Total Volatile Basic Nitrogen Production Research Articles

Effects of CO2 on the physicochemical, microbial, and sensory properties of pork patties packaged under optimized O2 levels

The storage quality characteristics of fresh pork patties were investigated under 80% O2 modified atmosphere packaging (MAP80:20 = 80% O2/20% CO2) and 40% O2 MAP with various CO2 levels (MAP40:20 = 40% O2/20% CO2/40% N2; MAP40:40 = 40% O2/40% CO2/20% N2; MAP40:60 = 40% O2/60% CO2). Packaged patties were stored for 16 days at 4 °C to monitor their physicochemical (pH, instrumental color, oxidative stability, and fatty acid profile), microbial, and sensorial changes. Results suggested that decreasing O2 levels from 80% to 40% significantly inhibited the lipid oxidation of patties but led to a lower (P < 0.05) color stability. Elevating CO2 levels from 20% to 60% in combination with 40% O2 significantly suppressed bacterial growth and total volatile basic nitrogen production, and thus rendered patties with a better sensory quality and a similar meat color to 80% O2. However, increased CO2 levels promoted lipid oxidation through reducing the antioxidant capacity of patties, which was attributed to a CO2-induced reduction in superoxide dismutase and glutathione peroxidase activities during storage rather than a pH reduction or changes in fatty acid composition. Overall, 40% O2/40% CO2/20% N2 is a realistic alternative for pork patties to improve meat quality and extend the shelf-life to over 16 days.

Photodynamic inactivation of spoilers Pseudomonas lundensis and Brochothrix thermosphacta by food-grade curcumin and its application on ground beef

This study evaluated the bactericidal effects of curcumin-mediated photodynamic inactivation (PDI) combined with citric acid on meat spoilage bacteria, and their preservative effects of refrigerated beef. After treatment of PDI (60 μM curcumin and 33.01 J/cm2) combined with 0.5 mg/mL citric acid, the populations of Pseudomonas lundensis and Brochothrix thermosphacta in PBS solution were reduced by 3.07 and 6.14 log CFU/mL, respectively, compared to 0.31 and 1.39 log CFU/mL for PDI. Combined treatment enhanced reactive oxygen species (ROS) activity in the two strains, and damaged their cell morphology, especially B. thermosphacta. With increasing curcumin concentration, the growth rate of spoilage bacteria was significantly inhibited (P < 0.05), and the changes of dominant spoilage species in bacterial community were retarded in aerobic-packaged and vacuum-packaged ground beef at 4 °C. Compared to the control, trichloroacetic acid-soluble peptide and total volatile basic nitrogen production were greatly restrained, and changes in pH values and brown color were apparently reduced for the combined treatment, which could extend the shelf life by 2 days. These results suggested the synergistic potency of PDI combined with citric acid against spoilage bacteria in meat products.Industrial relevance: The proliferation and spread of some psychrotrophs are major causes of quality deterioration and cross-contamination in fresh meat during cold chain. This study revealed that photosensitized curcumin combined with citric acid significantly decreased the survival of two psychrotrophic spoilage bacteria and extended the shelf-life of ground beef. Thus, curcumin-based PDI provides a new insight for the development of efficient and economic preservation in the meat processing industry.

Preparation of functional degradable antibacterial film and application in fresh-keeping of grass carp

