Ali Ehsani; Mohammad Sedigh Jasour
Volume 3, Issue 4 , December 2012, , Pages 269-273
Abstract
One of the simplest methods for short-term handling and storage of fish is the refrigeration in combination with dip treatments. This study was conducted to determine the effect of pre-storage α-tocopherol acetate dipping treatments on lipid stability of refrigerated rainbow trout fillets. Trout ...
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One of the simplest methods for short-term handling and storage of fish is the refrigeration in combination with dip treatments. This study was conducted to determine the effect of pre-storage α-tocopherol acetate dipping treatments on lipid stability of refrigerated rainbow trout fillets. Trout fillets were dipped in α-tocopherol acetate solutions (200 and 500 mg kg-1 flesh) and subsequently stored in a refrigerator at 4 ˚C for 12 days. Control samples received no α-tocopherol acetate during dip treatment. At the end of 0, 3, 6, 9 and 12 days of storage, lipid damage analysis of trout fillets was performed. A continuous notable increase (p < 0.05) in peroxide value (PV), thiobarbituric acid (TBA) and free fatty acid (FFA) was observed for all samples throughout the storage period. Although throughout the storage period the lipid hydrolysis (FFA) of fish fillets was not affected by α-tocopherol acetate solutions, successful (p < 0.05) inhibition of lipid oxidation (PV and TBA) in refrigerated trout fillets was possible with dip treatment in α-tocopherol acetate solutions (200 and 500 mg kg-1 flesh). There was no significant (p > 0.05) effect of increasing α-tocopherol acetate concentration on the lipid deterioration of fish fillets. These results indicated that α-tocopherol acetate especially at lower level (200 mg kg-1 flesh) was very effective in retarding the lipid oxidation.
Hassan Hassanzadazar; Ali Ehsani; Karim Mardani; Javad Hesari
Volume 3, Issue 3 , September 2012, , Pages 181-185
Abstract
Lactobacillus strains are a major part of the probiotics, microflora of the intestine and of fermented dairy products, and are found in a variety of environments. The aim of this study was to find out the ability of bile and acid tolerance and antibacterial properties of the twenty eight isolates of ...
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Lactobacillus strains are a major part of the probiotics, microflora of the intestine and of fermented dairy products, and are found in a variety of environments. The aim of this study was to find out the ability of bile and acid tolerance and antibacterial properties of the twenty eight isolates of three group lactobacilli namely Lactobacillus plantarum, Lactobacillus casei and Lactobacillus delbruki. For this purpose Twenty eight different Lactobacillus strains that isolated from Koozeh cheese as a traditional cheese were screened. The acid tolerance test was studied under pH 2.0 and 3.0 with 7.5 as control. The cell count for the acid tolerance test was obtained at an interval of 0, 1, 2 and 3 hours respectively and was pour plated on Man, Rogosa, and Sharpe (MRS) agar to be incubated at 37 °C for 24 hours. All cells were selected for bile tolerance test in MRS broth containing bile concentrations of 0% as control and 0.3% as test. Then cell counts were enumerated after 24 hours of incubation on MRS agar. Results showed twenty seven isolates did not have ability to tolerate acid and bile salts and antimicrobial activity against four indicator bacteria included Eshirichia coli, Listeria monocytogenesis, bacillus cereus, Salmonella entritidis. Only one Isolate namely Lactobacillus casei could tolerate acid and bile salt and had antibacterial activity against of L. monocytogenesis. Therefore we can consider this strain as a native probiotic but extra examinations was required.
Razzaqh Mahmoudi; Hossein Tajik; Ali Ehsani; Payman Zare
Volume 3, Issue 3 , September 2012, , Pages 193-197
Abstract
Increasing incidence of food-borne disease along with its social and economic consequences have led to conducting extensive research in order to produce safer food and develop new antimicrobial agents; among them, extensive use of probiotics and bacteriocins as biological additives is of significant ...
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Increasing incidence of food-borne disease along with its social and economic consequences have led to conducting extensive research in order to produce safer food and develop new antimicrobial agents; among them, extensive use of probiotics and bacteriocins as biological additives is of significant importance. The aim of the present study was to evaluate the interactions (growth behavior and survival) of Listeria monocytogenes and Lactobacillus acidophilus in various stages of production, ripening and storage of Iranian white cheese. Changes in pH values at different stages of cheese ripening, along with changes in organoleptic properties of cheese were also assessed. Compared to other treatments, in the treatment of cheese with probiotic agent without starter, the most significant decrease in Listeria monocytogenes count at the end of ripening stage was observed (3.16 Log per gram cheese compared with the control group) (p < 0.05). Survival of probiotic bacteria in control samples of cheese were significantly higher when compared to cheese sample contaminated with Listeria (p < 0.05). White probiotic cheese with starter had the highest of sensory acceptability (p < 0.05). Listeria Monocytogenes count decreased during ripening period of probiotic white cheese but the bacteria survived in probiotic white cheese. Lactobacillus acidophilus count decreased during ripening period of white cheese but it did not lower to less than 106 CFU per g at the end of ripening and storage periods.
