Olga Kosakowska

Antimicrobial Activity of a Pullulan–Caraway Essential Oil Coating on Reduction of Food Microorganisms and Quality in Fresh Baby Carrot

This research evaluated the antimicrobial efficacy of pullulan films containing caraway essential oil (CEO). The films were prepared from a 10% of pullulan, containing from 0.12% to 10.0% of CEO. The composition of the CEO was analyzed with the use of gas chromatography. The antimicrobial activity of the CEO was evaluated with the method of serial microdilutions, and the films containing CEO-with the agar diffusion method against selected Gram-negative, Gram-positive bacteria, and fungi. The structure of the film surface and its cross-section were analyzed using a scanning electron microscope (SEM). Analyses were also carried out to determine the efficacy of a pullulan coating with 10% CEO on baby carrots experimentally inoculated with Salmonella enteritidis, Staphylococcus aureus, Saccharomyces cerevisiae, or Aspergillus niger and stored at a room temperature for 7 d. At a concentration of 0.12%, CEO inhibited the growth of all the tested microorganisms. Pullulan films containing 8% to 10% of CEO were active against all tested microorganisms. Populations of S. aureus on carrot samples were reduced by approximately 3 log CFU/g, while those of A. niger and S. cerevisiae by, respectively, 5 and 4 log CFU/g, after 7 d of storage. S. enteritidis was the most resistant among the tested species, since it was not significantly reduced after 7 d of storage. At the end of storage, samples treated with pullulan-caraway oil coating maintained better visual acceptability than control samples. Results of this study suggest the feasibility of applying a pullulan film with incorporated CEO to extend the microbiological stability of minimally processed foods.

Preservation of Brussels Sprouts by Pullulan Coating Containing Oregano Essential Oil

In this study, the effectiveness of pullulan (a fungal polysaccharide) film containing oregano essential oil (OEO) at 1.0 to 10.0% was evaluated against bacteria, yeasts, and molds. The quality of the sprouts, as determined by weight loss, color, and appearance, was monitored during storage at 2 and 16°C. An organoleptic evaluation of odor preference and odor acceptability of OEO on the Brussels sprouts was also conducted. The antimicrobial activity of pullulan films with OEO increased significantly with the increase in OEO concentration (1 to 10%). Pullulan films with OEO were more effective for inhibiting the growth of yeasts and molds than for inhibiting gram-positive and gram-negative bacteria. Pullulan with 1.0% OEO was an effective combination and was used subsequently as the base coating for maintaining the safety and quality of fresh Brussels sprouts stored at 16°C for 14 days. The pullulan coating containing 1.0% OEO reduced Aspergillus niger populations by 2 log CFU/g. This coating also reduced weight loss in the sprouts. Compared with uncoated Brussels sprouts, the percent weight loss after 14 days was reduced in samples coated with pullulan and with pullulan plus 1% OEO by 3.81 and 6.06%, respectively, after storage at 2°C and by 8.04 and 9.30%, respectively, after storage 16°C. The coating also significantly reduced changes in general appearance and color during storage. Evaluation of the organoleptic properties indicated that pullulan containing OEO had only a slight detrimental effect on odor properties. Incorporating OEO into a delivery system for antimicrobial compounds in pullulan coatings extended the microbiological shelf life of Brussels sprouts.

Setting of southern sweet-grass plantation with stem cuttings obtained by division of maternal plants

Summary Southern sweet-grass (Hierochloë australis /Schrad./ Roem. & Schult.) is a perennial, wild growing tuft grass occurring in North-East Poland, Belarus and Finland. In Poland the species is under the partial legal protection. The raw material harvested from this plant are leaves rich in coumarins, mainly in coumarin responsible for specific sweet aroma of leaves. They are used mostly for the aromatization of alcohol and tobacco products. Due to high demand for the raw material and decrease in the natural resources of the species, it is advisable to introduce the plant into cultivation. In the presented study vegetative planting stock (1-, 2-, and 4-stem cuttings) were used to set the plantation of southern sweet-grass. The influence of the planting stock type on the mass of leaves and their quality in the first and second year of plant vegetation as well as the mass of seeds from two-year-old plants were investigated. The highest number of well rooted plants was obtained from 4-stem cuttings (74.07%) and the least - from 1-stem cuttings (47.53%). Both, on one- and two-year-old plantations the plants from 4-stem cuttings were characterized by the highest mass of leaves (7.73 and 24.65 g ˟ plant-1, respectively). The plants were also characterized by the highest number of generative shoots (40.71 pcs. ˟ plant-1) and mass of seeds (4.62 g ˟ plant-1). The total contents of coumarins and phenolic acids did not depend on the type of planting stock. The contents of these compounds was higher in two-year-old plants than in one-year-old ones, whereas the content of flavonoids was higher in one-year-old plants.

