chapter  6
34 Pages

Fermented Legumes: Soybean and Non-Soybean Products

ByToshirou Nagai, Jyoti Prakash Tamang

Among the legumes, soybeans are mostly fermented traditionally and made into recipesmostlybytheethnicpeopleofAsia.Thepreparationandconsumptionofsticky, nonsalty,•avorsomefermentedsoybeanfoodsarethetraditionalwisdomofthe peoplefromseveralSouth-EastAsiancountries,whichhavefosteredadistinctfood cultureofthepeople(Tamang2010).Bacillus subtilisisanimportantstarterculture formanyAsianandAfricanfermentedsoybeanfoods(Kiersetal.2000).Soybeanis amajorleguminouscropintheworld,anditsutilizationasfoodismostlycon™ned toAsia.Someofthecommonethnic,nonsaltedstickyfermentedsoybeanfoodsare natto(Japan);kinema(India,Nepal,andBhutan);tungrymbai,bekang,hawaijar, aakhuni,andperuyaan(India);thua nao(Thailand);chungkokjang(Korea);pepok (Myanmar);andsieng(Cambodia).Nonsaltedfermentedsoybeanfoodsareconcentratedinaregionoftheworldrepresentedbyatrianglewiththreevertices,oneeach onJapan(natto),Nepal(kinema),andIndonesia(tempe).Nakao(1972)namedthis trianglethe“nattotriangle”andincludedallfermentedsoybeanproductsincluding miso,soysauce,andtempeandextendedthistriangleuptoIndonesia(Figure 6.1). Tamang(2010)renamedthishypotheticaltrianglethe“kinema-natto-thua naotriangle”(KNTtriangle).Withintheproposedtriangle-boundcountries,manyfermented stickynonsaltysoybeanfoodsareconsumedbythedifferentethnicgroupsofpeople inCambodia,Laos,Vietnam,DarjeelinghillsandNortheaststatesinIndia,easternpartofNepal,southernpartofBhutan,Myanmar,andsouthernpartsofChina (Figure6.2).Beyondthishypothetical“KNTtriangle,”thereisnoreportofkinemalikeproductsthatarestickyandammonia-•avoredfermentedsoybeanfoods,and theproposed“KNTtriangle”doesnotincludesalted,nonstickyandnon-bacillifermentedsoybeanproductssuchastempe,miso,sufu,soysauce,etc.(Tamang2010). Althoughthemethodofproductionandculinarypracticesvaryfromproducttoproduct,allbacilli-fermentedAsiansoybeanfoodshaveacharacteristicstickinessand typical•avor.Haraetal.(1995)reportedthattheplasmidofBacillus subtilis(natto) strainresemblesthatofBacillus subtilisisolatedfromthua naoandkinema.AphylogeneticanalysisshowedthesimilarityamongthestrainsofB. subtilisisolatedfrom commonstickyfermentedsoybeanfoodsofAsia(Tamangetal.2002,Meeraketal. 2007). This suggests that B. subtilis strains responsible for the fermentation of sticky soybean foods of Asia might have originated from the same stock.