IDDSI Webinar – Part 2 Starchy Foods2 Nov 2018
Following on from our discussion on the fundamentals of choosing and cooking meats we now look at the characteristics of starchy foods and some of the challenges around modifying them for IDDSI Levels. We focus here on IDDSI Level 4 – Pureed.
Check out the link to our webinar at the bottom of the page for more details and recipes.
Starchy Foods – Rice, Potatoes and Pasta
Starch – A very quick look at the chemistry
Starch is made by plants in order to store energy for periods of time when it might be in short supply. Sugars that we taste as sweet can be made of one or two units – starches can be made of millions of units!
There are 2 types of starch found in plants Amylose and Amylopectin. These are stored in granules in the plant cells.
Amylose is a relatively straight, linear polysaccharide that can be made up of several thousand units.
Amylopectin is a branched polysaccharide that can be made up of several million units.
Linear molecules find it easier to stick together than kinked or branched ones do. This affects the properties of food stuffs that contain the different types of starch and will contribute to the qualities of foods with different proportions of the 2 types of starch.
The last thing we will say at this stage is that starch swells when heated in water. At temperatures between 50C-60C the starch will usually unravel, creating a tangled mesh of starch molecules that traps the water. This is called gelation and is the property of starch that allow for the thickening of sauces, texture of bread and the mouthfeel of noodles.
The starch molecules’ ability to bind therefore makes it sticky – something we need to avoid when creating modified foods for the IDDSI Levels.
There are thousands of different varieties of rice with a broad range of characteristics. At one end of the range is ‘sticky’ rice – this is made up primarily of amylopectin, the branched variety of starch. As the branches reduce the stability of the connecting molecules of starch the result is that it leaches easily into the cooking water. When the grains are fully cooked and drained the starches freed during the process sticks the rice together making it cohesive and giving its name.
Short grains such as arborio, carnaroli and pudding rice have similar characteristics to sticky rice.
Long grain rice have proportionally much more amylose than the shorter grain varieties. This is more stable during the cooking process and so once fully cooked the grains will be fluffy and separate.
Long grains include Basmati rice.
In our research we fully cooked (overcooked) both varieties and then blended with water, oil and a combination of both. The biggest finding was that the shorter, so called ‘sticky’ varieties were less sticky than their long grain cousins.
Ultimately both varieties had overly sticky textures that would be unsuitable at IDDSI Level 4 – and on it’s own pureed rice is not very pleasant.
Rice is usually eaten with other elements that are usually wet and saucy. We took our thinking down this path and made risotto style dishes, blended these down and added other purees that complimented the flavour. This started to soften the sticky nature of the rice purees and made them delicious to eat.
Again there are lots and lots of varieties of potato. In our efforts to find some clarity around making potato puree suitable for IDDSI Level 4 we looked into ‘pomme puree’ recipes served in top restaurants around the world (Including Heston Blumenthal and Joel Robuchon) and spoke with potato producers and suppliers. This gave us a great insight into the make up of potatoes, dry matter and such – however the characteristics of theses luxurious preparations with their unctuous mouthfeel make them unsuitable within the IDDSI framework.
So if you can pardon the pun – when we boil it down there are waxy salad potato varieties such as Charlotte and mealy floury varieties such as Maris Piper.
For an IDDSI Level 4 texture we found that the mealy floury varieties were best.
Scrub and cut the potatoes into 1 cm slices (by leaving the washed skins on the potatoes the earthy potato flavour is developed) and cook in well seasoned water.
As soon as the potatoes are totally soft pass through a sieve or a ricer and add in oil and full fat milk to the desired consistency.
We looked at 100% Durum wheat pasta for our study. Different varieties of pasta had the same characteristics – the only difference was in the length of time it took to fully cook (overcook) the pasta.
Quantities of pasta to liquid in the blending process was around 50/50 and we found that using thin but flavourful sauces helped in reducing the sticky nature of the starchy pasta. Pasta is served coated with a sauce so this is the same thinking as with the rice modifications.
When developing recipes around starchy foods be careful as they can thicken quite considerably as they cool. You will find that if you are making your IDDSI texture checks when the food is piping hot the food will over-thicken as it cools. Leave it to an eating temperature before you test the texture – you will find that this problem is greatly reduced. If your proportion of pasta to sauce is right the purees you make should be IDDSI Level 4 compliant.
Click HERE to watch the webinar in full…