Reduce water use while peeling fruit

A recently developed system that uses air, rather than water, to blast peels off fruit could reduce water use by 80%.

The peeling technology, developed by Fresno State Professor Gour Choudhury has been three years in the making and could provide an eco-friendly solution for processors of peaches, tomatoes and other soft fruit that needs to be peeled.

Traditionally, processing plants slice fruit in half, remove any pits and wash them in a lye solution that loosens the skin. Then a jet of water knocks off the skin as the fruit moves along a conveyor belt.

In the new system, blasts of moisturised air replace water in the final step. Some water is still needed to rinse away the lye, but far less than traditional systems can require.

The invention began after Choudhury, a former professor at the University of Wisconsin-Stout, arrived in Fresno in 2003. One day he visited Bill Smittcamp’s Wawona Frozen Foods plant in Clovis to find out what his biggest challenges were.

The family-run company is a pioneer in the frozen fruit industry, making products for food manufacturers, food service distributors, restaurants, resorts, supermarkets and schools. More than 100 Wawona products are sold and distributed throughout North America.

“I wanted to know what some of the major problems the industry was facing, and Bill told me: ‘Water, water, water,’” Choudhury said. Water is expensive to buy, and the lye contamination requires treatment - also expensive.

After months of research and experimentation, Choudhury and his students designed a prototype that slashed Wawona’s water usage per ton of fruit from 900 L an hour to 180.

A prototype set up in the Wawona plant has worked well, the company says. Fully implemented, it could save the plant at least US$50,000 a month in water and wastewater charges, Choudhury says.

Fresno State submitted a patent application for Choudhury’s system last year. Now university officials are working out who will manufacture the equipment, who will sell it and what it will cost.

As far as Choudhury is concerned, this is just the beginning of the possibilities for his department.

He is already working with a local tomato processor to test the equipment’s effectiveness on peeling tomatoes. And he is working on neutralising the lye in the peach peels to make it suitable as cattle feed. If he can figure out how to remove the pectin from the peel and sell it as by-product, he will do that too.

“There are many, many possibilities,” Choudhury said.