Effect of UV‐C treatments on quality and browning‐related enzyme activity of fresh‐cut eggplant ( Solanum melongena L.) during cold storage

Abstract

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.

Impact of Agronomic Treatments on the Enzymatic Browning of Eggplants (Solanum melongena L.)

“…Moreover, Lemos et al (2022) evaluated the effect of UV on fresh-cut eggplants. They reported that the PPO activity in UV-treated eggplants was between 5.98 and 6.38 AU/min/mg protein [35]. These results were lower than the results obtained in the present work, which could be due to the better efficiency of UV in the deactivation of PPO than agronomic treatments.…”

“…One of the main problems with eggplants is enzymatic browning on the cut surface, which limits the eggplant's shelf life [35]. Table 2 shows the color properties of fresh-cut eggplants, fertilized with chicken manure, which were exposed to air over time at room temperature.…”

“…The first principal component factor (PC 1, horizontal axis) Lemos et al (2022) evaluated the effect of UV-C treatments on the browning of fresh-cut eggplant. They reported that the BI value increased during storage due to the production of brown polymers stemming from the enzymatic browning that occurs immediately after cutting [35].…”

Use of an eco‐friendly preservation technology as a strategy to increase the microbiological shelf‐life of a novel ready‐to‐eat salad containing vegetable by‐products

“…This trend was also observed in other vegetables products. Lemos et al (2022) observed inhibition of PPO activity by low UV‐C doses (1 and 2 kJ/m 2 ) in fresh‐cut eggplant, while highest doses increased its activity up to control samples during storage. Probably, the irradiation with low doses could modulate a signaling pathway which leads in a decrease or stabilization of the PPO activity (Lemos et al, 2022) maintaining the total polyphenol content during storage as it was shown in Section 3.1.2 in the present investigation.…”

Characterization of Browning, Chlorogenic Acid Content, and Polyphenol Oxidase Activity in Different Varietal Types of Eggplant (Solanum melongena) for Improving Visual and Nutritional Quality

“…Non-enzymatic browning reactions, particularly the Maillard reaction, have been reported as notable contributors [ 33 , 34 ]. Furthermore, some studies have reported the important roles of other antioxidants, various enzymes, and environmental factors such as temperature and pH, along with specific storage conditions, as influencing factors in the browning of eggplants [ 35 , 36 , 37 , 38 ].…”