Phenolics in Primula veris L. and P. elatior (L.) Hill Raw Materials

Primula veris L. and Primula elatior (L.) Hill represent medicinal plants used for the production of herbal teas and preparations with antioxidant and expectorant activity. Flowers and roots of both species possess the same biological activity. In the presented study, raw materials of wild growing P. veris and P. elatior were compared in terms of the content and composition of phenolic compounds using a fast and simple HPLC-DAD method. The study showed that flowers of both species were rich in flavonoids. However, P. veris flowers were characterized with a distinctly higher content of isorhamnetin-3-O-glucoside, astragalin, and (+)-catechin, whereas P. elatior occurred to be a richer source of rutoside and isorhamnetin-3-O-rutinoside. Hyperoside was found exclusively in P. elatior flowers. Phenolic glycosides (primverin and primulaverin) were identified only in the roots. Their content was about ten times higher in P. veris in comparison with P. elatior underground organs. The obtained results clearly show that both Primula species differ distinctly in terms of the content and composition of phenolic compounds. The compounds differentiating both species to the highest degree (hyperoside, in flowers, as well as primverin and primulaverin, in the roots) may be useful chemical markers in the identification and evaluation of both species.

Accumulation of phenolic compounds in the purple betony herb (Stachys officinalis L.) originated from cultivation

Summary Introduction: Purple betony (Stachys officinalis L., Lamiaceae) is a perennial of versatile medicinal usage. Nowadays, in Poland betony herb is collected exclusively from wild growing plants. Decreasing number of its natural sites results in lack of the herb supply and thus, in its limited usage. Objective: The aim of the study was to determine the effects of the age of plant and term of raw material harvest on its yield and quality in cultivation conditions. Methods: The observations were carried out on 2- and 3-year-old plants. During vegetation the herb was collected for four times. The raw material was subjected to chemical analysis. Tannins (as pyrogallol equivalent) were determined according to Polish Pharmacopoeia, phenolic acids and flavonoids – by HPLC. Results: The mass of herb, both in the second and third year, had increased from the beginning of vegetation up to seed setting. The highest content of tannins was found in the herb collected at the vegetative stage of plant development (2.05% in the second and 2.91% in the third year). Four phenolic acids (chlorogenic, ferulic, caffeic and rosmarinic acids) and five flavonoid compounds (orientin, luteolin-7-glucoside, apigenin-7-glucoside, apigenin-3-glucoside, apigenin) were identified in the obtained raw materials. In these groups, the dominant compounds were caffeic acid and apigenin. The highest content of caffeic acid was found at the beginning of plant vegetation, whereas apigenin – at the stage of full blooming and seed setting. Conclusion: In cultivation conditions, purple betony produces high mass of herb which may be used as a valuable raw material in herbal industry.

Variability of southern sweet-grass (Hierochloë australis /Schrad./ Roem. & Schult.) wild growing populations occurring in eastern Poland

Summary Southern sweet-grass is a perennial grass distributed through north-eastern Europe. In Poland, this rare, partially protected plant grows wild in well-lit coniferous or mixed forests. Its leaves, rich in coumarin compounds, are used for aromatization of alcohols. Taking into account high demand on this raw material and decrease in the number of southern sweet-grass populations it is recommended to introduce the plant into cultivation systems. In this study 12 populations of southern sweet-grass were selected and assessed in terms of their cultivation usefulness. The presence of associated plant species growing on its natural sites was investigated as well as light irradiance on those stands. The species was found in 3 types of forest communities. Air dry mass of leaves per plant varied in analyzed populations from 1.73 to 11.07 g. They were significantly diversified in the total content of coumarins (0.36–0.96%), flavonoids (0.09–0.26%) and polyphenolic acids (0.13–0.29%). The diversity concerning the content of coumarin, a quality indicator of leaves, was even higher. The content of this compound varied from 52.03 to 275.74 mg/100 g d. m. Among the analyzed populations, the most interesting seem to be population No. 12 (Jedwabno) and population No. 10 (Ruciane) characterized with relatively high mass of leaves and the highest content of the identified active compounds, including coumarin.

Antioxidant and Antibacterial Activity of Roseroot (Rhodiola rosea L.) Dry Extracts

Roseroot (Rhodiola rosea L.) belongs to plants revealing adaptogenic properties, which are attributed to the presence of specific phenolic compounds and are reflected mainly as antioxidant activity. The aim of the present study was to determine the antioxidant and antibacterial activity of various products obtained from R. rosea (underground organs as well as their aqueous and ethanolic dry extracts) in relation to the chemical profiles of phenolic and essential oil compounds. The chemical profiles were determined by High-performance Liquid Chromatography with a diode-array detector (HPLC-DAD) and Gas chromatography-mass spectrometry (GC-MS), antioxidant activity by (1,1-Diphenyl-2-picrylhydrazyl) Scavenging Capacity Assay (DPPH), (2,2′-Azino-bis(3-ethylbenzothiazoline-6-sulphonic acid)) Scavenging Capacity Assay (ABTS) and Ferric Reducing Antioxidant Power Assay (FRAP) and antimicrobial properties were expressed as minimum inhibitory concentration (MIC) and minimum bacterial concentration (MBC) values following the broth microdilutions method. The results show that the investigated samples differed in terms of their chemical compositions and biological activities. The extracts were more abundant in phenolic compounds (salidroside, tyrosol, and rosavin derivatives) in comparison to dried underground organs. The content of the determined phenolics in the analyzed extracts was affected by the solvent used for extraction. The ethanolic extract was characterized by the highest content of these substances in comparison to the aqueous one and the dried raw material, especially with regard to rosavin (969.71 mg/100 g). In parallel, this extract showed the strongest antioxidant and antibacterial activity. However, dried R. rosea underground organs also revealed strong antibacterial effects against, for example, Staphylococcus strains.

