Effects of foreign matter on the color of cane juice
The research project carried out by Cenicaña also contemplates quantifying the impact of the variety on pigments in juices.
The increase in mechanized tasks such as green harvesting in the Colombian sugarcane agribusiness has a direct impact on the amount of foreign matter that enters the milling and, in turn, on the color of the sugarcane juice during the manufacturing process.
In fact, in recent years, when the mechanical harvest went from 39% (2013) to 51% (2015) in the sector, it has been possible to show an increase in the color of the diluted juice of 16000 Icumsa units (with 6 ± 1% of foreign matter) to 25000 units (with foreign matter of 8 ± 4%).
The amount of color in the juice determines the additional crystallization and refining processes that must be carried out in factories and, therefore, is essential to guarantee the performance and quality of sugar.
Taking into account the above, Cenicaña is advancing in an investigation with the purpose of knowing which compounds are the ones that most impact the color of the juice and in what quantity.
According to Tatiana Sánchez, chief chemist at the Research Center, to begin with, the most concentrated natural dyes were identified in three commercial varieties of sugarcane and their relationship with increased color; Later, the contribution of these dyes was evaluated by the type of foreign matter that enters the mill.
In the experimentation with the varieties it was found that the juices of clean stems with higher color units showed high concentrations of the natural flavonoid dyes, anthocyanins, phenols and chlorophylls.
Furthermore, an analysis of the data showed a 71% correlation between the color increase and the presence of anthocyanins.
Natural colors of sugar cane
- Phenols: They are the main pigments present in cane juice and responsible for the return of color to sugar when it is stored. They act as a defense mechanism against diseases and participate in the growth of the plant.
- Flavonoids: pigments responsible for the yellow color in plants. Among its functions are the attraction of insects, protection against factors such as UV radiation and dangerous animals or insects.
- Anthocyanins: the color of the leaves and the stem of the sugar cane is due to the effect of this compound. They are often found in greater proportion in the senescence leaves and act as a defense against diseases.
- Amino-nitrogenous: They are involved in protein production, they act as metabolic intermediaries and are important in cell growth. During the process of obtaining sugar, they favor the production of color generators and increase the volatile compounds that contribute to the odor of cheeks.
- Chlorophyll: They are green pigments that undergo oxidation processes and are responsible for the increase in the color of the juice over time.
Subsequently, the evaluation of the contribution of color by type of foreign matter revealed that the highest concentration of anthocyanins is in the dry leaves and there is a 48% correlation between the increase in color, the anthocyanins and the iron present in the dry leaves.
With the investigation it was determined that the pigments or colored compounds of sugar cane change according to age, agronomic management conditions, soil characteristics and variety. The latter is the most decisive.
The experimentation developed so far focused on the effects of foreign matter coming from the cane; The next step is to analyze the impact on the color of the juice of other types of substances, especially those derived from the manufacturing process, other than the plant.
"With this research, the agribusiness is gaining knowledge regarding the effects of foreign matter and varieties on the color of the juice, which is projected as a tool that, in the future, will allow dyes to be removed in the first steps of factory processing for thus reducing reprocessing, and also contributing to research to obtain varieties, "added the chief chemist.
Currently the project includes a characterization of varieties in which the color variables and their generators will be included.
In Memories of the Factory Committee of May 18, 2016: Presentation: Analytical methodologies for the identification and quantification of dyes in the sugar sector.