Lipase and esterase: to what extent can this classification be applied accurately?

Enzyme technology is an ever-growing field of knowledge and, in recent years, this technology has raised renewed interest, due to the search for new paradigms in several productive processes. Lipases, esterases and cutinases are enzymes used in a wide range of processes involving synthesis and hydrolysis reactions. The objective of this work was to investigate and compare the specific lipase and esterase activities of five enzymes - four already classified as lipases and one classified as cutinase - in the presence of natural and synthetic substrates. All tested enzymes presented both esterase and lipase specific activities. The highest specific esterase activity was observed for Aspergillus 1068 lipase in natural substrate and for F. oxysporum cutinase in synthetic substrate, while the highest specific lipase activity was observed for Geotrichum sp. lipase in natural substrate and for F. oxysporum cutinase in synthetic substrate. These results display some interface-independent lipolytic activity for all lipases tested. This is in accordance with the rationale that a new and broader definition of lipases may be necessary.

Chemometrics applied to the incorporation of omega-3 in tilapia fillet feed flaxseed flour

This study evaluated the effect of adding flaxseed flour to the diet of Nile tilapia on the fatty acid composition of fillets using chemometrics. A traditional and an experimental diet containing flaxseed flour were used to feed the fish for 60 days. An increase of 18:3 n-3 and 22:6 n-3 and a decrease of 18:2 n-6 were observed in the tilapia fillets fed the experimental diet. There was a reduction in the n-6:n-3 ratio. A period of 45 days of incorporation caused a significant change in tilapia chemical composition. Principal Component Analysis showed that the time periods of 45 and 60 days positively contributed to the total content of n-3, LNA, and DHA, highlighting the effect of omega-3 incorporation in the treatment containing flaxseed flour.

Effect of modified atmosphere applied to minimally processed radicchio (Cichorium intybus L.) submitted to different sanitizing treatments

Stability of minimally processed radicchio (Cichorium intybus L.) was evaluated under modified atmosphere (2% O2, 5% CO2, and 93% N2) on 3, 5, 7 and 10 days of storage at 5°C. The samples were hygienized in sodium hypochlorite or hydrogen peroxide solutions to identify the most effective sanitizing solution to remove microorganisms. Microbiological analysis was conducted to identify the presence of coliforms at 35°C and 45°C, mesophilic microorganisms, and yeast and mold. Physicochemical analyses of mass loss, pH, soluble solids, and total acidity were conducted. The color measurements were performed using a Portable Colorimeter model CR-400. The antioxidant activity was determined by 2,2-diphenyl-1-picrylhydrazyl and 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic methods. The sensory evaluation was carried out using a hedonic scale to test overall acceptance of the samples during storage. The sodium hypochlorite (150 mg.L-1) solution provided greater safety to the final product. The values of pH ranged from 6.17 to 6.25, total acidity from 0.405 to 0.435%, soluble solids from 0.5 to 0.6 °Brix, mass loss from 1.7 to 7.2%, and chlorophyll from 1.068 to 0.854 mg/100g. The antioxidant activity of radicchio did not show significant changes during the first 3 days of storage. The overall acceptance of the sample stored in the sealed package without modified atmosphere was 70%, while the fresh sample was obtained 77% of approval. Although the samples packaged under modified atmosphere had a higher acceptance score, the samples in sealed packages had satisfactory results during the nine days of storage. The use of modified atmosphere, combined with cooling and good manufacturing practices, was sufficient to prolong the life of minimally processed radicchio, Folha Larga cultivar, for up to ten days of storage.