Nada Č. Nikolić

Optimization of Microwave-Assisted Extraction of Cherry Laurel Fruit

Response surface methodology was used to optimize the influence of microwave power (300–600 W), plant material-to-solvent ratio (0.05–0.2 g/cm3), and extraction time (10–30 min) on the efficiency of microwave-assisted extraction of the cherry laurel (Prunus laurocerasus L.) fruit. From experimental data, a quadratic polynomial mathematical model (R2 = 0.9949) was developed to predict the extract yield. All considered factors were statistically significant for extraction efficiency, while the most important factor was extraction time. Microwave power of 550 W, plant material-to-solvent ratio of 0.05 g/cm3, and time of 25 min were determined as optimal conditions with a maximum yield of 9.36 g/100 g fresh plant material, which was confirmed through laboratory experiments (9.12 ± 0.61 g/100 g fresh plant material). An economic condition for simultaneous maximum extract yield (7.58 g/100 g fresh plant material) with minimal energy and solvent consumption was determined by the desirability function method (18.2 min, 300 W, and 0.2 g/cm3). Additionally, the total phenol and flavonoid quantification and antioxidant activity of both extracts were tested. There is no statistically significant difference in the total flavonoid content in the extracts obtained under both proposed conditions, while the total phenolic content and antioxidant activity of the extract obtained under economic conditions were slightly lower.

The effect of hydrodistillation technique on the yield and composition of essential oil from the seed of Petroselinum crispum (Mill.) Nym. Ex. A.W. Hill

The essential oil was isolated from the seed of Petroselinum crispum (Mill.) Nym. ex. A.W. Hill by using different techniques of Clevenger-type hydrodistillation. The highest yield of oil, after five consecutive hydrodistillation runs (3.9 mL/100 g of plant material), was obtained by the technique in which water from the still flask was separated by filtration and used together with fresh water for immersing the plant material in a subsequent distillation. Regardless of the technique used, the oil contained different amounts of α-pinene, s-p/nene, limonene, 2,3,4,5-tetramethoxy-1-allylbenzene, apiole and 1,2-benzenedicarbonic acid.

Isolation of solanidine from haulm and tuber sprouts of potato (Solanum tuberosum L.)

SummaryThe kinetics of enzymatic transformation of total glycoalkaloids (TGA) in haulm and tuber sprouts of potato to solanidine and the kinetics of solanidine isolation from plant material were studied. The optimum reaction conditions for the enzymatic TGA transformation were found for haulm to be: plant material to liquid phase 1:4 w/v, temperature 35°C, pH 5.4; and for tuber sprouts: plant material to liquid phase 1:3 w/v, temperature 37°C, pH 5.4. The. maximum degree of enzymatic transformation of TGA in haulm and tuber sprouts of 65 and 75%, respectively, was achieved after 50h. Carbon tetrachloride was the best solvent for solanidine extraction from the plant materials. The optimum ratio of plant material to carbon tetrachloride for the isolation of solanidine was 1:8 w/v for both extraction cycles, ensuring a yield of solanidine of approximately 55 and 65% from haulm and tuber sprouts, respectively, after 30 min.

Hydrodistillation kinetics and essential oil composition from fermented parsley seeds

The effect of fermentation conditions on the yield and composition of the essential oil from Petroselinum crispum (Mill.) Nym. ex. A.W. Hill seeds was studied. The yield of essential oil was determined by a Clevenger-type apparatur, and the composition of the oil by GC analysis. The highest yield of essential oil (5.90 mL per 100 g, i.e. 96.7% in regard to the oil content in parsley seeds) was obtained from disintegrated parsley seeds fermented for 4 h at 30°C with a hydromodulus of 1:20 w/v, after the sixth hydrodistillation each lasting 240 minutes. The obtained oil contained α-pinene, s-pinene, sabinene, myristicin, 2,3,4,5-tetramethoxy-1-allylbenzene, apiole and 1,2 benzene-dicarbonic acid. The density of the oil (d25) was 1.039 g/mL3, the refractive index, (nD20) was 1.5214 and the oil solubility was 8 volume parts of 80% vol. ethanol for 1 mL of oil.

The effect of parsley (Petroselinum crispum (Mill.) Nym. Ex. A.W. Hill) seeds milling and fermentation conditions on essential oil yield and composition

Parsley (Petroselinum crispum (Mill.) Nym. ex. A.W. Hill) is well known as a medicinal herb with antimicrobical, hypotensitive, diuretic, laxative and spasmolitic effects. Essential oil is present in all parts of the herb. In this paper the effect of parsley seeds milling and fermentation conditions on the essential oil yield and composition were studied. The essential oil yield was determined by a Clevenger-type apparatus, and the oil composition by GC analysis. The obtained oil contained α-pinene, β-pinene, sabinene, myristicin, 2,3,4,5-tetramethoxy-1-allylbenzene, apiole and 1,2 benzene-dicarbonic acid. The physico-chemical properties of the isolated oil were determined and found to correspond to the standard values.

Hydrolysis of glycoalkaloids fromSolanum tuberosum L. haulm by enzymes present in plant material and by enzyme preparation

SummaryThis paper deals with the kinetics of enzymatic hydrolysis of glycoalkaloids from potato (Solanum tuberosum L.) haulm. The hydrolysis was carried out by the action of the enzymes present in fresh haulm, juice of fresh haulm and in haulm dried at various temperatures. The highest degree of enzymatic hydrolysis of 90% was obtained during fermentation of haulm dried at 40 °C after 30 h incubation time. The enzyme preparation was obtained from the juice of fresh potato haulm by using capillary dialysator HM 16 (AQM 1681, 1.6 m2 Hemofan 8 υ). The best degree of enzymatic hydrolysis by enzyme preparation, 68%, was achieved after 20 h time of incubation. The enzyme preparation from juice of fresh haulm was characterized by Km of 0.70 mM at pH 5.5 and 35 °C.