Fried foods are popular with consumers, but their high fat content can contribute to health challenges like obesity and hypertension. If the food industry can offer lower-fat options of similar quality, people can more easily make health-conscious food choices.

Researchers at the University of Illinois Urbana-Champaign have explored microwave frying of French fries, providing insights that can help food manufacturers modify their production methods. They propose combining conventional frying with microwave frying to provide the desired crispiness and texture while reducing the cooking time and oil absorption.

“Consumers want healthy foods, but at the time of purchase, their cravings often take over. High oil content adds flavor, but it also contains a lot of energy and calories. My research team studies frying with the aim of obtaining lower fat content without significant differences in taste and texture,” said principal investigator Pawan Singh Takhar, professor of food engineering in the Department of Food Science and Human Nutrition, part of the College of Agricultural, Consumer and Environmental Sciences at U of I.

In two new publications, Takhar and Yash Shah, a doctoral student in FSHN, discussed their findings from studies exploring what happens during microwave frying of French fries.

For the first study, they collaborated with colleagues at Washington State University, who developed a special microwave fryer that could operate both at 2.45 gigahertz (similar to a regular microwave oven) and 5.8 gigahertz.

The sample potatoes were rinsed and peeled, then cut into strips, blanched, and salted. Batches of potato strips were then fried in soybean oil preheated to 180 degrees Celsius. The researchers measured temperature and pressure during and after frying, as well as volume, texture, moisture, and oil content of the fried samples.

The challenge is to keep the oil from entering the food during and after the cooking process, Takhar said.

In the beginning of the frying process, the potatoes’ pores are filled with water, so there is nowhere for the oil to go. But as frying progresses, the water starts evaporating, so pore spaces are opened and oil is sucked into the food through negative pressure.  

“Think about a straw in a drink. If you push air into the straw, it creates positive pressure and any liquid will be pushed out. But if you suck on the straw, the liquid moves upward. Now imagine food materials have lots of tiny straws. When there is positive pressure, the oil stays out. But if there is negative pressure, the oil starts moving in,” Takhar explained.

Up to 90% of frying happens under negative pressure, so there is continuous suction potential. The goal is to keep the pressure positive longer and shorten the duration of negative pressure to prevent oil from entering the food.

“When we heat something in a conventional oven, the heat moves from outside to inside, but a microwave oven heats from the inside out, because the microwaves penetrate everywhere in the material. The microwaves oscillate water molecules, causing more vapor formation and thus shifting the pressure profile towards the positive side. The higher pressure in microwaves helps reduce oil penetration,” Takhar said.

In parallel with the lab experiments, the second paper complements the results through mathematical modeling, which allows for much more detailed exploration of a variety of factors in the frying process.

The researchers explored the effects of temperature, pressure, volume, texture, moisture, and oil at 2.45 GHz, 5.8 GHz, and conventional frying. Overall, they found that microwave frying resulted in faster moisture loss, shorter cooking time, and lower oil intake. 

“However, if you just use microwave frying, you get soggy food. To obtain a crispy texture and taste, you need conventional heating. Therefore, we propose combining the two approaches in the same unit. Conventional heating maintains the crispiness, while microwave heating lowers the oil intake,” Takhar said. 

Continuous fryers used for industrial-scale production of fried foods can be modified by incorporating microwave generators, which are inexpensive and readily available. Thus, this approach is likely to be economically feasible for industrial use, the researchers conclude.

The first paper, “The Effect of Conventional and Microwave Frying on the Quality Characteristics of French Fries,” is published in the Journal of Food Science. Authors are Yash Shah, Xu Zhou, Juming Tang, and Pawan Singh Takhar.

 The second paper “Predicting the quality changes during microwave frying of food biopolymers by solving the hybrid mixture theory-based unsaturated transport, and electromagnetics equations,” was published in Current Research in Food Science.

School days bring excitement for students with classroom fun, exploration of new subjects, time with friends and extracurricular activities like sports and clubs. They also mean hectic schedules for families, especially parents looking to keep nutrition top of mind in spite of jam-packed weeknight calendars.

Help your kiddos stay energized for each school day (including those dreaded homework hours) with nutritious snacks that prioritize hydration. As a satisfying sweet treat thanks to its taste and nutritional value, watermelon provides a year-round solution to rehydrate as part of simple, kid-friendly meals and snacks.

Sweet watermelon, salty cottage cheese and pops of berries make this Watermelon Berry Fruit Salad with Cottage Cheese hard to top after a long day in the classroom. A sprinkle of fresh mint is a perfect final addition to this after-school treat.

Or for an easy, fast, no-mess meal that can be prepared for homework sessions or taken as a lunchbox treat, look no further than Watermelon Kebabs. Just cube watermelon, turkey breast and cheddar cheese and thread on coffee stirrers or beverage straws then share with your loved ones while tackling dinner and prepping for the next day of learning.

Any way you slice it, watermelon is a nutrient-dense food you can feel confident stocking in your kitchen and feeding to your family. It provides 21 grams (8% of the recommended daily value) of natural carbohydrates and is especially energizing when paired with protein like cottage cheese or turkey for a balanced snack.

