Microgreens are an excellent source of health-maintaining compounds, and the accumulation of these compounds in plant tissues may be stimulated by exogenous stimuli. While light quality effects on green basil microgreens are known, the present paper aims at improving the quality of acyanic (green) and cyanic (red) basil microgreens with different ratios of LED blue and red illumination. Growth, assimilatory and anthocyanin pigments, chlorophyll fluorescence, total phenolic, flavonoids, selected phenolic acid contents and antioxidant activity were assessed in microgreens grown for 17 days. Growth of microgreens was enhanced with predominantly blue illumination, larger cotyledon area and higher fresh mass. The same treatment elevated chlorophyll a and anthocyanin pigments contents. Colored light treatments decreased chlorophyll fluorescence ΦPSII values significantly in the green cultivar. Stimulation of phenolic synthesis and free radical scavenging activity were improved by predominantly red light in the green cultivar (up to 1.87 fold) and by predominantly blue light in the red cultivar (up to 1.73 fold). Rosmarinic and gallic acid synthesis was higher (up to 15- and 4-fold, respectively, compared to white treatment) in predominantly blue illumination. Red and blue LED ratios can be tailored to induce superior growth and phenolic contents in both red and green basil microgreens, as a convenient tool for producing higher quality foods.
Tomato is considered the most important vegetable crop worldwide. Improving the nutritional value of fruits must be based on sustainable production in terms of varieties and fertilization management. This study aimed to improve the nutritional value (total soluble solids, acidity, lycopene, β-carotene, polyphenols, macro and microelements) of two tomato varieties (‘Cristal’ and ‘Siriana’) under three fertilization types (NPK chemical fertilizer, chicken manure and biological fertilizer with microorganisms) for the greenhouse. Primary metabolism compounds do not vary significantly according to the type of fertilizer used. The results for the antioxidant compounds showed a better effect of biological fertilization compared to chemical fertilizer and control unfertilized. Thus, the antioxidant activity was improved by 28% compared to chemical fertilization, the lycopene content by 36% and β-carotene by 96%, respectively. The tomato fruits from the local cultivar (‘Siriana’) are richer in nutritional compounds such as rutin, regardless of the type of fertilization, which denotes a good ability to adapt to crop conditions. Tomato cultivars reacted positively to microbiological fertilization compared to chemical, thus producing nutritious fruits under sustainable management. Tomato fruits were richer in the quality of microelement contents.
The use of cold plasma in the treatment of seeds before sowing presents a promising technique for sustainable agriculture. The objective of this study is to evaluate the effect of cold plasma treatment on the morphology of wheat seeds (Triticum aestivum L. ‘Dacic’ and ‘Otilia’), their germination, biochemical composition, and the nutritional quality of wheat grass. Wheat seeds were morphologically and elementally characterized by atomic force microscopy (AFM), scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDX), X-ray computer tomography (CT), and particle-induced X-ray emission (PIXE). Helium was used as a working gas for plasma generation and the analysis of the species produced showed the presence of NOγ, OH, N2 and N2+ and O. Evaluation of germination and plant growth for 10 days (wheat grass stage) highlighted a specific trend for each cultivar. The biochemical analysis of wheat grass highlighted an increase in the chlorophyll content in the plasma-treated variants, an increase in the flavonoid and polyphenol content in ‘Dacic’-treated variant, while the soluble protein content, antioxidant activity, and color were not affected. The analysis of the nutritional quality of wheat grass by the FT-NIR analytical technique highlighted an increase in the ash content in the plasma-treated wheat cultivars, while the humidity, proteins, neutral detergent fiber (NDF), acid detergent fiber (ADF), and energy values were not affected.
In recent years, rhubarb is being increasingly cultivated, as it provides early yields when the vegetables supply to market is deficient and shows high levels of both polyphenols content and antioxidant capacity in edible parts. In 2017, we investigated crops of the rhubarb cultivar Victoria to the fifth year of production. Comparisons were performed between three root phase fertilizations—chemical (NPK 16-16-16®), organic (Orgevit®), and biological (Micoseeds MB®)—plus an unfertilized control. The determinations of polyphenols, the antioxidant capacity, and the yield indicators from the stalks (petioles) of rhubarb were made at each out of the 10 harvests carried out. The highest yield (59.16 t·ha−1) was recorded under the chemical fertilization. The total polyphenols content and antioxidant capacity varied widely from 533.86 mg GAE·g−1 d.w. and 136.86 mmol Trolox·g−1 d.w., respectively in the unfertilized control at the last harvest, up to 3966.56 mg GAE·g−1 d.w. and 1953.97 mmol Trolox·g−1 d.w. respectively under the organic fertilization at the four harvest. From the results of our investigation, it can be inferred that the chemical fertilization was the most effective in terms of yield, whereas the sustainable nutritional management based on organic fertilizer supply led to higher antioxidant compounds and activity.
The aim of this study was to establish the kinetics regression models for yield and composition of Ruta graveolens fruit and Hyssopus officinalis subsp. aristatus aboveground biomass essential oil (EO), collected at different time intervals during the hydrodistillation process. The hypothesis was that collecting the EO fractions during specific time frames may result in EOs with dissimilar composition that may have differential use by the industry. Furthermore, we calculated the kinetics regression models for the composition of EO, isolated by hydrodistillation in a Clevenger-type apparatus and characterized by GC-MS and GC-FID analyses. The EO yield of R. graveolens fruits was 0.39% (relative area % of GC-FID chromatogram), with major constituents in the Control fraction (0–90 min) being 2-nonanone, 2-undecanone, and 2-undecanol, representing 65% of the total oil. The highest concentration of 2-nonanone (60%) was found in the 30–60 min oil fraction, the concentration of 2-undecanone (35%) was highest in the Control (0–90 min) fraction, and the concentration of eucalyptol (19%) was highest in the 5–10 min fraction. The EO yield of H. officinalis subsp. aristatus dried biomass was 1.12%. The major constituents in the Control fraction (0–90 min) of H. officinalis biomass were eucalyptol, α-pinene, sabinene, β-pinene, and cis-3-pinanone, representing 86% of the total. Eucalyptol (58%) was the highest in the 0–5 min fraction. The highest β-pinene (15%) and cis-3-pinanone (20%) contents were found in the 20–40 min fraction. The kinetics regression models that were developed for EO composition of R. graveolens were second-order polynominal, Michaelis–Menten, and Exponential decay, while for EO composition of H. officinalis subsp. aristatus biomass were Exponential decay and Power. The results from this study could benefit the EO industry.