku processing procedures used. The aim ofthis study was to: (1) identify the variants of yanyanku pro-cessing technologies used by local producers in Benin; (2)enumerate the dominant microorganisms involved in yan-yanku fermentation; and (3) define the chemical compositionof yanyanku produced by different processing methods.

MATERIALS AND METHODS

Materials

Dried malvacene beans (H. sabdariffa beans) were collectedfrom local producers and used as raw materials to produceyanyanku.

Methods

Survey of Yanyanku Processors. A survey of yanyankuprocessors was carried out in Killir, Founga, Lokpaoulo,Nalohoui, Bougou, Nangatchori, Paparaganra, Ananiga,Gahounga and Sassirou, 10 localities in the municipality ofDjougou in the North of Benin. Processors in these localitiesare generally considered to be the most knowledgeable in yan-yanku processing in Djougou (Azokpota 2005). Ten produc-ers of yanyanku were randomly selected in each of these 10localities and were interviewed, making a total of 100 produc-ers. Information on the processor, processing procedure, rawmaterials and equipment were collected during the interview.

Yanyanku Processing Mass Balance Analysis. All thevariants of yanyanku processing methods identified duringthe survey were grouped into categories based on their simi-larity. One producer per category of yanyanku processingvariant was randomly selected to reproduce yanyanku at threedifferent times, and the mass balances as well as processingduration were determined. Samples of yanyanku were col-lected for microbiological and chemical analyses.

Microbiological Analysis. The population of aerobicmesophilic bacteria, vegetative cells and spores of Bacillus,Staphylococcus, Enterobacteria, yeast and mold were enumer-ated as follows: Aerobic mesophilic bacteria were counted onAgar (PCA, Oxoid, CM 463, Basingstoke, Hampshire, U.K.),after incubation for 3 days at 30C. Vegetative cells of Bacilluswere enumerated on Dextrose Tryptone Agar (Oxoid, CM75), after incubation at 37C for 48 h, as described by Guiraudand Galzy (1980). Quantitative determination of the numberof endospores of Bacillus sp. was made by surface plating onthe same medium. To detect Bacillus spores, the medium wassupplemented with 0.2% soluble starch (Merck, D-6100,Darmstadt, Germany) under the same incubation conditionsafter the inoculum had been heated at 80C for 10 min(Guiraud and Galzy 1980). For confirmation, about 10 colo-nies of Bacillus from the highest dilution plates were selectedat random and Bacillus sp. were recognized by microscopyshowing typical cell morphology and endospores. Yeasts andmolds were counted after incubation at 25C for 5 days on maltextract, yeast extract, glucose, bacteriological peptone supple-mented with chloramphenicol and chlortetracycline accord-ing to Jespersen et al. (1994). Staphylococci were enumeratedon Baird-Parker (Oxoid, CM 275) supplemented with 5%sterile egg yolk-tellurite emulsion (Oxoid, SR 54). Staphylo-cocci were recognized as Gram positive, catalase positive, coccishowing fermentative utilization of glucose in Hugh andLeifson medium according to Harrigan and McCance (1976).Enterobacteria were determined on violet red bile glucose agar(Oxoid, CM 485) after incubation at 37C for 72 h.

PROCESSING AND CHARACTERIZATION OF YANYANKU P. AZOKPOTA ET AL.

814 Journal of Food Processing and Preservation 35 (2011) 813–821 © 2011 Wiley Periodicals, Inc.

Physicochemical Analysis. The pH was measuredaccording to the method described by Nout et al. (1989) andmodified as followed: 10 mL homogenized sample was fil-tered (0.45 mm, Millipore, Bie and Berntsen, Rødovre,Denmark), before measuring the pH using a PHM250 ionanalyzer (Eutechn Instruments, St. Leon-Rot, Germany). Thedry matter, lipids, proteins and ash contents were analyzed,using Association of Official Analytical Chemists (AOAC)methods 27.005, 27.006, 27.007 and 27.009, respectively(AOAC 1984). Crude fiber content was determined asdescribed by Osborne and Voogt (1978). Carbohydratescontent (Y) was estimated as follows:

Y (%, dry weight basis) = 100 - X; X representing the sumof proteins, lipids, fiber and ash contents expressed in percentof dry weight basis.

Statistical Analysis. The variants of yanyanku processingmethods were first recorded against production sites and thengrouped into categories using an average test of cleanlinessperformed by MINITAB 15 version 2009 (MINITAB Inc.,State College, PA). Results of the microbiological and physi-cochemical analyses were expressed as means � SD values.Statistical comparison of results was performed by analysis ofvariance and least significance difference (Student–Newman–Keuls test) using SAS Statistical Software package(SAS, release 8.1, Cary, NC). Differences at P < 0.05 were con-sidered to be significant.

