Potatobreeding #89 specific gravity, underwater weight, dry matter content, starch content

Specific gravity, underwater weight, dry matter content, starch content. I'm going to try to explain. Specific gravity is expressed in kilograms per cubic decimeter. 10 by 10 by 10 cm or 1 liter. With water this is 1. But with some shapes this is difficult to measure. With this weight this may still be doable, but it can also be done differently. Now we go to underwater weight and it's about displacement. This 5 kg weight naturally displaces much less than 5 liters of water. But what is the specific gravity? Now we weigh this 5 kilograms of iron underwater. It now weighs 4295 grams. So it has moved 5000 minus 4295 is 705 cubic centimeters of water, and we immediately know the content of this weight. Now we have the formula: specific gravity = 5000 / (5000 - underwater weight ). In this case 5007 / (5007 - 4295) = Specific gravity 7.1. Now let's go to the potato. Here we have 5 kilograms of potatoes that have an underwater weight of 455 grams. Then the specific gravity is 5000 / (5000 - 455) = 1.1. The net content of these 5 kilograms of potatoes is therefore 5000 - 455 = 4545 cubic centimeters. Dry matter content is the content that remains when all moisture has evaporated from it under laboratory conditions. Fortunately, we have a formula for this. Dry matter = (underwater weight × 0.0493) + 1.95 . In our case, 455 × 0.0493 + 1.95 = 24.39 percent. Starch content we also have a formula for (owg - 70.3) × 0.04772 and our example is 18.36 percent. Fortunately, we have a table that contains everything.
#specificgravity #underwaterweight #drymatter

[@marekhorecny]

Dear Jan
I want to thank you for the content that you create on this channel. This is unique informations that are not normally available in this form and I really appreciate the work and time you devote to creating these videos...

[@Jan-Boer]

Thanks.

[@stefanielange89]

How do you determine the standard numbers for the starch content calculation? Is this calculation only applicable for 5 kg or dry weight potatoes?

[@Jan-Boer]

I never work with starch content, it seems to be a fixed percentage of the dry matter. So if you can determine dry matter, you can always calculate or read the starch content in a table.

[@maamaraljabiri1174]

What if i dont have 5kgs of potato can i use the weight then determine what the weight would be if 5kgs

[@Jan-Boer]

That's right, you can simply calculate it back to 5 kilograms.