Plus, with just 80 calories in two cups, it’s a high-volume food that can fill you up at mealtime. Once you’ve enjoyed the delicious watermelon flesh, make sure to avoid waste by using the rind in recipes like stir fries or salads, or encourage little ones to get creative with watermelon rind crafts to let their creativity shine.

Find more school year snacks and meals by visiting Watermelon.org.

Watermelon Berry Fruit Salad with Cottage Cheese
Recipe courtesy of the National Watermelon Promotion Board

            Watermelon
1          package raspberries
1          package strawberries
1          package blueberries
1          package blackberries
1          container cottage cheese
1          bunch mint leaves
            honey, to taste (optional)

Cut watermelon with star-shaped cookie cutter or into cubes.

In large bowl, mix watermelon with raspberries, strawberries, blueberries and blackberries. Add dollops of cream cheese on top of fruit.

Garnish with mint leaves and drizzle with honey, to taste, if desired, prior to serving.

Watermelon Kebabs
Recipe courtesy of the National Watermelon Promotion Board
Servings: 6

18        seedless watermelon cubes (1/2 inch each)
6          cubes smoked turkey breast
6          cubes cheddar cheese
6          coffee stirrers or beverage straws

Thread cubed watermelon, cubed turkey and cubed cheese on stirrers or straws.

A crucial component of overall well-being, heart health can be a barometer for living a long, healthy and happy life. Because heart disease is the leading cause of death in the US, according to the Centers for Disease Control and Prevention, taking steps to reduce your controllable risk factors – including poor diet, stress and inactivity – can set you on the right path.

From regular checkups and reducing stress to eating well – including heart-healthy snacks like grapes – and exercising regularly, these simple steps can help boost your heart health.

Know Your Numbers
Knowing key health metrics such as blood pressure, cholesterol levels, blood sugar levels and body mass index can help you and your health care provider identify potential risks early. Schedule annual checkups and discuss any concerns you may have about your heart health. Early detection and risk factor management can reduce the likelihood of developing heart disease.

Eat More Fruits and Vegetables
Incorporating a variety of colorful fruits and vegetables into your diet can ensure you get a broad range of vitamins, minerals, fiber and antioxidants, all of which contribute to a healthy cardiovascular system. For example, leafy greens like spinach and kale are high in potassium, which helps manage blood pressure. Fresh grapes contain 7% of the daily recommended intake of potassium, are a good source of vitamin K and are also a natural source of beneficial antioxidants and other polyphenols, including flavonoids, that can help relax blood vessels and promote healthy circulation. Some studies also suggest grapes have a beneficial impact on blood lipids and more.

In fact, one study found women who consumed 1 1/4 cups of grapes every day benefited from reduced blood triglyceride levels, LDL cholesterol levels, inflammatory proteins and other markers of heart disease.

Bright, juicy and bursting with flavor, Grapes from California can be enjoyed by the handful or blended with rich bananas, tangy Greek yogurt and a hint of almond in The Great Grape-Acai Smoothie Bowl for a delicious blend of fruity flavors at breakfast, lunch or snack time – it not only tastes great, but supports a healthy heart. 

Get Moving
Regular physical activity is one of the most effective ways to improve heart health. Exercise strengthens the heart muscle, improves blood circulation and helps maintain a healthy weight. Aim for at least 150 minutes of moderate-intensity aerobic exercise per week, as recommended by the American Heart Association, such as walking, jogging or swimming with strength training exercises like lifting weights or using resistance bands mixed in to help reduce the risk of heart disease and improve overall cardiovascular health.

Manage Stress
Consider your stress level: chronic stress can negatively impact heart health, increasing blood pressure and other risk factors for heart disease. Techniques such as deep breathing, meditation, yoga and regular physical activity can help manage stress levels and maintain a healthy heart. Additionally, taking time to engage in hobbies, spending time with loved ones and ensuring adequate sleep are stress-reducing activities that improve overall well-being and heart health.

To learn more about the heart-health benefits of grapes, and find additional heart-friendly recipes, visit GrapesFromCalifornia.com.

The Great Grape-Acai Smoothie Bowl
Servings: 1

1/2       cup red Grapes from California, fresh or frozen
1/2       banana
1          frozen acai fruit pack (3 1/2 ounces)
1/2       cup plain, nonfat Greek yogurt
1/4       teaspoon almond extract

Topping:
1/4       cup sliced red Grapes from California
1          tablespoon sliced, toasted almonds
1          tablespoon pepitas
1          teaspoon chia seeds

In small blender, combine grapes, banana, acai, yogurt and almond extract; process until smooth.

Pour into bowl and top with sliced grapes, sliced almonds, pepitas and chia seeds.

Nutritional information per serving: 420 calories; 19 g protein; 63 g carbohydrates; 12 g fat (26% calories from fat); 2.5 g saturated fat (5% calories from saturated fat); 5 mg cholesterol; 45 mg sodium; 8 g fiber.