Silver nanoparticles (AgNPs) are antimicrobial agents that have a wide spectrum of action, including against pathogenic bacteria and spoilage fungi. However, their mechanism of action is not completely clarified. Nowadays, scientific interest on biological synthesis of AgNPs is growing, with emphasis in their extracellular biosynthesis by microbial cells, as it is the most reliable and ecologically correct method for production, yielding no toxic residues. AgNPs may be incorporated to biodegradable and non-biodegradable polymers for the production of food packages with antimicrobial properties, leading to greater safety and longer shelf life. However, it is important to carry out migration tests for new food packages incorporated with AgNPs, based on the effective levels for their inclusion in the packaging materials.

Minced fish (MF) is an interesting material for development of novel fish products; however, the mechanical deboning process interferes with MF quality, by increasing the lipid oxidation. This study reports the effect of Ceylon cinnamon (Cinnamomum zeylanicum) hydro-ethanolic bark extracts as natural antioxidants on both washed and unwashed MF of broadband anchovy during six months of storage at -18 °C. Spray-dried cinnamon extract (DC) and spray-dried cinnamon extract using maltodextrin 10DE (DCM) as a carrier were evaluated in relation to antioxidant activity in vitro. DC and sodium erythobarte were added to both washed and unwashed MF at 0.25% (w:w), whilst DCM was added at 1.055% (w:w). The DC extract presented higher antioxidant activity in vitro compared to DCM extract. The addition of cinnamon extracts reduced the lipid oxidation in washed and unwashed MF compared with the controls. C. zeylanicum extracts can be used to prevent lipid oxidation in MF during the frozen storage and are alternatives for food industries that seek to meet the demand of consumers increasingly concerned with the consumption of healthy foods.

Consumers are demanding for healthier and safe products. In this context, we proposed the development of an intelligent sheep milk yogurt, with a natural coloring agent, that changes color as the acidity increases, an indicative of shelf life decay. For that propose, jabuticaba (Myrciaria jaboticaba) syrup (15%, 30%, and 45% soluble solids) was added to the milk before fermentation. Yogurts ability in reporting acidity by changing color was observed by correlating yogurt titratable acidity (Dornic) and pH with visual and colorimetric parameters (L, a, and b). Other physical-chemical parameters as fat, protein, moisture, and ash were also analyzed to evaluate the syrup addition effect on yogurts composition. Statistical analysis of the data was performed through analysis of variance and the means were compared by the Tukey test at 5% of probability. Results have indicated that intelligent yogurts naturally colored with jabuticaba syrup, was able to change color from light purple to dark purple pigmentation, indicating pH decrease. Jabuticaba syrup affected yogurts composition, increasing titratable acidity, fat and ash as jabuticaba syrup soluble solids concentration increased.