Food Biotechnology
Soheyl Reyhani Poul; Sakineh Yeganeh; Reza Safari
Abstract
IntroductionOne of the synthetic and harmful preservatives used in sausage formulation is sodium nitrite. This compound helps to increase the shelf life and marketability of meat products by preventing the growth of anaerobic bacteria, especially clostridium, exerting an antioxidant effect, stabilizing ...
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IntroductionOne of the synthetic and harmful preservatives used in sausage formulation is sodium nitrite. This compound helps to increase the shelf life and marketability of meat products by preventing the growth of anaerobic bacteria, especially clostridium, exerting an antioxidant effect, stabilizing the red color of meat and improving the taste. Despite these benefits, sodium nitrite is very dangerous for health and it can cause malignant diseases. For this reason, it is necessary to replace this substance using a natural preservative. Pigments extracted from aquatics such as astaxanthin due to having antioxidant activity, antimicrobial properties and pink color may be a good substitute for sodium nitrite. However, these pigments must be nanoencapsulated at first due to their sensitivity to food processing conditions, including high temperatures. The aim of the current research at the first was to extract astaxanthin from Haematococcus pluvialis microalgae using the acid-acetone method and pigment nanoencapsulation using maltodextrin-sodium caseinate combined coating. Then, sodium nitrite in the sausage formulation was replaced by the carrier nanocapsules with different proportions and oxidative and microbial spoilage tests, color and sensory evaluations were performed for different treatments. Materials and MethodsAt first, astaxanthin pigment was extracted from Haematococcus pluvialis using the acid-acetone technique. Then, the extracted pigment was nanoencapsulated using maltodextrin-sodium caseinate combined coating and the resulting (carrier) nanocapsules in the form of treatments A (120 mg/kg sodium nitrite), B (120 mg/kg nanocapsules carrying astaxanthin), C (90 mg/kg sodium nitrite+30 mg/kg nanocapsules carrying astaxanthin), D (60 mg/kg sodium nitrite+60 mg/kg nanocapsules carrying astaxanthin) and E (30 mg/kg sodium nitrite+90 mg/kg nanocapsules carrying astaxanthin) were replaced sodium nitrite in the sausage formulation. These treatments were evaluated in terms of oxidative and microbial spoilage, color indices and sensory properties during 28 days of storage at refrigerator along with the control (without sodium nitrite and carrier nanocapsules). This research was conducted in a completely randomized design. Data were analyzed by one-way analysis of variance and the difference between the means was evaluated by Duncan's test at 95% confidence level. Results and DiscussionAccording to the results, the lowest levels of thiobarbituric acid and peroxide value during the storage period were related to treatments B, E and D (p>0.05). Treatments A and C had no significant difference in terms of thiobarbituric acid and peroxide value until day 14 (p>0.05), but with increasing storage time, this difference became significant and treatment A showed higher values (p<0.05). The results of this section showed that the power of astaxanthin in controlling oxidative spoilage is significantly greater than sodium nitrite, and if the purpose is only to control this type of spoilage, there is no need to replace or use sodium nitrite. The results also showed that in terms of controlling microbial spoilage, sodium nitrite has more power than nanocapsules carrying astaxanthin. So that, the lowest amount of total volatile basic nitrogen (TVB-N) and the most standardized pH were related to treatments A, C and D (p>0.05) during the storage period (p<0.05). Treatments B and E (p>0.05) were ranked next (p<0.05) in terms of the two mentioned indicators. The results of this section showed that if sodium nitrite reduced from 120 mg/kg to 60 mg/kg and replaced by nanocapsules carrying astaxanthin in the sausage formulation, the resulting product has the same antimicrobial power as the product containing 120 mg/kg sodium nitrite. Evaluation of the color and sensory properties of treatments showed that A, C and D treatments are at a higher level than B, E (treatments) and control in terms of color indices and general acceptance (p<0.05). The comparison of the color indices and sensory properties of the treatments on days 0 and 28 of storage at refrigerator showed that the color and sensory indices remained constant in the formulated treatments, unlike the control. Conclusion Nanocapsules carrying astaxanthin with maltodextrin-sodium caseinate combined coating as a natural product with many properties in health, control and prevention of various diseases, have a high efficiency to replace the sodium nitrite in sausage formulation. So that, if 30 to 60 mg/kg of the permissible limit of 120 mg/kg of sodium nitrite in the sausage formulation is replaced by nanocapsules carrying astaxanthin, the resulting product will be similar to the product containing 120 mg/kg of sodium nitrite in terms of shelf life, resistance to oxidative and microbial spoilage, color indices and sensory properties.
