Astronauts Jing Haipeng (right) and Chen Dong salute inside the spacecraft at the moment of launching on Monday. [Photo/Xinhua]

The two astronauts headed for the Tiangong II space laboratory aboard the Shenzhou XI enjoyed their first meal about four hours after the spacecraft blasted off at 7:30am on Monday.

The lunch included eight types of food, ranging from grain crackers, canned apples, flatfish, spicy tofu, chicken sausages to lemon tea and stomach friendly beverage.

The recipe will change every five days during their 33-day stay in space, said Cao Ping, a nutrition researcher at the Astronaut Center of China in Beijing.

After Shenzhou docks at the space laboratory, the astronauts will have six types of meals thrice a day - staple and non-staple food, instant food, beverages, flavoring and functional food, and the meal time will synchronize with that on the earth.

Compared to previous space missions, the food on Shenzhou XI has a wider variety of Chinese delicacies.

In 2003, there were 20 or 30 types of food for China's first astronaut, Yang Liwei, who was carried aloft by Shenzhou V. On Shenzhou VII which blasted off in 2012, there were about 70 types of items.

Shenzhou XI, on the other hand, carries more than 100 types of food and beverages, including spiced beef and shredded pork in garlic sauce, a popular dish in almost every Sichuan-cuisine restaurant, and desserts such as ice cream, according to Cao.

Recipes were designed and arranged in accordance with nutritional requirements in different phases of the mission.

For example, the astronauts can eat congees if they lack appetite during their first days in space; Chinese food therapy will be adopted in the middle phase in line with the changes in the astronauts' physical conditions; while in the latter stage, food with low dietary fiber along with multivitamins will kick in.

The daily calorie intake, based on the working load of the astronauts, will be converted to the weight of food, equaling about one or two kilograms.

Cao said the ground crew of Shenzhou XI will keep a close eye on the meals and make evaluations so as to keep the astronauts posted.

The astronauts will use a food heater developed by the Fourth Academy of China Aerospace Science and Industry Corp.