RESULTS AND DISCUSSION

None of the yanyanku producers interviewed had any formaleducation. They were all women and produced yanyankuindividually at household level as a purely traditional com-mercial activity. They used culinary or rudimentary equip-ment such as marmite, bowls, bassinets, calabash, baskets, jutesacks, clothes and mortar. According to the producers, yan-yanku is used to accelerate the fermentation of African locustbeans to produce good quality sonru. The yanyanku pro-duced is used for food preparation at household level and alsosold on local and regional markets. H. sabdariffa bean is pref-erably used as raw material to produce yanyanku; however,Gossypium hirsutum and Adansonia digitata beans can also beused singly or in combination, especially when H. sabdariffabeans are not available or are expensive.

All theyanyankuprocessingtechnologiesweregroupedintothree categories: Yanyanku var. 1, Yanyanku var. 2 and Yan-yanku var.3 (Figs. 1–3).For all three variants,yanyanku is pro-cessed by spontaneous fermentation of H. sabdariffa beans.The Yanyanku var.1 process involves cooking the beans aftercleaning and washing them. An amount of potash (Fig. 1) isadded to the beans before cooking. The cooked beans wereallowed to undergo a first step of fermentation for 72 h. Thebeans from the first fermentation were pounded into big balls

to get a fermented mash which was allowed to undergo asecond step of fermentation for 24 h, followed by sun drying(Fig. 1). The Yanyanku var. 1 processing technology is used by25% (25/100) of the interviewed producers.TheYanyanku var.2 processing differs from that ofYanyanku var.1 by the fact thatin this case, the beans are pounded before cooking and also anash filtrate solution is added to the beans which are poundedagainbefore fermentationfor72 h(Fig. 2).Inaddition,duringtheYanyanku var.2 processing, the fermented mash is partiallysun dried, milled and sun dried again (Fig. 2). This variant isused by 15% (15/100) of the producers surveyed. The Yan-yanku var. 3 processing differs from the Yanyanku var. 1 andYanyanku var. 2 processes, principally by the length of the fer-mentation period. Potash is added to the cleaned and washedbeans before cooking (Fig. 3).The cooked beans are allowed toundergo fermentation for 7 days. The fermented beans arepounded into big balls before milling and sun drying (Fig. 3).This variant is used by 60% (60/100) of the yanyanku produc-ers surveyed. The Yanyanku var. 3 process is similar to themethod previously described by Azokpota et al. (2006a), butthe cleaned beans are soaked in ash solution for the 7 days offermentation without cooking.

The mass balance of yanyanku processing was determinedto evaluate the rentability of the processing. (Figs. 1–3). Allquantities reported were based on an initial weight of 1,000 g(wet basis) of raw H. sabdariffa beans materials. During theprocessing, losses of solids were observed whatever thevariant, principally during the step of pounding when testa isremoved. However, solids weight increased after cooking. Aswater was added to the beans before the cooking, it is evidentthat during the cooking, the beans progressively gained mois-ture which contributed to increase its weight. After thecooking step, the mass was not balanced, because the amountof water which was evaporated during the cooking and thesun drying or released from the fermentation steps could notbe determined. The processing yield was about 40% for theYanyanku var. 1 and var. 3 (Figs. 1 and 3) and 37% for the Yan-yanku var. 2 (Fig. 2).

In the future investigation, complementary details(i.e., materials and processing costs) are needed to pointout whether or not the yanyanku processing is economicallyrentable.

The processing duration is also important to evaluate therentability of yanyanku production. The yanyanku process-ing is considered laborious and time consuming (Table 1).Although, the Yanyanku var. 3 process is more time consum-ing, principally because of the long fermentation period, it isthe process used by the majority of producers surveyed, whichmeans that Yanyanku var. 3 could probably have the bestability for the fermentation of African locust beans toproduce Beninese condiments of good quality.

