Effect of different drying and cooking treatments on phytochemicals and antioxidant activity in broccoli: an experimental in vitro study

Abstract

The current study aimed to assess broccoli's phytochemical profile and determine its antioxidant activity. Fresh broccoli was procured from a local farm and divided into two major treatment groups (cooked and dried). There were five sub-treatments in the cooking group (conventional, microwave, boiling, blanching, and steaming) and three treatments in the drying group (sun drying, freeze drying, and hot air drying). Ascorbic acid content, total carotenoids, TPC, TFC, and antioxidant activity were evaluated for every sub-treatment. The results depicted that the antioxidant constituent of cooked broccoli was complementary to dried broccoli samples. The maximum amount of ascorbic acid content (10.80 mg/100 g), total carotenoids (3.976 mg/g), total phenolic contents (225.80 mg/g), and the total flavonoid contents (42.92 mg/g) were found in freeze-dried broccoli. Freeze-dried broccoli also showed the highest antioxidant activity for DPPH free radical scavenging assay (62.45%), hydrogen peroxide radical scavenging assay (53.67%), and ABTS radical scavenging assay (65.84%).

Assessment of the Effects of Roasting, Contact Grilling, Microwave Processing, and Steaming on the Functional Characteristics of Bell Pepper (Capsicum annuum L.)

“…Different results were obtained in a study by Özgür et al in 2011 [ 27 ], where the total content of polyphenolic compounds in green bell peppers was reduced from 96.04 to 55.47 mg GAE/g during conventional oven drying, and in a study by Hameed et al in 2023 [ 28 ], where steamed fresh green broccoli ( Brassica oleracea ) showed a higher total content of polyphenolic compounds (191.75 mg/g d.b.) compared to samples after microwave treatments (180.03 mg/g d.b.)…”

“…), relative to the raw material [ 26 ]. Also, in a study conducted by Hameed et al in 2023 [ 28 ], it was shown that a steam treatment of fresh green broccoli (Brassica oleracea) preserves higher antioxidant activity (58.80 DPPH (%)) (expressed as a percentage of DPPH radical neutralization) than a microwave treatment (54.95 DPPH (%)). However, in the same experiment, a hot-air treatment (oven roasting) (expressed as a percentage of neutralized DPPH radicals) proved almost as beneficial as the steam treatment and gave the tested broccoli an antioxidant activity of 58.36 DPPH (%) [ 28 ].…”

“…A 2023 study by Hameed et al [ 28 ] similarly showed that fresh green broccoli (Brassica oleracea), after steam treatment, exhibits a higher antioxidant activity (64.28 DPPH (%)) (expressed as percentage of the DPPH radical neutralization) than after microwave treatment (57.60 DPPH (%)). In the same experiment, hot-air treatment (baking) proved significantly less favorable than steam treatment and conferred antiradical activity on the tested broccoli (expressed as a percentage of the neutralized ABTS cation radicals at 63.69 ABTS (%)) [ 28 ].…”

Modern and traditional cooking methods affect the antioxidant activity and phenolic compounds content of Trachystemon Orientalis (L.) G. Don

“…Antioxidants have been proven to have an essential role in preventing cancer, cardiovascular diseases, diabetes, neurological diseases and immune system diseases by clearing reactive species in the body [14]. Phenolic compounds are natural antioxidants.…”