Influence of corn starch based bio-active edible coating containing fumaric acid on the lipid quality and microbial shelf life of silver pomfret fish steaks stored at 4 °C.

The present study aimed at assessing the impact of addition of fumaric acid (0.5%), as an active agent, in a corn starch (2%) based edible coating, on the lipid quality and microbial shelf life of silver pomfret (Pampus argenteus) fish steaks stored at 4 °C. Treating fish steaks with FA resulted in a bacteriostatic effect leading to reduced counts of total mesophilic and psychrotrophic bacteria, H2S producing bacteria and Pseudomonas spp. The total mesophilic bacterial count of uncoated control sample exceeded the permissible limit of 7 log cfu g-1 on 6th day and had the lowest microbial shelf life. FA incorporation in the CS coating improved the microbial stability of fish steaks resulting in a shelf life of 15 days. The outcomes of the study suggest that CS based coating is beneficial in delaying lipid oxidation as displayed by the lower TBA and PV values while FA is an effective agent for further increasing the preservative action of CS coating by significantly inhibiting microbial growth as well as lipid quality deterioration, which could be exploited by the seafood industry as an active packaging component.

Intrinsic properties of chitosan on the characteristics of gold nanoparticles and its application as smart packaging device.

Storage temperature fluctuation is a major problem faced in food and pharmaceutical industry, apart from prevailing fraud in marketing frozen products as fresh. The present work aimed to study the effect of intrinsic properties of chitosan on synthesis and performance of gold nanoparticles as smart packaging devices. Different types of Chitosan from shrimp waste were used as reducing and capping agent in the synthesis of metal nanoparticle. Time is taken to reduce gold atom to gold nanoparticles varied with the type of reducing agent, between 6 min 40 s to 15 min 02 s. The maximum absorbance (λmax) for AuNPs was observed between 517 and 530 nm. An increase in the concentration of chitosan resulted in smaller and uniform size AuNPs with size ranging from 8.09 to 9.95 nm compared with 14.44 to 19.88 nm for lower concentration of chitosan. Visible ruby red colour of AuNPs synthesised using trisodium citrate (TSC) and lower concentration of chitosan (0.1%) changed to colourless and grey to blue, respectively upon exposure to frozen condition (-18 °C ± 1 °C). UV Visible spectra indicated distinctly different (broader) spectrum with reduced peak intensity. A visible change in colour from ruby red to bluish and colourless state indicates that irrespective of the properties of available chitosan, it can be used for synthesis of gold nanoparticles as smart packaging to distinguish packed fresh/chilled/refrigerated products from frozen ones.