NPC user guide

A weight change factor of 200% does not indicate that the food doubles in weight. Rather, the food gains twice its original weight on cooking and it has tripled in weight.

You don't have to calculate a weight change factor. Simply make notes of your own recipe weights for before and after cooking. Then type the final weight into the NPC.

Download a list of common weight change factors on our NPC database files and supporting documents page.

Specific gravity

Paragraph 5(1)(b) of Standard 1.2.8 requires that the average quantity of a beverage or other liquid food in a serving must be expressed in millilitres in your NIP.

In the NPC, specific gravity is the ratio of the weight of an amount of a liquid compared to the same amount of water. For example, it is known that 100 mL of cold water weighs 100 g. In comparison, 100 mL of honey weighs 143 g. By dividing the weight of the honey by the weight of the water, we get the specific gravity of honey: 1.43.

The specific gravity of a liquid can vary for a number of reasons. The specific gravity can increase or decrease depending on what is in it. It increases with the amount of solids, such as sugars. It decreases with the amount of alcohol and fat present in a liquid, or air present in a whipped ingredient. It can also vary with the temperature of the ingredient. The way you pack the food in the measuring instrument can influence it. For example how tightly packed the brown sugar is in the measuring cup.

The specific gravity is relevant at two places in the NPC and will likely not be the same at both places.

Specific gravity in step 1

In step 1 of the calculations, you have the option to add ingredients in g, kg, mL and L units. The NPC does all calculations in step 1 using gram weights. So if you choose to enter an ingredient in mL or L, you must convert these values to grams. All liquid ingredients in FSANZ database have been allocated a specific gravity to allow this conversion. If you create a custom ingredient that is a liquid, you must enter a specific gravity if you plan to add the ingredient using the mL or L units.

Specific gravity in step 3

In step 3 of the calculations, you can select a serve size for your final product that is in g, kg, mL or L units. If you select mL or L units, you must then enter a specific gravity to allow the NPC to convert your NIP values from per 100 g to per 100 mL.

Specfic gravity difference examples

The specific gravity value in step 1 is different to the specific gravity value in step 3 in a banana milkshake, as set out below.

Common specific gravities

The specific gravities we have here derive from several recognised literature sources 29, 30 and are exactly the same as those provided in the NPC. These values are provided solely as a guide. It is better to calculate your own specific gravity value for your recipe using the Final weight of your product and its corresponding volume and the following equation:

Specific gravity (g/mL) = weight of 100 mL of food ÷ 100

Read more about common specific gravities on our NPC database files and supporting documents page.

Creating custom ingredients

We've developed a database to support the NPC containing average values for a range of foods. We intend you use these values if you don't have data on foods you're using to make your final product. You should consider creating a custom ingredient if you:

• have nutrition information for foods you have used in your recipe
• are using a food that isn't in our database and you have an alternative data source.

When you add a custom ingredient, it'll automatically be stored as one of your custom ingredients and will be displayed as a search result for you to add to future recipes.

Only you can use your custom ingredients. They don't become part of our NPC database.

If you obtain nutrient data from another source, make sure:

1. you have values for energy and the six mandatory nutrients
2. the values are per 100 g edible portion, if you have data for a liquid food that is provided per 100 mL, multiply the per 100 mL values by the specific gravity to get per 100 g values
3. the Saturated fat is less than or equal to the Total fat
4. the Sugars are less than or equal to the Carbohydrates
5. the sum of Protein, Fat and Carbohydrate are less than 100 g
6. the data meet the requirements of the Australia New Zealand Food Standards Code. Make sure that the carbohydrate values have been derived by one of the two methods specified in clause 1 of Standard 1.2.8. Make sure that the correct energy factors have been used to calculate the total energy. See Standard 1.1.1 and Standard 1.2.8 of the Code.

You can create a custom ingredient on the Manage recipe ingredients page as part of step 1. You can copy and delete stored custom ingredients in the search results box of step 1.

Special notes for boiled, fried, baked and fermented foods

The NPC has limits when the preparation of your food involves certain cooking, preparation or processing methods. The following sections have advice on what you can do to use the NPC to obtain a representative NIP.

Boiled foods

Boiling dry foods such as rice, pasta and dried legumes will result in a net weight gain because they absorb water. Steaming a raw food may also result in a weight gain due to absorbed water. The weight gain during steaming may not be the same as the weight gain that occurs during boiling.

There are two methods to calculate a NIP that will take into account the absorbed water.