To explore new, green and effective low-temperature preservation technology, β -cyclodextrin ( β -CD) embedded Elsholtzia essential oil (EEO) was used as an antibacterial agent, and polybutylene adipate- co -terephthalate (PBAT) and polylactic acid (PLA) were used as the base material to extend grass carp fillets shelf life. Active antibacterial PBAT/PLA, PBAT/PLA-EEO, and PBAT/PLA- β -CD els films were prepared using a casting film-forming process. The changes in total viable count (TVC), pH, total volatile basic nitrogen (TVB-N), and thiobarbituric acid-reactive substances values of grass carp fillets during storage at 4 °C were studied. The results showed that, compared with the PBAT/PLA film, the oxygen transmission rate of PBAT/PLA- β -CD els decreased from 868.02 to 566.80 cm 3 m 2 •24 h•0.1 MPa −1 . During preservation, compared with the PBAT/PLA film, the PBAT/PLA- β -CD els film effectively lowered TVC and delayed TVB-N production. The results revealed that PBAT/PLA- β -CD els film with β -CD-embedded EEO positively affected grass carp quality maintenance and extended its shelf life. Overview of the experiments. PLA pellets and PBAT pellets were blended with β -CD els . After the modified resins were prepared using a single-screw plastic extrusion device to obtain active films. Then apply it to the preservation of grass carp. • We explored a new, green, and effective low-temperature preservation technology. • β -cyclodextrin-embedded Elsholtzia essential oil was used as an antibacterial agent. • Polybutylene adipate- co -terephthalate and polylactic acid were used as a base. • Fresh-keeping was assessed in grass carp fillets preserved in β -CD-embedded EEO. • The film with positively affected grass carp quality and extended its shelf life.

Inactivation of microbial loads and retardation of quality loss in Asian hard clam (Meretrix lusoria) using high-hydrostatic-pressure processing during refrigerated storage

The effects of high pressure processing (HPP) at 200, 300, 400, 500, and 600 MPa for 3 min on physicochemical quality and inactivation of microbial loads of Asian hard clam (Meretrix lusoria) were evaluated. In addition, the retardation effects in microbial growth and quality loss of pressurized hard clams stored at 4 °C were investigated. Results showed that the expanding rate, moisture content, shucking ratio, pH, L* (lightness), and W (whiteness) of clam meat increased significantly with the increase in pressure, but a* (redness) and b* (yellowness) values decreased. With the increase in pressure, the levels of aerobic plate count (APC), psychrotrophic bacteria count (PBC), coliform, and Vibrio parahaemolyticus in clam meat significantly decreased. Furthermore, HPP with a pressure of >400 MPa on clam samples significantly delayed the increase in APC (by 6–9 days within Taiwan's regulation standard limit) and PBC during storage at 4 °C. However, the samples pressurized more than 300 MPa had significantly lower levels of total volatile basic nitrogen (TVBN) than control samples during storage. Overall, the results indicated that pressurization at least 400 MPa for 3 min on Asian hard clam were able to reach the highest expanding rate and moisture content, and 100 % shucking, while it can reduce the coliform, and V. parahaemolyticus to a non-detectable level. In addition, HPP conditions of ≥400 MPa for 3 min significantly extended the shelf-life of hard clam during refrigerated storage. Therefore, HPP is a useful technique to preserve Asian hard clam meats due to its ability to reduce bacterial load and retard TVBN production.

Application of antimicrobial peptide mytichitin-CB in pork preservation during cold storage

The antibacterial peptide mytichitin-CB has been highly expressed in Pichia pastoris. In this study, we aim to investigate its potential for application in pork preservation. P. pastoris-derived mytichitin-CB exhibited broad and potent antibacterial activity against four common foodborne bacterial pathogens and two food spoilage bacteria of Pseudomonas spp. with low minimal inhibition concentrations of 0.23–1.24 μg/mL. Mytichitin-CB effectively suppressed the growth of the microflora and significantly reduced the increases in pH, drip loss, total volatile basic nitrogen (TVB-N), and thiobarbituric acid reactive substances (TBARS) of fresh pork during storage at 4 °C. Consequently, the fresh pork maintained its desirable sensory properties. Mytichitin-CB could also effectively inhibit the growth of Staphylococcus aureus, Escherichia coli O157, and Pseudomonas fluorescens in a pork spoilage model. Combining mytichitin-CB with chitosan and nisin at the optimal proportion further enhanced the antibacterial activity and effects of food preservation on fresh pork, as evidenced by improved sensory properties, lowered drip loss and TVB-N production, and reduced change in pH during storage. However, combining these three agents failed to further increase antioxidant activity against lipid oxidation. Overall, the combination of 4 mg/L of mytichitin-CB with 10 g/L of chitosan incorporated with 300 mg/L of nisin exhibited the best performance in fresh pork preservation. The combined findings suggest that treatment with mytichitin-CB alone or in combination with chitosan and nisin has considerable potential in the preservation of fresh meat products to extend the shelf life and assure the quality and safety of meat.

