Impact of different pre-treatments and drying methods on the physicochemical properties, bioactive compounds and antioxidant activity of different tomato (Solanum lycopersicum) cultivars

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A green pre-treatment approach, microwave (MW) and ultrasound (US), along with drying methods [hot air (HA) and freeze-drying (FD)], was assessed for colour properties, phenolics, carotenoid components and antioxidant activity DPPH, ABTS, FRAP assays of three tomato cultivars (Zzx171, Zzx162 and Zzx65). All three cultivars showed a reduced colour difference (ΔE) after US-FD. The US-FD method retained higher levels of total carotenoids, lutein, β-carotene, lycopene and antioxidant activity in all cultivars than other methods. While US-HA drying retained the highest level of total phenolic content, chlorogenic acid, 4-O-caffeoylquinic acid, rutin, protocatechuic acid and ABTS•+ scavenging activity in powders of all cultivars. ‘Zzx162’ is best suited for US-FD to produce tomato carotenoids-rich functional powder. Powders of ‘Zzx162’ showed the highest lycopene (14.40 mg/g), β-carotene (6.13 mg/g), and ABTS•+ scavenging activity (8.37 SC50 mg/mL). While ‘Zzx162’ with US-HA produced powders rich in chlorogenic acid (58.48 mg/100 g) and rutin (50.33 mg/100 g). These findings suggest that ultrasound pre-treatment is the preferred technology for developing functional tomato powder.