Food Biotechnology
Soheyl Reyhani Poul; Sakineh Yeganeh; Zeynab Raftani Amiri
Abstract
Introduction Since heat treatments and special standards are not used in the production of traditional (homemade) tomato paste, fungal and bacterial spoilage in the product occurs extensively during storage in the refrigerator (4°C). Astaxanthin extracted from aquatics has antimicrobial activity ...
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Introduction Since heat treatments and special standards are not used in the production of traditional (homemade) tomato paste, fungal and bacterial spoilage in the product occurs extensively during storage in the refrigerator (4°C). Astaxanthin extracted from aquatics has antimicrobial activity and color similar to tomato and can probably be effective in preventing spoilage of tomato paste. In addition, astaxanthin has other properties in the field of preventing and controlling diseases and maintaining human health, which justifies its use in food formulations as an enrichment. Since heat, enzyme, acid, etc. treatments are practiced during the production of tomato paste, these factors may change the structure and thus the function of astaxanthin. For this reason, astaxanthin nanoencapsulation is necessary for its use in tomato paste formulation. Materials and Methods In this research, first, astaxanthin was extracted from Haematococcus pluvialis microalgae using the acid-acetone combined method. Then, this pigment was nanoencapsulated using maltodextrin-sodium caseinate coating and the resulting nanocapsules were used together with the pure form of astaxanthin in the formulation of tomato paste. The research treatments were control, tomato pastes containing 3 and 6% astaxanthin (A and B, respectively) and also 3, 6 and 9% nanocapsules carrying the pigment (C, D and E, respectively). These treatments were kept at refrigerator for 28 days and were evaluated (on days 0, 7, 14, 21 and 28) in terms of the total number of fungi, Howard's number (HMC), pH, fungal flora, total bacteria count, amount of lactic acid bacteria and sensory properties. This research was conducted in a completely randomized design. Data were analyzed by One-way Anova and the difference between the means was evaluated by Duncan's test at 95% confidence level. Results and Discussion The results showed that the fungi proliferation, total count and lactic acid bacteria were slower than the control during the storage period in the treatments containing astaxanthin and its carrying nanocapsules, and the minimum number of the mentioned microorganisms and Howard's number were related to treatments D and E (p>0.05). Treatments C, B and A were ranked next in this respect (p<0.05). The number of fungi in two treatments D and E from day 0 to 28 varied from 128 to 332 cfu/gr. Also, the Howard number of these treatments was recorded from 18 to 34% in the mentioned time period. However, these two indices in the control ranged from 121 to 792 cfu/gr and 18 to 91%, respectively, during the storage period. The count of total bacteria and the amount of lactic acid bacteria in the control on day 28 were equal to 8.9 cfu/gr and 311 mg/kg, respectively, but these two values were recorded in the E and D treatments on the same day, about 4.8 cfu/gr and 110 mg/kg, respectively. Counting the total number of fungi, bacterias and also Howard's number in control and other treatments showed that the effect of nanocapsules carrying astaxanthin on microbial growth and proliferation is significantly greater than pure astaxanthin (p<0.05). The pH of the treatments varied from 3.9 to 5.8 during the storage period and the most standardized pH (3.9-4.4) was recorded in C, D and E (p>0.05) treatments (p<0.05). The pH of two treatments A and B (p>0.05) was higher than the three mentioned treatments and lower than the control (p<0.05). This finding showed that nanocapsules carrying astaxanthin have a greater effect on controlling the pH of tomato paste than pure astaxanthin during storage at refrigerator (p<0.05). The identification of the fungal flora of the treatments on the 28th day confirmed that two genus of Penicillium and Aspergillus form the main flora of the product. The results of the sensory evaluation of the treatments on day 0 showed that adding astaxanthin and its carrier nanocapsules does not change the color, aroma, taste and texture indicators (subsequently the general acceptance) of tomato paste (p>0.05). On the 28th day, the mentioned sensory indices only in the two treatments D and E were not significantly different from the 0 day, but they changed negatively in the other treatments (p<0.05). Conclusion According to the findings of the present research, astaxanthin extracted from Haematococcus pluvialis microalgae has the ability to inhibit fungal and bacterial spoilage and stabilize the sensory properties of tomato paste stored at refrigerator. This properties were improved by adding nanoencapsulated pigment using maltodextrin-sodium caseinate combined coating. Since there were no significant differences between the two treatments containing 6% and 9% of nanocapsules carrying astaxanthin (D and E) in terms of quality indices and microbial spoilage, therefore, the treatment containing 6% nanocapsules is introduced as the optimal treatment.