AprD is important for extracellular proteolytic activity, physicochemical properties and spoilage potential in meat-borne Pseudomonas fragi

Pseudomonas fragi is a common spoilage agent of aerobically stored chilled meat. Its extracellular protease contributes to the spoilage of meat. AprD is considered an important component involved in the secretion of an alkaline extracellular protease in Pseudomonas. Thus, it is very possible that aprD plays an important role in spoilage regulation in P. fragi. The objective of the present study was to investigate the effects of aprD on bacterial proteolytic activity, biological properties, and in situ spoilage potential, as well as the mode of action of the protease AprA in spoiled meat. The results showed that aprD is important for surface-associated behaviors, as an ΔaprD mutant altered autoaggregation, swimming motility, and biofilm formation. aprD also contributes to the spoilage activities of P. fragi by affecting extracellular protease activity, total volatile basic nitrogen production, pH and the sensory traits of meat samples. These results highlight the presence of aprD-mediated regulation profiles in P. fragi and may provide new perspectives on chilled meat preservation.

Effect of antioxidant extracted from bamboo leaves on the quality of box-packaged sturgeon fillets stored at 4 °C

The effect of antioxidant extracted from bamboo leaves (AOB) on the quality of sturgeon fillets during chilled storage was examined via three parameters: total volatile basic nitrogen (TVB-N), pH and bacterial community composition. The samples treated with 0.05% (w/v) AOB exhibited the best quality, as evidenced by retarding both pH changes and the production of TVB-N. Pseudomonas and Aeromonas were the dominant indigenous bacteria present in fresh sturgeon fillets, whereas the presence of Janthinobacterium and Pedobacter increased gradually throughout the storage process. A significant (P &lt; 0.05) positive correlation was observed between the pH, TVB-N and two bacterial groups, Pseudomonas and Pedobacter. Based on the TVB-N assessment, the fillets began to decompose at the ninth day in the control samples and the twelfth day in the 0.05% AOB-treated samples. The relative abundance of Pseudomonas, Janthinobacterium and Pedobacter in the 0.05% AOB treatment group was lower than in the control group. Therefore, our results showed that treatment with 0.05% AOB improved the quality of fillets during the box-packaged storage.

Effect of Chinese Rice Wine on the Endogenous Protease Activity, Myofibrillar Degradation, and Quality Characteristics in Topmouth Culter (Culter alburnus)

ABSTRACT The aim of this study was to investigate the influence of rice wine (Jinbiao, Yinbiao, Wunianchen, Nv’erhong) on the endogenous protease activity, myofibrillar degradation, and quality characteristics of topmouth culter (Culter alburnus). Rice wine had a pH of 4.3 and calcium ions ranging from 89.30 to 123.70 μg/mL. Nv’erhong rice wine had the highest total phenolic content of 583.38 μg gallic acid equivalent (GAE)/mL, while Wunianchen rice wine (WNC) showed the strongest total antioxidant capacity of 87.29 U/mL. WNC presented the optimum inhibitory effect on endogenous proteases of calpain and cathepsin B, D, and L, delaying the degradation of myosin heavy chain and α-actinin, which are important to muscle softening. The quality characteristic evaluation indicated that the addition of rice wine could maintain the hardness and chewiness, increase the springiness of the fish fillet, as well as inhibit the total volatile basic nitrogen production. These results suggest that rice wine had effects of inhibiting endogenous proteases, delaying myofibrillar degradation, and maintaining the sensory quality of topmouth culter.

Effects of Antimelanosis Agents on Quality and Shelf-life of Tropical Brackish Water Shrimp (Penaeus notialis) during Storage at 0°C and 7°C

