Harvest Stage and Brewing Conditions Impact Mineral Content, Phenolic Compounds, and Antioxidant Capacity of Lemon Balm (Melissa officinalis L.) Herbal Tea.

Lemon balm (Melissa officinalis L.) is commonly consumed as an herbal tea for its antioxidant health benefits. Young seedlings known as microgreens are popular for their distinct flavors and can contain higher mineral content on a dry weight basis compared to their adult counterparts. However, the use of microgreens for herbal teas has not been previously investigated. In this study, lemon balm was grown to adult and microgreen harvest stages and prepared as herbal teas by brewing with boiled (100 °C) water for 5 minutes and room temperature water (22 °C) for 2 hours. The effects of harvest time and brewing method on the mineral content, phenolic compounds, and antioxidant capacity of lemon balm herbal teas were assessed. Results showed that adult lemon balm tea contained higher total phenolics, total flavonoids, rosmarinic acid, and antioxidant capacity than microgreen teas, with hot preparations containing the highest amounts (p ≤ 0.05). In contrast, microgreen lemon balm teas contained higher amounts of minerals (p ≤ 0.05), including calcium, potassium, magnesium, sodium, phosphorus, copper, and zinc. In general, brewing conditions did not impact the content of most minerals. Overall, the results support the potential of using dried microgreens as herbal teas. Microgreen lemon balm teas prepared hot and cold offer antioxidant compounds and are richer sources of minerals than adult teas. The ease of growth for microgreens offers consumers the opportunity for home preparation of a novel herbal tea beverage.

Biofortification of Sodium Selenate Improves Dietary Mineral Contents and Antioxidant Capacity of Culinary Herb Microgreens.

Selenium biofortification of plants has been suggested as a method of enhancing dietary selenium intake to prevent deficiency and chronic disease in humans, while avoiding toxic levels of intake. Popular herbs such as basil (Ocimum basilicum L.), cilantro (Coriandrum sativum L.), and scallions (Allium fistulosum L.) present an opportunity for biofortification as these plants are used for added flavors to meals and are available as microgreens, young plants with increasing popularity in the consumer marketplace. In this study, basil, cilantro, and scallion microgreens were biofortified with sodium selenate under hydroponic conditions at various selenium concentrations to investigate the effects on yield, selenium content, other mineral contents (i.e., sodium, potassium, calcium, magnesium, phosphorus, copper, zinc, iron, manganese, sulfur, and boron), total phenol content, and antioxidant capacity [oxygen radical absorbance capacity (ORAC)]. The results showed that the selenium content increased significantly at all concentrations, with scallions demonstrating the largest increase. The effects on other minerals varied among herb species. Antioxidant capacity and total phenol content increased in all herbs at the highest selenium treatments, but basil and scallions demonstrated a decreased crop yield. Overall, these biofortified culinary herb microgreens are an ideal functional food for enhancing selenium, other dietary minerals, and antioxidants to benefit human health.

Time-course transcriptomic analysis of Petunia ×hybrida leaves under water deficit stress using RNA sequencing.

Water deficit limits plant growth and development, resulting in quality loss of horticultural crops. However, there is limited information on gene regulation and signaling pathways related to water deficit stress response at multiple time points. The objective of this research was to investigate global gene expression patterns under water deficit stress to provide an insight into how petunia (Petunia ×hybrida 'Mitchell Diploid') responded in the process of stress. Nine-week-old petunias were irrigated daily or placed under water stress by withholding water. Stressed plants reduced stomatal conductance after five days of water deficit, indicating they perceived stress and initiated stress response mechanisms. To analyze transcriptomic changes at the early stage of water deficit, leaf tissue samples were collected 1, 3, and 5 days after water was withheld for RNA sequencing. Under water deficit stress, 154, 3611, and 980 genes were upregulated and 41, 2806, and 253 genes were downregulated on day 1, 3, and 5, respectively. Gene Ontology analysis revealed that redox homeostasis processes through sulfur and glutathione metabolism pathways, and hormone signal transduction, especially abscisic acid and ethylene, were enriched under water deficit stress. Thirty-four transcription factor families were identified, including members of AP2/ERF, NAC, MYB-related, C2H2, and bZIP families, and TFs in AP2/ERF family was the most abundant in petunia. Interestingly, only one member of GRFs was upregulated on day 1, while most of TFs were differentially expressed on day 3 and/or 5. The transcriptome data from this research will provide valuable molecular resources for understanding the early stages of water stress-responsive networks as well as engineering petunia with enhanced water stress tolerance.

Development of iGrow: A Curriculum for Youth/Adult Dyads to Increase Gardening Skills, Culinary Competence, and Family Meal Time for Youths and Their Adult Caregivers.

This manuscript describes the development of a “learn by actively participating” curriculum for youth and their adult caregivers (dyad pair) to increase gardening skills, culinary competence, and family meal time. The curriculum was developed by integrating “iCook 4-H” and Junior Masters Gardener “Health and Nutrition from the Garden”, and “Essential Elements of 4-H Youth Development” curriculums with additional resources for gardening activities from the USDA’s My Plate and garden-based recipes. Expert reviewers (n = 11) provided feedback on the curriculum content, session structure, dosage, age appropriateness, and balance of the three focused areas. Seven family dyads (n = 14) participated in focus groups about understanding of need, interest, barriers, and potential engagement. A 10-week curriculum was developed and named: iGrow. The curriculum is a hands on, active learning program delivered through five, two-hour sessions using a family dyad model. Three main focus areas included gardening, culinary skills, and family conversation/interaction that all focused on togetherness. For the final iGrow curriculum, expert-level content review and feedback from focus group dyad pairs was used to revise the curriculum which further enhanced the approach and balance of the curriculum content. Focus group feedback supported appropriateness, dosage and learning objectives, and content depth. This curriculum has been developed to provide knowledge of gardening and culinary skills with the goal of increased consumption of fruit and vegetables.