~ 212 ~
International Journal of Fisheries and Aquatic Studies 2017; 5(5): 212-218
E-ISSN: 2347-5129
P-ISSN: 2394-0506
(ICV-Poland) Impact Value: 5.62
(GIF) Impact Factor: 0.549
IJFAS 2017; 5(5): 212-218
© 2017 IJFAS
www.fisheriesjournal.com
Received: 27-07-2017
Accepted: 28-08-2017
James Banda
Fisheries Science Department,
Mzuzu University, Private Bag
201, Mzuzu 2. Malawi, East
Africa
Petros Chigwechokha
Fisheries Science Department,
Mzuzu University, Private Bag
201, Mzuzu 2. Malawi, East
Africa
Wales Singini
Fisheries Science Department,
Mzuzu University, Private Bag
201, Mzuzu 2. Malawi, East
Africa
John Kamanula
Chemistry Department, Mzuzu
University, Private Bay 201,
Luwinga, Mzuzu 2. Malawi, East
Africa
Orton Msiska
Fisheries Consultant, P.O. Box
833. Mzuzu, Malawi, East Africa.
Jupiter Simbeye
Mathematics Department,
Chancellor College, P.O Box 280,
Zomba, Malawi, East Africa.
Correspondence
James Banda
Fisheries Science Department,
Mzuzu University, Private Bag
201, Mzuzu 2. Malawi, East
Africa
The Shelf life of Solar Tent Dried and Open Sun Dried
Diplotaxodon limnothrissa (Ndunduma)-Pisces;
Cichlidae
James Banda, Petros Chigwechokha, Wales Singini, John Kamanula,
Orton Msiska and Jupiter Simbeye
Abstract
The study evaluated changes in chemical, physical, microbial quality of solar tent dried and open sun
dried Diplotaxodon limnothrissa fish species from Malembo landing site after 9 weeks of storage at
ambient temperature. The shelf life of solar tent dried and open sun dried Diplotaxodon limnothrissa fish
species was estimated at 7 and 3 weeks respectively. Spoilage indicators Total Volatile Basic Nitrogen
(g/100mg) and pH range were 15.45-17.31, 6.26-6.6.35 for solar tent dried fish and 15.74-20.56, 6.32-
6.41 for open sun dried fish. At the period of sensory rejection, total bacteria viable counts, Total Volatile
Basic Nitrogen and pH were 5.7×10
6
cfu/g, 18.98 and 6.38, respectively, for open sun dried. On the other
hand, solar tent dried fish registered 4.1×10
2
cfu/g total bacteria viable counts, 17.28 Total Volatile Basic
Nitrogen and pH 6.33. Relatively higher levels of Esherichian coli, Salmonella, Vibrio and Micrococcus
bacteria were detected in open sun dried compared to the solar tent dried fish. Protein range for solar tent
dried and open sun dried samples were 63.3±0.15-61.09±0.07% and 63.3±0.34-58.19±0.21%
respectively. Moisture content remained constant and significant (p= 0.001) at 8.3±0.12 and 17.0±0.01%
for solar tent dried and open sun dried Diplotaxodon limnothrissa respectively. Visible fungal growth
was observed from week 2 of storage in open sun dried fish and the isolates of Aspergillus 3.3×10
1
and
Penicilium 3.3×10
1
were identified. The results confirmed the application of solar tent drying as an
efficient technology for fish processing in Malawi. The study recommend use of solar tent drying to
increase shelf life and safeguarding markets for value addition of small fish products in Malawi.
Keywords: Diplotaxodon limnothrissa, sensory, microbiological analysis, chemical analysis, Lake
Malawi
1. Introduction
The global consumption of fish and fish products has greatly increased in recent decades, due
to a number of factors
[1]
. Foremost among these factors is the growing knowledge that fish
constitute an important and healthy part of the human diet, mainly owing to the presence of ω-
3 polyunsaturated fatty acids, which play an essential role in human health, presence of
micronutrients (vitamins, minerals) and proteins with a high biological value
[2]
. Fish constitute
a significant proportion of diets in Malawi, contributing over 50% total animal protein
consumption by the population
[3]
. Several fish species, including Diplotaxodon limnothrissa
probably the most abundant cichlid with high biomass estimates in the pelagic zone alone are
popular diet constituents in Malawi. The species is exploited commercially in the South
Eastern and Western Arm of the lake
[4]
.
Fish is recognised as being highly perishable, having a relatively short shelf life. Fish’s shelf
life is influenced by a number of factors. The peculiarity chemical composition of fish is a
major factor responsible for their high perishability
[5]
. The high content of water, non-protein
nitrogenous compounds, unsaturated fatty acids, presence of bacterial flora on the skin surface
and in gastro-intestinal tract and the activity of endogenous enzymes contribute to the high
perishability of fish. Furthermore, the high ambient temperature hastens fish spoilage by
accelerating the activities of bacteria, enzymes and chemical oxidation of fat in fresh fish
[6]
.
This call for proper processing technologies to minimize rate of spoilage and increase shelf life
of processed fish. It is reported that fish processing reduces spoilage and microbial
contamination that would pose a threat to the health and safety of the consumer
[7]
. A number
of studies have indicated that quality is still the key buying cue for fish purchasers
[8]
.