The effect of UV‐C (1, 2, 5, and 10 kJ/m2) on sensory attributes, browning index (BI), ascorbic acid (AA), total phenolic compounds, and browning‐related enzymes (i.e., polyphenol oxidase, PPO; phenylalanine ammonia lyase, PAL) of fresh‐cut eggplants throughout 10 days at 4°C was studied. Untreated samples were used as control. Treatments with 5 and 10 kJ/m2 presented higher values of PPO activity and BI, with a loss of 50% and 30% of AA and phenols compared with the control, and sensory quality fewer than 4 days. In contrast, 1 and 2 kJ/m2 did not affect PAL activity and 1 kJ/m2 showed sensory acceptance for at least 6 days, with significantly low BI values and PPO activity, and higher phenol and AA content, compared with the other treatments. Therefore, 1 kJ/m2 could be an effective technology to maintain quality and delay the browning of fresh‐cut eggplants. Novelty impact statement Enzymatic browning is the main factor limiting the shelf life of fresh‐cut eggplants. Therefore, to reduce this problem, the effect of UV‐C radiation on the quality of this vegetable was studied. The dose of 1 kJ/m2 had a beneficial impact on the reduction of enzymatic browning since it induced the least increase in PPO activity, the highest retention of AA and total phenols, and not affected PAL activity.

Research background. Fresh-cut fruits and vegetables are considered sources of antioxidant compounds. However, their shelf life is limited due to nutritional, quality and safety deterioration. Therefore, in recent decades, various methods have been reported for food processing and preservation, as well as for the determination of antioxidant compounds, due to their many benefits when consumed. The aim of the present work is to compare the performance of electrochemical and spectrophotometric methods in the analysis of the content of polyphenolic compounds and ascorbic acid in extracts from fruits (eggplant), edible roots (carrot) and leaves (rocket, lettuce and chard), and evaluate their capability to detect small changes in the antioxidant content in the eggplant extracts previously irradiated with different UV-C light intensities. Experimental approach. Polyphenolic compounds and ascorbic acid were determined by electrochemical and spectrophotometric methods. An enzymatic biosensor and a nanocomposite sensor were used for polyphenolic compounds and ascorbic acid, respectively, in electrochemical measurements, while Folin-Ciocalteu and Kampfenkel methods were used for spectrophotometric measurements. Results and conclusion. Results obtained through the different methodologies were comparable and consistent with each other. Both methods allowed determining the content of ascorbic acid and polyphenolic compounds in the fruit and vegetable extracts. Moreover, both techniques enable the detection of the analyte concentration changes in samples exposed to different UV-C intensities and storage days. Finally, it was observed that the antioxidant capacity depends on the type of food, treatment and storage period. Novelty and scientific contribution. Both methodologies were suitable for the quantification of analytes; however, the electrochemical sensors provided higher specificity and selectivity, applicable to different fruit and vegetable matrices, obtaining results with higher precision, in shorter time and with a smaller sample volume, minimizing the economic costs because of the lower consumption of reagents.