Birmingham-based independent chain Pak Supermarkets is opening the UK's largest ethnic food supermarket, it claims, in a bid to tap the fast-growing market for speciality foods.

The 80,000 sq ft superstore is due to open in August and its backers said the £7m project would cater for Muslims, as well as Afro-Caribbeans, Eastern Europeans and the areas's large Somali population.

"The mainstream supermarkets have been to slow to cater for Asian and African customers and mainly aim specialist foods at the non-ethnic minority consumer," said Pak Supermarkets development director Mohammed Nazir. "There are a lot of great ready-made products from companies such as Patak's and Noon, but most ethnic minority customers want to buy authentic spices and ingredients and cook a meal with them at home."

Pak's superstore, built on the site of a former bus depot in Washwood Heath, Birmingham will stock established brands as well as loose pickles, spices and sauces from abroad.

The chain, which has four smaller stores in the Birmingham area, claims that its prices will be lower than those at the major grocery chains.

According to advertising giant JWT, Asian foods represent Britain's biggest untapped market. In a report last week the agency said that although the two million Muslims in the UK were among the most deprived groups, they had estimated spending power of £20.5bn.

"Retailers still seem wary of targeting Muslims even though they have been part of British society for years," said JWT chief marketing officer Marian Salzman.

"They were very quick to put up the welcome sign to Polish immigrants and produce special Eastern European lines

"But it has taken a long time to come around to the spending power of Muslim consumers.

"It is the next big thing - retailers need to get out of their comfort zone."