How is PAC and POD calculated?

When adding ingredients most data is usually quite straightforward to calculate. You can use the Nutrition label information or the USDA database to input the data for an ingredient.
However calculating the PAC and the POD is a little more complicated.

First let’s recap what PAC and POD is.

PAC
PAC stands for ‘Potere Anti Congelante’ can also be called AFP-‘Anti Freezing Power’ or FDPF-‘Freezing Point Depression Factor’
This is a measure of how much the freezing point of the water is depressed. What it means is that the water freezes at a lower temperature. Different sugars affect the freezing point the most and salt and alcohol even more. The higher the PAC the softer the ice cream.

POD
POD ‘Potere Dolcificante’ is the relative sweetness of the ice cream. Another acronym is SP “Sweetening Power”.
The POD tells you how sweet the ice cream is.

For both PAC and POD sucrose (table sugar) is used as a reference with a PAC and POD of 100.
Other sugars and salts have different PACs and different PODs.
The smaller the molecule the more it will depress the freezing point and the PAC is higher.

To calculate the PAC you can use the molecular weight.
Sucrose has a molecular weight of 342.30 g/mol.
So, for example we calculate the PAC of Fructose. Fructose is a monosaccharide or simple sugar and it is smaller than sucrose (a disaccharide).
Fructose has a molecular weight of 180.156 g/mol
We just divide the molecular weight of sucrose with the molecular weight of fructose.
342.3/180.156=1.9
So, 100*1.9=190
The PAC of fructose is 190.

So, if you know the molecular weight of a sugar you can calculate the PAC.

To calculate the POD is a bit more complicated. The relative sweetness of a sugar compared to sucrose is not something we can actually calculate. Instead a panel will simply taste a solution of the sugar or sweetener and compare it to sucrose. So, all different sugars and sweeteners have been analyzed and tested and a relative sweetness has been defined.
Another problem is that the sweetness profile is different for different sugars, that is how fast and long the sweetness develops and lingers. Other sugars also does not taste the same as sucrose and some have side effects like off tastes or chilling sensations etc…

So why can it be hard to calculate the PAC and/or POD of an ingredient?
Well, the problem is that nutrition labels does not have to specify the exact carbohydrate profile of the ingredient. It only has to declare the total amount of sugars.
It also only have to declare mono- and disaccharides as sugars, higher order sugars are counted as carbohydrates.
So, if we read a nutrition label and it has 34g of sugars and 50g of carbs per 100g we don’t actually know what sugar or sugars it contains.
This is true for nutrition labels and in many of the ingredients in the USDA database.
If the sugar composition is not available the calculator assumes all the sugar is sucrose and calculates the PAC and POD for that.
(Unless you check the Dairy checkbox then all the sugar is assumed to be Lactose, the sugar in milk).
If you know the sugar composition you can use the PAC/POD tool and input the sugars for a better approximation.
If the USDA database ingredient has the sugar composition available that will also be used automatically. (Some ingredients have this info).

So, what do you do if you don’t know what sugar/sugars are used?
In the general case it can be hard, you can analyze the ingredient list of the item you like to add and see if it declares any specific sugars. If it does you can make an educated guess of the composition.
The best is if you can get a technical data sheet where the PAC and POD is declared or where the carbohydrate profile is declared. This is however usually not possible for normal supermarket ingredients. Even if you get a technical data sheet the PAC and POD is normally not declared unless the ingredient is specific for the ice cream market.

To summarize.
To calculate the PAC and POD of an ingredient without detailed information of the sugars it contains is not possible and the calculator will assume all the sugar is sucrose.