Trimethylamine Nitrogen Content Research Articles

Kinetics of Total Volatile Basic Nitrogen and Trimethylamine Formation in Stored Rohu (Labeo rohita) Fish

ABSTRACTFish freshness estimation has been mostly studied in terms of total volatile basic nitrogen (TVB-N) and trimethylamine nitrogen (TMA-N) determination and partially addresses the kinetics, which limits its practical utility. In this study, TVB-N and TMA-N content of Rohu stored under limited refrigerated (5 and 0°C) and frozen (−5°C) conditions for 42 days showed an increasing trend, respectively. TVB-N and TMA-N formation in stored Rohu was higher at higher temperature and their initial and final values were found 4.57 ± 0.321, 0.14 ± 0.047 mg/100g and 46.56 ± 0.994, 3.24 ± 0.112 mg/100g, respectively. The volatile formations in Rohu at −5°C were slow, as the frozen storage arrests the enzymatic and microbial activities in comparison to 0°C and above. The kinetics of TVB-N and TMA-N were investigated using zero, first, and nth-order reaction model. First-order kinetics exhibited the best fit model for TVB-N (R2 = 0.98; χ2 = 0.045), whereas TMA-N formation showed nth-order kinetics (n = −0.4608, R2 = 0.96, χ2 = 0.028) as best fit model. The first-order kinetic reaction contributed activation energy of 58.16 kJ/mol for TVB-N and 10.86 kJ/mol for TMA-N. TVB-N and TMA-N formations were influenced by storage temperature and duration as expected. Kinetic parameters were also significantly (P ≤ 0.05) affected by storage temperatures.

Isolation and identification of hyper-ammonia-producing bacteria from commercial fermented skates (Raja kenojei).

Ammonia-producing bacteria were isolated and identified from five commercial fermented skates (A1, A2, A3, A4, and A5). In addition, the pH, ammonia nitrogen, total volatile nitrogen (TVBN), trimethylamine nitrogen (TMAN), and amino nitrogen contents of skate samples were also determined. A total of 88 strains of ammonia-producing bacteria was isolated and seven hyper-ammonia-producing bacteria isolates (A2-2, A2-3, A2-12, A2-18, A2-20, A3-6 and A3-14) were selected based on ammonia nitrogen producing ability. Those isolates were identified as Proteus hauseri (three strains), Providencia rustigianii (three strains), and Kurthia gibsonii. The pH and ammonia nitrogen content in skate samples were ranged from 8.63 to 9.03, and 4.86 to 7.31g/kg, respectively. No significant difference of pH values was observed in skate samples A2, A3, A4 and A5. While, skate samples A3, A4 and A5 showed similar level of TVBN and TMAN content. Skate sample A2 showed the highest amino nitrogen content among all samples, which indicated the highest degree of protein degradation of skate muscle during fermentation. Bivariate cluster analysis showed that skate samples A3, A4, and A5 clustered together at a relatively high level, implying a similar microbial environment during fermentation. The cluster analysis allowed different commercial fermented skates to be clearly differentiated based on the characteristics determined in this study. This study can provide important information for investigating the mechanisms underlying ammonia flavor formation in skate muscle during fermentation.

Effects of Chitosan Coatings Incorporated with Garlic Oil on Quality Characteristics of Shrimp

