NADES blend for bioactive coating design as a sustainable strategy for postharvest control.

Bioactive functional coatings constitute a trendy topic due to they reduce postharvest fruit losses worldwide. Also, they could be carriers of biocompounds providing health benefits to the consumer. In this work, an innovative natural bioactive coating based on Natural Deep Eutectic Solvents (NADES) and Larrea divaricata extract was optimized by mixture-mixture design for the management of postharvest diseases caused by Monilinia fructicola. A NADES composed of lactic acid-glucose-water (LGH) for phenolic extraction from L. divaricata was optimized by a Simplex Lattice design and response surface methodology (RSM).Then, a d-optimal mixture-mixture design was carried out in order to optimize the bioactive coating composition, being the optimal proportion of 0.7 L. divaricata-LGH extract and 0.3 NADES plasticizer (composed by glycerol, citric acid and water). The optimal biocoating achieved an in vitro antimicrobial activity of 72 % against M. fructicola. Interestingly, NADES plasticizer improves the biocoating functionality, creating a smooth and uniform surface.

Phenolic characterization and antimicrobial activity of folk medicinal plant extracts for their applications in olive production.

Phytophthora spp is important in plant pathology due to the importance of the diseases it causes. In olive trees, severe damages are caused by the disease known as "dry branch" occasioned by Phytophthora nicotianae, P. citrophthora and P. palmivora. Much effort has been made to find efficient methods of control, with a low negative impact on environment. In this regard, treatment with plant extracts is a valid strategy. The aims of the present study are (i) to determine the polyphenol composition of extracts of Thymus vulgaris, Origanum vulgare, Matricaria recutita, and Larrea divaricata by CZE, (ii) correlate the analytical composition of these extracts with the inhibition on the mycelial growth, and (iii) determine the individual antimicrobial activity of the most active ingredients. A simple methodology was developed for the determination of catechin, naringenin, cinnamic acid, syringic acid, chlorogenic acid, apigenin, vanillic acid, luteolin, quercetin, and caffeic acid in plant extracts by CZE. The extraction of phenolic compounds in extract was performed by a miniaturized solid phase extraction using a home-made minicolumn packed with suitable filtering material (C18 , 50 mg). The optimized analyses conditions were: 30 mM boric acid buffer, pH 9.50; capillary, 57 cm full length, 50 cm effective length, 75 µm id, hydrodynamic injection 30 mbar, 2 s; 25 kV; 25°C, detection by UV absorbance at 290 nm. Sample results suggest that phenolic composition seems to have a great influence on inhibition of pathogens. The highest inhibitions of mycelial growth were observed for cinnamic acid and naringenin.