Insights into profiling of p-coumaric acid treatment on delaying the yellowing of broccoli

Postharvest yellowing is a prominent problem in the broccoli industry. Here, we investigated the impact of p-coumaric acid (p-CA) treatment on the sensory quality of broccoli during shelf life. The 0.5 mmol L−1 p-CA treatment delayed yellowing, as indicated by higher -a/b (chromaticity value), fluorescence decline ratio, and maximum quantum yield value, as well as lower levels of yellowing index. Meanwhile, chlorophyll content in the treated group was higher compared to the control, due to the restriction of p-CA treatment on the increase of chlorophyll-degrading enzyme activities. The inhibition of up-regulated expression of genes involved in chlorophyll catabolism following p-CA treatment supported the above argument. Additionally, treatment improved the activities of antioxidant enzymes and total phenol concentration to impede the accumulation of malondialdehyde and superoxide anion, alleviating oxidative damage. Statistical analysis further proved that p-CA treatment reduced chlorophyll degradation and enhanced antioxidant capacity as the mechanism to delay yellowing.