AbstractThe effect of chitosan‐based edible coatings (CC) incorporated with garlic (Allium sativum) oil at 0.5, 1.0 and 1.5% on shrimp (Parapenaeus longirostris) meat quality was investigated during refrigerated storage (4C) for 11 days. CC application resulted in lower pH (P < 0.05) as compared with the uncoated control. Reductions in aerobic plate counts (APC) up to 2 log units were promoted by CC. Combined effect of garlic oil (GO) and CC was observed. CC resulted in lower APC with GO (P < 0.05) toward the end of storage. CC reduced total volatile base nitrogen and trimethylamine nitrogen contents in comparison with C (P < 0.05), with no significant effect of GO incorporation (P > 0.05). Antioxidant activity of CC was only apparent during the earlier periods of storage, while GO accelerated lipid oxidation as measured by thiobarbituric acid value. CC application with or without GO generally resulted in higher lightness (L*), and lower redness (a*) and yellowness (b*) values. Minimum concentration of GO incorporation (0.5%) into chitosan coating could be useful in extending the shelf life of shrimp meat during refrigerated storage.Practical ApplicationsApplication of edible films and coatings with natural active compounds for enhancing storage stability of food products is a promising active packaging approach. Several biopolymers with the inclusion of antimicrobial and/or antioxidant active agents have been tested in vitro; however, limited studies have been conducted for real food applications of these antimicrobial/antioxidant packaging systems. Chitosan, commercially produced from processing the waste of crustaceans, is an important biopolymer that possesses antimicrobial and antioxidant activity as well as enormous economic value. In the current study, chitosan coatings with the inclusion of garlic oil (GO) were applied to shrimp meat as an alternative natural method to extend shelf life. The obtained results suggest that chitosan coatings with minimum concentration of GO (0.5%) addition could be used as a natural antimicrobial and antioxidant packaging system for preservation of shrimp meat in a fresh state during refrigerated storage.

Influence of Heat Penetration on the Quality of Canned Ribbon Fish (Trichiurus lepturus )

Influence of heat penetration on the quality changes of ribbon fish canned in different media, oil and curry using tin-free steel cans, was assessed. The total process time for ribbon fish in oil pack was 47 min, and curry pack was 68 min, with a lethality value of 12.84 and 10.8 min for oil and curry pack, respectively. The biochemical and sensory analysis of the products was done during a storage period of 5 months. Total volatile base nitrogen and tri-methylamine nitrogen contents were found to be slightly higher but within the acceptable limit at the end of 5-month storage, while thiobarbituric acid and free fatty acid content increased slightly in curry and oil pack at the end of the storage period. The sensory quality of the processed products was rated as good by the taste panel, and the products were in acceptable condition even after storage of 5 months at room temperature (28 ± 2C). Practical Applications The present work on the development of ready-to-serve ribbon fish canned products will help in meeting the present demand in the market; if commercialized, it may be a better method of utilization of this presently underutilized fish to fetch higher value to both fishermen and processor besides providing a new and low cost raw material base to canning industry as well as it forms a means of diversification. It was found that tin-free steel cans are suitable for processing fish products, so they can be used as an alternative to tin and aluminum cans because of their capacity to withstand all the conditions of thermal processing.

COMPARISON OF SUPERCHILLING AND FREEZING ON THE MICROSTRUCTURE, MUSCLE QUALITY AND PROTEIN DENATURATION OF GRASS CARP (CTENOPHARYNGODON IDELLUS )

Quality changes in grass carp during superchilled storage at −2C were evaluated in terms of the microstructure, drip loss, pH value, total volatile basic nitrogen (TVB-N), trimethylamine nitrogen (TMA-N), water holding capacity (WHC), salt soluble protein (SSP) and Ca2+-ATPase activity by comparison with frozen storage at −18C. The microstructure of grass carp muscle was seriously damaged with the exhibition of myofibril shrinkage and breakage under frozen storage. Both TVB-N and TMA-N contents in superchilled grass carp were controlled under the acceptable values within 21 days of storage. Significant lower drip loss and higher WHC under superchilled storage was observed compared with frozen storage. Superchilling attenuated the denaturation of myofibrillar protein and the damage of muscle structure associated with freezing, where extractability of SSP and Ca2+-ATPase activity were reduced. A shelf life of 21 days for superchilled grass carp could be estimated by the overall quality evaluation. PRACTICAL APPLICATIONS Traditional frozen fish can be extended for a long time. However, large amounts of water frozen out lead to serious texture change and drip loss after thawing. This study evaluated the potential of superchilling technology to keep the quality of grass carp with little damage caused by freezing storage. The results confirmed that superchilled grass carp could maintain the fresh quality up to 3 weeks. The present study provided a possible application of superchilling for medium period storage of freshwater fish.