Morphological and chemical variability of common oregano (Origanum vulgare L. subsp. vulgare) occurring in eastern Poland

Summary Introduction: Common oregano is an important medicinal and aromatic plant, characterized by a high morphological and chemical variability. Objective: The aim of the work was to determine the diversity of 14 common oregano populations introduced into ex situ conditions, in respect of morphological and developmental traits as well as content and composition of essential oil in herb. Methods: Observations and harvest of raw material were performed in the second year of plant vegetation. Morphological and developmental characters were estimated. Total content of essential oil was determined according to European Pharmacopoeia 8th. The composition of essential oil was carried out by gas chromatography. Results: Populations differed in respect of examined traits, i.a.: plants height from 52.13 to 88.66 cm, number of stems per plant from 45.6 to 123.3, number of internodes per stem from 4.6 to 9.2. Fresh mass of herb was at a level of 249.0–896.6 g per plant. Total content of essential oil ranged from 0.35 to 0.87%. Sabinene, 1,8-cineole, linalool, p-cymene, β-caryophyllene and caryophyllene oxide were the dominant compounds in essential oil. Conclusions: Number of stems and fresh mass of herb differentiated examined populations at the highest degree. Most of populations were classified as a sabinyl chemotype rich in sesquiterpenes.

Chemical compounds and antimicrobial activity of petitgrain (Citrus aurantium L. var. amara) essential oil

Summary Introduction: Due to its low cost and easy availability on the market, the petitgrain oil is commonly used in food, cosmetics, and aromatherapy. Objective: The examination of chemical composition and antibacterial activity of commercial petitgrain oil. Methods: Identification of chemical components of the petitgrain oil was performed by gas chromatography (GC). The minimum inhibitory concentrations (MIC) and minimum bactericidal/fungicidal concentrations (MBC/MFC) were determined using macrodilution method for the reference strains of bacteria and fungi. Results: Twenty components were identified. The petitgrain oil contained mostly oxygenated monoterpene hydrocarbons (98.01%), and the main components included linalyl acetate (48.06%) and linalool (26.88%). The MIC/MBC of the petitgrain oil for bacteria was in the range of 0.63-5.0/1.25-5.0 mg/ml and for fungi in the range of 1.25-40/5.0-80 mg/ml. Conclusion: The petitgrain oil had higher antibacterial activity than antifungal activity. Bacillus subtilis among the tested bacteria and Aspergillus niger and Penicillium expansum among the fungi were found to be highly inhibited by the petitgrain oil.

Experimental Paper. Intrapopulation variability of flavonoid content in roots of Baikal skullcap (Scutellaria baicalensis Georgi)

Summary Introduction: Baikal skullcap (Scutellaria baicalensis Georgi) is an important medicinal plant, indigenous to Asia. Due to a wide range of pharmacological activities, its roots has been used for ages in Traditional Chinese Medicine. Recently, the species has become an object of interest of Western medicine, as well. Objective: The aim of the study was to determine the variability of Baikal skullcap population originated from Mongolia and cultivated in Poland, in terms of content and composition of flavonoids in the roots. Methods: The objects of the study were 15 individual plants, selected within examined population and cloned in order to obtain a sufficient amount of raw material. The total content of flavonoids in roots was determined according to Polish Pharmacopeia 6th. The qualitative analysis of flavonoids was carried out using HPLC, Shimadzu chromatograph. Results: The dry mass of roots ranged from 25.88 to 56.14 g × plant-1. The total content of flavonoids (expressed as a quercetin equivalent) varied between 0.17 and 0.52% dry matter (DM). Nine compounds were detected within the group, with oroxylin A 7-Oglucuronide (346.90-1063.00 mg × 100 g-1 DM) as a dominant, which differentiated investigated clones at the highest degree (CV=0.27). Baicalin (391.40-942.00 mg × 100 g-1 DM), wogonoside (324.00-641.10 mg × 100 g-1 DM) and hesperetine 7-O-glucoside (163.00-346.32 mg × 100 g-1 DM) were also present in a considerable amounts. Clone 7 was distinguished by the highest content of all investigated compounds, except wogonin and oroxylin A 7-O-glucuronide. Conclusions: Results obtained in present study show a high variability within Baical skullcap investigated population in respect of flavonoid compounds detected in roots. Thus, the results may be used in future investigations concerning the selection and breeding of this species.