Antioxidant compounds from cyanobacteria may constitute a natural alternative to current synthetic antioxidants, which contain preservatives and suspected toxicity. In this work, we evaluate the antioxidant potential of cyanobacterial strains of distinct species/genus isolated from freshwater (n = 6), soil (n = 1) and wastewater (n = 1) environments. Lyophilized biomass obtained from in-vitro cultures of those strains was extracted with ethanol and methanol. The antioxidant potential was evaluated by chemical (DPPH scavenging method, β-carotene bleaching assay, determination of total phenolic and total flavonoid compounds) and biological (H2O2-exposed HEK293T cell line model) approach. Some strains showed high yields of antioxidant activity by the DPPH assay (up to 10.7% IP/20.7 TE μg/mL) and by the β-carotene bleaching assay (up to 828.94 AAC), as well as significant content in phenolic (123.16 mg EAG/g DW) and flavonoid (900.60 mg EQR/g DW) compounds. Normalization of data in a “per cell” or “per cell volume” base might facilitate the comparison between strains. Additionally, most of the cyanobacterial extracts conferred some degree of protection to HEK293T cells against the H2O2-induced cytotoxicity. Freshwater Aphanizomenon gracile (LMECYA 009) and Aphanizomenon flos-aquae (LMECYA 088), terrestrial Nostoc (LMECYA 291) and wastewater Planktothrix mougeotii (LEGE 06224) seem to be promising strains for further investigation on cyanobacteria antioxidant potential.

The present research intents to study the evolution of the skin fatty acids and physiological disorders through cold storage in ‘Golden Delicious’ apples treated with 1-MCP and calcium. Harvested fruit were treated with calcium chloride (Ca), 1-MCP (MCP), Ca+MCP or no treatment (control) then subjected to cold storage at 0.5 ºC for 6 months. Fatty acids composition, Malondialdehyde (MDA) and the physiological disorders bitter pit (BP), superficial scald and diffuse skin browning (DSB) were measured at harvest and after storage plus 7 days shelf-life at room temperature ≈22 ºC. Palmitic acid decreased and linoleic acid increased through time, while oleic and stearic acids had few changes. Unsaturated/saturated fatty acids and MDA increased through time, despite Ca and Ca+MCP were related to lower MDA and lower BP and rotten fruit, after cold storage and shelf-life. In those treatments, the unsaturated/saturated fatty acids were higher, mainly due to higher linoleic acid and lower palmitic acids. Further research is needed to clarify the changes in membrane properties and the effect of some treatments in response to chilling injury through storage.