Volatile Basic Nitrogen Production Research Articles

Optimisation of treatment conditions for reducing Shewanella putrefaciens and Salmonella Typhimurium on grass carp treated by thermoultrasound-assisted plasma functionalized buffer

A novel method of thermoultrasound-assisted plasma functionalized buffer (PFB) for decontaminating grass carp was evaluated using the Box–Behnken design (BBD) with processing variables including PFB generating voltage (PV), ultrasound treatment time (UT) and temperature (TP). The predicted models were found to be significant (p < 0.05) and displayed sufficient fitness with experimental data as indicated by non-significant (p > 0.05) lack of fit and high coefficient of determination (R2≥0.97) values. The optimum decontamination conditions for the responses of S. putrefaciens and S. Typhimurium were PV of 66 V, UT of 14.90 min and TP of 60 ℃, achieving reductions of 4.40 and 3.97 log CFU/g, respectively, with a desirability of 0.998. Among the variables, temperature presented higher significance for inactivating bacteria and the production of volatile basic nitrogen and lipid peroxidation under the optimized conditions were within the limits of freshness for grass carp. Additionally, the effects of PFB and the optimized thermoultrasound-assisted PFB decontamination were mild on the microstructure of grass carp with slight ruptures and loose myofibril structures, indicating the potential of thermoultrasound-assisted PFB for seafood products decontamination with reduced processing time.

Plasma-treated polyethylene coated with polysaccharide and protein containing cinnamaldehyde for active packaging films and applications on tilapia (Orechromis niloticus) fillet preservation

This study aimed to develop an antimicrobial active packaging using carboxymethyl cellulose (CMC) or collagen (COL) as carriers of cinnamaldehyde (CNMA) coating on plasma-treated low density polyethylene (LDPE) for application on tilapia fillet packaging. COL carriers exhibited stronger antimicrobial and antioxidant activities than no carrier and CMC. The films also showed good physical and mechanical properties after coating. The results on tilapia preservation analysis showed that the COL with 6% CNMA slowed the total plate count and growth of Vibrio parahaemolyticus by about 1.82 log colony-forming units (CFU)/g and 1.76 log CFU/g compared to the control at day 14. All active films were better than Control in delaying the production of volatile basic nitrogen and thiobarbituric acid during storage whilst simultaneously maintaining organoleptic properties. Based on results, the antimicrobial active films significantly prolonged the shelf life of tilapia fillets to 3 days compared with the Control group. The COL with 6% CNMA may potentially play an effective role in maintaining and preserving the microbial qualities of tilapia fillets.

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.

Use of the plasma-treated and chitosan/gallic acid-coated polyethylene film for the preservation of tilapia (Orechromis niloticus) fillets

In this study, a polyethylene (PE) film coated with chitosan (CS) and gallic acid (GA) was prepared using plasma modification technology and applied for the preservation of tilapia fillets. Based on the analysis of surface morphology and surface functional groups, it was shown that plasma modification allowed CS and GA coating on PE. And GACS/PE demonstrated better antioxidant ability than CS/PE and GA/PE individually. The results of the tilapia freshness test showed that the total plate count showed that GACS/PE can inhibit 1.52 log CFU/g and delay the production of volatile basic nitrogen below 15 mg/100 g after 14 d of storage. Moreover, GA/PE (0.26 mg MDA/kg) and GACS/PE (0.24 mg MDA/kg) showed better thiobarbituric acid inhibitiry effect than control (0.30 mg MDA/kg) on day 14. These results indicate that these packaging films are efficient in extending the shelf life of tilapia fillets.

Effects of Chitosan on Clostridium perfringens and Application in the Preservation of Pork Sausage

The effects of chitosan with 95% deacetylation degree (DD95) on the spore germination, cell proliferation, and heat resistance of Clostridium perfringens CCRC 10,648 and CCRC 13,019 were investigated, and its application on pork sausage with sodium nitrite reduction was also evaluated. DD95 chitosan can strongly reduce the heat resistance of both strains. The D80 and D100 values for strain CCRC 13,019 decreased from 40.98 and 4.64 min to 39.21 and 3.26 min, respectively, as a result of adding 250 ppm DD95; meanwhile, addition of chitosan decreased the D80 and D100 values for CCRC 10,648 from 41.15 and 6.46 min to 39.52 and 3.78 min, respectively. In pork sausage, addition of 3000 ppm DD95 chitosan considerably slowed down the bacterial proliferation and volatile basic nitrogen production. There were no significant differences in color (L* and b* values), shearing force, and hardness in the pork sausages with or without DD95 chitosan during storage at 4 and 25 °C. However, the addition of DD95 chitosan in pork sausage significantly retarded the decrease of the a* value. Therefore, DD95 chitosan could reduce the concentration of sodium nitrite required in pork sausages for color retention.

Application of atmospheric cold plasma-activated water (PAW) ice for preservation of shrimps (Metapenaeus ensis)

In this paper, plasma-activated water (PAW) ice is proposed for the preservation of fresh shrimps. The changes in microbiological, physical, chemical and protein properties were investigated during storage with conventional tap water (TW) ice and PAW ice. Compared with TW ice, PAW ice showed significant advantage for inhibition of microbial growth, extending the storage time by 4–8 days. The pH of shrimps treated with PAW ice remained below 7.7 during storage. The deteriorating changes in color characteristics and hardness were delayed by the PAW ice treatment. The production of volatile basic nitrogen (TVBN) was reduced to below 20 mg/100 g during PAW ice storage, significantly lower (p < 0.05) than that of the samples treated with TW ice. In addition, PAW ice did not result in adverse changes in shrimp proteins. Therefore, the study showed that PAW ice may be used in preservation of fresh seafood.

Chemical stability of rainbow trout in icing medium containing pistachio (Pistachia vera) green hull extract during chilled storage.

In this study, the effect of icing medium containing different concentration of pistachio (Pistacia vera L. cv. Akbari) green hull extract (PHE) was investigated on the chemical stability of rainbow trout. The fishes were stored for 12days in flaked ice containing 0, 0.1, 0.2 and 0.3% PHE and the parameters of pH, total volatile base nitrogen (TVB-N), histamine, free fatty acids, peroxide and thiobarbituric acid index (TBA-i) were periodically evaluated. In all experiments, a significant difference was evident between control and fish muscles stored in ice containing PHE. Fish icing with 0.3% PHE could considerably retard the oxidative and hydrolytic rancidity. In addition, it had significant effect on prevention of pH increase and production of volatile basic nitrogen during 12days storage. PHE could diminish histamine accumulation in fish muscle and improve safety of rainbow trout. Consequently, PHE could have potential of application in icing medium for preservation of fish quality especially fatty ones.