Open Access Original Research Article

Optimizing Salting and Immersion Time in Liquid Smoke of Farmed Gilthead Sea Bream (Sparus aurata) Fillets Using Response Surface Methodology

Maria Makri, Xanthe Douvi, Giorgia Ioannidoy

Biotechnology Journal International, Page 1-15
DOI: 10.9734/BBJ/2016/27867

Aims: To produce smoked gilthead sea bream fillets using the liquid smoke dipping method during brining and optimize the brining-smoking process using the response surface method.

Study Design: The experimental design was a two-level Central Composite Design that included 14 runs divided into two blocks. 

Place and Duration of Study: Department of Fisheries and Aquaculture Technology, Technological Educational Institute of Western Greece, Messolonghi, Greece, between April 2015 and December 2015.

Methodology: Second order polynomial models for yield, moisture content, salt content, water activity, pH, redness index and instrumental texture parameters of salted and smoked with liquid smoke gilthead sea bream filets were developed as a function of salt brine content  (from 8.7 to 19.3% (w/w)) and immersion time (from 30 to139 minutes) in brining solutions that contained 10% w/w liquid smoke. A numerical optimization was used to find the optimum values for salt brine content and immersion time. For the confirmation of the models, smoked gilthead sea breams were prepared using the optimal settings of the factors. The yield, salt content, water content, water activity, redness index and the textural parameters were determined. The results were statistically compared to the values predicted by the mathematical models. A consumer panel evaluated the smoked gilthead sea breams prepared using the optimal settings of the factors. The proximate composition of the smoked gilthead sea bream was also determined.

Conclusion: Within the range of brine salt content and immersion time used in the present work, the response surface model analysis and the model derived from the numerical optimization method proved useful in determining the optimum settings for salting and smoking with the liquid smoke of gilthead sea bream fillets. The optimal conditions for salt brine content and immersion time were 15.867% (w/w) and 109.975 minutes, respectively. Under optimal conditions, yield, water and salt content, water activity, pH, redness index, maximum shear force and work of smoked gilthead sea bream were 79.73%, 61.99%, 3.81% 0.94, 5.55, 0.41, 1269.1 (g*) and 3659.8 (g* sec), respectively. The water, protein, lipid and ash content of the smoked product were 61.87%, 20.89%, 12.43% and 3.56%, respectively, and the consumer panel highly accepted it.

Open Access Original Research Article

Water Quality and Distribution of Pathogenic Microorganisms along Kabianga River in Kericho County, Kenya

Kemboi Douglas, Selina Kotut, Soimo Allan Kiplangat

Biotechnology Journal International, Page 1-9
DOI: 10.9734/BBJ/2016/27279

Background: Safe and clean water is of major concern to mankind because it is directly linked with the health and their wellbeing. The disposal of different kinds of pollutants and nutrients through sewage, agricultural runoff and industrial effluents into rivers and water bodies effect a sequence of changes in its physicochemical characteristics. Kabianga River is known for provision of clean drinking water, a habitat for many aquatic plants and living organisms and irrigation water to farmlands. Excessive industrialization and consequent urbanization has led to several problems of water quality management of the river.

Aim: This research was aimed at assessing the quality of Kabianga river by ascertaining the levels of microorganisms and if it meets the local and international microbiological standards.

Study Design: The study used experimental design.

Methodology: The water samples were collected during rainy and dry seasons. Standard bacteriological techniques was used to describe bacteria content from water samples. 

Results: The results indicates that water is highly contaminated with human pathogenic bacteria. The most dominant bacteria in both seasons were Escherichia coli, Salmonella, Shigella, Proteus and Pseudomonas aeruginosa.

Conclusion: From the findings it can be concluded that the water from this river is not fit for human consumption or for domestic uses. Therefore regular monitoring of the water microbiological quality and public health education should be carried out to sensitize the residence on the dangers of using the polluted water. 

Open Access Original Research Article

Assessment of Antiproliferative Potential of Hexalobus crispiflorus (Annonaceae)

Samuel E hiabhi Okhale, Adeniyi Yahaya Tijani, Brendan Okechuchwu Ezugwu

Biotechnology Journal International, Page 1-7
DOI: 10.9734/BBJ/2016/21696

Background: Hexalobus crispiflorus root aqueous extract (HC) is used to treat breast cancer in Nigeria.

Aim: To evaluate the antiproliferative effects of HC using Sorghum bicolor seed radicle as test subject.

Materials and Methods: Ten millilitres each of one to seven mg/ml HC in distilled water was poured into 9 cm wide Petri dishes overlaid with cotton wool and filter paper. Twenty viable seeds of Sorghum bicolor (Guinea corn)  were spread on each plate and incubated in the dark. The lengths (mm) of the radicles emerging from the seeds were measured at  48, 72, and 96 h. The control seeds were treated with 10 ml of distilled water containing no extracts. The experiments were carried out in triplicates. The mean radicle lengths (mm) and percentage inhibition were determined. HC was characterized using colour reactions and HPLC-UV-DAD.

