Customers with Prada handbags and Gucci sunglasses sometimes stand in line for hours and hungrily wait outside the restaurant door, feasting their eyes on the delicacy that awaits inside: a bowl of ramen.

Ramen has long been known as a staple of construction workers and penny-pinching students.

But in a push to win over new clientele, ramen chains are going upscale, serving special pork and organic vegetables at eateries featuring dark-wood interiors and soft lighting.