2018 ASHS Annual Conference

Defined as an excess of potassium (K) in the blood (≥ 5 mmol L^-1), hyperkalemia is a potentially life-threatening clinical condition affecting an increasing number of people worldwide. Commonly associated with chronic kidney disease (CKD) and other comorbidities (diabetes, cardiovascular disease, and hypertension), hyperkalemia derives from an impaired capacity to excrete K, or maintain its homeostasis between intra- and extra-cellular compartments. Patients affected by hyperkalemia must reduce the daily dietary intake of K limiting the consumption of high-K fruit and vegetables. Thereby, reducing also the intake of vitamins and bioactive compounds normally assured by the consumption of fruit and vegetables. Aiming to improve and enrich the diet of patients affected by hyperkalemia, a study was conducted to investigate the possibility to produce high quality low-K microgreens suitable for raw consumption. Broccoli (Brassica oleracea L. conv. botrytis (L.) Alef. var. cymosa Duch.), rapini (Brassica rapa L., Broccoletto group), and red cabbage (Brassica oleracea L. var. capitata f. rubra DC.) microgreens were grown in a soilless subirrigation system with nutrient solutions (NS) containing 3 (K₃), 0.75 (K_0.75), or 0 (K₀) mM of K. At harvest, 12 days after sowing, yield components, mineral content, total phenols (TP), and total antioxidant activity (TAA) were examined for all three species. The three species responded similarly to reduced K inputs. Potassium content of microgreens of the three species grown with K₃ NS ranged between 191 and 255 mg 100 g^-1 of fresh product, which may provide between 9.5% and 17.0% of the daily recommended intake of K for people affected by hyperkalemia. Fertigation with K_0.75 or K₀ decreased microgreens K content by 49-59% and 79-82%, respectively, which may supply about 2.0% to 8.7% of the daily recommended intake of K. Fertigation with K_0.75 had no effects on yield and dry matter (DM) content compared to the standard NS; while fertigation with K₀ decreased microgreens yield by 28% and increased DM content by 21%. TP increased with decreasing the level of K in the NS. TAA was on average 35% higher in microgreens grown with reduced level of K compared to those grown at the standard level. In conclusion, reducing the level of K in the NS, it is possible to produce high-quality low-K microgreens suitable to satisfy the dietary needs of patients affected by hyperkalemia, with no or limited microgreens yield decrease.