A Fresno State faculty-student research team specializing in extrusion technology has worked to benefit the region’s fruit processing industry by providing ingredients for a new, nutritious breakfast cereal.

Food science professor Dr. Gour Choudhury, now on the faculty at Cal Poly, San Luis Obispo, and Fresno State graduate Preetam Sarkar led the work featuring the use of peach pomace as a base material for the cereal mix.

“The fruit processing industry has been generating increasing amounts of solid co-products as a result of a growing demand for processed fruits,” Choudhury said in outlining the project.

“However, technology developments to open new and profitable markets for fruit processing co-products have been limited. Our study sought to develop value-added extrusion processes for fruit processing co-products such as peach pomace.”

Peach pomace is a slurried byproduct of fruit processing. It consists of fine fruit parts in liquid and is most often simply disposed of by processing plants. However, as a fruit product, pomace contains an assortment of healthful fruit constituents such as polyphenol antioxidents, carotenoids, fiber and other bioactive compounds, Choudhury noted.

“Until now, there has been very little commercial utilization of these co-products that could be profitable to processing companies,” Choudhury said.

The project goal was to develop and evaluate an extrusion process for a new generation of food products from peach and nectarine pomace.

Extrusion technology is used commercially for food products from chips and cheese puffs to breakfast cereals, Choudhury noted. And while the technology is not new, the application of fruit pomace is. A major part of this research involved developing a process for drying and formulating the peach pomace into a substrate that would be suitable for extrusion.

Choudhury said multiple settings of the equipment (temperature, pressure, flow rate, etc.) work comprehensively to affect the density, volume, porosity, color and taste of the final product.

The formula developed by Choudhury and Sarkar included dried peach pomace mixed with rice flour, which enhanced the consistency of the mix and the extruded product.

“We have established quite firmly that we can use peach pomace to make an excellent breakfast cereal,” Choudhury said. “Now we need to establish process parameters that will enable us to produce a consistent and flavorful product.”

Second year work on the project continues, with Choudhury at Cal Poly. Additional research will seek to fine tune the extrusion process with continuing adjustments of various processes to enhance the final product.

Sarkar’s work on the project was part of a successful thesis project entitled “Peach Pomace Utilization Using Twin Screw Extrusion Processing.” Sarkar earned admission to Purdue University, where he is pursuing his doctorate in nanoscience.

This project has been partially funded by the California State University Agricultural Research Institute.

For more information, contact Choudhury at gchoudhu@calpoly.edu.