Structural characterization of Himalayan black rock salt by SEM, XRD and in-vitro antioxidant activity

Sci Total Environ. 2020 Dec 15:748:141269. doi: 10.1016/j.scitotenv.2020.141269. Epub 2020 Jul 27.


Salt is an essential component of daily life that balances the physiological functions of the human body as well as other living systems. Different varieties of salts are available in the global market. Out of many salt varieties, Himalayan rock salts have gained tremendous importance among consumers due to its diverse nutritional and medicinal properties. There are two types of Himalayan rock salts. One is the Himalayan pink salt and the other one is Himalayan black salt. Out of the two, the Himalayan pink salt is studied extensively but the black salt is underexplored. In the present study, the Himalayan black rock salt was explored to generate more scientific evidence in terms of its geochemical characterization using FE-SEM, X-ray diffractometry (XRD), elemental content using atomic absorption spectrophotometry (AAS) and in vitro antioxidant activity by different methods for the first time. The study revealed that Himalayan black salt was irregular in shape with a quadrilateral, cubic, irregular crystalline structure. The Himalayan black salt exhibited antioxidant effect and interestingly showed low Na levels than common sea salt and Himalayan pink salt. The Himalayan black salt also contained important minerals like iron, calcium and magnesium which are beneficial to human health thus exhibiting superior characteristics over other conventional table salts.

Keywords: AAS; Antioxidant activity; Himalayan rock salt; SEM; XRD.