Buhler develops vitamin-enriching rice extrusion process

Vitamins and minerals tend to be lost during the whitening and polishing of rice, but a new extrusion mechanism has been developed that transforms rice brokens into vitamin-enriched rice pellets.

The resulting rice pellets can be customised in terms of colour, shape, and size, according to the company, and the composition of their component substances and their cooking characteristics can also be tailor-made.

Depending on the specific process applied, the extruded product may serve as instant rice pellets, as quick-cooking rice pellets, or as a product for admixture to natural rice.

The process works like this. Rice brokens obtained during whitening, which up to now were usually sold as a low-grade animal feed, are finely ground and transformed by cooking extrusion into rice-like grains.

Unlike conventional means, in which, say, a vitamin mix is added to the rice in the form of a powder or sprayed directly onto the rice, the new process integrates the vital substances in the extruded rice grains themselves.

This, claims Buhler, conserves most of the sensitive vitamins during storage, washing and even cooking, and results in more efficient rice processing.

The technology could be particularly important in developing countries where fortified foods are one of the most cost-effective ways of preventing deficiencies. One in three people around the world do not receive adequate amounts of vitamins and minerals, according to a report from UNICEF and The Micronutrient Initiative released earlier this year.

Buhler has begun construction of a production plant in China which will apply this new form of enrichment and admixture. Buhler, which has developed this new technology with DSM Nutritional Products, believes that the technique could have a number of interesting applications in rice processing.

Quick cooking rice for example, which can be cooked within eight to 14 minutes after undergoing various thermal processes, has become hugely popular. The rice pellets used for quick cooking rice need to be barley distinguishable from natural rice. This is especially significant as quick-cooking rice pellets are also marketed in transparent packaging.

Instant rice ready for consumption within a very short time after hot water has been poured over it can also be achieved through cooking extrusion.

However, such rice products differ very widely in their visual appearance from natural rice grains. The addition of water during preparation, called rehydration, then produces rice-like textures.

The visual similarity of instant rice pellets to natural rice is not so important though, since the instant pellets are typically already pre-mixed with the other ingredients of the meal in the package and only require hot or boiling water for their preparation.

Buhler​ claims that it is possible to enrich the rice pellets with various micronutrients such as vitamin A and the vitamins of the B complex in addition to minerals and trace elements. But in addition, proteins, essential amino acids, fatty acids, and antioxidants plus probiotic and prebiotic ingredients can also be added.

Depending on the degree of enrichment, one enriched grain will then, for example, be added to 100 normal rice grains. This allows micronutrient deficiencies that may be caused by the exclusive consumption of white rice to be effectively prevented.