Results: Phytochemical investigation revealed the presence of tannins, saponins, glycosides, alkaloids, flavonoids, terpenes and steroids. HPLC spectrum gave nine peaks with caffeic acid and rutin eluting at 5.22 and 7.76 minutes respectively. HC significantly (P < 0.001) inhibited S. bicolor seed growth over a period of 48 – 96 h against the control seeds. At 96 h, HC dose-dependently inhibited seed growth, gave inhibition of 35.41%, 40.67%, 58.24%, 61.34% and 63.68% for seeds treated with 1 mg/ml, 2 mg/ml, 4 mg/ml, 6 mg/ml and 7 mg/ml respectively with IC50 of 3 mg/ml. Methotrexate 0.176 mg/ml as positive control gave inhibition of 99.11% at 96 h.

Conclusion: This result indicates the propensity of HC to inhibit the proliferation of S. bicolor seed radicle, hence provide preliminary evidence for its use to treat breast cancer.


Open Access Original Research Article

Phenotypic Detection of Virulence Markers, Antibiotic and Disinfectant Susceptibility of Bacterial Isolates from Automated Teller Machine Keypads, Computer Keyboards and Mice in Uyo, Nigeria

O. J. Akinjogunla, O. K. Fatunla, E. S. Udofia

Biotechnology Journal International, Page 1-15
DOI: 10.9734/BBJ/2016/27517

The occurrence and virulence markers of bacterial isolates from Automated Teller Machine Keypads (ATM), Computer Keyboards (CK) and Computer Mice (CM) were determined using standard bacteriological methods. The susceptibilities of the isolates to antibiotics and disinfectants (Savlon, Dettol and hydrogen peroxide) were determined by disc diffusion techniques. The bacterial isolates on the 12 CMs from cyber cafés were Staphylococcus aureus 7 (58.3%), Bacillus spp 5 (41.7%), Staphylococcus epidermidis 4 (33.3%), Streptococcus spp 4 (33.3%), Escherichia coli 2 (16.7%), Enterococcus spp 2 (16.7%) and Pseudomonas aureginosa 1(8.3%). S. aureus was the predominant bacterial isolate from CKs and ATM keypads, while Bacillus spp. had the lowest percentage of occurrence. A total of 23 (47.9%) CK swab samples had single bacterial growth, while 25 (52.1%) had mixed bacterial flora. Of the 12 CM from cybercafés, 3/12 (25.0%) showed growth of single bacterial isolate, while 9 /12 (75.0%) had mixed bacterial growth. More than 52% S. aureus, Streptococcus spp and Enterococcus spp were sensitive to ofloxacin and streptomycin, while ≥ 39.1% E. coli were resistant to ceftriaxone and ampicillin. The results showed that between 46/146 (31.5%) and 61/146 (41.8%) of the isolates produced DNase, TNase and amylase. Of the 73/146 (50.0%) lipase producing bacterial isolates, the widest clear zone was observed on the tributyrin agar plate containing S. aureus SA-C2. More than 21.9% bacterial isolates produced capsules, haemolysins, caseinase and gelatinase. Savlon showed the highest antibacterial activities than Dettol and hydrogen peroxide. The highest and lowest inhibitory zones were observed in the plates containing P. aureginosa PA-B2 and S. aureus SA-A6 having the mean ± SD of 14.0 ± 0.5 mm and 6.4 ± 1.2 mm, respectively. The ATM, computer keyboards and mice harboured multidrug resistant pathogenic bacteria that may be transferred to / among the users and Savlon could be first choice of disinfectant for the cleansing / disinfecting of these fomites.

Open Access Original Research Article

Analysis of Gene Expression Associated with Copper Toxicity in White Birch (Betula papyrifera) Populations from a Mining Region

C. L. Djeukam, G. Theriault, P. Michael, K. K. Nkongolo

Biotechnology Journal International, Page 1-10
DOI: 10.9734/BBJ/2016/28425

The Greater Sudbury Region (GSR) is one of the most ecologically disturbed regions of Canada. Recent studies have shown that Betula papyrifera accumulate metals in roots or leaves. The main objectives of the present study were to 1) determine the effects of copper treatment on                           B. papyrifera under controlled conditions and 2) assess the level of expression of genes associated with copper resistance in B. papyrifera populations from metal-contaminated and uncontaminated areas. Significant differences for damage rating were observed among copper dosages after eight days of treatment. There was also a trend of reduced plant growth as the dosage increased. RT- qPCR analysis showed 2x to 25x increase in leaves compared to roots of the expression of the gene for Multi-drug resistance associated protein (MRP4) belonging to the subfamily of ATP-binding cassette (ABC) transporters. A significant upregulation (ranging from 3x to 8 x increase) of the Metallothioneins (MT2B) gene in leaves compared to roots was also observed in three of the five sites studied. There were significant differences in expression of MRP4 and MT2 genes among sites, but no association between metal contamination and gene expression was identified. Likewise, no difference in expression of targeted genes was observed among the copper dosages used in growth chamber experiments.