Soheyl Reyhani Poul; Sakineh Yeganeh; Reza Safari
Abstract
[1]Introduction: Nisin is one of the antimicrobial substances that is used today as a preservative in various foodstuffs. It is a bacteriocin comprised of 34 amino acids and a molecular weight of 3.5 Da. With all the benefits of nisin, there are barriers to its use in dairy and protein rich products. ...
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[1]Introduction: Nisin is one of the antimicrobial substances that is used today as a preservative in various foodstuffs. It is a bacteriocin comprised of 34 amino acids and a molecular weight of 3.5 Da. With all the benefits of nisin, there are barriers to its use in dairy and protein rich products. One of these barriers is the combination of nisin with fats, proteins and sugars and the consequent reduction of its antibacterial activity. In the food science and industry, the use of the technique of encapsulation and production of liposome is the best possible solution in such cases. Also, by adding an antimicrobial agent such as chitosan to the coating of nanoliposomes, the antibacterial activity of the product may be increased. The aim of the present research was to produce nanoliposomes carrying nisin with (and without) chitosan coating and to evaluate the physical and antibacterial properties against two gram-positive bacteria, Bacillus cereus and Staphylococcus aureus. Materials and Methods: In this study, four treatments of nanoliposomes carrying nisin (NN), nanoliposomes carrying nisin coated with chitosan 0.05% ((NN-CH (0.05)), nanoliposomes carrying nisin coated with chitosan 0.1% (NN-CH (0.1)) and nanoliposomes carrying nisin coated with chitosan 0.5% (NN-CH (0.5)) were prepared and examined in terms of physical properties (average particle size, particle dispersity index, zeta potential and encapsulation efficiency) and antibacterial activity (against two gram-positive bacteria, Bacillus cereus and Staphylococcus aureus with two diffusion methods in agar medium and microdilution test). This research was conducted in a completely randomized design and SPSS and EXCEL softwares were used for statistical analysis and drawing of diagram, respectively. Data were analyzed by one-way analysis of variance and the difference between the means was evaluated by Duncan's test at 95% confidence level. Results and Discussion: The results showed that the average particle sizein different treatments with each other are significantly different (P<0.05) and vary from about 110 to 327nm; Also as the amount of chitosan in the coating increased, the particle size increased (P<0.05). This indicates the successful binding of chitosan to the surface of the nanoliposome, which results in the formation of a layer around the nanoliposome and an increase in particle size. Particle dispersity index was recorded less than 0.3 in all treatments and was not related to the amount of chitosan in the coating. With increasing the amount of chitosan in the coating of nanoliposomes, zeta potential increased significantly (P<0.05). This index changed from -55.34 in NN treatment to 53.14 mV in NN-CH (0.5) treatment. In fact, chitosan as a cationic polysaccharide changes the potential to positive values. As the amount of chitosan in coating of nanoliposomes increased, the encapsulation efficiency increased significantly in the treatments (P<0.05); this index increased from 32.19% in NN treatment to 75.14% in NN-CH (0.5) treatment. The results of the antibacterial activity of nisin in two methods of diffusion in agar medium and microdilution test showed that its antibacterial activity increased with nanoencapsulation of nisin with (and without) chitosan coating (p<0.05). Also, with the increase in chitosan concentration, the antibacterial activity of carrier nanoliposomes increased and the highest antibacterial activity was recorded in NN-CH (0.5) treatment (p<0.05). The diameter of the non-growth halo of Bacillus cereus against the research treatments (with five concentrations of 2.5 to 25 μg/ml) varied from about 4.5 to 17.5 mm. This amount for Staphylococcus aureus was recorded from 2.1 to 26.5 mm. By increasing the concentration of nisin and carrier nanoliposomes, the diameter of the halo of non-growth of both bacteria increased significantly (p<0.05). But an exception was recorded in this case; The diameter of the non-growth halo for Staphylococcus aureus in two concentrations of 2.5 and 5 μg/ml of treatments was the same and had no significant difference (p>0.05). The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of