Method 1 - select the boiled or cooked ingredient

Step 1 of the maintain recipe ingredients screen is when you select the ingredients for your recipe. So instead of selecting the raw version, select the cooked version. For example, instead of selecting Pasta, white wheat flour-based, dry, select Pasta, white wheat-flour based, boiled from dry, no added salt. This is the preferred method. The results you get using this method will probably be better than those you would get using method 2. However, you should note that the extent of the water absorption depends on your particular processing conditions. For example, the size of the cooking container and whether or not you use a covering will effect water absorption.

Use this method when an ingredient must be boiled or cooked before it is added to a recipe requiring further cooking. A lasagne is a good example of this. In this case, the boiled or cooked ingredient would be the pasta, which is then added to the lasagne and baked.

Method 2 - select the uncooked ingredient and add a weight change

This method may be useful if you can't find a suitable cooked version on the NPC. At step 1 of the maintain recipe ingredients screen when you select the ingredients for your recipe, select the uncooked version. For example, select Pasta, white wheat-flour based, dry and enter the uncooked weight for example 500 g. You don't need to add the boiling water as a second ingredient.

At step 2, enter a final weight or weight change for the boiled food. For example, for 500 g of dry pasta which has been boiled, a weight change of 131% would be entered resulting in a final weight of 1155 g.

Or you can weigh your boiled ingredient and enter the result as the final weight.

You can also use this method when an ingredient must be boiled or cooked before it is added to a recipe requiring further cooking. Using the lasagne example, follow the steps above to create an NIP for your cooked pasta. You can then use this data to create a custom ingredient for boiled pasta and add it as an ingredient to your recipe.

Adding salt to the cooking water

Most of the boiled or cooked ingredients in the NPC are without added salt. If your recipe requires you to add salt to the cooking water, it's important to note that not all of this salt will end up in your food.

Salt, or sodium chloride is made up of 39.3% sodium and 60.7% chloride. Salt is normally added to the cooking water to make up a 0.5% salt solution13. A 0.5% salt solution increases the sodium content of a cooked food by approximately 80 mg per 100 g. This is assuming your food started off unsalted. 

So how much salt do you need to add to your current ingredients list to get the desired sodium increase of 80 mg per 100 g of boiled food, for your NIP?

The trick is to work out how much sodium chloride contains 80 mg of sodium.

If there are 39.337 mg of sodium in 100 mg of sodium chloride, then by doing a simple cross-multiplication, there will be 80 mg of sodium in 203 mg of sodium chloride.

So, when using the NPC, first, select the boiled ingredient. Then add it to your current ingredients list.

Then select salt and add an amount of 203 mg (which is the same as 0.2 g) for every 100 g of your boiled food. For example for pasta, use the following equation to calculate the amount of salt:

Amount of salt (g) = Amount of boiled pasta (g) x amount of salt per 100 g of food (g)

100 = 1000 g x 0.2 g

100 = 2 g

Fried foods

Frying foods such as potato chips and meat will result in a weight change due to loss of water and absorption of cooking fat or oil. The NPC can't calculate a NIP for fried foods without you doing some manual adjustments first. This is because it can't determine how much cooking fat will be absorbed by a particular food.

Given the NPC's limits, the preferred method of producing an NIP for a fried food is to have the nutrient content of your fried food determined by laboratory analysis. We strongly recommend you make use of this option wherever possible.

The following technique helps get around the problem that not all of the cooking fat used in the recipe for frying will be absorbed by the food.

In this scenario, you have fried regular potato chips in peanut oil, which resulted in a final weight of 250 g.

a) Find a weight change factor.

Choose a weight change factor that describes your fried food.

In this example, the weight change factor for fried chips is -27.0%.

b) Work out the weight of ingoing ingredients.

Manually calculate the initial weight of the ingoing ingredients to get the final weight of the cooked chips of 250 g using the weight change factor you just found and the following formula:

(Final weight x 100) ÷ (100 - weight change factor) = Initial weight of ingoing ingredients

where:

(250 x 100) ÷ (100 - 27) = 343 g of ingoing ingredients

These calculations show that to obtain a final weight of the cooked chips of 250 g, 343 g of raw potatoes and oil were required.

At this stage, we don't know what proportion of each makes up the finished product. This is what we are trying to find out.

c) Add the ingredients.

On the Maintain recipe ingredients screen at step 1, add the uncooked potato ingredient. Add a temporary yet sensible Amount, in this case say 300 g, which you will later change. Note down the total fat content.

d) Search for the frying fat used.

On the Maintain recipe ingredients screen at step 1, search for the frying fat. Add this to your ingredient list with a temporary ingoing amount, in this case say 43 g, to make up the total ingoing weight of 343 g, which you will later change.

In this example, you would select the raw ingredients 'POTATO, SEBAGO, PEELED, RAW' (food id 13A11490), with a total fat of 0.2 g and 'OIL, PEANUT' (food id 04C10061).

e) Look for a similar cooked product.

