There are many types of starch available in the market, but not all may be suitable for your specific needs. While suppliers may have knowledge about their own products, they may not fully understand your requirements. To select the right type of starch that best fits your needs, you can consider important conditions and ask your self/ your suppliers the following questions:
What function do you need the starch to perform?
Once you have determined the food product, it’s important to identify the specific function(s) you want the starch to perform. Will it serve a single purpose or act as a multifunctional ingredient? Answering this question can help you determine whether you need a single type of starch, a blend of starches, or an ingredient system. If a blend is required, the ratio between starches becomes critical to achieving the desired physical properties. By answering this one question, you can narrow down your options and make informed choices about selecting the right starch or considering other ingredients, such as hydrocolloids.
How do you plan to process the starch?
The answer to this question will determine whether you need to cook the starch or not. If your process is a dry mix or a non-cooking preparation, you may want to consider using instant starches. However, if thermal processing is required, it is suggested to use cook-up starch as the first choice for cost and functional reasons. For dry mix foods, it is important to consider what happens post-blending or when the consumer interacts with the product.
What is the pH of the food system you are working with?
It is important to know the pH level of the finished food product for both processing and food safety purposes. Different acids have different “pk” values (titratable acidity), which affects the total acidity of the food system. Titration is a more accurate method to calculate total acidity. Starches are considered neutral when the pH is between 4.6 and 7.5. Foods with a pH value above 7.5 may develop off-flavors and require sterilization for long shelf-life. Starch selection for sterilized foods depends on the required processing temperature. Foods with a pH below 3.5 can potentially hydrolyze starch, which means that the degree of cross-linking and finished texture will determine starch selection. Foods with a pH range between 3.5 and 4.6 offer several starch options. The texture, processing, container size, and cooling requirements of the product will determine the best starch or starch blend for your needs.
How does the processing method impact starch selection?
The answer to this question helps determine how to maintain granule integrity during and after processing. If granule integrity is not important, an instant starch may suffice. However, if water management is critical, granule stabilization is important. Shear can damage starch granules, similar to heat and acidity. For instance, simple milling can fracture granules, but high shear conditions such as homogenization or vacuum cooling can be even more damaging, particularly under stress conditions such as low pH and/or high heat. Improper handling or an incorrect starch selection could cause granule damage, free water, and instability during storage.
How much water-soluble material will be present?
The presence of ingredients that hydrate water can limit the availability of water for starch granule hydration, swelling, and viscosity generation. Starch requires a minimum level of water to function fully. When other soluble materials are present and the total soluble solids exceed 45%, the starch may be limited in hydration under atmospheric conditions. At soluble solids less than 20%, the water phase is in excess compared to the percentage of starch used, making it typically incapable of managing the water compared to food systems with soluble solids between 20% and 45%. Therefore, to stabilize the water phase, the technologist must increase the percentage of added starch or other total soluble solids to greater than the desired amount as originally identified.
Are you using fats, salts, or gums in your product?
These ingredients can affect how starch hydrates and functions. Gums, like starches, can impact texture and mouthfeel, but also compete with water and affect starch hydration. Salts can hydrate water and affect flavors, and also have thermal properties that can affect cooking and alter flavors. Fats and oils do not hydrate water but can affect the rate at which starch hydrates, which can impact the final product. Identifying the correct order of ingredient addition is important for controlling the final product’s characteristics and stability, especially in dry mixes.
Will the finished food be cooked again?
If yes, the food scientist needs to choose the right starch and processing method to ensure the final product meets the requirements. They need to know how the consumer will cook or heat the food to select the right ingredients. For foods that will be post-processed, a blend of starch and hydrocolloids may be used.
How will the food be stored?
This is an important question for food scientists. They need to know how long the food will be stored, and under what conditions, so they can choose the right ingredients and process for the food. For example, if a food will be frozen for more than a year, the scientist needs to know the storage conditions to decide whether to slow or fast freeze it. Starch alone may not be the best solution, but a combination of modified starch and gum can provide the necessary stability.
Questions to Ask Before Selecting a Starch
1. What is the desired function for the added starch?
- a. thickener
- b. binder
- c. stabilizer
- d. bulking agent
- e. texturizer
- f. several
- g. emulsifier
2. What is the processing method?
- a. cooking (liquid)
- b. dry mix
- c. noncook (liquid)
- d. several
3. What is the pH of the food system?
- a. >4.5
- b. <3.5
- c. <4.5
- d. unknown
4. What is the percent soluble solids? (ingredients that hydrate water)
- a. >45%
- b. <20%
- c. <45%
- d. varies
- e. >55%
5. What is the shelf-life expectancy?
- a. <30 days
- c. >1 year
- b. 1-6 months
- d. unknown
6. How will the finished product be stored?
- a. ambient temperature
- b. frozen
- c. combinations
7. What is the desired product texture?
- a. smooth
- b. nonsmooth
- c. grainy
- d. other
8. What is the desired eating quality (mouth-feel)?
- a. creamy
- b. jelly
- c. fudge
- d. pasty
- e. unknown
9. What is the desired surface appearance?
- a. sheen
- b. translucent
- c. opaque
- d. dull
- e. unknown
10. How will you measure or determine viscosity? And when?
- a. Visco-Amylo-Graph
- b. Fluidity (funnel)
- c. Brookfield
- d. Rapid-Visco-Analyzer
- e. Bostwick
- f. unknown
11. Is high or excessive shear introduced?
- a. homogenization
- b. direct steam injection
- c. milling
- d. pumping > 25 ft. hot
- e. vacuum
- f. several
12. Will the process involve one or more of the following?
- a. hot filling
- b. blast or quick freezing
- c. ambient filling
- d. reheating (reconstitution)
- e. refrigeration
- f. steam tables
- g. slow freezing
- h. yours
13. If fat is used, what type?
- a. liquid
- b. lard
- c. solid
- d. blend
- e. shortening
14. Are salts utilized?
- a. what type
- b. percent
- c. blends
- d. other
15. Are other hydrocolloids used?
- a. what type
- b. blends
- c. unknown
16. Is the final product a dry mix?
17. If yes to 16, what does the process involve?
- a. blending
- b. extruding
- c. agglomerating
- d. combinations
18. Is moisture content of the added starch critical?
19. If yes to 18, what is the anticipated packaging?
- a. paper
- b. heat-sealed
- c. wax-coated
- d. combination
- e. poly-lined
20. If not a dry mix, what is the anticipated packaging?
- a. glass
- b. paper
- c. can
- d. plastic
- e. pouch
- f. tote
- g. drums
- h. several
21. Is the added starch to be used in more than one product?
If yes, consider similar events for the other products and identify the critical functions contributed by the starch.
22. How important is ingredient economics?
- a. very
- b. quality dependent
- c. not very
- d. unknown