ABSTRACTTropical brackish water shrimp (Penaeus notialis) is an important commercial species in West Africa. Sulfiting agents, which may pose a risk to human health, are still intensively used to prevent melanosis in P. notialis. In this study, the effectiveness of a generally recognized as safe (GRAS) chemical product (4-hexylresorcinol (4-HR)) and a plant phenolic compound (catechin) in preventing shrimp spoilage was assessed. Freshly caught shrimps were treated with three 4-HR concentrations (0.005%, 0.01%, and 0.1%) and three catechin concentrations (0.05%, 0.1%, and 0.2%) and stored at 0°C and 7°C. Shrimp samples treated with sodium metabisulphite (1.25%) and untreated samples were used as positive and negative controls, respectively. At appropriate time intervals, samples were taken for microbiological, chemical, and sensory analysis. Total volatile basic nitrogen (TVBN) data were used to validate a previously developed model that predicts TVBN production in P. notialis. At 0°C, 4-HR, even at the lowest concentration, significantly (P < .05) inhibited melanosis formation. Catechin (0.2%) significantly lowered melanosis formation in P. notialis during the first two days of storage at 7°C. At 0°C, 4-HR treatments extended shrimp sensory rejection time by one week; while at 7°C, only a slight (<1 day) prolongation of sensory rejection time was noticed.

Effect of modified atmosphere and vacuum packaging on TVB-N production of rainbow trout (Oncorhynchus mykiss) and carp (Cyprinus carpio) cuts

The aim of our research was to examine the influence of packaging in modified atmosphere and vacuum on the total volatile basic nitrogen (TVB-N) content in muscle of rainbow trout (Oncorhynchus mykiss) and common carp (Cyprinus carpio), as well as to determine the most suitable gas mixtures for packing of these freshwater species. Three sample groups of trout and carp cuts were investigated. The two groups were packaged in modified atmosphere with different gas ratios: 90%CO2+10%N2 (MAP 1) and 60%CO2+40%N2 (MAP 2), whereas the third group of fish cuts were vacuum packaged. During trials, the trout and carp cuts were stored in refrigerator at 3°C±0.5°C. Determination of TVB-N was performed on 1, 4, 7, 9, 12 and 14 days of storage. The obtained results indicate that the investigated mixtures of gases and vacuum had a significant influence on the values of TVB-N in trout and carp cuts. The lowest increase in TVB-N was established in trout and carp cuts packaged in MAP 1, whereas the highest increase was established in vacuum packaged cuts. Based on the obtained results, it can be concluded that the gas mixture consisting of 90% CO2 and 10% N2 was the most suitable for packaging of fresh trout and carp cuts in terms of TVB-N value.

Anthocyanins Based Indicator Sensor for Intelligent Packaging Application

Natural dyes extracted from the flower of rose and red cabbage were immobilized on filter paper as carrier to prepare a colorimetric sensor for application in intelligent packaging. Indicator sensor was based on natural flavonoids (anthocyanins) extracted from red cabbage and rose whose colour changed from red to green with increase in pH. On characterization of extracts by UV–Vis spectrophotometer, absorption maximum of 530 nm was observed which is ascribed to anthocyanin present in two extracts. The characteristics of sensor including response time, reproducibility, reversibility, stability towards light and the storage stability were also studied. Sensors were also kept in atmosphere of ammonia simulating total volatile basic nitrogen production which changed its colour from red to green with increase in pH. Since pH value of flesh foods concerns their freshness, the indicator sensor is expected to provide a convenient, non-destructive and visual method for flesh food spoilage in storage condition and also for the prediction of shelf life.

Regulation of Spoilage-Related Activities of S hewanella putrefaciens and S hewanella baltica by an Autoinducer-2 Analogue, (Z)-5-(Bromomethylene)furan-2(5H)-One

Shewanella putrefaciens (SHP) and S. baltica (SHB) are involved in spoilage of refrigerated shrimp (Litopenaeus vannamei). The bacteria possess the luxS gene and produce autoinducer-2 (AI-2). (Z)-5-(bromomethylene) furan-2(5H)-one (BMF), an AI-2 inhibitor, significantly (P < 0.05) decreased luxS expression and AI-2 activities of SHP and SHB. BMF inhibited extracellular proteolytic activities, but increased biofilm formation. Total volatile basic nitrogen production and emission levels of some sulfuric compounds (dimethyl trisulfide, sulphuric acid dibutyl ester, methanethiol and methyl disulfide), aldehydes and ketones (acetone, acetaldehyde, methyl-glyoxal aldehydes), and alcohols (2-methyl-2-propanol, 3-methyl-1-butanol, 2-ethylhexan-1-ol) in shrimp meat samples inoculated with SHP and SHB were significantly (P < 0.05) decreased by the BMF treatment. Practical Applications Our findings provide evidence for the potential application of AI-2 inhibitors in prolonging the shelf life of fresh shrimp meat.

