No abstract

The objective of the study was to perform micromorphological analyses of the secretory structures of leaves and stems of oil-bearing industrial plants from the Lamiaceae family such as lemon balm (Melissa officinalis L.), peppermint (Mentha × piperita L.), sage (Salvia officinalis L.), marjoram (Origanum majorana L., syn. Origanum dubium Boiss.), rosemary (Rosmarinus officinalis L.) and common thyme (Thymus vulgaris L.) using light microscope and scanning electron microscope. In addition, an estimation of the content of volatile substances in the plant species under study was performed using GC-MS, as well as the qualitative and quantitative analysis of essential oil, that is an important component in terms of the estimation of raw material applicability for use in the industry. In the epidermal cells of studied plants, 2 types of Lamiaceae-type glandular trichomes were identified: short- and long-stalked capitate glandular trichomes with single- and bicellular secretory capitulum, and peltate glandular trichomes with eight- and over a dozen-cell secretory capitulum. Capitate trichomes were densely distributed on the surface of the epidermis, while peltate trichomes were sparse, though regular, and were situated in depressions. Glandular trichomes were found more frequently on leaves than on stems. The cuticle of the abaxial of leaf was characterized in most cases by the occurrence of larger average diameter peltate trichomes compared to the cuticle of the adaxial side of leaf. Peppermint produced the largest structures accumulating essential oil on the leaves (average diameter of peltate trichomes – 78.48 µm on the adaxial side of leaf, up to 96.43 µm), while on the stem, the highest average diameter of the peltate trichomes was observed in sage (an average of 75.53 µm, up to 85.99 µm). The lemon balm was characterized by the presence of capitate and peltate trichomes with the smallest diameter (an average of 44.26 µm). Lemon balm was characterized by the greatest density of glandular trichomes compared to other plant species. Among the plants studied, the highest content of oil was noted in the case of thyme and peppermint (2.22% and 2.20% v/w, respectively), and the lowest in green parts of lemon balm (0.17% v/w). The isolated essential oils contained predominantly components from the groups of monoterpenes and sesquiterpenes, and it is the presence of those substances that determines the possibility of utilizing the plants studied for a variety of purposes.

Minimally processed Brussels sprouts were coated which carboxymethyl cellulose/candelilla wax emulsion, packed in boxes with perforated wrap, and stored at 8°C. It was found that the emulsion not only was deposited on the surface but also penetrated into the inside of the heads through vascular system in stems and leaves. The coating did not affect weight loss, moisture content, and texture of the vegetables. In turn, reduced respiration rate, accelerated chlorophyll degradation, and increased activity of polyphenol oxidase was noticed in the coated Brussels sprouts. Consequently, the coating decreased the sensory quality of the vegetables. Furthermore, the coating favored fungal growth in the artificially contaminated Brussels sprouts. The changes in the vegetables were likely due to excessively decreased gas exchange performance, including ethylene accumulation. Practical applications Edible coatings are a particular form of packaging directly applied to the surface of perishables. It is widely believed that coating treatment enhances the quality of fruits and vegetables, protecting them from postharvest decay. Nevertheless, not all coatings will work well on a specific horticultural crops nor will all horticultural crops have the same needs. Consequently, when the coating material is not adequately selected, edible coatings can cause anaerobic respiration by acting as a barrier for the gas exchange between fresh produce and the surroundings. Since the coatings can be produced from various edible biomolecules, selecting a proper coating is quite problematic. In this context, the presented work shows that carboxymethyl cellulose/candelilla wax‐based coating is not suitable for the minimally processed Brussels sprouts. The results reported here could help other scientists adjust their research plans and increase their chances of success in extending postharvest shelf‐life of Brussels sprouts.

Flawonoidy są najbardziej rozpowszechnioną i jednocześnie najbardziej złożoną grupą polifenoli roślinnych. Są aktywnymi antyoksydantami i dzięki temu zapobiegają rozwojowi choroby wieńcowej, mają działanie hepatoprotekcyjne, przeciwzapalne, przeciwnowotworowe oraz przeciwwirusowe. W tkankach roślinnych pomagają w zwalczaniu stresu oksydacyjnego i działają jako regulatory wzrostu. Flawonoidy są syntetyzowane przez rośliny w odpowiedzi na stresy biotyczne. Wzrost zainteresowania tymi substancjami wynika z potencjalnych korzyści zdrowotnych wynikających z aktywności przeciwutleniającej tych związków.