The Raj did not control the export import trade of India. The grain trade was almost wholly carried out by private dealers, with no relation to the government.

The government generally avoided interventions into the grain trade for the most part, which meant that even as late as 1941 the trade in rice, which formed the largest chunk of the grain trade, was purely carried out commercially by private dealers (as shown by the Marketing Report of Indian rice).

Now, it is untrue that England during this period was facing crop failure and thus food was taken away from India to feed England. There was an increased demand of wheat (with the consequently recorded export in 1877-78) due to the Russo Turkish war, as is seen from the following statement from the Bengal Administration Report of 1877-78, pg. 184:

By virtually closing the Black Sea ports and cutting off one of the main sources of the wheat supply of Europe, the war in Turkey had a direct tendency to increase the exports of wheat from India.

But the question of wheat itself is irrelevant. The famine affected areas of 1876-77 were majority millet and rice growing areas (Famine Commission: Appendix I, 40), divided in the following percentages:

Bombay: 7% Wheat, 83% Millets, 10% Rice

Madras: 0.1% Wheat, 67% Millets, 33% Rice (figures do not add up to hundred because of acreage under gram, minor non food crops, rounding, etc).

From this one can see that the staple diets of the people affected would be some combination of rice and millets. Furthermore, simple wheat substitution would not have worked either, as shown by the opposition starving people demonstrated to US aid wheat in the 1950s in independent India. Therefore, wheat exports is a complete red herring, especially in relation to some kind of agricultural distress in England.

Finally, the mass of exports was minute (less than 3% of all kinds of total food grains). Clearly, the majority of food wasn't shipped off and thus starving Indians.

Sources:

Fred J. Atkinson, Rupee Prices in India, 1870 to 1908; with an Examination of the Causes Leading to the Present High Level of Prices, Journal of the Royal Statistical Society, Vol. 72, No. 3 (Sep., 1909), pp. 496-573.

Report of the Indian Famine Commission: Part I. (1880).

Famine Commission: Appendix I [Miscellaneous Papers Bearing Upon the Condition of the Country and People of India]. (1881).

Report on the Marketing of Rice in India and Burma, 1941.

Report on the Administration of Bengal: 1877-78. (1878).

Sherman, T. C. (2013, September 17). From ‘Grow More Food’ to ‘Miss a Meal’: Hunger, Development and the Limits of Post-Colonial Nationalism in India, 1947–1957. South Asia: Journal of South Asian Studies, 36(4), 18.