Satyen Kumar Panda

Development and characterization of an LDPE/chitosan composite antimicrobial film for chilled fish storage.

An antimicrobial packaging material was developed by uniformly embedding 1, 3 and 5% chitosan (w/w) in low density polyethylene matrix using maleic anhydride grafted LDPE as a compatible agent. The materials were mixed by compounding and blown into monolayer films via blown film extrusion. The developed films showed good barrier properties against oxygen. Characterization of the composite films with Fourier transform infrared spectroscopy revealed that chitosan and LDPE interacted well with each other. Overall migration showed better release of chitosan adduct from the LDPE matrix which enhanced the antibacterial properties of the films. The interaction between the LDPE/CS and maleic anhydride grafted LDPE had a decreasing effect on the tensile strength and heat sealing properties. Investigation on antimicrobial properties of LDPE/CS films showed 85-100% inhibition of Escherichia coli. Efficacy of LDPE/CS films was evaluated by using them as packaging material for chilled storage of Tilapia (Oreochromis mossambicus). Analysis of storage quality indices (peroxide value, free fatty acid, total volatile base nitrogen and aerobic plate count) revealed good antibacterial property and extension of shelf life of Tilapia in the chitosan incorporated novel composite films compared to virgin LDPE film.

Assessment of polyaromatic hydrocarbons and pesticide residues in domestic and imported pangasius (Pangasianodon hypophthalmus) fish in India

BACKGROUND The pangasius catfish (Pangasianodon hypophthalmus) is a ubiquitous item of seafood in global markets. However, pesticide residues in aquaculture fish, arising from agricultural run-off and/or direct application during pond preparation, pest control and harvest, are a potential food safety concern. This study assessed the level of chemical hazard in domestic and imported pangasius fish in India. RESULTS A total of 119 contaminants, including polyaromatic hydrocarbons (PAHs), organochlorines (OCs) and other groups of pesticides, were screened in 148 samples during 2014-2015 as the first endeavour of its kind in an Indian context, employing a validated gas chromatography/tandem mass spectrometry (GC/MS/MS) method. Apart from the low-level incidence of OCs, pesticides such as quinalphos, malathion, parathion-methyl, etc. were detected in 38% of the samples. In comparison with Indian pangasius, fewer contaminants at low residue level were detected in pangasius fillets imported from Vietnam. CONCLUSION The human dietary exposures of the residue concentrations detected were less than the maximum permissible intakes and hence appeared safe. However, detection of commonly used pesticides indicated their direct application in aquaculture and contamination from agricultural run-off. This emphasizes the need for continual residue monitoring in aquaculture fish.

Packaging performance of organic acid incorporated chitosan films on dried anchovy (Stolephorus indicus).

Antimicrobial chitosan films were prepared with acetic acid and propionic acid with glycerol as plasticizer and its efficiency was compared with polyester-polyethylene laminate (PEST/LDPE). The tensile strength of acetic acid/chitosan (ACS) films were higher than propionic acid/chitosan (PCS) films. The elongation percentage (6.43-11.3) and water vapour permeability (0.015-0.03 g/m(2)/day) were significantly lower (p<0.05) for chitosan films when compared to control. Oxygen transmission rate (OTR) of control and propionic acid/chitosan (PCS) films were significantly higher (p<0.05) than acetic acid/chitosan (ACS) films. Dried anchovy (Stolephorus indicus) wrapped in these films were stored at ambient temperature for three months. Quality indices like peroxide value (PV), thiobarbituric acid value (TBA) and microbiological parameters such as aerobic plate count (APC) and total fungal count (TFC) were periodically determined. In terms of microbial and chemical indices, anchovies wrapped in ACS and PCS films were superior to those wrapped with PEST/LDPE films during storage. Study revealed the suitability of chitosan film as wraps for increasing storage stability of dried fish.

Effect of high pressure treatment on microbiological quality of Indian white prawn (Fenneropenaeus indicus) during chilled storage.

