The concept is to use rice paper wrapping with a very fine element (thin rice paper) that is optimally hydrated for microwaving...
So the paper must be very very thin but also strong, so that it can be steamed in a small electric/microwave heated steamer..
It has to be said that Japanese sushi is a very enjoyable meal, most important of all from our point of view of space and weight economy ..
The fish and meat can be freeze dried for weight reduction and time preservation, also freeze dried product is 100x more resistant;
To the storage of space radiation and the spoiling that results from micro radiation damage,
You see the water in protein and vitamin products renders the contained chemicals vulnerable to radiation damage..
Also the hydrated state of the food allows radio active elements a more welcoming environment for their containment & the resulting decay results..
So in order to provide an economic and very tasty meal for astronauts; Cereal and rice products are not impossible for space use,
As long as the food is cooked and hydrated in an optimized, cooking chamber with wasted element recovery.
A : A steam cooker ( this technology is both low powered and optimum for cooking needs )
B : The cooker water is heated up with a small microwave jet element and surrounds the food in the correct amount of heated steam..
at a good and safe temperature, This can also hydrate the food while steaming it.
C : The chambers temperature is monitored for cooking and safety needs, also the hydration levels..
D : As the food cools to mouth watering temperatures of yummyness, the extractor can recuperate the excess healthy water for drinking..
E : Because the steam contains nutritional elements as the cooking is done; It makes a healthy supplement to the diet and can be served cooled or warm or as soup in flasks.
The rice and or starch hydrate material is ideally thin and will melt in the mouth; leaving the food simply to be tasted,
The usage of rice and other particulates is then possible without the usage of a bag or mess.
An alternative principle is to use the lab containment vessel principle (such as is used in biological research),
As such a self expanding polymer bad can be used with glove compartments; to allow the eating of more normal but exciting meals.