Globally, the yanyanku process is similar to the procedureused for the processing of some traditional African condi-

P. AZOKPOTA ET AL. PROCESSING AND CHARACTERIZATION OF YANYANKU


ments such as bikalga (Burkina Faso), dawadawa botso(Niger), datou (Mali), furundu (Sudan), mbuja (Cameroon)(Parkouda et al. 2008). The initial unit operations used toproduce bikalga are the same as those for the three variants ofyanyanku processing, except that bikalga is steamed over-night. The Yanyanku var. 3 processing is similar to thefurundu and mbuja processes in which a single lengthy fer-mentation period of 7–10 days is required with or withoutovernight steaming (Harper and Colins 1992; Yagoub et al.2004; Mohamadou et al. 2007). Differences were alsoobserved in the use of the products: whereas yanyanku is usedas an additive to produce food condiments in Benin (Azok-pota et al. 2006a), bikalga dawadawa botso, datou, furundu,mbuja are used directly as condiments for the preparation ofsauces in Burkina Faso, Mali, Niger, Nigeria, Cameroon orSudan (Yagoub et al. 2004; Mohamadou et al. 2007)

Yanyanku processing can generally be summarized into thefollowing major steps or unit operations: cooking of H. sab-dariffa beans after addition of potash or ash solution; fermen-

tation; pounding; milling; and sun drying. Each processingstep probably affects the chemical and microbial composi-tions of yanyanku (Tables 2 and 3).

The dry matter content in the three variants increased, withno significant difference (P > 0.05) (Table 2). This increase indry matter content is probably because of the fermentationwhich drained water from the beans. In addition, the potashor ash filtrate solution used during the process could increasethe dry matter content. Ash content also showed a substantialincrease in the three products with no significant difference(Table 2). During the process, ashes from sorghum plant(Yanyanku var. 2) and potash (Yanyanku var. 1 and Yanyankuvar. 3) were added to the beans. Sorghum ash and potashcontain potassium bicarbonate which contributes to theincrease of mineral contents of bikalga (Parkouda et al. 2008).

Fermentation is important and common to all three yan-yanku variant processing methods investigated. Technically,the term fermentation is used to describe a strictly anaerobiccarbohydrates breakdown processes (Caplice and Fitzgerald

Sorting and cleaning

Washing

Cooking

Draining of supernatant

Fermentation 1(72h)

Pounding (Big balls)

Milling

Fermentation 2 (24 h)

Sun drying

Dirty beans (158. 8g)

Cleaned beans (840.2g)

Dirty water, dishes (4.74 L = 4740g)

Washed beans (1100.2g)

Supernatant (3.85 L = 3850 g)

Cooked beans (1755.2g)

Fermented beans (1251.8g)

Pounded beans (1146.4g)

Paste (1038.3 g)

Fermented paste (806.9g)

Yanyanku var. 1 (405.5 g)

Water (5 L=5000g)

Potash (5g) Water (5L=5000g)

Hibiscus sabdariffa beans (1000g)

FIG. 1. FLOWCHART OF YANYANKU VAR. 1PROCESSING



1999). During fermentation, the cooked H. sabdariffa beanswere spread on basket trays to allow the water to drain off; thetrays are wrapped with several layer of jute sack and cloth andpacked together. The same method is used for the fermenta-tion of African locust beans to produce afitin, iru or sonru(Azokpota et al. 2006a). It is likely that this traditional proce-dure used to ferment H. sabdariffa beans created anaerobiccondition which was favorable for the degradation of pro-teins, carbohydrates and lipids from the beans and whichwere metabolized and utilized by the microorganisms fortheir growth. During yanyanku fermentation, the pHincreases and rises to alkaline levels in the final product(Table 2), suggesting that the fermentation is alkaline. Asreported in the literature, it is a common fact that Bacillus sp.are the dominant microflora involved in the alkaline fermen-tation of African locust beans to produce food condiments(N’Dir et al. 1994, 1997; Ouoba et al. 2003, 2007; Azokpota2005). The increase of the pH could be attributed to the addi-tion of potash and ash solution filtrate. However, it might

principally be because of the activities of the microbial popu-lation of the fermented product which was dominated byBacillus sp., particularly Bacillus sp. spores, in all three variantmethods (Table 3). The pH values of Yanyanku var. 1 andYanyanku var. 3 did not show any significant difference(P > 0.05). However, the pH of both products presents sig-nificant difference (P < 0.05) with the pH of Yanyanku var. 2(Table 3). The presence of Bacillus spores in yanyanku wasnot surprising, as Bacillus sp. have been reported to be alkali-resistant bacteria (Guiraud and Galzy 1980; Moir 2006; Blacket al. 2007; Ouoba et al. 2007). The principal unit operationsthat occurred during the yanyanku processing, i.e., the longfermentation process, grinding, molding, milling and dryingprobably created optimal conditions for the Bacillus cells tosporulate. Enterobacter, molds and yeasts were not detected inany sample. The process conditions were probably not favor-able for their growth (Guiraud and Galzy 1980). Staphylo-cocci, as well as vegetative forms of Bacillus sp. wereencountered at low levels, compared with the aerobic meso-


