Enhancement of capsicum (Capsicum annuum L.) functional food value through nutrient supplementation with a biostimulant complex comprising triacontanol, phosphate, and potassium

Capsicum (Capsicum annuum L.) is a popular fruit (culinary vegetable) which is consumed for its flavour and functional food potential, associated with the abundance of antioxidant phytochemicals present such as phenolics and flavonoids. This study aimed to explore the impacts to capsicum growth and functional food value from supplementation with a biostimulant complex (TRIA-PK) comprising triacontanol (TRIA), phosphorous (P), and potassium (K). Plants were grown hydroponically under controlled conditions wherein TRIA-PK was provided to treatment plants within the liquid nutrient solution. Ripe fruits were sampled and compared for impacts to yield, quality, and functional food measures. Application of TRIA-PK significantly increased total phenolics (p = 0.014), flavonoids (p = 0.003), and peroxidase activity (p = 0.030), which reflect increased functional antioxidant activity within fruits. Of note, this increased functional food value also aligned with a 9-day reduction in median harvest timing (p < 0.001) and did not come at the cost of plant yield, with no statistically significant differences between treatments. These results provide valuable information to capsicum farmers, highlighting that supplementation of fertiliser solutions with a TRIA-PK complex is a potential strategy for enhancing the functional food value of capsicum for consumers.