Cold Pressing and Supercritical CO2 Extraction of Hemp (Cannabis sativa) Seed Oil

In the past few decades, the Cannabis sativa L. hemp variety has been unfairly neglected because of its similarity to the illegal kind Cannabis indica used as a narcotic. The objective of this study was to evaluate the process of oil extraction from Cannabis sativa seeds by cold pressing, followed by extraction with supercritical CO2. In the pressing experiments, the response surface methodology was conducted in order to study the effects of temperature, frequency, and nozzle size on oil recovery and quality parameters. The optimal condition for obtaining the highest oil recovery (23.34 %) and the best oil quality within the experimental range of the variables studied was at temperature of 60 °C, frequency of 20 Hz, and nozzle of ID 6 mm. The residual oil (10.33 %) in the press cake was extracted totally by supercritical CO2 in a newly designed supercritical fluid extraction system. Oregano essential oil was the most effective in protecting the oil from oxidative deterioration

Phenotypic correlates of spermatozoon quality in the guppy, Poecilia reticulata

The phenotype-linked fertility hypothesis suggests that a female can benefit directly from mate choice when the cues she uses indicate the quantity and/or quality of his spermatozoa. We tested the link between sperm quality and male body size and coloration in the resource-free mating system of the guppy, a tropical fish characterized by strong female choice. Larger males possessed larger testes and are therefore predicted to produce larger numbers of spermatozoa than smaller males. Larger male guppies also produced longer spermatozoa than smaller males. Degree of carotenoid coloration did not predict either the quantity or the quality of a male's spermatozoa. These results are consistent with a previous study that showed that female guppies in the study population prefer larger males to brightly colored males. The male-size directed increase in spermatozoon size may be the result of interplay between sperm competition and the coevolution of spermatozoon traits with the female reproductive tract. Copyright 2007.male size; phenotype-linked fertility; Poecilia reticulata; sperm size; sperm velocity