16
Tracking Moisture Content
After working through the material balance example in the previous chapter, you may be wondering why we care about tracking moisture through a process. There are a few reasons why, although tedious, tracking moisture is important.
- It helps us understand what is happening through the process, especially when comparing one experiment to the next.
- For instance, if the first experiment included raw fruit and the second experiment included frozen fruit puree, how did the initial water content of the fruit (and possibly the particle size) affect the final water content and consistency of the product?
- If the first experiment included a step to cook a filling on top of the stove for 5 minutes and the second experiment modified that step to cook a filling for 15 minutes, how much water was cooked off in both and how did that affect the finished product texture, color, and flavor?
- Tracking moisture content helps convert liquid ingredients to dry ingredients – like fluid milk to nonfat dry milk or liquid egg to egg powder.
- Lastly, and very important for this course, it allows an accurate Nutrition Facts Panel to be generated in Genesis. The Nutrition Facts Panel serving size is based on the finished product weight.
- If moisture is lost through cooking or baking, the calories and nutrients are concentrated in the final product.
- If water is added through processing, it dilutes the calories and nutrients.
- Lastly, tracking moisture through an experiment makes sure you are paying attention to details and observing what is happening during the formulation experimentation process.
Here is an example of tracking the moisture content of ingredients in order to convert from liquid ingredients to dry ingredients. Whenever you are doing formula calculations, it is very important to think through what you know and what you are trying to find. You may need to write it out or draw a picture to help yourself. Then use logic and stop and ask yourself “does that make sense” along the way. For this example, you may want to open your own Excel file and/or write out the calculations to think through the steps. Your layout may look a bit different than what is shown in Tables 1 and 2 and that is okay. Take it slow and make sure you understand each step along the way.
Omelet Formulation Calculation Example – Tracking Moisture and Converting to Dry Ingredients
What you know (or can find out):
- The current formula using liquid ingredients
- The water content (and solids content) of those liquid ingredients
What you want (need) to know:
- Weight of dry ingredients plus the weight of water needed to replace the liquid ingredients
Logic and checkpoints – If you take the water out of the ingredient, you will need less of the dry ingredient.
There are a few ways to calculate a conversion from wet or fully-hydrated ingredients to dry ingredients. Here is an example of converting an omelet formula with fresh/wet ingredients to dry ingredients plus water.
| Fresh Ingredients Formulation | |||||
|---|---|---|---|---|---|
| Ingredients | Batch in grams | % by Weight | Water Content % | Water Content in grams | Dry Weight in grams |
| Egg |
150.0 |
60.0 |
75.8 |
113.7 |
36.3 |
| Cheddar Cheese |
50.0 |
20.0 |
41.1 |
20.5 |
29.5 |
| Skim Milk |
50.0 |
20.0 |
89.0 |
44.5 |
5.5 |
| Total | 250.0 |
100.0 |
n/a |
178.7 |
n/a |
| Converting to Dry Ingredients | |||||
|---|---|---|---|---|---|
| Ingredients | Batch in grams | % by Weight | Water Content % | Water Content in grams | Dry Weight % |
| Dried whole egg powder |
40.3 |
16.1 |
10 | 4.0 | 90 |
| Dried shredded cheese |
31.0 |
12.4 |
5 | 1.6 | 95 |
| Nonfat dry milk |
6.1 |
2.4 |
10 | 0.6 | 90 |
| Water | 172.5 |
69.0 |
100 | 0 | |
| Total | 250.0 |
100.0 |
n/a |
6.2 |
n/a |
Steps for Calculating the Conversion:
1. Fill out the batch weights and % by weight for your current formula.
2. Water or moisture content of each food can be found in the USDA food database, calculated from an ingredient Nutrition Facts Panel, or from an ingredient specification sheet. (If water is not listed, take the total grams & subtract fat, protein, & carbohydrates to find the water content in grams.)
3. Water content in grams = batch weight x water content %
4. Dry weight in grams = batch weight in grams – water content in grams
5. Convert to dry ingredients or to ingredients with a lower moisture content.
6. List new ingredients & find water content percent for each new ingredient.
7. Find the Dry Weight % for each ingredient = 100% – Water Content %
8. To find the new batch weights in grams, take the dry weight in grams of the original formula & divide by the dry weight % of the new formula.
