The ultrasonic extraction (UE) of oil from the seeds of a semi-oriental tobacco (Nicotiana tabacum L.) plant strain by using n-hexane and petroleum ether was studied at different temperatures and seeds-to-solvent ratios. The oil yield depended on the seed comminution, the extraction temperature, the seeds-to-solvent ratio and the type of solvent. The oil yield was much higher if the seeds were ground before extraction. The oil yield increased with increasing the extraction temperature and with decreasing the seeds-to-solvent ratio. n-Hexane was somewhat more efficient in the oil extraction than petroleum ether. In recovering the tobacco seed oil (TSO), the UE was less efficient than the Soxhlet extraction. The advantage of the UE was a relatively high oil yield at 25 degrees C in a shorter time. The kinetics of UE of TSO was described using the model of unsteady diffusion through plant material.

No abstract

The yield and fatty acid (FA) composition of the oil obtained from the seeds of a semi-oriental tobacco (Nicotiana tabacum L.) plant, type Otlja, by various recovery techniques, which are: Soxhlet extraction (SE), maceration (ME), indirect and direct ultrasonic extraction (IUE and DUE, respectively) and cold pressing (CP), were compared. The solvent extractions of ground tobacco seeds (TS) were carried out by n-hexane, while CP was used to recover the oil from the TS. The highest oil yield (32.9 g/100 g, i.e. 93% of the oil content in the seeds) was achieved by CP. Ultrasonically assisted solvent extractions appear to be inefficient in recovering the oil from the ground TS, as the oil yields were only 45-55% of the oil content, depending on the extraction conditions. Independently of the technique applied, linoleic acid was the major FA of the tobacco seed oil (TSO). The compositions of the TSO extracted by SE, ME, IUE and CP were very similar to each other, and the composition of the TSO recovered by DUE depended on the ultrasonic power input. The content of linoleic acid was reduced, while the content of saturated FA was increased by increasing the ultrasonic power from 5 to 50 W.

No abstract

This paper presents a comparative study of the anti-oxidant and anti--microbial activities, total phenolic compounds and total flavonoids in extracts obtained from houseleek (Sempervivum marmoreum L.) leaves by the classical (maceration), ultrasonic and Soxhlet extraction (CE, UE and SE, respectively). The extract obtained by the CE contained higher amounts of phenolic and flavonoid compounds and showed a better antioxidant activity than those obtained using other two techniques. All the extracts, independent of the extraction technique applied, showed antimicrobial activities against Aspergillus niger and Candida albicans only but not against the tested bacteria.