Parboiling with reduced water improves nutrient content of rice


The Problem: 

Rice is a staple food for billions of people around the world. However, people relying on rice as their main source of energy are most likely to suffer from nutrient deficiencies such as iron and calcium. Additionally, potassium deficiencies are of concern in the United States. Iron is a key component of blood’s hemoglobin, which carries oxygen around the body. Calcium helps fight osteoporosis, high blood pressure and colon cancer. Potassium is essential in maintaining fluid balance and the electrical impulses that enable muscles to contract. Fortifying rice with essential nutrients could help improve health for its consumers.


The Research

Graduate student Annegret Jannasch, working with Food Science Professor Ya-Jane Wang, examined whether fortification by parboiling using a more environmentally friendly soaking condition could help rice deliver these necessary nutrients while reducing the amount of waste water generated by the parboiling process. Other methods of fortification, such as dusting the grains with a nutrient powder, adding a waxy coating of nutrients, and extrusion of reconstituted grains, all have significant drawbacks in retaining the added nutrients through cooking. They also lack consumer acceptance because of taste, color or texture.

It’s estimated that 15 to 20 percent of the world’s milled rice is consumed as parboiled rice. Therefore, fortification by parboiling could be an excellent tool to deliver micronutrients to a large number of people. However, parboiling has a significant drawback because it uses large amounts of water during the process of soaking the grains, then by steaming, drying and milling.

Jannasch and Wang tried soaking the rice with smaller volumes of water than are typically used. They found that limiting the amount of water improved mineral retention by the rice after washing. Limited water soaking also did not affect milling quality and the color of the parboiled rice. The process also reduced the amount of solids in the wastewater as well as the overall volume of wastewater by 86 percent. 


The Bottom Line

This research indicates that parboiling is a practical method to fortify rice with needed nutrients. Limited water soaking can enable parboiling with much less water wasted.


The Researcher

Annegret Jannasch

Annegret Jannasch

Graduate Assistant, Department of Food Science

Annegret Jannasch is seeking a master’s degree in Food Science at the University of Arkansas. She came to Fayetteville from the Weihenstephan-Triesdorf University of Applied Sciences near Munich, Germany.  This research is supported by funding from the Arkansas Biosciences Institute.