Washing

Pounding 1 (Big balls)

Cooking


Pounding 2

Fermentation (72h)

Sun drying 1

Milling

Sun drying 2


Dirty beans (162 g)

Cleaned beans (834 g)

Washed and cleaned beans (1382.4)

Dirty water, dishes (4.25 L = 4250g)

Cooked beans (1611.8g)

Fermented mash (1091.3g)

Dried fermented mash (657. 8g)

Powder (595.8g)

Yanyanku var. 2 (376.7g)

Water (5 L=5000g)

Pounded beans 1 (1280.2 g)

Water (5 L=5000g)

Ash solution filtrate (2.5 ml=25g)

Supernatant (2.825 L = 2825 g)

Pounded beans (2) (1536.6g)




philic bacteria (Table 3). Staphylococci have been reported asnonresistant microorganisms and their presence in yanyankucould probably be because of contamination of the finalproduct.

It seems that the rate of nutrients degradation in the beansdepends on the level of Bacillus concentrations in yanyanku.The samples from the Yanyanku var. 1 and var. 3 had higherconcentration of Bacillus spores (Table 3). In these samples, a


Washing

Cooking


Fermentation (7 days)

Pounding (Big balls)

Sun drying

Milling


Dirty beans (156g)

Cleaned beans (842 g)

Dirty water, dishes (4.83L=4830g)

Washed and cleaned beans (1010.8 g)

Supernatant (3.58 L=3580g)

Cooked beans (1005.3 g)

Fermented beans (780.8 g)

Fermented paste (640.5 g)

Yanyanku var. 3 (400.2g)

Water (5 L=5000g)

Potash (5g) Water (5 L=5000 g)

Dried fermented mash (405.2 g)


TABLE 1. PROCESSING DURATION OF YANYANKU (MIN)

Processing steps

Processing duration (min)

Yanyanku var. 1 Yanyanku var. 2 Yanyanku var. 3

Sorting, cleaning 8 � 1 9 � 2 10 � 1Washing 8 � 2 10 � 1 10 � 2Pounding 1 (before cooking ) – 14 � 3 –Cooking 600 � 5 1,080 � 3 600 � 04Draining of supernatant 2 � 1 3 � 1 2 � 1Pounding 2 (after cooking and before fermentation 1) – 8 � 2 –Fermentation 1 4,320 � 8 4,320 � 5 10,080 � 5Pounding 1 (after cooking and fermentation 1) 8 � 1 – 10 � 2Milling after fermentation 1 and before fermentation 2 10 � 3 – –Fermentation 2 1,440 � 8 – –Sun drying after fermentation 2 2,880 � 7 – –Sun drying 1 after fermentation 1 – 2,880 � 6 2,880 � 9Milling after fermentation 1 and between sun drying 1 and sun drying 2 – 17 � 3 –Sun drying 2 – 1,440 � 8 –Milling after sun drying – – 15 � 4Total duration 9,276 9,781 13,607

Yanyanku var. 1; Yanyanku var. 2 and Yanyanku var. 3: Samples collected from the first, second and third variants of yanyanku processing, respectively.Values after � are standard deviations.–, absent.



great decrease of lipids (13%), proteins (18%) and carbohy-drates (52%) was observed (Table 2). The rate of the decreaseof lipids, proteins and carbohydrates was 7, 13 and 33%,respectively, in Yanyanku var. 2 in which the concentrations ofBacillus sp. are seen to be lower (Table 3). Because of theirhigh proteolytic activity (Azokpota et al. 2006b), Bacillus sp.are responsible for the degradation of proteins into aminoacids which produce ammonia, contributing to the decreaseof protein content in all three yanyanku variants, concomi-tant with the increase in Bacillus spores (Tables 2 and 3), par-ticularly in Yanyanku var. 1 and Yanyanku var. 3, whichshowed significant difference (P < 0.05) with the proteincontent of Yanyanku var. 2. An increase in crude proteins hasbeen reported for furundu (Harper and Colins 1992),dawadawa botso (Odunfa 1985; Aderibigbe and Odunfa1990; Allagheny et al. 1996), soumbala (Ouoba et al. 2003),iru and sonru (Azokpota et al. 2006a). However, contradic-tory results have been reported for bikalga (Bergaly et al.2006) and afitin (Azokpota et al. 2006a).

