The little-known riches of Algerian rapeseed

Rapeseed (Brassica napus L.) is an oilseed plant valued for its oil and protein-rich meal. This study focuses on the Algerian variety ’Zitna’ and its meal obtained after cold extraction. Physicochemical, mineral, phenolic and antioxidant analyses were carried out. The meal has a higher protein content (4.92 0.04 mg/mL) than the seeds (3.79 0.01 mg/mL), reflecting a concentration effect after extraction. Mineral analysis by flame atomic absorption spectrometry (FAAS) revealed a high potassium content (27.2 0.8 mg/L). Acetone extracts show the highest polyphenol content (67.7 4.3 mg EAG/g for seeds) and methanolic extracts show the highest flavonoid content (23.5 0.6 mg EQ/g). Antioxidant activity (IC₅₀) is more pronounced in seeds (6.5 mg/mL) than in oilseed meal (14.2 mg/mL), with a strong negative correlation between polyphenols and IC₅₀. HPLC analysis identified sinapic acid as the dominant compound and gossypin as a novel bioactive flavonoid, confirming the added value of Zitna rapeseed by-products.