You now need to access either the Australian Food Composition Database - Release 1 or AUSNUT 2011-13 databases to search for a fried version of the food. Note down its total fat content per 100 g.

In this example, an appropriate fried version would be 'F007236: Potato, chips, regular, fast food outlet, deep fried, monounsaturated oil, salted, from Release 1. This chip is fried using monounsaturated oil as the frying medium, and is appropriate because peanut is also a monounsaturated oil. The total fat content is 12.2 g per 100 g.

The ingoing quantities of potatoes and oil must now be manipulated to reflect a total fat content of 12.3 g per 100 g, as shown in the nutrition information panel.

f) Enter the serve size and serves per package.

This is necessary so that the NPC has all of the mandatory information required to calculate the NIP as you adjust the ingredient amounts in the next step.

g) Adjust ingredient amounts.

Use the total weight of the ingoing ingredients to begin your adjustment. This is the initial weight as a constant, in this case it’s 343 g. Now, incrementally adjust the amount of both ingredients in opposite directions. The aim is to obtain a total fat value of 12.3 g per 100 g in the NIP.

In this example, you started with 300 g of raw potato and 43 g of peanut oil. Now edit each ingredient amount in turn, in opposite directions, making sure the initial weight stays the same, in this case 343 g. As you make the changes to the amounts, the NIP is automatically recalculating, so you can easily see the total fat change as you adjust the ingredient amounts.

Using this process you will find that you need 312.5 g of raw potato and 30.5 g of peanut oil to produce 250 g of cooked chips with a total fat content of approximately 12.2 g per 100 g, as shown in the NIP.

This example highlights how frying foods such as potato chips can result in a substantial weight change due to the loss of water and absorption of cooking fat or oil.

Other processing practices

There are many processing practices apart from boiling and frying that may result in changes to the nutrient composition of the finished product14. These include, but aren't limited to those listed below. The NPC isn't able to adjust nutrient values to account for any changes in composition to the raw ingredient that may occur as a result of these practices. Such changes may be highly variable depending on the specific product and the particular processing method employed. If you feel that the NPC may not accurately represent your product, we suggest that you have the nutrient content of your fried food determined by laboratory analysis wherever possible.

Baking

Baking may affect carbohydrate and thus energy levels. During baking, some of the starch in the food for example baked potatoes, may be converted into a form of unavailable carbohydrate known as 'resistant starch'. This may result in a slight reduction of the available carbohydrate, and thus energy, in the finished product.

Also during baking, carbohydrates may participate in a range of browning reactions. In the finished product, this again leads to a slight reduction in available:

• carbohydrate
• sugars (and thus energy)
• or both.

Fermentation

Fermentation may also have an effect on carbohydrate, and thus energy levels. The final carbohydrate content of the fermented product depends on the extent of fermentation. Fermentation generally involves the conversion of sugars, which are a carbohydrate component, into gases, alcohols and acids, the latter is often carbon dioxide and organic acids such as lactic acid.

Fermentation takes place in the production of yeasted baked goods. It results in all of the following:

• the conversion of starch to resistant starch or sucrose
• the conversion of sucrose to glucose
• the conversion of glucose to carbon dioxide in sour dough breads, wines and beers, sauerkrauts and other fermented vegetables, yogurts, cheeses, and other fermented dairy goods.

The NPC includes nutrient values for many of the above fermented foods. If one of your ingredients is a fermented food, using the already fermented, rather than the raw or unfermented version from the NPC is probably a better option. Having said this, it is important to note that the final carbohydrate content of the fermented product depends on the extent of fermentation. So, NPC values may not always adequately represent your product.

Considering all of this, you can expect to obtain better results selecting the fermented version rather than the unfermented version from the NPC.

Soaking, washing, rinsing and draining

The nutrient composition of foods may also be affected by soaking, washing, rinsing and draining. For example, this may affect cereal foods such as pasta and rice, where these process may remove carbohydrates which impacts the energy.

Some ingredients may be supplied packed in brine such as vine leaves, or salt such as capers. So you may need to wash and rinse these ingredients before using them in a recipe. In this instance, the extent of washing or rinsing may affect the amount of sodium, a component of salt or sodium chloride remaining.

Draining brine or oil from canned and bottled products, such as canned fish, can also affect the final nutrient values of your product. This depends on how much of this fluid is drained off.

In any of the situations we describe above, it’s important to note, NPC values may not always adequately represent your product.

Trimming of fats

Any fat trimmed off meat carcasses or cuts, including poultry, may impact the fat content of your final product.

We recommend taking great care when selecting trimmed meat cuts from the NPC to choose the one that best reflects your ingredient.

Related links

• Nutrition Panel Calculator
• NPC 'how to' videos