Innovations in the production of kenkey, a traditional fermented maize product of Ghana : nutritional, physical and safety aspects

P.F. Nche

Research output: Thesisinternal PhD, WU

Abstract

<p>Kenkey is traditionally made from a dough obtained by soaking maize (1-2 days, room temperature), milling and then fermenting naturally for 2-4 days. This thesis was aimed at improving not only the nutritional quality of kenkey, but also the production process. The traditional method for making kenkey was scaled down to a laboratory process and the microbiological, physical and nutritional quality of both maize and maize- cowpea kenkey were investigated. Natural fermentation for 48h or 72h at 30°C was sufficient to obtain properly acidified maize (pH 4.07) or maize-cowpea (pH 4.08) doughs, respectively. Lactic acid bacteria were mainly responsible for acidification. Supplementation of maize (on a replacement basis) with 20% white cowpea resulted in significant increases in protein (by 20.5%) and available lysine (by 74%) contents. This also resulted in significant increases in biogenic amines (total amines &lt; 500 ppm, mainly putrescine and tyramine) compared with maize kenkey (total amines &lt; 60 ppm). Histamine was absent (&lt; 5 ppm). Acceptability tests in Ghana, however, showed that only a 10% cowpea level was comparable with the traditional kenkey in terms of flavour and texture. Process options for producing a dehydrated kenkey meal (kenkey dry- mix) were investigated with the aim of developing a product with a longer shelf-life than traditional kenkey. An <em>in vitro</em> method was developed for determining the digestibility and flatulence potential of kenkey. Soaking of grains effected the highest increase in <em>in vitro</em> digestibility. <em>Clostridium perfringens</em> strain NCTC 8239 produced more gas from the solid residue left over from the <em>in vitro</em> digestion of maize-cowpea samples than from the resulting supernatant which contained low molecular weight oIigosaccharides, traditionally held responsible for intestinal flatus induction, suggesting that non-starch polysaccharides contribute significantly to the flatulence potential of cowpea-supplemented kenkey.
Original languageEnglish
QualificationDoctor of Philosophy
Awarding Institution
Supervisors/Advisors
  • Rombouts, F.M., Promotor, External person
  • Nout, M.J.R., Promotor
Award date10 Feb 1995
Place of PublicationS.l.
Publisher
Print ISBNs9789054853534
Publication statusPublished - 1995

Keywords

  • zea mays
  • maize
  • fermentation
  • food biotechnology
  • ghana

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