BEIJING - Media reports suggesting Ajisen Ramen uses cheap powders and other instant seasoning for its noodle soup, instead of boiling pig bones for hours as its advertisements suggest, have failed to deter the chain's customers in China.

"I don't mind their using concentrated soup as long as it is proved to be healthy," said Lin Li, a customer in Jiangsu province, adding that using concentrated soup to make noodle soup is "totally understandable".

"For restaurants like Ajisen Ramen, which are always crowded with people, they don't have time to cook soup on the spot," Lin said.

However, the reports did prompt some customers and media to request access to the kitchens at some branches of Ajisen (China) Holdings Limited, but these were denied.

"Anyone that is not working at Ajisen is not allowed to enter the kitchen," said a staff member surnamed Zhu at an Ajisen branch at Wangfujing in Beijing, adding this was to protect "trade secrets".

But Hao Xiong, head of the department of investor relations, Ajisen (China), said the concentrated soup is made in Japan - by stewing pig bones slowly - and then delivered to Ajisen's branches in China, where it is then diluted with water.

One kilogram of concentrated soup can make about 100 bowls of noodle soup, according to Hao.

"If Ajisen Ramen indeed makes its noodle soup from pig bones, it cannot be considered fraud, even if they don't cook it in their own kitchens," said Xiang Yang, a lawyer at Beijing's Yingke Law Firm.

Ajisen (China) Holdings Limited is the sole franchisee of Japan's Ajisen branded restaurant in China. It is one of the country's largest restaurant chain operators and now has 585 branches in China.