THESE UNIQUE El Hassane Kéhien-Piho TOU - Nutridev

ARTICLE IN PRESS
E.H. Tou et al. / LWT 40 (2007) 1561–1569 1567
for the organoleptic characteristics of the resulting
MG-CMI gruel with possible enhancement of both the
sweet and sour taste. The effect of these changes in
organoleptic characteristics on the acceptability of the
gruel will have to be assessed. As previously observed in
the traditional fermentation process (Tou et al., 2006),
the kinetics pattern indicates the same metabolic dominance
of homofermentative LAB during the fermentation
step (i.e. longer and higher production of lactic acid than of
ethanol).
3.2. Changes in microbial counts during the fermentation
step in MG-T and MG-CMI processing methods
The microbial composition (mesophilic aerobic bacteria
(MAB), yeasts, LAB and (ALAB) of fermented pastes was
analysed during the fermentation step (Table 2).
The number of MAB and LAB increased slowly during
fermentation in both processing methods, whereas yeast
counts were lower and more variable with a decrease at the
end of the fermentation. Similar microbiota characteristics
were reported in fermented pearl millet porridge by Thaoge
et al. (2003). In all processing methods, LAB were the
dominant microflora and their number increased during
fermentation in all samples of MG-T and MG-CMI, to
reach final values of 8.83 and 8.79 log CFU/ml, respectively.
Surprisingly, the lactic microflora counts were
similar in both MG-T and MG-CMI pastes in the early
stage of fermentation despite the fact that inoculation by
backslopping was introduced in the MG-CMI processing
method. This could be due to the fact that backslop
inoculation enabled the microflora in MG-CMI paste to be
restored to the same level as the microflora in the MG-T
paste. It is interesting to note that in the MG-T processing
method, the ALAB/LAB ratio decreased during fermentation,
whereas in the MG-CMI processing method it
remained of the same order of magnitude from the onset
to the end of fermentation. One possible explanation is that
in the MG-CMI process, pre-cooking before fermentation
gelatinizes starch, which is a substrate for ALAB.
3.3. Nutritional value of final gruels
3.3.1. Proximate composition
The proximate composition of MG-T and MG-CMI
gruels was similar (Table 3). As expected, the incorporation
of groundnuts into the pearl millet before fermentation
enables a substantial increase in protein and lipid contents
and DM energy value which meet recent recommendations
for complementary foods (Lutter & Dewey, 2003). These
results are consistent with other studies that have shown
improvement of the nutritional balance of traditional
fermented foods by incorporation of protein-rich materials
such as grain legumes (Sanni et al., 1999; Egounlety, 2002;
Table 2
Changes in microbial counts in MG-T and MG-CMI pastes during fermentation
Microbial numbers (log CFU/ml)
MG-T
MG-CMI
Fermentation time (h) 0 4 8 24 0 4 8 24
MAB 8.36 8.66 8.71 8.87 8.18 8.49 8.60 8.81
Yeasts 6.32 6.80 6.20 5.81 6.00 6.73 6.59 5.86
LAB 8.26 8.58 8.65 8.83 8.15 8.43 8.60 8.79
Ratio LAB/Yeasts 86 60 281 1046 140 50 102 835
ALAB 7.04 6.77 6.48 6.40 6.79 6.62 7.18 6.97
Ratio ALAB/LAB 0.06 0.02 0.007 0.004 0.04 0.02 0.04 0.02
MAB: mesophilic aerobic bacteria; LAB: lactic acid bacteria; ALAB: amylolytic lactic acid bacteria.
Table 3
Proximate composition and phytate content of raw materials and fermented gruels (results are expressed for 100 g of dry matter)
Raw materials
Millet (M) Groundnut (G) Formula (M/G/
Sugar: 65/20/15)
Sweetened gruel (taking the addition of 15% of sugar into
account)
Traditional bensaalga
MG-T MG-CMI
a
Energy (kcal) 409.2 631.7 452.2 407.7 462.5 458.2
Protein (g) 8.4 29.3 11.3 7.070.7 11.670.3 11.770.1
Fat (g) 5.6 52.9 14.2 4.070.7 14.570.5 14.670.6
Carbohydrates (g) 81.3 9.6 69.8 86.071.7 71.470.1 70.070.1
Fibre (g) 3.4 5.8 3.4 1.870.4 1.170.1 2.470.1
Ash (g) 1.3 2.4 1.3 1.270.2 1.470.1 1.370.1
Phytate (mg) 546 832 604 192797 388720 297730
a Lestienne (2005).