What efforts have scientists made to help you eat more sweeter sugarcane? (Part 1)

Produced by: Science Popularization China

Author: Yin Xin (Institute of Microbiology, Chinese Academy of Sciences)

Producer: China Science Expo

Editor's note: In order to decode the latest mysteries of life science, the China Science Popularization Frontier Science Project has launched a series of articles called "New Knowledge of Life" to interpret life phenomena and reveal biological mysteries from a unique perspective. Let us delve into the world of life and explore infinite possibilities.

When people think of sugar, they probably think of a hidden revolution that has not only changed our taste buds, but has also played a major role in history. As the book Sweetness and Power explains, sugar was once a luxury item, but is now part of every kitchen. [1]

In modern life, whether it is coffee, desserts, or festive delicacies, the sweetness of sugar is everywhere. But you may not know that behind every bite of sweetness, there are hard work of scientists.

Where does sugar come from: Cane versus beets

When it comes to the source of sugar, China's sugar comes mainly from two major sugar crops: sugar cane and sugar beet [2] . At present, the distribution of sugar crops in China is "sugar cane in the south and sugar beet in the north", which is due to the different preferences of the two crops for climate and soil.

Sugarcane likes warmth, light and large water requirements, and is suitable for growing in the warm and humid environment of southern my country; while sugar beets are suitable for growing in colder environments because of their good cold resistance, and are mainly produced in northern my country. According to statistics, the output ratio of sugarcane sugar to beet sugar in my country is about 9:1.

Beets and sugar

(Photo source: veer photo gallery)

Sugarcane and sugar

(Photo source: veer photo gallery)

What is the difference between cane sugar and beet sugar?

In fact, the difference in sugar content between the two crops is not that big. Sugar cane contains about 12-14% sugar, and sugar beet contains about 16-20% sugar. However, in the process of sugar production, the two processes are slightly different. Sugar cane has a relatively higher sugar extraction efficiency and a relatively lower cost, which is suitable for large-scale industrial production.

The chemical composition of white sugar made from sugar cane and sugar beet is sucrose. From a chemical point of view, there is no essential difference between sugar cane sugar and beet sugar . Since sugar cane has been used by working people to make brown sugar, yellow sugar and syrup since ancient times, people are more accepting of sugar cane sugar. People often think that brown sugar made from sugar cane has a mellower flavor, and products such as brown sugar and yellow sugar are also more popular.

What is the difference between brown sugar, white sugar and yellow sugar?

Sugarcane goes through a complex process from the field to the table. First, the juice is extracted from the sugarcane, followed by concentration, filtration, crystallization, and finally the brown sugar, white sugar, and yellow sugar we are familiar with [3].

Different types of sugar

(Photo source: veer photo gallery)

The main difference between the three lies in the degree of refining and processing.

Brown sugar has a low degree of refining, retains more molasses and rich vitamins and trace elements, has a high nutritional value, and has a relatively low purity of sugar crystals. The sugar content is about 95%. It is generally dark brown in appearance, moist or loose, and has a strong taste.

White sugar is highly refined. It is further purified and decolorized on the basis of brown sugar. Its sucrose purity can be as high as 99.8%. It is white in appearance, dry and uniform in particles, and tastes sweet. If white sugar is further "crystallized and enlarged", it will form crystal clear large crystal sugar.

The degree of refining of brown sugar is between that of brown sugar and white sugar. It retains a portion of molasses and is light yellow or golden yellow in color. The particles are relatively loose and the taste is between that of white sugar and brown sugar.

What factors are related to the sugar yield and quality of sugarcane?

The sugar yield of sugarcane depends on many factors, including the quality of sugarcane germplasm, planting conditions, harvesting time and processing technology.

In order to obtain more sugar, people often give priority to planting high-sugar sugarcane varieties. However, it is far from enough to focus only on the sugar content, because the planting conditions of sugarcane are also very important. If drought, cold damage, typhoons (causing lodging) or pests and diseases are encountered during the planting process, the sugar production capacity of sugarcane will inevitably be affected. Therefore, in addition to sugar content, sugarcane germplasm must also consider yield, lodging resistance, disease resistance and the ability to adapt to different environments.

Different varieties of sugarcane mature at different times. China's sugarcane crushing season is from October to April of the following year. Early-maturing, mid-maturing, and late-maturing varieties of sugarcane reach their peak sugar content in the early, middle, and late stages of the crushing season, respectively. Reasonable planning of harvesting time based on the characteristics of different varieties will also help improve sugarcane yield and the utilization rate of sugar mill equipment.

The above factors complement each other. "Good seeds, good fields, and good methods" are all important factors in determining the sugar yield of sugarcane. Only under suitable conditions and environment can the sugarcane germplasm realize its maximum potential.

In addition to sugar production, sugar quality is also an important indicator. Most of the sugarcane sugar-making enterprises in Guangxi use the "one-step method" (sulfite purification process) to produce white sugar. Only a few enterprises use the internationally accepted "two-step method" process, that is, sugarcane is first processed into raw sugar, and the raw sugar is then refined into refined sugar or white sugar according to demand [5]. Compared with the two production processes, the "two-step method" produces high-quality products and greatly reduces the sulfur content of white sugar, which can further ensure food safety and improve sugar quality and market competitiveness.

By applying scientific sugarcane breeding methods, advanced sugarcane planting techniques and modern sugar production technology, the efficiency of the production process has been improved and the sugar extraction rate of sugarcane has steadily increased.

Scientists' efforts on sugarcane yield and quality have not only improved the efficiency of global sugar supply, but also enabled us to enjoy higher quality sugar products.

Conclusion

In fact, there are many stories to tell about sugarcane breeding.

Did you know that sugarcane germplasm and variety are actually two different things?

Did you know that compared to humans, which are diploid organisms, sugarcane is actually polyploid and that “each one is different”?

What efforts have scientists made to make sugarcane produce more and sweeter sugar? Please listen to the next episode for details.

References:

1.Mintz, SW (1985). Sweetness and Power: The Place of Sugar in Modern History. Penguin Books.

2.Eggleston, G., & Legendre, BL (2003). Quality management of sugarcane juice to raw sugar: Louisiana factory operations. International Sugar Journal, 105(1256), 8-18.

3.Rein, P. (2007). Cane Sugar Engineering. Bartens.

4. De Souza, AP, Grandis, A., Leite, DC, & Buckeridge, MS (2014). Sugarcane as a bioenergy source: history, performance, and perspectives for second-generation bioethanol. Bioenergy Research, 7(1), 24-35.

5. Tang Liangdong. (2024). Green and low-carbon development of sugarcane sugar industry in Guangxi: current situation, challenges and strategies. Sugarcane Sugar Industry, 53(3): 74-79.

6. Dong Guangrui, Shi Jiaxian, Hou Ailing, Zhang Jisen. (2018). Research progress on sugarcane genome. Biotechnology, 28(3): 296.

7.International Human Genome Sequencing Consortium. (2004). Finishing the euchromatic sequence of the human genome. Nature, volume 431, 931–945.

8. Jisen Zhang, Qing Zhang, Leiting Li, Haibao Tang, et al. (2018) Recent polyploidization events in three Saccharum founding species. Plant Biotechnol J, 17(1), 264-274