N.M. Sachindra

In vitro antioxidant activity of liquor from fermented shrimp biowaste.

Shrimp waste was fermented using lactic culture and the separated fermented liquor was lyophilized. In vitro antioxidant activities of the lyophilized powder were evaluated with respect scavenging of different radicals and quenching of generated singlet oxygen. The sample showed strong radical scavenging and singlet oxygen quenching in a dose dependent manner (p<0.001). The sample exhibited 40% scavenging of DPPH radical at 1.0mg/ml concentration while the ABTS radical scavenging was 95% even at 0.5mg/ml concentrations. Hydroxyl radical scavenging activity as measured by chemiluminescence technique showed 80% scavenging and peroxyl radical scavenging was 65% at 1.0mg/ml concentration. The singlet oxygen quenching ability of the powder was 68.3% at 1.0mg/ml concentration. The sample was found to contain low molecular weight proteins. The formation of peptides and amino acids during hydrolysis of shrimp waste protein during fermentation is expected to be responsible for the antioxidant activity. In addition as the product also contains carotenoids, it can be used as an ingredient in aquaculture feed formulations for beneficial effects.

Effect of Acid Ensiling on the Stability of Visceral Waste Proteases of Indian Major Carp Labeo rohita

ABSTRACT The effect of acid ensiling on the stability of different classes of proteases present in the visceral wastes of a major freshwater carp is presented. The changes in moisture, fat and ash content were not significant (P ≥ 0.05) during the storage period of 4 weeks at ambient temperature of 27 ± 2°C. Fresh visceral waste of the freshwater major carp Labeo rohita had considerable protease activity and buffer extractable proteins (2.7% w/w). There was a significant reduction in buffer extractable proteins (BEP) immediately after acidification (P ≤ 0.05), which later increased in the first two weeks before decreasing further during storage. Marked decreases (P ≤ 0.05) in specific activity (Umg−1 protein) of acidic, neutral and alkaline proteases were observed during storage. The stability of proteases was negatively affected by acid ensiling, even with the use of weak acids like propionic and formic acid.