Vol.4, No.5B, 96-99 (2013) Agricultural Sciences
doi:10.4236/as.2013.45B018
Thermal properties of some selected nigerian soups
Raji Akeem Olayemi1, Akinoso Rahman2
1Department of Food Agric and Biological Engineering, College of Engineering and Technology, Kwara State University, Malete,
Ilorin, Nigeria; akeem.raji@kwasu.edu.ng
2Department of Food Technology, University of Ibadan, Oyo State, Nigeria; akinoso2002@yahoo.com
Received 2013
ABSTRACT
A preliminary investigation was carried out on the
thermal properties of “Ewedu” (Corchorusolito-
rus), “Ila” (Hibiscus esculentus), “Ogbono” (Irvin-
gi a gabon ensis) and ” Kuka” (Adanso nia digitata)
soups, because information on the thermal prop-
erties of these soups has not been established.
The specific heat capacity, thermal conductivity
and thermal diffusivity parameters were deter-
mined as a function of their proximate composi-
tions by applying additivity principles. The proxi-
mate composition obtained for the soups were:
ewedu (moisture content; 88.60 ± 0.14% , protein;
6.00 ± 0.01%, fat; 1.05 ± 0.05% , ash; 1.81 ± 0.01% ,
crude fiber; 1.47 ± 0.02%, carbohydrate; 1.05 ±
0.04% and energy 34.27 ± 1.89 k/cal/10 g), Ila
(moisture content; 77.25 ± 0.35%, protein; 15.94
± 0.08%, fat; 2.13 ± 0.04%, ash; 1.90 ± 0.14%,
crude fiber; 1.15 ± 0.07%, carbohydrate; 1.48 ±
0.11% and energy 87.61 ± 3.31 k/cal/10 g), Og-
bono (moisture content; 68.87 ± 0.14%, protein;
18.70 ± 0.42% , fat; 6.12 ± 0.11%, ash; 4.55 ± 021% ,
crude fiber; 1.04 ± 0.60%, carbohydrate; 1.90 ±
0.01% and energy; 133.08 ± 0.60 k/cal/10 g) and
Kuka (moisture content; 78.54 ± 0.06%, protein;
8.80 ± 0.41%, fat; 2.29 ± 0.01% , ash; 2.09 ± 0.01% ,
crude fiber; 0.88 ± 0.02%, carbohydrate; 7.42 ±
0.08% and energy 85.64 ± 0.17 k/cal/10 g). The
specific heat capacity, thermal conductivity and
thermal diffusivity for the soups were; ewedu
(3.851 kJ/ kg/K, 0.530 W/m/K and 1.358 x 10-7
m2/s), Ila (3.554 ± 0.01 kJ/kg/K, 0.483 W/m/K and
1.281 x 10-7 m2/s), ogbono (3.332 kJ/kg/K, 0.447
W/m/K and 1.220 x 10-7 m2/s) and kuka (3.586
kJ/kg/K, 0.494 W/m/K and 1.296 x 10-7 m2/s)re-
spectively. The values obtained for the thermal
properties showed that the soups can mildly
retain or dissipate heat during canning and
freezing.
Keywords: Soups; Proximate Composition;
Thermal Properties; Processing
1. INTRODUCTION
Vegetables are important constituents of any type of
diet in many Nigerian homes. Despite that, they add va-
rieties to the menu. As valuable sources of nutrients es-
pecially in rural areas where they con tribute substantially
to protein, mineral, vitamins, fiber and other nutrients
which are usually in short supply in most daily diets [1].
Besides, they add flavour, variety, taste, colour and aes-
thetic appeal to what would otherwise be a monotonous
diet [2,3]. They are mostly in abun dance shortly after the
rainy season but become scarce during the dry season
when cultivated types are used. Some eventually find
their way to urban markets [1].Vegetables have gained a
widespread acceptance as a dietary cons tituent in Nigeria,
generally forming a substantial portion of the diet in the
preparation o f sou ps and stews[3].
Nigeria is a multi-cultural society with different tradi-
tional soups which are indigenous to differen t ethnic groups
and tribes. The soups are consumed along with traditional
dietary staples, obtained from cassava, yam, cocoyam,
sweet potatoes, plantain and maize [4]. Though, there is
no universally accepted short list of such plants men-
tioned above, different tribes in Nigeria have evolved
their preferences and feedi ng habits.
During processing and storage, many foods are either
heated or cooled. Cooling, cooking, pasteurization, de-
hydration, commercial sterilization and freezing involve
heat transfer [5] and the design of such processes re-
quires a detailed knowledge of the thermal properties of
the materials involved.
Although the recipe and nutritional contents of stews
and soups commonly consumed in Nigeria had been es-
tablihed in order to serve as a reference for interested
individuals, corporate organizations, researchers, medical
practitioners, nutritionists and dieticians, public health
workers and food technology programmes [6], informa-
tion on the thermal p r op erties of these so up s has not been
established. The parameters stated above will serve as a
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