Control of the potential health hazards of smoked fish by gamma irradiation

This study aims to control the presence of Listeria monocytogenes and Vibrio parahaemolyticus and the formation of biogenic amines in cold-smoked salmon by gamma irradiation. Irradiation at doses of 3 and 1kGy inactivated 6.59 and 6.05log cfu/g of L. monocytogenes and V. parahaemolyticus in the inoculated samples, respectively. Furthermore, irradiation of the un-inoculated samples significantly decreased their microbial populations of mesophilic aerobic bacteria, anaerobic bacteria, psychrophilic bacteria, lactic acid bacteria, and molds and yeasts. The Enterobacteriaceae were almost undetectable in samples irradiated at 2kGy dose. The concentrations of biogenic amines significantly decreased in the irradiated samples due to microbial inactivation. However, irradiation of samples had no significant effects on their moisture and salt contents as well as on their pH values, total volatile base nitrogen, and trimethylamine nitrogen contents, but significantly decreased their amounts of phenolic compounds and increased their levels of thiobarbituric acid reactive substances. Moreover, irradiation treatments at doses up to 3kGy showed no significant effect on the sensory acceptability of samples. Therefore, gamma irradiation at dose of 3kGy can be successfully applied to provide significant improvement in the safety of cold smoked salmon with respect to L. monocytogenes, V. parahaemolyticus, and biogenic amines without adverse effects on chemical or sensory quality attributes of the product.

PLEROCERCOID GYMNORHYNCHUS (CESTODA: TRYPANORHYNCHA) IN LEPIDOPUS CAUDATUS: INTERFERENCE ON TMA-N AND TVB-N DETERMINATION

Total Volatile Basic Nitrogen (TVB-N) and Trimethylamine Nitrogen (TMA-N) are the most important freshness indicators in fish. The present report demonstrates that the Gymnorhynchus gigas plerocercoid may interfere on TVBN and TMA-N determination. The study was carried-out on 101 samples: 37 Mp (muscle portions around the parasite), 32 P (larvae of Gymnorynchus gigas extracted from muscle) and 32 Mnp (muscle portions parasite-free), obtained from 10 specimens of Lepidopus caudatus kept at several temperature for different time. The TVB-N and TMA-N contents of each sample were measured using the Conway microdiffusion method. Statistically significant differences (p < 0.05) between Mp and Mnp for TMA-N were found from 24h of storage at 4 and 15°C. No significant differences (p < 0.05) between Mp and Mnp for TVB-N were observed from 48h of storage at 4 and 15°C. TVB-N and TMA-N content was variable in larvae.

Efficacy of lactic acid bacteria in the reduction of trimethylamine-nitrogen and related spoilage derivatives of fresh Indian mackerel fish chunks

Different strains of lactic acid bacteria (LAB) such as Pediococcus acidilactici , Pediococcus pentosaceous , Streptococcus thermophilus , Lactococcus lactis , Lactobacillus plantarum , Lactobacillus acidophilus and Lactobacillus helveticus were procured from the NCL (National Chemical Laboratory), Pune, India. These LAB cells were individually coated on the dressed fresh mackerel fish chunks and incubated at 37°C for two days. Different quality indices such as trimethylamine nitrogen (TMA-N), total volatile basic nitrogen (TVB-N), peroxide value (PV) and free fatty acids (FFA) were estimated for 2 days period. P. acidilactici cell coat reduced 40 mg% of TMA-N, 47.66 mg% of FFA, 97 mg% of PV and 97 mg% of PV when compared with control. The TMA-N content was reduced to 20 mg% by S. thermophilus cell coat on the treated fish when compared with control, while no reduction was observed on TVB-N. Out of the seven LAB tested for TMA-N reduction, Lb. helveticus and Lc. lactis reduced 150 mg% identically. All the LAB grew in increasing and decreasing trends using available carbohydrate present in the fish. For, FFA reduction, Lb. plantarum showed the highest (188%) as compared to P. pentosaceous and P. acidilactici followed by S. thermophilus . P. pentasaceous and P. acidilactici showed the highest PV reduction as 98 and 83 milli equivalent fat/kg of fats, when compared with Lb. plantarum in the control. Out of seven LAB tested for quality indices reduction, Lb. helveticus , Lc. lactis and P. acidilactici were the best LAB to control TMA-N and TVB-N, respectively. Lb. acidophilus, showed the best in the reduction of FFA. Therefore, this study confirms that LAB can be used to preserve freshfish through controlling spoilage bacteria and amines for a short period of time. Inplace of chemical preservatives, LAB may be use to extend the shelf life of fish. Keywords: Lactic acid bacteria, reduction of spoilage indices, trimethylamine nitrogen (TMA-N), total volatile basic nitrogen (TVB-N), peroxide value (PV), free fatty acids (FFA), mackerel chunks

