Title : Effect of fertigation levels on bioactive compounds in fruit and plant waste of Capsicum
Abstract:
Capsaicinoids are groups of alkaloids synthesised in plants through a chain of metabolic reactions and source of pungency. Capsaicin and dihydrocapsaicin are the major members comprising almost 90% of this group in capsicums and chillies. The major production and accumulation site is the non-edible part of fruit i.e., placenta. Other parts of the plant like stem, leaves, pericarp and seeds also contain these compounds. However, it is evident that significant amounts of capsaicinoids can be extracted from parts of the plant which are ultimately treated as waste biomass, or waste materials. Capsaicinoids are enriched with properties like analgesic, anti-inflammatory, anti-microbial, anti-carcinogenic and anti-diabetic. The study examined three different nutrient treatments for growth, yield and capsaicinoids concentration in capsicum and chilli fruits and their plant wastes. Three capsicum (Royston, Groote and Owen) and two chilli varieties (Jet and Caysan) were grown in a high-tech glass house facility in Sydney, Australia. Plants were treated with three levels of fertigation i.e., EC 1.8, EC 2.8 and EC 3.8 (dS/m). Samples were further separated by edible and non-edible (seed and waste) parts. Solvent extraction procedure is used to extract the secondary metabolites followed by UPLC and UPLC-MS for targeted and untargeted analysis of the compounds, respectively. The results indicated non-significant impact of different fertigation levels on yield of capsicum fruit. Overall EC 2.8 gave the better fruit yield of capsicums, and those fruits have the higher capsaicinoids concentration. Capsaicinoids profile was dominated by dihydrocapsaicin in capsicum fruits and seeds and plant waste samples and by capsaicin in chilli samples.
These findings promoted the optimal use of fertilisers to achieve sustainable crop production, resulting in maximum yields with lower input costs. Moreover, the research findings endorse that capsicum and chilli have great bioactive potential and crop waste needs further investigation to be functionalised as a sustainable source of capsaicinoids. In future, the project aims to develop the health beneficial products from the isolated bioactive compounds.
