Gustavo Schiedeck

Physical properties of botanical surfactants

Some vegetal species have saponins in their composition with great potential to be used as natural surfactants in organic crops. This work aims to evaluate some surfactants physical properties of Quillaja brasiliensis and Agave angustifolia, based on different methods of preparation and concentration. The vegetal samples were prepared by drying and grinding, frozen and after chopped or used fresh and chopped. The neutral bar soap was used as a positive control. The drying and grinding of samples were the preparation method that resulted in higher foam column height in both species but Q. brasiliensis was superior to A. angustifolia in all comparisons and foam index was 2756 and 1017 respectively. Critical micelle concentration of Q. brasiliensis was 0.39% with the superficial tension of 54.40mNm-1 while neutral bar soap was 0.15% with 34.96mNm-1. Aspects such as genetic characteristics of the species, environmental conditions, and analytical methods make it difficult to compare the results with other studies, but Q. brasiliensis powder has potential to be explored as a natural surfactant in organic farming. Not only the surfactants physical properties of botanical saponins should be taken into account but also its effect on insects and diseases control when decided using them.

Antioxidant and antifungal activities of the flowers’ essential oil of Tagetes minuta, (Z)-tagetone and thiotagetone

ABSTRACT Herein, we describe our results on the determination of the chemical profile of the essential oil (EO) of flowers from Tagetes minuta L. grown in Southern Brazil. The major component of the EO is (Z)-tagetone 1 (70.64% w/w). Thiotagetone 6, a semi-synthetic derivative, was prepared from 1 in 82% yield. Compounds 1 and 6 and the EO were evaluated for their antioxidant and antifungal activities in vitro. All the tested samples presented antioxidant effect in scavenging radical and in the lipid peroxidation assays. A good antifungal activity against Candida lipolityca, Candida parapsilosis, Trichosporon asahii and Sphaceloma ampelinum was observed. (Z)-Tagetone 1 inhibited the mycelia growth of S. ampelinum around 80% at 6 days. No acute toxicity (200 mg/kg) was observed in mice for the EO or the compounds 1 and 6. The lack of toxicity is an indicative for additional studies aiming their potential therapeutic use.

TREATMENT OF INEDIBLE POULTRY CARCASSES THROUGH COMPOSTING

A trial was conducted to evaluate the treatment of inedible poultry carcasses through composting. Physical and chemical transformations of biomass were monitored during 180 days of composting. A completely randomized design was used and data were subjected to ANOVA and polynomial regression at 5%. Moisture was not a conditioning factor for efficiency of second stage of composting, highlighting the significance of intermittent revolving of composting material. Poultry litter supplied nitrogen (N) for the microorganisms, hence should not be used as a carbon (C) source for composting of inedible poultry carcasses and must be replaced for materials containing a high C:N ratio. The mixture of inedible poultry carcasses and poultry litter resulted in a low initial C:N ratio, leading to volatilization of N and, as a consequence, increasing C:N ratio during the whole composting process. As a result, additional time was needed for proper stabilization of biomass. The final compost showed a high pH and therefore may be used for correcting acid soils. Composting process increased nutrients concentration in the biomass. The values herein obtained were within limits of environmental legislation of some countries, such as Brazil (Normative Instruction No25/2009). In conclusion, composting is an alternative for ecologically correct disposing of inedible poultry cuts and ought to be used for poultry producers and industry, helping achieving its environmental sustainability.