the examined treatments for Bacillus cereus were in the range of 100 to 400 and 200 to 500 μg/ml, respectively. These two concentrations for Staphylococcus aureus were recorded as 50 to 200 and 100 to 400 μg/ml respectively. Based on the values of diameter of non-growth halo, MIC and MBC it can be claimed that Bacillus cereus is more resistant to the examined treatments than Staphylococcus aureus.Nanoencapsulation of nisin in the form of carrier nanoliposomes with chitosan coating is a suitable solution to improve its physical and antibacterial properties. In such a way that by increasing the concentration of chitosan in the coating, both of the aforementioned properties improved significantly. Nanoliposomes carrying nisin with (and without) chitosan coating have the ability to inhibit the growth and killing Bacillus cereus and Staphylococcus aureus bacteria. The antibacterial activity increases with the increase in nisin and carrier nanoliposomes concentrations. The value of non-growth halo, minimum inhibitory concentration and minimum bactericidal concentration confirm that Bacillus cereus is more resistant to nisin and its carrier nanoliposomes than Staphylococcus aureus.
Food Technology
Soheyl Reyhani Poul; Sakineh Yeganeh
Abstract
Introduction: Shrimps are highly sensitive to oxidation at refrigerator temperature. On the other hand, storage of shrimp in freezing conditions leads to a decrease in product quality after thawing. It should be noted that shrimp oxidation also occurs in freezing conditions, but the oxidation rate in ...
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Introduction: Shrimps are highly sensitive to oxidation at refrigerator temperature. On the other hand, storage of shrimp in freezing conditions leads to a decrease in product quality after thawing. It should be noted that shrimp oxidation also occurs in freezing conditions, but the oxidation rate in these conditions is much slower than storage in refrigerated conditions. Therefore, it seems necessary to use a method that can control the oxidation of shrimp in both freezing and refrigerating conditions. The aim of this study was to evaluate the feasibility of controlling shrimp oxidation (at refrigerator temperature) using whey protein coating containing ascorbic acid or α-tocopherol, and to compare the efficacy of these antioxidants (in combination with whey protein). Materials and Methods: In order to advance the purpose of the research, shrimp fillets were stored in four treatments, including treatments No. 1 (control), 2 (shrimp fillet coated by whey protein), 3 (shrimp fillet coated by whey protein + ascorbic acid) and 4 (shrimp fillet coated by whey protein+ α-tocopherol) at refrigerator temperature for 9 days. In order to evaluate the oxidation intensity and also the stability of the treatments against oxidative damage, peroxide indices, free fatty acids, anisidine and thiobarbituric acid of the treatments were determined on days 0, 3, 6 and 9. This study was implemented in form of completely randomized design and data were analyzed by one-way ANOVA. Significant differences among means were tested by Duncan's test at 95 confidence level. Results and Discussion: The results showed that whey protein alone (treatment 2) as shrimp coating can partially control the oxidation process of fillet fats compared to control. But when whey protein was combined with ascorbic acid (treatment 3) and α-tocopherol (treatment 4), the coatings' strength against oxidative deterioration significantly increased (p<0.05). According to our findings, during the storage period, the lowest amount of peroxide, free fatty acids, anisidine and thiobarbituric acid indices were related to treatment 3 (p<0.05). During the storage period, all the mentioned indicators (in all treatments) had an increasing trend, but the slope of this trend was different and the lowest slope was related to treatment 3. Comparison of fresh shrimp fillet fatty acid profile with fatty acid profile of treatments at day 9 showed that the whey protein coating combined with ascorbic acid (treatment 3) had the most protective effect on the structure of fatty acids. Overall, according to the results of the present study, it can be claimed that whey protein- ascorbic acid coating is more effective than whey protein-α-tocopherol coating to increase the oxidative stability of shrimp fillet. Therefore, the ascorbic acid is more efficacious than α -tocopherol (in combination with whey protein) in controlling the oxidation of shrimp fillets.