Besides, the decrease of carbohydrates can be explained bythe fact that the amount of carbohydrates could be lostthrough water or supernatant from washing and cooking orthrough drained water from the fermentation. Moreover, it ispossible that carbohydrates were hydrolyzed into reducingsugars which were easily metabolized by Bacillus sp. as energy

source (Azokpota et al. 2006a). This makes yanyankusomehow parallel to kudeme which also introduces Bacillusspecies into agbélima fermentation for their cellulolytic activ-ity which results in the breakdown of cassava tissue (Amoa-Awua and Jakobsen 1995). The decrease of carbohydrates hasbeen also reported in afitin, iru, sonru (Azokpota et al.2006a), and in dawadawa botso (Ibrahim and Antaï 1986).

In summary, this is a preliminary study which has charac-terized yanyanku used as inoculum enrichment or an starterculture-like additive to produce food condiments in Benin.The possibility of using yanyanku for the production of foodcondiments needs to be investigated in depth and the presentfindings represent a first step which could help in thisresearch. The principal unit operations of the yanyanku pro-cessing, particularly cooking, fermentation and/or sundrying, create appropriate conditions for Bacillus spores togrowth. These conditions probably inhibited growth ofpathogenic and spoilage bacteria in the final product, makingit safe and extending its shelf life. It is probable that yanyankuplays similar role and serves the same purpose as a starterculture because of the presence of Bacillus spores in highnumbers. It is likely that yanyanku is a concentrate of Bacillusspores which germinates into vegetative cells during con-trolled fermentation when appropriate incubation condi-tions are created for Bacillus sp. to growth. This hypothesis

TABLE 2. PROXIMATE COMPOSITION OF THE THREE VARIANTS OF YANYANKU*

Samples pH

Chemical components of yanyanku (g/100 of samples)

Crude proteins Crude lipids Crude fiber Total carbohydrates Ash Dry matter

Cooked malvacene beans 5.12 � 0.04c 25.32 � 0.02a 24.21 � 0.14a 16.21 � 0.02a 23.13 � 0.03a 6.54 � 0.0b 85.65 � 0.21b

Yanyanku var. 1 9.95 � 0.06a 20.73 � 0.13c 21.05 � 0.31c 11.10 � 0.024c 11.12 � 0.04c 9.65 � 0.01a 92.2 � 0.3a

Yanyanku var. 2 8.23 � 0.04b 22.05 � 0.15b 22.56 � 0.28b 13.54 � 0.04b 15.52 � 0.06b 9.73 � 0.01a 93.54 � 1.43a

Yanyanku var. 3 10.14 � 0.02a 20.63 � 0.06c 20.74 � 0.06c 10.95 � 0.05c 10.95 � 0.04c 9.75 � 0.02a 92.72 � 0.13a

* Values are means � SD of three different determinations. Means with the same superscript letters in the same column are not significantly different(P > 0.05).Yanyanku var. 1, Yanyanku var. 2 and Yanyanku var. 3: see Table 1.SD, standard deviation.

TABLE 3. MAIN MICROBIAL POPULATION INVOLVED IN THE THREE VARIANTS OF YANYANKU

Samples

Main microorganisms (log10 [cfu/g])

Mesophilicaerobic bacteria

Bacillus sp.

Staphylococcus sp.Spores Vegetative

Cooked and nonfermentedHibiscus sabdriffa beans

3.42 � 0.04c 1.42 � 0.03c 1.13 � 0.02b 1.25 � 0.05b

Yanyanku var. 1 9.82 � 0.01a 8.95 � 0.03a 2.38 � 0.02a 2.42 � 0.02a

Yanyanku var. 2 8.55 � 0.04b 8.22 � 0.03b 1.15 � 0.04b 2.62 � 0.03a

Yanyanku var. 3 9.95 � 0.08a 9.55 � 0.02a 2.44 � 0.05a 2.35 � 0.06a

* Values are means � SD of three different determinations. Means with the same superscript letters in the same column are not significantly different(P > 0.05).Yanyanku var. 1; Yanyanku var. 2 and Yanyanku var. 3: see Table 1.SD, standard deviation.



needs to be proved. In addition, this investigation should beextended to others parts of Benin including Parakou, Porto-Novo, Pobé, Sakété and Kétou where other additives similar toyanyanku are also produced and used to prepare fermentedfood condiments.

ACKNOWLEDGMENTS

This study was carried out with financial assistance from theInternational Foundation for Sciences (IFS). The authors aregrateful to the IFS and the traditional yanyanku processorsfrom Djougou for their fruitful cooperation.

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EVALUATION OF YANYANKU PROCESSING, AN ADDITIVE USED AS STARTER CULTURE TO PRODUCE FERMENTED FOOD CONDIMENTS IN BENIN