Mahua (Madhuca longifolia (L.) J. F. Macbr.) is a multipurpose tropical tree mainly cultivated or harvested in the wild in South Asia for its edible flowers and oil seeds (CJP, 2007; Fern, 2014; Orwa et al., 2009).
Mahua is a medium-size, deciduous tree, up to 16-20 m high. It has a short, stout trunk, 80 cm in diameter. The crown is rounded, much branched. The bark is grey, vertically cracked and wrinkled, exfoliating in thin scales. The leaves are alternate clustered at the end of branchlets. The leaf blade is simple, 10-25 cm long x 6-12 cm broad, oblong-shaped, rigid, thick and firm, wooly at the lower face and exudating a milky sap when broken. Young leaves are pinkish, reddish-brown. Flowers are borne on green or pink, furry bunches, each bunch consisting of 12 fragrant cream-coloured flowers. The flowers live only one night and then fall to the ground. Pollinated flowers develop into a fleshy, greenish ovoid fruit containing 1-4 shiny, oily brown seeds. The seeds are 3-5 cm long, elliptical, flattened on one side (Trees India, 2016; FOI, 2016; Fern, 2014; Orwa et al., 2009).
Mahua flowers, fruits and leaves are edible and used as vegetables in India and other South Asian countries. The sweet, fleshy flowers are eaten fresh or dried, powdered and cooked with flour, used as sweetener or fermented to make alcohol (Fern, 2014). The fleshy outer coat of the fruit is used as a vegetable. In India, during periods of scarcity, a combination of mahua flowers and sal seeds (Shorea robusta) is boiled to prepare a substitute for grain staples (Sunita et al., 2013). Mahua is an oil plant whose seeds yield between 35 and 47% oil (CJP, 2007; Ratnabhargavi, 2013). Mahua oil is used to make soaps and candles and is a treatment against pest infestations in seeds (Orwa et al., 2009). Oil produced in smallholder farms is of low quality and is mainly used as a ghee substitute or adulterant (Fern, 2014). Mahua oil was reported to have potential use in biodiesel production. In India, potential mahua oil production could be up to 60 million t/year (CJP, 2007). The oil cake resulting from oil extraction is used as a fertilizer, and could be used to control root-knot nematode and fungal infections as the high saponin content reduces nematodes and phytopathogenic fungi (Gupta, 2013; Orwa et al., 2009). Mahua trees host Antheraea paphia, the tassar silkworm which produces silk traditionally used in sari (Vantomme, 2002). Mahua is also used for its hard, strong, dense and reddish timber (Orwa et al., 2009). Mahua flowers produce a nectar that is very valuable to honey bees in periods of scarcity (Singh et al., 2008). Mahua is reported to have many applications in traditional medicine, and to provide several environmental services (see Environmental impact below).
Several mahua products are used to feed livestock. Leaves, flowers and fruits are lopped to feed goats and sheep (Singh et al., 2008). The mahua oil cake (usually called mahua seed cake in India) is used for ruminants in areas where mahua oil production is important, but is generally considered detrimental to livestock performance due to its high content in saponins (Singhal et al., 1986). Spent flowers, the by-product alcohol production, are another by-product of mahua that is occasionally fed to livestock (Reddy et al., 1966).