Process and Operations

Yesterday’s Waste, Tomorrow’s Profits

Mining the byproducts of food production for untapped value can be a game-changer.

By Kevin T. Higgins, Managing Editor

Whether it’s gelatin from steer hooves or protein isolate from soy meal, there’s a long history of mining value from the waste of food production.

Baby carrots exemplify the game-changing potential of byproducts. When Grimmway Farms in Bakersfield, Calif., began cutting and peeling thinly tapered carrots into baby carrots in the early 1990s, the process left almost as much waste as finished goods. Animal feed is the go-to option for much food waste, but company engineers devised a process to turn the carrot scraps into carrot juice concentrate.

The market for carrot juice concentrate wasn’t America but Japan, where its nutritional value was prized. Processors in Australia were supplying concentrate to the Japanese market, but their business model was no match for a new competitor with minimal raw material costs. In short order, there was only one concentrate supplier, and that supplier was in North America.

Few byproducts are as disruptive to existing markets, but the baby carrot illustrates the hidden value that can be mined from materials regarded as waste. Sometimes value is discovered by happenstance; other times, necessity drives it. The poster child for the latter is cheese whey.

For centuries, cheesemakers skimmed the curds and dumped the whey in the quickest and most convenient way possible, even though whey contains as much milk protein as the curds. With the advent of environmental regulations, sewer drains and land applications became options for a declining number of cheesemakers. Shipping a byproduct that is 93 percent water to a further processor isn’t simply an added cost: if that processor was hundreds of miles away, the financial drain could force a shutdown of the cheese plant.

One of the first cheesemakers to tap the potential goldmine in whey was Cabot Creamery, which built a state-of-the-art processing system adjacent to its Middlebury, Vt., cheddar plant around the turn of the century. The $21 million project relieved the cooperative of trucking 1.3 million lbs. a day of waste as far as Louisville, Ky. Instead, lactoferrin was isolated using chromatographic separation, creating a very pure protein.

The plant then shifted to whey concentrated to 80 percent protein (WPC80). The drying process extends to the remaining permeate of sugar and minerals, leaving nothing but cow water, some of which is polished and reused.

Annual production of WPC80 now stands at 50 million lbs., half again the amount in 2002 and pushing throughput close to capacity. Much of the raw materials are trucked in from sister plants in Cabot, Vt., and Chateaugay, N.Y., home of McCadam cheese. Another 9 million lbs. of permeate is dried and crystallized.

The Cabot experience highlights the nimbleness and flexibility necessary in byproduct processing. Chromatography is an expensive batch process, and few companies apply it. Cabot isn’t one of them, in part because the market for whey isolate isn’t what it once was.

Ditto permeate, a commodity subject to big price swings. Instead, Cabot, a division of Agri-Mark Inc., is focusing on specialty products, such as heat-stable Grade A WPC80, while exploring new opportunities like adding permeate to flour to retain moisture

Better membranes

A best-in-class approach had to be taken when Cabot integrated the evaporators, crystallizers, membrane filtration and multi-stage drying system that includes two 94-ft. high units. “It’s off the shelf technology now,” observes Karen Smith, dairy processing technologist at the University of Wisconsin’s Center for Dairy Research in Madison, Wis.

Off the shelf or not, there’s room for improvement, particularly in the area of membranes. “All membranes aren’t created equal,” notes Smith, and continuous advancements by filtration suppliers and spurred by researchers are making it possible to fractionate whey to produce distinct products, such as heat stable WPC and concentrates with reduced lipids.

Demand also is growing for niche products, like nonallergenic whey from sheep and goat cheese or organically certified whey. Separation of casein in milk once was deemed impossible, but the technical hurdles have been cleared and today’s technology makes casein separation a common practice.

Collaborations between suppliers and processors open new possibilities. However, unless or until a market exists, commercial production won’t occur. A case in point is a beta casein separation process developed by Smith and her colleagues, John Lucey and James O’Mahony, a decade ago. The process is applied to low-fat milk upstream of cheese production.

The researchers were awarded a patent last year, and some processors are testing it at the lab and pilot plant level, but the process is caught in Catch 22 limbo. Beta casein has potential as an emulsifier in a variety of foods, though there are no commercial applications, and removing it could be beneficial to individuals who experience digestive problems when consuming milk. In the absence of an established market, however, no companies are applying Smith’s process.

The popularity of Greek yogurt has created a waste stream looking for a use. The high protein in Greek yogurt means there is very little protein in the leftover acid whey, so named because lactose, permeate and acid are essentially the only constituents. Separating them also is an issue.

“Acid whey is a problem child,” Smith points out. “The equipment just doesn’t like it.” The material coats nanofiltration membranes, closing the pores and resulting in extended processing time and additional equipment. Nonetheless, the byproduct will have to be dealt with.

Ingredients supplier DuPont Nutrition & Health (the former Danisco group) may have a solution, aided in part by DuPont's substantial filtration know-how. While doing product development on yogurt ingredients in the New Century, Kan., office, one technician added the "waste" acid whey to sorbet and orange juice. Coworkers liked the resulting products. The byproduct has little nutritional value of its own, but it does impart a mildly pleasant taste; moreover, it's better than flushing it down a drain.

Meal time

Membrane filtration also figures prominently in protein extraction from vegetable oil byproducts. Randy Willardsen, senior vice president-processing at Burcon Nutrascience Corp., Vancouver, British Columbia, honed his skills in membrane filtration of whey before segueing to canola, soy and pea protein isolates. He has been instrumental in R&D at the 16-year-old firm, which is protecting its intellectual property with 59 U.S. and 129 international patents, with another 375 applications pending.

Burcon distinguishes itself by using mechanical extraction instead of acid extraction, which can result in a beany taste with plant proteins, according to Willardson. Before ultrafiltration is applied, the meal’s protein is solubilized with salt and cold water, causing the protein to form hydrophobic micelles. Oil extraction must be done at lower temperatures than is typical, a restraint that isn’t a major impediment for Burcon’s licensee, Archer Daniels Midland.

ADM has rolled production, sales and marketing of Burcon’s soy protein isolate into its Wild Flavors & Specialty Ingredients business. (In late 2014, ADM bought Wild Flavors for $3.1 billion, its largest acquisition ever.) ADM also is the licensee of Burcon’s soy protein isolates and egg-white substitute, which can be used as an alternative to eggs in mayonnaise-like dressings such as Hampton Creek’s Just Mayo.
Heavy bets are being placed on the potential for plant proteins, though work is ongoing to resolve issues of off odors, solubility, clarity and sour flavor notes. While their projected sales volume is speculative, the key takeaway is that they are value-added products derived from a waste stream that otherwise would go to animal feed.