Water activity relations of spoilage fungi associated with smoke-dried catfish (Clarias gariepinus) sold in some open markets in Nigeria

Author(s):  
Ayodeji A. Fasuan ◽  
Bola Akin-Obasola ◽  
Borisade Omotoso Abiodun
2020 ◽  
Vol 34 (2) ◽  
pp. 143-151
Author(s):  
U.D. Enyidi ◽  
F.N. Joseph

The study evaluated effects of different processing methods (charcoal smoking, electric and gas drying) on proximate composition and stability status in fillets of Clarias gariepinus. The stability indices were evaluated after 60-days storage of the processed fish. Standard methods were employed in all the analyses. The results showed that electric-dried fillets recorded the highest protein content (16.97±0.12%), the lowest water activity (0.49±0.05mg/100g), the highest water resumption (60%) at room temperature and the lowest TVB-N value of 5.0±0.01mg/100g. Proximate analysis revealed that smoked fillets had the lowest protein content of 11.30±0.08%, the highest lipid (6.99±0.15%), the highest water activity 0.71±0.14 and the lowest water resumption at room temperature (36.5%). Fish fillets processed with gas oven had intermediate values of various indices tested when compared with other methods. Keywords: Smoking, electric drying, gas drying, shelf life, proximate composition


2019 ◽  
Author(s):  
K Kuchta ◽  
W Waser ◽  
S Cameron ◽  
H Rausch
Keyword(s):  

Author(s):  
Dyah Anggraeni ◽  
Nurlela Nurlela

Background: Natural preservatives are compounds produced by natural ingredients that can suppress bacterial growth and development. Natural preservatives are carried out because most of the preservatives circulating are chemicals and unsafe for the body. One of the natural preservatives is by using garlic extract (Allium sativum L).  Objective: This study is aimed to determine the effectiveness of the antibacterial garlic (Allium sativum L) as a natural preservative in fresh African catfish (Clarias gariepinus).  Method: This research used the Pour Plate iroculation method. African catfish (Clarias gariepinus) which is soaked with garlic (Allium sativum L) with a concentration of 7%, 14% and 21% for 30 minutes, then the fish will be kept at room temperature with a storage period of 24 hours and 48 hours and calculated growth in bacterial numbers with the Colony counter.  Result: Based on the research result, it was found that garlic extract (Allium sativum L) can obstruct the effectiveness of antibacterial in African catfish (Clarias gariepinus) at a concentration of 14%.


2020 ◽  
Vol 4 (2) ◽  
pp. 41-45
Author(s):  
Sadam Sulaiman Indabo ◽  
Rufai Zakari

Dermestes maculatus is a major pest of stored fish in Nigeria, fish is preserved with highly persistent synthetic chemicals. There have been an increasing effort at developing plant-based toxicants that are environmentally friendly. Therefore, this study was conducted to screen the leaf extract of Azadirachta indica for phytochemical constituents. The efficacy of the methanolic leaf extract of the plant against D. maculatus was also evaluated. The leaves of A. indica were obtained, processed and taken to laboratory for methanolic extraction. Phytochemical screening was carried out to identify saponins, flavonoids, alkaloids, tannins, steroids, cardiac glycosides, glycosides, triterpenes and carbohydrates using standard procedure.  Both clean and infested samples of smoke-dried Clarias gariepinus were purchased from Sabon Gari Market, Zaria. The infested samples were used as initial source of D. maculatus larvae. Range finding test was carried out prior to the bioassay. During the bioassay, clean un-infested fish samples were weighed and introduced into kilner jars and respective dosages of 0.2g, 0.4g, 0.6g and 0.8g of extract were added. Another set of fish samples without the extract were maintained as control. The experiment was arranged in Completely Randomized Design with three replicates. Fifteen larvae of D. maculatus were introduced into both treated and control containers and covered. Mortality was recorded after 24, 48, 72 and 96 hours. Data obtained revealed an increase in mortality with increasing dose and time. Mortality ranged from 1.67 to 11.00. Therefore, leaf extract of A. indica should be incorporated in the development of larvicide against D. maculatus.   


2019 ◽  
Vol 23 (2) ◽  
pp. 193-198
Author(s):  
Monica Mironescu ◽  
Laura Fratila ◽  
Alexandru Hupert ◽  
Ion Dan Mironescu

Abstract This research investigates the physical-chemical, sensorial and mechanical characteristics of starch-based edible films incorporating three types of bee hive products: honey, propolis and bee bread, in concentrations varying from 1% to 3%, reported to starch. The results indicates an increasing of films moisture, water activity, ash content and acidity, in the order: honey<propolis<bee bread, all values increasing with the increasing of hive products percentage into the control film; aw is remaining at very low values, under 0.4. Sensorial analysis indicated honey as the better suited for improving taste and flavour and bee bread for increasing colour intensity of the films; the sensorial characteristics are maintained during 30 days of films storage, in all cases. Compared with the control starch-based film (which is elastic, brittle and hard), the films containing 2% bee hive products are elasto-plastic and more resistant to penetration, the resistance increasing in the order: bee bread<propolis<honey.


2010 ◽  
Vol 9 (1) ◽  
Author(s):  
Lutfi Lutfi

<p><em>Effect of four types of diluents</em><em>s</em><em> and four concentration of DMSO (5%, 10%, 15% and 20%) against the motility of African catfish sperm were evaluated after storage at freezing temperatures. </em><em>The steps in preparation the 16 treatments combination of the diluents</em><em> </em><em>are </em><em>preparation of diluents, mixing </em><em>diluents </em><em>with DMSO, packing </em><em>of semen </em><em>in</em><em>to</em><em> 0.3-ml straw, equilibration of </em><em>semen </em><em>at 4 °C for 30 minutes, freezing </em><em>of </em><em>semen in nitrogen vapor liquid </em><em>at </em><em>a height of 6.5 cm for 10 minutes</em><em>,</em><em> and subsequent</em><em>ly</em><em> storage of </em><em>semen </em><em>in liquid nitrogen (-196</em><em> <sup>0</sup></em><em>C) for further analy</em><em>sis</em><em> </em><em>of </em><em>post-thawing motility (PTM). </em><em>The result showed that t</em><em>he highest level of motility of spermatozoa </em><em>was </em><em>in </em><em>treatment </em><em>P</em><em><sub>1</sub></em><em>D</em><em><sub>15 </sub></em><em>(45.7 ± 4.3%) and the lowest </em><em>was </em><em>in </em><em>treatment </em><em>P<sub>2</sub>D<sub>20</sub> (14.5 ± 13.2%). The best diluent </em><em>in </em><em>this observation </em><em>was </em><em>diluents containing NaCl, KCl, CaCl<sub>2</sub> and NaHCO<sub>3</sub>. The best concentration </em><em>was </em><em>DMSO 15%. While the best interaction between the concentration of DMSO diluents is P<sub>1</sub>D<sub>15</sub> treatments containing NaCl, KCl, CaCl <sub>2</sub> and NaHCO<sub>3</sub> with a combination of 15% DMSO concentration. </em><em>The </em><em>conclusion </em><em>of the research is that </em><em>diluents containing NaCl, KCl, CaCl<sub>2</sub> and NaHCO<sub>3</sub> with a combination of 15% DMSO concentration</em><em> can be used in </em><em>cryopreservation of African catfish semen</em><em>.</em></p>


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