
Indian dishes liberally use yoghurt in their non-vegetarian dishes. But beyond adding a sour taste and creamy texture to the preparations, yoghurts are also used to soften the muscular fibres of meat and make the flesh porous and melt-in-your-mouth.
For aeons now, this milk derivative is added to beef curries and chicken recipes to whip up succulent, luscious, fall-off-the-bones meat dishes. Yoghurt has a similar effect on fish too. Freshwater fish, especially the fatty kind like Ilish (Hilsa), Catla, Rui (Rohu) or Pona, do wonderfully well with an addition of curd, undercutting the greasiness from the lard.
Doi Maach or Dahi Machha, as the Odiyas term it, has been one of the most savoured items to come out of the culinarily rich Odisha. The preparation involves a meticulous process of marinating the fish with yoghurt, turmeric, garlic, garam masala, mustard, a fine chilli paste and tomato purée. The Odiya variant of the dish generally favours the locally cultivated Bhakura (Catla). Turmeric lends the dense gravy the rich yellow colour. Not just that, turmeric is an anti-inflammatory agent that ensures the gravy never becomes too rich for the body to digest properly.
The dish requires minimal effort and can be made in no time. But to ensure a smooth cook, it needs to be ensured that the fish marries well with the marinade. The yoghurt mixed with spices not only seasons the fish but also softens it. Once put in the hot pan, it keeps simmering in its own broth. After a sustained period of continuous heat, the fish begins releasing oils, which add the extra layer of umami to the dish.
The Bangladeshi version of Doi Maach has a much higher spice level. A green chilli paste is not only added to the marinade, but the curry is spruced with laal lonka (red, dry chillies). This odd double spiced aberration is mainly because the Bangal (residents of erstwhile East Bengal, present day Bangladesh) community prefer a high spice quotient in their dishes. Though generally Bangals adopt multiple Bengali dishes, they just tweak the mild flavours for more bold undertones with generous use of black peppers, red, and green chillies. Hence, whole black peppers and cardamoms are a regular feature in the Bangal way of cooking Doi Maach.