Analysis of indigenous spices widely consumed in Bangladesh: An assessment to explore its proximate contents, minerals, phytochemical compositions, and antioxidant activities

Spices are common flavoring ingredients used in the preparation of culinary items and food products. Spices, unlike other components of food, are considered non-nutritive elements and they do not have to meet rigid nutritional quality standards. Therefore, the present study focused on the investigation of proximate contents, minerals, phytochemical components, and antioxidant activity of 9 indigenous spices (cardamom, clove, cinnamon, red chili, black pepper, cumin, coriander, fennel seed, and ginger) consumed in Bangladesh. A range of proximate compositions of spices including protein (2.70-15.44%), fat (4.33-19.04%), fiber (4.70-9.37%), ash (2.25-9.16%), moisture (5.34-10.48%), carbohydrate (50.15-75.87%), and energy (322.36-422.68 kcal/100g) were recorded. They contained a considerable amount of sodium (15.72-111.13 mg/100g), potassium (17.35-1452.86 mg/100g), calcium (7.37-481.54 mg/100g), and manganese (17.64-4615.33 mg/100g). Spices in water and ethanol had a significant content of total phenols (6.24-139.32 mg gallic acid equivalent/g), flavonoids (2.87-89.60 mg quercetin equivalent/g), and antioxidant capacity (8.94-86.50 mg ascorbic acid equivalent/g). Different extents of DPPH radical scavenging activity (2.62-94.16% by 100 ppm of extract) among them were reported. The content of total carotene ranged from 0.02 to 1.27 mg/g. Moreover, correlation and principal component analysis provide evidence that polyphenolic compounds are responsible for their potent antioxidant properties. Thus, these findings will be helpful by proving a baseline for spices towards being an essential ingredient of nutraceuticals as well as enhancing their consumption and production.