While the famous kaoliang (高粱酒) produced in Kinmen has already brought enormous income to the offshore island, researchers say they have now developed new technologies to make the wasted sorghum grains into value-added products.
National Quemoy University’s (NQU) Department of Food Science assistant professor Lin Chi-fan (林志芳) said more than 100 tonnes of waste sorghum grains — the by-product of the fermentation process — are being produced at government-owned Kinmen Kaoliang Liquor Co every day and are mainly used as fertilizers, which he said was not the best way of recycling them.
Kinmen Kaoliang Liquor’s statistics showed that about 25 million tonnes of kaoliang was produced last year, bringing in about NT$13.6 billion in revenue. It is estimated that kaoliang production may reach 27 million tonnes this year.
After experimenting with different ways to recycle the waste sorghum grains, Lin discovered that by extracting them into a powder and adding them to various food products, it enhanced the flavor and the nutritional value of the food.
“They can be added into bread and cookies, as people now like to eat whole-grain products for health reasons, and because they have a special flavor and high acidity they can also be put into preserved sour cabbages,” Lin said, adding that high acidity of lower than a 4.6 pH level can serve as a preservative agent and that they can used to make soy sauce.
Other than being used as a food ingredient, NQU’s Department of Food Science assistant professor Lai Ying-Jang (賴盈璋) has developed a method to make dried waste sorghum grains into activated carbon, which can be used as a filtration or moisture-proof preservative in several ways — such as being added to spice containers to keep them dry and to absorb odors, for filtering drinking water or in medical products.
“Results showed that about 25kg of activated carbon can be produced from every 100kg of dried waste sorghum grains,” he said, adding that activated carbon is smaller, easier to store and that it cost about 10 times the price of sorghum grains.
The results of a collaborative research project by NQU and National Chiayi University, Lai said the team plans to apply for a patent for the technology that produces activated carbon from dried waste sorghum grains.