Effects of conventional cooking techniques on the glucosinolate content and antioxidant properties of red cabbage (Brassica oleracea var. capitata f. rubra) and white cabbage (Brassica oleracea var. capitata f. alba)

• Main Authors: Almonte, Ma. Katrina R., Tuason, Angelique Yvonne Q.
• Format: text
• Language: English
• Published: Animo Repository 2021
• Online Access: https://animorepository.dlsu.edu.ph/etdb_chem/1
• Institution: De La Salle University

Glucosinolates are biologically active compounds found in the Brassicaceae family and they, along with their hydrolysis products, have been studied due to their anticancer properties. The present study analyzed the glucosinolate content and biological properties of extracts from samples of red cabbage (Brassica oleracea var. capitata f. rubra) and white cabbage (Brassica oleracea var. capitata f. alba) prepared using different cooking techniques; including, microwaved, stir-fried, boiled, blanched, steamed, and raw (unprocessed). HPLC technique was used to determine the glucosinolate content of the samples. It was found that raw white cabbage had higher concentration of glucosinolates (39.09 μmol/g sample) than red cabbage (28.32 μmol/g sample). Moreover, the analysis revealed the decrease in the glucosinolate concentration in boiled and stir fried red and white cabbage, and blanched and steamed white cabbage. The decrease in the glucosinolate content could be attributed to thermal degradation or leaching out of glucosinolates in the water or oil medium used for processing. On the other hand, an increase in glucosinolate concentration was observed in microwaved red and white cabbage, and blanched and steamed red cabbage, possibly due to increase in the extractability of glucosinolates or the decrease in leaching of glucosinolate as water or oil was not added as a medium in the processing. Furthermore, the biological properties of the samples were assessed using the DPPH free radical scavenging assay and PrestoBlueTM cell viability assay. The DPPH assay resulted in a strong antioxidant activity of the methanolic and aqueous red cabbage extracts, while PrestoBlueTM assay revealed cytotoxicity of red cabbage towards cancer cell lines (H69PR, MCF-7, HT-29, and THP-1). On the other hand, white cabbage extract exhibited weak scavenging activity but exhibited cytotoxicity towards H69PR and HT-29 cancer cell lines. Both red and white cabbage samples did not exhibit cytotoxicity towards HDFn normal cell lines, confirming the selectivity of the extracts in targeting cancer cells. Keywords: white cabbage, red cabbage, glucosinolates, cooking techniques, antioxidant, anticancer