Quality Changes in Gamma Irradiated Marinades of Anchovy (Engraulis anchoita) During Refrigerated Storage

The effect of gamma irradiation (0, 1.8, and 3.3 kGy) on the microbiological, chemical, and color characteristics of marinated (7% acetic acid and 10% NaCl) and vacuum-packed anchovy fillets was analyzed during 20 months of refrigerated storage (4 ± 1°C). Acidity, pH, water activity (aw), total volatile basic nitrogen (TVBN), lipid oxidation, and color parameters were determined. Mesophilic and psychrotrophic bacteria, sulphite-reducing clostridia, total and fecal coliforms, Staphylococcus spp., yeasts, and molds were investigated. Gamma irradiation reduced the initial mesophilic bacterial counts and inhibited mesophils growth during 20 months. As a result, the production of TVBN during storage was lower in irradiated samples than in control. Also, lipid oxidation was lower in irradiated samples than in nonirradiated. The color of anchovy fillets was not affected by the irradiation treatment. Even if nonirradiated anchovy fillets presented a high stability in comparison with the traditional product (in flasks with vegetable oil and spices), gamma irradiation improved the microbiological and chemical quality of anchovy fillet marinades without inducing changes on its characteristic color for 20 months.

Modeling total volatile basic nitrogen production as a dose function in gamma irradiated refrigerated squid rings

The behavior of a chemical spoilage index for marine products (total volatile basic nitrogen – TVBN) was modeled as a function of the irradiation dose in Illex argentinus rings stored in refrigeration. The effect of gamma irradiation at 0, 1.8, 3.3 and 5.8 kGy on TVBN was analyzed in vacuum-packed squid rings during storage at 4 ± 1 °C. The modified Gompertz model satisfactorily described TVBN behavior for each irradiation dose (R2 > 0.980; RMSE < 5.7). Gompertz model parameters (μ, A, L) were modeled with dose-dependent second order polynomials, for doses ranging between 0 and 5.8 kGy, in order to develop a complete model that is useful for predicting TVBN as a function of the dose in squid rings. Model validation was carried out using independent data of TVBN in squid rings irradiated at 4.8 kGy. The developed model can be used to predict TVBN production in gamma irradiated squid meat.

Gamma radiation effect on quality changes in vacuum‐packed squid (Illex argentinus) mantle rings during refrigerated (4–5 °C) storage

SummaryThe effect of gamma radiation (0, 1.8, 3.3 and 5.8 kGy) on microbiological, chemical and colour characteristics of vacuum‐packed squid (Illex argentinus) mantle rings was studied. Total viable counts; psychrotrophic bacteria counts, Escherichia Coli, Staphylococcus aureus and Clostridium perfringens; total volatile basic nitrogen (TVBN) and colour difference were analysed during 29 days of storage at 4–5 °C. Higher doses of gamma radiation significantly reduced Total Viable, phychrotrophic counts and TVBN production (P &lt; 0.05) in a dose‐dependent way, delaying squid spoilage. Colour difference of non‐irradiated samples with respect to first day significantly increased while it was constant in radiated samples during 22 days (P &lt; 0.05). Independently from the dose, radiation avoided colour changes of squid rings. Gamma irradiation was effective in delaying deterioration reactions, improving microbiological, chemical and colour quality of vacuum‐packed squid rings stored at 4–5 °C.

