Nutritional profile and physicochemical analysis of two indigenous cultivars of black cumin (Nigella sativa) seeds and oil in Bangladesh

Abstract

The black cumin (Nigella sativa) seed oil has a long history of use for food ingredients. The goal of this study is to figure out the nutritional and physicochemical properties of two indigenous black cumin cultivars (locally known as "Kali Jira" and "Kalonji") seed and oil. Additionally, the effects of extraction time and particle size on oil yield generation was investigated. The values of moisture content, crude protein content, crude fat, crude fiber, total ash, and carbohydrate of Kali Jira seed were 5.29%, 19.83%, 41.3%, 18.96%, 5.10%, and 9.52% whereas Kalonji had 5.43%, 19.95%, 40.3%, 14.28%, 4.35%, and 14.69%, respectively. In the Kali Jira and Kalonji types, the mineral analysis revealed significant potassium levels (829.11 mg/100 g, 746.27 mg/100 g), followed by phosphorus, calcium, sodium, iron and zinc. The minimum oil yield was 46.77% in the Kalonji variety compared to Kali Jira, which had 49.57% after the extraction time of 2 hrs for 1.4-2.5 mm particle size. On the other hand, a maximum oil yield of 91.08% and 94.77% was found in Kalonji seed and Kali Jira seed, respectively, following a 6-hour extraction time for 0.25-0.5 mm particle size. Characterization of extracted seed oil (iodine value, saponification value, and acid value) indicated the abundance of unsaturation in oil. FTIR analysis was used to investigate functional groups. According to the findings of this study, black cumin and extracted oil are rich in nutrients and can be used to treat lifestyle problems.