Keivan Ali Asgari; Sakineh Yeganeh; Seyed Ali Jafarpour; Reza Safari
Abstract
Introduction: Nowadays, use of new processing method is important for converting by-products into more marketable and acceptable forms to achieve a better utilization. Sea food processing generate protein rich by-products that their quantity depends on processing method. One of the methods for effective ...
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Introduction: Nowadays, use of new processing method is important for converting by-products into more marketable and acceptable forms to achieve a better utilization. Sea food processing generate protein rich by-products that their quantity depends on processing method. One of the methods for effective protein recovery from this protein rich by-product is preparation of protein hydrolysate through enzymatic, autolytic and chemical hydrolysis. Enzymatic hydrolysis is widely employed to improve the functional and nutritional properties of the fish byproducts. Hydrolysis may be conducted as a method of separating soluble nitrogenous compounds from insoluble particles and fish oil, and offers good predictability of the products. So nitrogen recovery assay can determine enzyme efficiency in separation of soluble protein from insoluble protein. Different factors (Enzyme level, temperature, pH, enzyme to substrate ratio) can effect on the hydrolysis degree, nitrogen recovery and functional properties of protein hydrolysate, so optimization method is used for obtaining the best condition. RSM is a statistical model frequently used for the optimization of complex systems and uses quantitative data from an appropriate experimental design to determine and simultaneously solve multivariate problems. Based on the experimental data, RSM could tell us the optimum conditions to obtain the desired responses, as well as the mathematical model in explaining the relationship between the experimental variables and its responses. Alcalase has great ability to solubilize fish protein and is nonspecific, with an optimum temperature that ranged from 50 to 70°C. It has optimal pH range at the value of 8 to 10 that could reduce the risk of microbial contaminations. Moreover, it has been reported that produced protein hydrolysate by Alcalase had less bitter principles compared to those prepared with papain. Furthermore Alcalase has been documented to be a better candidate for hydrolyzing fish proteins based on enzyme cost per activity.
The Cuttlefish (Sepia offıcinalis) can be found in the south water of Iran including Persian Gulf and Oman Sea and their catch has been recorded about 5102 t according to FAO Statistic. This species has been considered for exporting to other country. During Cuttlefish processing, 30-35 % byproducts including head, arms and viscera are generated that can be invaluable products and environmental pollution while it is protein rich source. The objective of this study was to optimize nitrogen recovery in the enzymatic hydrolysis of head and arms of cuttlefish (Sepia pharaonis) using Alcalase.
Materials and methods: Response surface methodology (RSM) based on Box-Behnken was employed to investigate the effects of different operating conditions including temperature (45, 50 and 55˚C), pH (7.5, 8 and 8.5) and alcalase enzyme to substrate ratio (1, 1.5 and 2) on the nitrogen recovery as a surface response. Referring to the R2 of 0.96 for nitrogen recovery, the mathematical model showed acceptable fitness with the experimental data, which indicated that major part of the variability within the range of values studied could be explained by the model.After obtaining optimum condition for nitrogen recovery, freeze dried protein powder was produced by optimized condition and analyzed for amino acid composition, chemical score of cuttlefish protein hydrolysate and protein efficiency ratio.
Results & Discussion: The obtained results showed the interactive effect of temperature and enzyme to substrate ratio was not significant (P> 0.05) but the interaction effect of enzyme to substrate ratio and pH and the interaction effect of temperature and pH was significant (P