Acidity, Proteolysis and Lipolysis Changes in Rapid-Cured Fermented Sausage Dried at Different Temperatures

Two batches of dry-cured fermented sausage were made by industrial methods at pilot scale. The difference between them was the drying temperature applied (5 or 12 °C) for a period of time extending from the moment when pH = 5 was attained until a weight loss of 20% was achieved. The other conditions were the same for the two processes. Changes in pH, total acidity, D and L-lactic acids, acetic acid, total volatile basic nitrogen (TVBN), free amino acids (FAA) and free fatty acids (FFA) were studied, and a discriminatory sensory analysis of the ready-to-eat product was carried out. Only L-lactic acid and total acidity within the acidity parameters showed substantial differences halfway through the drying process. No significant differences were found in any of the acidity variables at the end of the process. The drying temperature encouraged the production of TVBN, but no direct relationship was established between it and the quantity of FAA. The three fractions of FFA [SFA (saturated fatty acids), MUFA (monounsaturated fatty acids) and PUFA (polyunsaturated fatty acids)] increased during the curing period, always higher at 12 °C than at 5 °C throughout the process. No differences between the two processes were detected by the discriminatory sensory analysis.

Time Courses of Total Volatile Basic Nitrogen (TVB-N) in Seafoods Inoculated Singly or as Mixtures with Spoilage Yeasts or Bacteria

Previously, we reported on the amount of T-VBN produced by yeasts or bacteria. Candida lipolytica produced the largest amount of T-VBN among the 5 yeast species tested, while Staphylococcus epidermidis produced the smallest amount, and Pseudomonas fluorescens produced the largest amount among the 4 bacterial species tested. In this paper, the microbiological and chemical changes of these 3 species were compared. C. lipolytica, S. epidermidis and P. fluorescens were inoculated singly or as mixtures into 3 different kinds of sterile seafood homogenate (common mackerel, black tiger shrimp and neon flying squid), and incubated at either 5, 15 or 25°C. The time courses of viable counts, pH values, and TVB-N values determined according to the microdiffusion method of Conway were observed for up to 7 days.(1) Viable counts: The growth curves of C. lipolytica at 15 and 25°C showed gradual slopes, and reached the stationary phase on day 7. The growth curves of P. fluorescens and a mixture containing C. lipolytica, S. epidermidis and P. fluorescens at 15 and 25°C reached the stationary phases on day 2. The growth curves of S. epidermidis at 5 and 15°C were lower than those of C. lipolytica, P. fluorescens and a mixture of all three.(2) pH: The pH values in the seafood homogenate inoculated with C. lipolytica, P. fluorescens and a mixture of all three increased with temperature and duration of incubation.(3) TVB-N: Whereas the viable counts at 25°C of C. lipolytica were less than those of P. fluorescens, S. epidermidis and the mixture, the production of TVB-N by C. lipolytica was at almost the same levels as those of P. fluorescens and the mixture, and considerably more than that of S. epidermidis. The results of the previous and present experiments have thus confirmed that the yeasts produced the same spoilage phenomenon as the bacteria.

Time Courses for Viable Counts, pH and Total Volatile Basic Nitrogen in Squid Homogenates (Ommastraphes bartrami) Inoculated with Spoilage Yeast or Bacteria

The spoilage patterns of Candida lipolytica, Pseudomonas fluorescens and Staphylococcus epidermidis in sterile squid homogenates were compared. The three species were inoculated singly or as a mixture, incubated for up to 7 d, and analyzed for viable counts, pH values and the amounts of total volatile basic nitrogen (TVB-N) produced. Incubation temperatures were 5, 15 and 25°C. When each species was separately inoculated, C. lipolytica showed slower growth than that of the two bacterial species, but TVB-N production in the homogenates increased to level that indicated spoilage. The TVB-N exceeded the concentration corresponding to the threshold value of spoilage on d 4 at 15°C or on d 2 at 25°C. The TVB-N values in the C. lipolytica inoculated homogenates reached 112 and 215 mg per 100 g of homogenate on d 7 at 15 and 25°C, respectively. On these occasions the respective pH values were 7.9 and 8.1, and the homogenates inoculated with the yeast showed spoilage emitting an ammoniacal odor. In general, TVB-N production by C. lipolytica was slightly less than that by P. fluorescens, but much more than that by S. epidermidis. The TVB-N curves obtained from the mixed cultures containing the three species were very similar to those obtained from the single cultures of P. fluorescens. Viable counts of the individual strains in the mixed cultures showed that the yeast strain grew independently without being suppressed by the growth of the two bacterial strains, and even 3 weeks after incubation the survival counts of the yeast strain were higher than those of the bacterial strain at 15 and 25°C, respectively.