9. Then find the water content in grams by multiplying the batch weight in grams by the water content %.
10. Find the sum of the water contents in grams. Then subtract the total from the water content in grams from the original formula.
178.7 grams total water minus 6.2 grams water from dry ingredients equals 172.5 grams water
11. Take the difference in water content and add that amount in grams of water to the new formula*.
12. Finish filling out the new formula % by weight and check your work.
*If the original formula contains more or less water than desired, it is okay to adjust the water level and overall moisture content.
Tracking Fat Content
Not all food products will need to track fat content changes, but it is still helpful to understand the process. The main application is for frying food. The other instance where tracking fat content is important is if meat is cooked and fat is rendered from the meat (think frying bacon or cooking ground beef or pork and skimming fat from the cooked meat). The importance of tracking fat changes is similar to that of tracking moisture changes. It explains what is happening through the processing steps and is also important for generating an accurate Nutrition Facts Panel in Genesis.
The example given here is for frying french fries. The difficult thing about tracking fat content through frying is that moisture is lost at the same time fat or oil is picked up.
The same guidelines apply here.
Whenever you are doing formula calculations, it is very important to think through what you know and what you are trying to find. You may need to write it out or draw a picture to help yourself. Then use logic and stop and ask yourself “does that make sense” along the way. For this example, you may want to open your own Excel file and/or write out the calculations to think through the steps. Your layout may look a bit different than what is shown and that is okay. Take it slow and make sure you understand each step along the way.
What We Know or Can Reason:
- If the weight of a food is the same before and after frying, the weight of moisture lost equals the weight of the oil gained.
- If the weight of the food is less after frying, more moisture is lost than oil is picked up.
- If the weight of the food is greater after frying, more oil is picked up than moisture is lost (this is less likely).
| Data Needed | Percent by Weight | Weight in Grams |
| Moisture Content Before Frying – This can be determined by moisture content in the formula (calculated in an Excel file or on Genesis) and/or by measuring moisture content on the moisture balance. | ||
| Moisture Content After Frying – This can be determined by measuring moisture content on the moisture balance and/or it can be calculated by fat content pickup weight lost through frying. | ||
| Moisture Lost During Frying – Calculated by subtracting the moisture content after frying from the moisture content before frying | ||
| Weight Before Frying (for the whole batch) – This can be determined by measuring the weights of a set amount of pieces or the whole batch. If the whole batch is used, account for processing loss (batter lost in the bowl, etc.). | ||
| Weight After Frying (for the whole batch) – Again, this can be determined by measuring the weights of a set amount of pieces or the whole batch. If the whole batch is used, account for processing loss (batter lost in the bowl, etc.). Make sure the product has cooled before weighing. | ||
| Weight Difference from Frying** (for the whole batch) Calculated by subtracting the weight after frying from the weight before frying | ||
| Oil Pick Up = Moisture Lost During Frying – Weight Difference from Frying |
| Data Needed | Percent by Weight | Weight in Grams |
| Moisture Content Before Frying – USDA Food Database | 83.29% | 166.6 |
| Moisture Content After Frying (measured by moisture balance) | 66.67% | 133.3 |
| Moisture Lost During Frying | 16.63% | 33.3 |
| Weight Before Frying (able to measure the whole batch for this example) | 100.00% | 200.0 |
| Weight After Frying (able to measure the whole batch for this example) | 91.70% | 183.4 |
| Weight Difference from Frying** | 8.30% | 16.6 |
| Oil Pick Up = Moisture Lost During Frying – Weight Difference from Frying | 8.33% | 16.7 |
Your product may not calculate perfectly like the example above. Determining the values in multiple ways is a great way to verify the results. Weighing the frying pot and oil in the pot at the beginning and end of frying (after the oil is cooled) is a good way to measure oil pick-up for an entire batch.
**If you measure the weight of part of the batch being fried, use the percent difference X the batch weight to get your total moisture loss in grams.
