Microwave Cooking Heats Up
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Here are some considerations for private label buyers looking to ensure high-quality products for the microwave.
A study produced on national eating trends from the NPD Group found that in 2009, 22.5 percent of all meals prepared in the home involved the use of a microwave oven. As use of this technology has increased, so has the sophistication around microwavable food products, which have advanced since the first patent for microwave prepared food (popcorn popped on the cob) was filed in 1946.
The Role of Packaging
Microwavable compatible packaging materials include polymers such as polypropylene (PP), Crystalline Polyethylene Terephthalate (CPET) and polylactic acid (PLA). Additionally, there are some materials considered dual-ovenable for use in the microwave oven and traditional oven. These packages are made from CPET, press board, folded board and aluminum materials. All materials have different pros and cons and should be considered based on application and desired attribute.
As microwave packaging grew in sophistication, researchers saw opportunities to engineer packaging to enhance the heating process. A prime example of this is steam-assisted cooking, which occurs when the package prevents the release of the vapor byproduct produced during the microwaving process. By retaining this vapor, steam that usually moves away from the product is harnessed to assist in the heating process. Any steam that can be harnessed to give its energy (heat) back to the product aids in the heating of the food product. Packaging that has the ability to “trap” in higher volumes of steam typically has a greater effect on the food product (heating and eating quality). This process also allows for more uniform, consistent heating.
More sophisticated examples of packaging designed to interact with microwave ovens are self-heating technologies referred to as susceptors. Susceptors incorporate a thin layer of conductive metal into the package in order to absorb microwaves while they travel through the product or container. The incorporation of susceptors into packaging, allows for the targeted crisping and browning of particular areas of the product, such as crisping only the bottom portion of a microwavable pizza.
Susceptor packaging can serve as a key way to increase the quality of microwavable food products and is generally safe to use as long as it meets the laid out optical density (OD) specifications for metallized films. If store brands are evaluating the incorporation of these technologies into their packaging formats, it is important that they work or partner with microwave technology and packaging experts to do so.
Impacts of Design & Formulation
The process of designing and formulating food products for the microwave is complex as well. Adapting re-heating instructions on products developed for conventional oven heating is not the way to succeed in microwavable formats. This is because microwaves consist of electric and magnetic waves so the electrical and thermal properties of the food itself will affect the way it heats in a microwave. For example, salt has little influence on oven heating, but it can enhance a product’s ability to absorb microwaves. As a result, foods with higher salt contents will absorb microwave power more effectively and exhibit strong surface heating.
Following is a list of additional items to consider when it comes to product development for microwave food products:
- The bigger the product, the more of a challenge it is to achieve favorable reheat performance
- Tray shape should be given special consideration as it can affect heating
Keep in mind that microwave power coupling is affected by volume, not mass
- Consider altering the size and shape of meat and vegetable inclusion pieces to reduce reheat times and eliminate superheating in focus areas
- Sauces can be used to eliminate superheating effects in parts of the product
- The higher the fat content in product components, the hotter those components will become. ■
* Sean Brady is the ready meals technical marketing manager for Sealed Air Cryovac Food Solutions North America and instructor of the Sealed Air Cryovac microwave heating course. For more information on Cryovac Ready Meals, including the Simple Steps microwavable package, please visit: www.cryovacsimplesteps.com.
