Effects of Organic and Mineral Fertilization on Yield and Selected Quality Parameters for Dried Herbs of Two Varieties of Oregano (Origanum vulgare L.)

Abstract

The purpose of the conducted study was to determine the effect of the applied organic and mineral fertilizer on the yield and the selected quality parameters of the obtained dried mass of Origanum vulgare L. A pot experiment was carried out involving two varieties of oregano (Aureum and Hot & Spicy), which were fertilized using organic and mineral fertilizer. The produced raw material underwent a drying process using the CPD-VMFD combination method, which involved convective pre-drying (40 °C and 0.8 m s−1) and vacuum-microwave finish drying at 240 W magnetron power. The resulting dry products were assessed in terms of color in CIE L * a * b * (Colour Ques spectrophotometer) and spectrophotometric analyses in order to determine the total content of polyphenols and antioxidant properties (ABTS and DPPH). Headspace solid phase micro-extraction (HS-SPME) from the obtained products was carried out, and their composition was determined by gas chromatography (GC-MS). The organic fertilizers used have resulted in the production of dry oregano herbs with a much higher bioactive potential than that of the herbs treated with material fertilizer. This phenomenon could be recognized as an elicitation effect associated with the use of common nettle extract. The organically fertilized oregano also contained an increased carvacrol content in the headspace, which resulted in a more intense odor of the dry herbs. The use of organic fertilizers in the cultivation of Origanum vulgare L. contributes to the production of raw material for direct consumption and drying, which has a higher bioactive potential and better organoleptic properties.

Effects of Ozone Treatment on Microbial Status and the Contents of Selected Bioactive Compounds in Origanum majorana L. Plants

“…[23]. Ozone fumigation took place in a plastic chamber described by Szpunar et al [33]. Subsequently, the aboveground biomass was harvested on the first and fifth day following the treatment, each time from half of the plant pots representing the specific variants of the experiment (duration of ozone treatment).…”

“…The contents of polyphenols in the leaves of Origanum majorana L. were measured in accordance with the methodology described by Matłok et at. [33]. Antioxidant potential of marjoram leaves was determined using the ABTS method described by Matłok et al [33] as well as by the DPPH method described by Oszmiański et al [34].…”

Influence of Agronomic Practice on Total Phenols, Carotenoids, Chlorophylls Content, and Biological Activities in Dry Herbs Water Macerates

“…Although determined higher polyphenols content in macerates for conventional cultivation stands against the work of Matłok et al, who determined the much higher bioactive potential of dry oregano cultivated with organic fertilizers comparing to conventional cultivation [ 27 ]. However, Lv et al compared peppermint and cinnamon cultivated organically and conventionally and determined in both herbs higher total phenolic content in conventionally cultivated herbs [ 28 ].…”

“…Matłok et al pointed on a strict correlation between chlorophylls content and carotenoids in foliar plants due to general biosynthetic pathways in the plants’ chloroplasts [ 27 ]. Therefore, the higher content of pigments involved in photosynthesis is related to higher carotenoid content (beta carotene) [ 21 ].…”

“…According to Skubij and Dzida, over the influence of organic fertilizers on the plants’ chemical compounds [ 35 ]. The other factor influencing carotenoid content is UV radiation that also increases antioxidant content [ 21 , 27 ].…”