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Category Archive: Vegetable Blanching

Tag Archive: Vegetable Blanching

  1. As frozen vegetable market expands, manufacturers must have adequate equipment

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    Vegetables are a staple in any healthy diet. They have key nutrients rarely found in other foods, and taste delicious with almost any meal.

    Fresh produce is delicious, but comes with some flaws. For one, it is seasonal, and when bought outside the natural growing season, vegetables can not only be pricey, but also lacking in flavor and color. Plus, fresh vegetables can expire quickly, giving consumers a limited time to enjoy their purchase.

    The answer to problems like this lies with frozen vegetables. Found in almost any grocery store in America, frozen veggies are not only widely available with a long shelf life, they are also often just as delicious as fresh ones, have the same nutritional value and are commonly more cost-effective.

    Consumers like it cold

    The frozen vegetable industry has grown significantly over the past half-decade. Currently, frozen fruits and vegetables comprise more than one-third of the fruit and vegetable processing industry, according to a report from IBISWorld.

    A number of factors have led to this expansion. For instance, many people have made a conscious effort to eat healthier, but the typical consumer is short on time for cooking. Frozen veggies offer a clear solution to this problem. Additionally, as the world’s middle class continues to grow, more people have access to freezers, allowing them to purchase and store frozen vegetables.

    The processed fruit and vegetable industry as a whole, which includes canned, dried and dehydrated pre-cut foods, pre-made meals and juices, is expected to grow 3 percent annually to $317.1 billion by 2021.

    As the industry continues to expand, and as more consumers show preferences for frozen vegetables, it’s crucial that manufacturers understand how to produce healthy and safe frozen products.

    How vegetables are frozen

    A consumer shopping in the frozen aisle of a typical grocery store may see printed on the side of a package a note boasting that the product inside was frozen just hours after picking. While this is likely true, there’s more to the process than the average consumer might expect.

    How Products Are Made broke down the manufacturing process of peas, a popular frozen vegetable. One of the key steps to the process, after picking and washing but before freezing, is the blanching.

    Blanching is the process of heating up a vegetable but not exactly cooking it. This is necessary for frozen vegetables because it eliminates enzymes and bacteria that could cause problems for consumers.

    PennState Extension explained that blanching also protects the flavor, texture and color of the vegetables. Plus, it shrinks the vegetables and removes air pockets, so more can fit into one bag and they take up less space.

    After blanching, the vegetables need to be cooled before being sorted, inspected and, finally, frozen.

    Turning up the heat

    Blanching requires vegetables to reach a certain temperature for a set period of time in order to inactivate destructive enzymes. According to Food Processing: Principles and Applications, the typical requirements in commercial blanching state that vegetables need to be brought to 212 degrees Fahrenheit or 150 degrees for a warm blanch, according to the Oregon Institute of Technology Geo-heat Center. In both cases, the potato is then cooled to 100 degrees.

    It’s important that frozen vegetable manufacturers know the specific requirements of the foods they are working with. But it’s also crucial that they know what kinds of equipment can help them safely and quickly achieve this state while also being conscious of cost.

    Shell and tube heat exchangers can be used in several capacities in these instances. First, they can be used to warm or cool the heating medium to prepare the food for blanching.

    Second, they can be used for heat recovery. In processes like blanching, heat and energy is given off and lost during the process, but a shell and tube heat exchanger can help capture it and reuse it elsewhere. It can even be used to continue to heat the water needed to blanch the vegetables.

    For information about how shell and tube heat exchangers can improve your vegetable processing operation, talk to the experts at Enerquip. Our team of engineers can work with you to find the perfect solution for your needs.

  2. New processing method creates better-tasting tomatoes

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    flavor A simple and inexpensive hot water bath could drastically change the flavor.

    If you’ve ever bought regular tomatoes from the grocery store, you might have had a few you’ve considered to be bland or flavorless. This notion is not uncommon in grocery stores since the majority of tomatoes come from the farm not fully ripened and green, which leaves them to turn red once they are already stored.

    This process can have tomatoes tasting boring before you even pick them out of the bin at the supermarket. In fact, chilling tomatoes has been found to degrade the flavor of these fruits and the overall quality, Gizmag reported.

    However, a new discovery from plant physiologist Jinhe Bai​ and a team of scientific researchers, found that better-tasting tomatoes could actually be a very simple fix.

    According to the researchers, adding a hot water treatment to tomatoes before they are chilled for storage and shipment increases the flavor of the fruit, Quartz magazine reported. The researchers tested green tomatoes from Florida by dipping the fruit in hot water – approximately 125 degrees Fahrenheit – for five minutes and by letting them cool at room temperature.

    “To produce a better tasting tomato, we added a hot water pre-treatment step to the usual protocol that growers follow,” Bai said. “We found that this pre-treatment step prevents flavor loss due to chilling.”

    Bai also worked with researchers from the University of Florida and the U.S. Department of Agriculture and the Agricultural Research Service to test the tomatoes.

    Counterbalancing preservatives and chemicals

    To keep tomatoes on the shelves longer, it’s no secret that chemicals are used to help the fruits ripen. However, these chemicals tend to deter the flavor of tomatoes. But the hot bath has proven to enhance flavor compounds.

    The very simple alteration to the tomatoes is completed before they are shipped, which produces more enhanced smells as well. Bai explained that the heat treatment regulates the ripening enzymes in the tomatoes and activates the production of a protein that can help prevent cell decay on the fruit.

    “Chilling suppresses production of oxygen, nitrogen, and sulfur-containing heterocyclic compounds, ketones, alcohols and aldehydes, including 13 important aroma components of tomato flavor,” Bai added. “But hot water-treated fruit actually produced higher concentrations of these important aroma contributors, even with subsequent chilling.”

    Heat exchangers in processing plants

    The team of researchers is still testing different stages of the tomatoes to determine the absolute best timing for the heat treatment process. Bai believes this will be the best method of action before offering these solutions to tomato processing plants. Some of the researchers’ tests used methyl salicylate​, which is wintergreen oil, instead of hot water to treat the tomatoes, Science 2.0, reported.

    The whole purpose is to help enhance the flavor of tomatoes, but to also provide a better solution to shipping the fruits. Since hundreds of thousands of tomatoes are shipped from the farm each day, processors could use the heat treatment to send more reliable products. Bai hopes the heat treatment process will take off and become a standard in tomato processing. The researcher even believes the adaptation could eliminate the need to chill tomatoes to begin with.

    As the heat treatment testing continues, processors should prepare their facilities with the most up to date shell and tube heat exchangers to help with heat treatment. This equipment can treat tomatoes before they are sent out for shipment, which ultimately provides a better product from the farmers.