Tomato’s Green Gold: Bioeconomy Potential of Residual Tomato Leaf Biomass as a Novel Source for the Secondary Metabolite Rutin

Abstract

At the end of the annual horticultural production cycle of greenhouse-grown crops, large quantities of residual biomass are discarded. Here, we propose a new value chain to utilize horticultural leaf biomass for the extraction of secondary metabolites. To increase the secondary metabolite content of leaves, greenhouse-grown crop plants were exposed to low-cost abiotic stress treatments after the last fruit harvest. As proof of concept, we evaluated the production of the flavonoid rutin in tomato plants subjected to nitrogen deficiency. In an interdisciplinary approach, we observed the steady accumulation of rutin in young plants under nitrogen deficiency, tested the applicability of nitrogen deficiency in a commercial-like greenhouse, developed a high efficiency extraction for rutin, and evaluated the acceptance of the proposed value chain by its key actors economically. On the basis of the positive interdisciplinary evaluation, we identified opportunities and challenges for the successful establishment of horticultural leaf biomass as a novel source for secondary metabolites.

Effect of UV Radiation and Salt Stress on the Accumulation of Economically Relevant Secondary Metabolites in Bell Pepper Plants

“…Commercial vegetable production is accompanied by large quantities of so far under-utilized green biomass in all stages of production and especially after harvest [1]. While the use of biomass for the purpose of energy production is becoming a standard procedure in northern Europe in recent years [2], the extraction and the use of high-value secondary metabolites (SMs) from vegetable plant leaves are just being developed. Research strategies in Europe are heading toward a cascade use of agricultural byproducts and pave the way for extracting and using "valuable substances or molecules before ultimately discarding the left-overs" [3].…”

“…However, differences in salt-stress Table 2. Interaction and main effect for treatments (control, salt-stress, combined-stress, UV-stress) and DATI (0, 2,7,9,15). To account for the unbalanced design (e.g., unequal numbers of observations within each level of DATI), type III ANOVA was selected to compare differences between factor means for FLAV values of "All leaves".…”

Coffee (Coffea arabica L.) by-Products as a Source of Carotenoids and Phenolic Compounds—Evaluation of Varieties With Different Peel Color

“…Because of the health beneficial properties of this flavonoid (antioxidant, antimicrobial, anti-inflammatory, anticancer, antidiabetic, antiallergic, etc. ), there is an increasing interest in identifying new rutin sources, and residual biomass has been the focus of recent research (Sharma et al, 2013;Gullón et al, 2017;Junker-Frohn et al, 2019).…”

Effect of UV Radiation and Salt Stress on the Accumulation of Economically Relevant Secondary Metabolites in Bell Pepper Plants

“…Commercial vegetable production is accompanied by large quantities of so far under-utilized green biomass in all stages of production and especially after harvest [2]. While the use of biomass for the purpose of energy production is becoming a standard procedure in northern Europe in recent years [3], the extraction and the use of high-value SMs from vegetable plant leaves are just being developed. Research strategies and legacy in Europe are heading towards cascade use of agricultural byproducts and pave the way for extracting and using "valuable substances or molecules before ultimately discarding the left-overs" [4].…”

“…The biochemical background of enhanced accumulation of SMs in plant leaves as a measure to cope with stress is a well described phenomenon [3,7,8]. In short, the cultivation of plants under suboptimal conditions leads to an increased amount of reactive oxygen species (ROS) in plant tissues.…”