Study of Nutritional and Antioxidant Compounds in Georgian Landraces of Proso Millet (Panicum miliaceum L.)

Abstract

Before rice and wheat gained widespread popularity, millets -  the oldest cultivated plants of the grass family were a staple food in the semi-arid regions of East Asia and even across much of the Eurasian continent. In these regions, millets remain important food crops to this day. The popularity of millets is not accidental. These plants possess numerous positive traits from both agricultural and nutritional perspectives. Renewed interest in millets today is linked to ongoing climate change. Different species of the genus Panicum, due to their drought and salt tolerance, low water and soil requirements, and high nutritional value, are considered reliable agricultural crops for arid regions under conditions of increasing climatic stress.  In various parts of the world, including Georgia, numerous local landraces of proso millet have developed. However, the Georgian landraces of proso millet are practically unstudied from the point of view of beneficial and nutritional compounds. Therefore, the aim of the present study was to investigate essential components of the human diet — proteins, carbohydrates, and health-beneficial antioxidant compounds — in seeds of local Georgian proso millet landraces: Panicum miliaceum L. ssp. contractum Alef., Panicum miliaceum L. ssp. effusum Alef., Panicum miliaceum L. ssp. subcinereum Alef., Panicum miliaceum L. ssp. contractum Alef., var. laetum Körn., as well as an imported millet purchased from the commercial market were studied. Spectrophotometric methods were applied. Obtained results demonstrate that, the local Georgian proso millet landraces differ from one another in the quantitative content of the studied compounds. Subspecies contractum can be considered a distinct landrace, as most of the studied parameters reached their highest values in this subspecies. Subspecies effusum and subcinereum were similar to each other. The lowest values of most studied indices were recorded in var. laetum and especially in the commercial millet. In the last carotenoids were 3,6 times lower, soluble carbohydrates – 4,6 times, proteins – 2,2 times and total phenols – 12 times lower than the maximum values of these indices. The results of the present study provide a basis for recommending local Georgian proso millet landraces as agriculturally promising, drought-tolerant cereal crops that may serve as reliable sources of nutrients and bioactive compounds under stress conditions.