Films based on starch-gellan blends at 9:1 and 8:2 ratios containing emulsified or lecithin encapsulated thyme (Thymus zygis) essential oil (EO) (0.25 or 0.5 g/g polymer), were obtained by casting method and characterized as to their structural, functional (mechanical, barrier and optical) and in vitro antifungal properties against Alternaria alternata (AA) and Botryotinia fuckeliana (BF). The EO retention during the film formation was also quantified. Lecithin encapsulation of the EO allowed for greater oil retention (45-55%), which enhanced the antifungal activity of the films, which were more effective against BF than AA. All films exhibited high oxygen barrier capacity, while lecithin improved the films water barrier properties and gloss, conferring them with a slightly brownish color. Lecithin also reduced the film stiffness and resistance to break and extensibility. Of the studied formulations, 8:2 S:G films with lecithin-encapsulated EO were very effective at controlling fungal growth, while exhibiting adequate functional properties as packaging/coating materials.
Biomass waste from rice straw has many management problems, including field firing causing severe air pollution and natural organic decomposition resulting in methane emission. The conversion of this waste to ashes may offer the possibility of reusing them in cementing systems. For the first time ashes from different parts of the rice plant (Oryza sativa) were characterised from the chemical composition point of view: rice leaf ash (RLA), rice leaf sheath ash (RlsA) and rice stem ash (RsA). Microscopic studies on ashes revealed heterogeneity in the distribution of chemical elements in the remaining cellular structure (spodograms). The highest concentration of SiO 2 was found in dumbbell-shaped phytoliths (%SiO 2 > 78%). In the global chemical composition of ashes, SiO 2 was also the main oxide present. According to Vassilev's classification of chemical composition, RLA belongs to the K-MA zone (medium acid), RlsA to the K-zone (low acid) and RsA to the S-zone (high acid). Calcination temperatures ≥550 • C completely removed organic matter from the straw and ashes underwent significant sinterisation by calcining at 650 • C due to the presence of potassium chloride. Here, ashes from global straw (rice straw ash, RSA) are characterised (via X-ray diffraction, Fourier transform infrared spectroscopy and thermogravimetry) and tested from a reactivity point of view (reaction towards calcium hydroxide) in order to assess the possibility for its reuse in cementing systems. Results from pastes made by mixing RSA and calcium hydroxide showed that the pozzolanic reactivity of the ashes is important (hydrated lime fixation of 82% for 7 days and 87% for 28 days in RSA:hydrated lime paste) and cementing C S H gel is formed after 7 and 28 days at room temperature. Compressive strength development of Portland cement mortars with 10% and 25% replacements by RSA yielded 107% and 98% of the strength of control mortar after 28 days of curing. Frattini test confirmed the pozzolanicity of the RSA blended cements. These reactivity results are very promising in terms of the potential reuse of ashes in cementing systems.
Agrowastes are being produced worldwide in huge quantities and they contain interesting elements for producing inorganic cementing binders, especially silicon. Conversion of agrowastes into ashes is an interesting way of yielding raw material used in the manufacturing of low-CO 2 binders. Silica-rich ashes are preferred for preparing inorganic
Please cite this article as: Santamarina, M.P., Roselló, J., Giménez, S., Blázquez, M.A., Commercial Laurus nobilis L. and Syzygium aromaticum L. Merr. & Perry essential oils against post-harvest phytopathogenic fungi on rice, ABSTRACT 18 Rice is exposed in the field and in stored conditions to a great variety of fungi that can cause a lot of 19 diseases with potential risk to consumers. In the present study, the chemical composition of commercial 20 Laurus nobilis L. and Syzygium aromaticum L. Merr. & Perry essential oils and antifungal activity against 21 five pathogenic fungi isolated from Mediterranean rice grains has been investigated. Thirty-seven 22 compounds accounting for more than 99.5% of the total essential oil were identified by GC and GC/MS. 23 1,8-Cineole (51.95%), α-terpinyl acetate (12.93%) and the monoterpene hydrocarbon sabinene (9.56%) 24 were the main compounds in bay leaf essential oil, while the phenylpropanoid eugenol (88.58%), and the 25 sesquiterpene hydrocarbons β-caryophyllene (8.13%) and α-humulene (2.35%) were found in clove 26 essential oil. Clove essential oils at 300 µg/mL showed more antifungal effect than bay leaf essential oil 27 against all tested strains. S. aromaticum essential oil showed the best antifungal activity towards 28 Fusarium graminearum and similar antifungal activity compared to pure eugenol against all tested 29 phytopathogenic fungi. In inoculated rice grain, clove essential oil significantly reduced the fungal 30 infection in food so S. aromaticum essential oil could be a good alternative as preservative in stored rice 31 grain.
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