THESE UNIQUE El Hassane Kéhien-Piho TOU - Nutridev

1562
ARTICLE IN PRESS
E.H. Tou et al. / LWT 40 (2007) 1561–1569
Burkina Faso, the most common cereal-based fermented
gruel called ben-saalga is prepared from millet. The
traditional processing method of ben-saalga, described
in detail in Tou et al. (2006) involves five main steps:
soaking, milling, sieving, settling—during which fermentation
occurs—and cooking.
To improve the nutritional value of ben-saalga and other
fermented cereal-based gruels, different modifications can
be implemented including adding protein or lipid-rich raw
materials to the cereal to improve the macronutrient
balance, partial starch hydrolysis to increase the energy
density (ED) of the gruel, or using a culture starter of lactic
acid bacteria (LAB) selected for their high phytasic activity
to improve nutrient bioavailability.
To improve the macronutrient balance of fermented
complementary food, several studies replaced part of the
traditionally used cereal with legume seeds (soybean,
cowpea and/or groundnut). Co-fermentation of cereal
and legume seeds has thus been frequently proposed to
produce protein-rich complementary foods (Sanni,
Onilude, & Ibidapo, 1999; Egounlety, 2002). The cofermentation
process is easy, inexpensive and appreciated
by the infants (Egounlety & Aworh, 1995; Ojofeitimi,
Abiose, Ijadunola, Pedro, & Jinadu, 2001; Egounlety, 2002).
Several methods based on partial starch hydrolysis have
been used to prepare high ED gruels with suitable
consistency and high dry matter (DM) content. They
generally include either thermo-mechanical treatments, such
as extrusion cooking (Mouquet, Salvignol, Van Hoan,
Monvois, & Tre` che, 2003), or enzymatic starch hydrolysis
which can be obtained by adding either industrial amylases
(Trèche, 1995) or germinated cereal flour (malt), combined
or not with lactic acid fermentation (Kitabatake, Gimbi, &
Oi, 2003; Thaoge et al., 2003; Onyango, Henle, Hofmann, &
Bley, 2004; Tou et al., 2007). Only a limited decrease in the
viscosity of cereal-based gruels was observed after natural
lactic acid fermentation alone, but the use of selected
amylolytic lactic acid bacteria (ALAB) as starter cultures
could be a new biotechnological method for the preparation
of high ED fermented gruels (Nguyen et al., 2007).
Cooking to pre-gelatinize starch delays the start of the
fermentation (Tou et al., 2007). To avoid this inconvenience,
Nout, Rombouts, and Havelaar (1989) added malt
to the gelatinized starch (gruel) at the end of processing (i.e.
after fermentation), while Tou et al. (2007) proposed the
addition of malt plus backslopping to restore the lactic acid
microbiota.
The objective of this study was to improve the nutritional
quality of ben-saalga by combining co-fermentation of millet
and groundnut to improve its macronutrient balance with
implementation of a modified processing method to increase
its ED. This modified processing method, called ‘CMI’ (Tou
et al., 2007) included additional steps: precooking, adding
malt and backslop inoculation. The CMI process enables
partial starch hydrolysis thus making it possible to prepare
concentrated high-ED gruels of suitable semi-liquid consistency.
In addition, backslop inoculation promotes better
hygienic conditions by immediate dominance of LAB (Nout
et al., 1989). In our study, acidification kinetics were
monitored, microbial counts were made and sugar contents
and fermentation products were analysed to characterize the
progress of fermentation. The nutritional quality of the
resulting enriched gruel is described and compared to that of
ben-saalga.
2. Materials and methods
2.1. Materials
The pearl millet (Pennisetum glaucum) and groundnuts
(Arachis hypogaea) used as raw materials in the preparation
of gruels, and the aromatic ingredients (ginger and
mint) were purchased at local markets. To increase the
protein and lipid contents of the gruel, groundnuts were
preferred to cowpea or soybean because they are cheap and
easily available at local markets. Malted barley seeds were
obtained from BRAKINA, an industrial brewery in
Ouagadougou, and ground (A10, IKA Labortechnik)
before being used in the laboratory.
2.2. Formulation of gruels
The proportions of millet and groundnut were calculated
taking into account their respective lipid and protein
contents as well as the addition of 15% of sugar before
consumption (Table 1) to obtain the protein, lipid and energy
Table 1
Formulation of gruels (millet co-fermented with groundnuts) taking into account 15% of added sugar, and estimation of their final protein and lipid
contents
Materials Proportions (g/100 g DM) Fat (g) Protein (g) Energy (kcal)
A B A B A B
Pearl millet 65 3.4 – 6.0 – 251.7 –
Groundnuts 20 9.6 – 5.1 – 119.0 –
Sugar 15 0 – 0 – 60 –
Total 100 13.0 413.7 11.1 6.7–10.7 430.7 440
A: Values were calculated using proximate composition data obtained on samples of raw materials from Burkina Faso analysed in our laboratory; B:
values recommended by Dewey and Brown (2003) for complementary food.