High pressure treatment of 250 MPa for 6 min at 25 °C was applied to headless Indian white prawn (Fenneropenaeus indicus) to evaluate changes in microbiological characteristics of the species during chilled storage. Changes in load of mesophilic bacteria, psychrotrophic bacteria, proteolytic bacteria, Enterobacteriaceae, Pseudomonas spp., H2S producing bacteria, lactic acid bacteria, Brochothrix thermosphacta and yeast & mold were estimated in pressurized and un-pressurized samples during chilled storage. All microbes were reduced significantly after high pressure treatment and there was significant difference in microbial quality of control and high pressure treated samples in the entire duration of chilled storage (p < 0.05). There was delay in the growth of Enterobacteriaceae and H2S producing bacteria up to 6th and 9th day of storage, respectively in high pressure treated samples. In high pressure treated sample, no lag phase (λ) was observed for psychrotrophic bacteria, H2S producing bacteria, B. thermosphacta, Pseudomonas spp. and lactic acid bacteria; however, other bacteria showed a reduced lag phase during chilled storage. Kinetic parameter such as specific growth rate (μmax) in high pressure treated samples was significantly reduced in most of the bacterial groups except for psychrotrophic bacteria, Enterobacteriaceae and lactic acid bacteria. Mesophilic bacterial count of control samples crossed the marginal limit of acceptability on 12th day and unacceptable limit on 18th day of storage, whereas high pressure treated samples never breached the acceptability limit during entire duration of chilled storage. The present study indicated that application of high pressure processing can be used to improve microbial quality of Indian white prawn and extend the chilled storage life.

Nutritional evaluation of processing discards from tiger tooth croaker, Otolithes ruber

Processing discards from tiger tooth croaker, such as head, viscera, and swim bladder, were analyzed for proximate, biochemical, fatty acid, and mineral composition. The proximate analysis showed high protein content (21.04%) in the swim bladder and high fat content (4.10%) and ash content (2.26%) in the head. The biochemical quality indices such as non-protein nitrogen, total volatile base, trimethylamine, free fatty acids, peroxide value, and thiobarbituric acid reactive substances in the viscera were higher than those in the head and swim bladder. Gas chromatographymass spectrometry analysis of fatty acids composition showed high polyunsaturated fatty acids in the head (58.82%), followed by the viscera (45.80%) and the swim bladder (35.57%). The major available saturated fatty acid, i.e., palmitic acid, was higher in the swim bladder (30.49%). Mineral and heavy metals analyzed via inductively coupled plasma-optical emission spectrometer showed high calcium, sodium, and magnesium contents in the head region (346.80, 62.55, and 14.89 mg/kg respectively). Heavy metal levels were within the permissible limit.

Effect of high pressure processing on textural and microbiological quality of pink perch (Nemipterus japonicus) sausage during chilled storage

The non-thermal high pressure (HP) processing was studied on fish sausage to enhance the quality during chilled storage. Pink perch (Nemipterus japonicus) sausages, packed in poly amide casing under vacuum were subjected to 400, 500 and 600 MPa pressures (dwell time: 10 min and ramp rate: 300 MPa/min) and compared with heat-set samples for physico-chemical and microbial quality parameters. Pressurized samples formed softer and glossier gels with a slight reduction in water-holding capacity. HP made the texture of sausage softer, cohesive and less chewy and gummier than heat-treated ones. Folding test seen higher acceptance values in samples treated at 500 and 600 MPa, during storage. Maximum log reduction in microbial count was observed in 600 MPa immediately, and significant difference in cooked and pressurized sausages was seen only up to 7th day. This revealed the potential application of HP in replacing conventional heat treatment for sausages preparation with enhanced shelf-life.

Polylactic acid/chitosan films for packaging of Indian white prawn ( Fenneropenaeus indicus )

Composite films were developed by embedding nanochitosan (0.5%, 1% and 2%) in a polylactic acid (PLA) matrix using polyethylene glycol as a cross linking agent and polyvinyl alcohol as plasticizer. The mixture was casted into films via solvent casting. The interaction between the polylactic acid/nanochitosan (PLA/NCS) and polyethylene glycol had a significant effect on the tensile strength and the heat sealing properties. Antimicrobial properties of PLA/NCS films have been confirmed against aerobic microorganisms. PLA/NCS solvent casted films were used to pack prawn meat (Fenneropeneaus indicus) which was further stored in chilled condition for 18 days. The study proved that microbial and biochemical quality indices of prawn samples packed in different PLA/NCS film were retained and concluded that PLA/NCS composite films can be used for packing of fresh prawn to increase its shelf life.