KANSAS CITY — A case study for the delivery challenges the restaurant industry faces is KFC, a restaurant chain owned by Yum! Brands, Inc. that plans to launch delivery services nationwide later this year. The choice of frying oil will impact how well the quality of KFC fried chicken pieces and seasoned potato wedges hold up during delivery. Ingredient suppliers point to high-oleic oils as tools to assist restaurant chains.

Food service delivery accounts for 3% of total industry sales, and that percentage is increasing, according to The NPD Group, Inc., Port Washington, N.Y. Generation Z and millennials account for half of all meals delivered in the United States, according to The NPD Group.

The quality of deep-fried products especially becomes an issue.

“During deep frying of food products like french fries, the food dehydration process, which is frying, sets the structure of the food, and when consumed within minutes out of the fryer delivers on aroma, texture and flavor,” said Roger Daniels, vice-president of research, development and innovation at Stratas Foods, Memphis, Tenn. “The challenge comes when the time out of the fryer increases due to the additional step of delivery. In this instance the food structural oil remains in place, but the food-penetrated-oil component contributes to the food surface oil, and the finished french fry loses consumer appeal in the earlier mentioned attributes of aroma, texture and flavor.”

Deep-fried items are most susceptible to negative impacts, he said.

“In the deep frying process, a food item that may be fresh, breaded, par fried or a combination of all three is introduced to frying oil at temperatures in some instances in excess of 350°F and held in the frying vat until the desired internal temperature is reached,” Mr. Daniels said. “During deep frying, water in the form of steam is liberated from the food item, the food item’s protein is denatured, starches are gelled and frying oil penetrates the food. The result is a food item that is crispy on the surface, has structure and a balance of liquid to solids that define the food product like chicken, french fries and onion rings. All classes of deep-fried products may be negatively impacted.”

Deep frying french friesOils used for deep frying have characteristic flavor profiles that may add to the flavor delivery of a fried food item, he said. High-oleic sunflower oil is a clean tasting and stable oil that pairs well with chips and other foods where the goal is for the natural taste of the food to come through, he said. High-oleic soybean oil has an adjusted fatty acid profile to confer stability, and its modest linolenic acid content enables the development of traditional fried flavors and aromas in starch-type products. Corn oil works in a blend. When corn oil breaks down in the fryer, its flavor contribution becomes more “corny” and is a good base oil component for protein, Mr. Daniels said.

Cargill, Minneapolis, recommends a high-stability oil like high-oleic canola oil, which combines a longer fry life with a neutral flavor profile, said Stacy Borders, technical sales manager, global edible oils solutions.

Healthy Food Ingredients, Fargo, N.D., offers expeller-pressed, high-oleic sunflower oil, said Jennifer Tesch, chief marketing officer. Expeller-pressed or mechanically pressed oil provides a healthier, clean option than solvent oil, she said.

“We are seeing an increased demand by food service and restaurant industry demanding these clean label, healthier oils in response to consumer demand,” she said.

Most fried food products lose some quality as they cool, especially if they are not allowed to vent and give off moisture as steam, said Rick Cummisford, director of quality control for Columbus Vegetable Oils, Des Plaines, Ill.

“Switching from one oil to another may not alter this too much, but perhaps consider looking at an oil or oil blend that has slightly higher saturated fat levels and may also provide some positive attributes, even as the food cools,” he said. “The increased level in saturated fats may allow the fat to crystalize on the fried food and appear less greasy. This may vary from one product to another and in some case may not result in any positive improvements.”

Oil management is important as well, Ms. Borders said.

Burger and fries delivery“To get the most out of a fry oil, it’s critical that food service staff filter the oil regularly, skim out any food particles left behind and maintain optimum fry temperatures,” she said. “Ice crystals from frozen french fries can also cause problems. So moisture control is another factor to consider.”

Mr. Cummisford said the oil stability in the fryer depends on several factors, and not all of them directly involve the type of oil used but rather the procedures used. The procedures include oil turnover (the rate that fresh oil is added to the fryer), straining and filtering the oil, quality checks and testing. Typically, higher stability oils will hold up better in the fryers, but they may be more expensive, he said.

Ms. Borders added, “When we fry a food, we’re essentially using oil and heat to dehydrate the product, pulling moisture out of the food and replacing it with oil. That’s what gives us the nice, crispy texture we associate with fried foods like french fries.

“To preserve that quality through delivery, the real keys are maintaining temperature and texture. Those aren’t oil issues. It’s really a total system challenge involving product, process and packaging. We have to find ways to hold the heat in without steaming the fried product and making it soggy. However, choosing the right fry oil and properly maintaining that oil go a long way toward ensuring that restaurateurs start with the best quality product possible.”

Mr. Daniels said the fat type could impact alternative meat ingredients, too.

“These alternative meat patties often make their way onto a grill and when served at the restaurant deliver on the consumer driven attributes,” he said. “However, add the step of delivery and its expanded time from cook to consumed, and there is the potential to underdeliver on the consumer’s expectations.”