Post-mortem Changes in Farmed Spotted Babylon Snail (Babylonia areolata) During Iced Storage

Post-mortem changes in farmed spotted Babylon snail stored in ice for 7 days were evaluated using nucleotide degradation products, K-value, total volatile base nitrogen (TVB-N), trimethylamine nitrogen (TMA-N), organic acid, free amino acids and biogenic amines. During a 7-day ice storage, K-value, TVB-N, TMA-N and organic acids contents increased with increasing storage time (p < 0.05). Changes in free amino acid, such as aspartic acid, serine, glutamic acid, glycine, arginine and proline were observed throughout the ice storage (p < 0.05), while total free amino acids were found to decrease significantly (p < 0.05). Biogenic amines found in snail muscle during ice storage were tyramine, putrescine, cadaverine, agmatine and histamine. Bacteria counts of snail muscle exceeded 7 log CFU/g, which was considered as the limit for acceptability after 7 days of iced storage. This result initiates the use of ice storage as a preliminary treatment for snails transported from farms.

Post mortem variation in Total Volatile Base Nitrogen and Trimethylamine Nitrogen between Galda (&lt;i&gt;Macrobrachium rosenbergii&lt;/i&gt;) and Bagda (&lt;i&gt;Penaeus monodon&lt;/i&gt;)

Total Volatile Base Nitrgen (TVB-N) and Trimethylamine Nitrogen (TMA-N) of Galda (Macrobrachium rosenbergii) and Bagda (Penaeus monodon) at ambient temperature was compared at Fish Quality Control Laboratory of Fisheries and Marine Resource Technology Discipline, Khulna University, Bangladesh. The TVB-N and TMA-N were determined by using Conway's Micro-diffusion Technique. The nature of biochemical changes was studied up to complete spoilage. The TVB-N contents of Galda and Bagda ranged between 6.65±0.12 mg- N/100g to 8475±0.22 mg-N/100g and 6.72±0.18 mg-N/100g to 91.43±0.49 mg-N/100g. The TMA-N contents of Galda and Bagda ranged between 6.64±0.12 mg-N/100g to 39.38±0.33 mg-N/100g and 6.81±0.17 mg-N/100g to 71.41±0.35 mg-N/100g. A slight higher amount of TVB-N was observed at all stages in Galda as compared to Bagda. TMA-N contents significantly varied between Galda and Bagda (P≤0.05). At all stages of spoilage Bagda showed higher amount of TMA-N. Keywords: Post mortem; TVB-N; TMA-N; Galda and Bagda. DOI: 10.3329/ujzru.v28i0.5278 Univ. j. zool. Rajshahi. Univ. Vol. 28, 2010 pp. 07-10

Effect of Tetracycline Antibiotics on Objective and Subjective Fish Quality Tests

The effect of the antibiotics chlortetracycline and oxytetracycline on certain fish quality tests (viable bacterial count, trimethylamine nitrogen content and organoleptic rating) was evaluated. The formation of trimethylamine by the reduction of trimethylamine oxide in lingcod muscle was suppressed when chlortetracycline and oxytetracycline were used as preservatives in storage tests at 0 and 4 °C. Results of the three tests on antibiotic-treated samples showed poor agreement; reasonable agreement was obtained from the tests on control samples.