Why is Cilembu Sweet Potato Sweeter When Baked? Here’s the Explanation from an IPB University Lecturer

Cilembu sweet potato, a local variety from Cilembu Village, Pamulihan District, Sumedang Regency, West Java, has long been known for its unique sweet taste, especially when baked. This sweetness does not come out to its fullest when boiled or steamed.

Ai Imas Faidoh Fatimah, STP, MP, MSc, a lecturer in the Food Quality Assurance Supervisor Program at IPB University’s Vocational School, explains the reason behind this. “Cilembu sweet potato is one of the sweet potato cultivars with a higher sugar content compared to other cultivars,” she said.

“The soil characteristics in Cilembu Village and the storage process for one to three weeks after harvest cause a natural increase in sugar content,” she added.

During storage, starch is hydrolyzed into disaccharides and monosaccharides or simple sugars through the action of active amylase enzymes.

Ai Imas explained that when sweet potatoes are roasted at high temperatures between 200°C and 240°C for 20-40 minutes, the process breaks down more starch into simple sugars such as glucose and fructose.

In addition, the roasting process also causes a caramelization reaction. “It is this caramelization that gives it its distinctive aroma and stronger sweet taste, and even produces a sticky liquid similar to honey. That is why Cilembu sweet potatoes are often called ‘honey sweet potatoes’,” she said.

Regarding the differences in the effects of the processing methods, Ai Imas stated that both steaming and baking affect the carbohydrate composition of sweet potatoes.

“Steaming tends to retain most of the starch. Meanwhile, roasting, due to its higher temperature, causes some of the starch to break down into simple sugars such as maltose, glucose, and fructose, making the sweetness more intense,” she explained further.

So, is roasted Cilembu sweet potato, which tastes sweeter, still safe to consume? According to Ai Imas, this is not a problem as long as it is consumed in reasonable amounts and without added sugar or fat.

“The sweetness in roasted Cilembu sweet potatoes comes from natural sugars converted from starch, not from added artificial sweeteners. Although the glycemic index of roasted sweet potatoes may be higher than boiled or steamed sweet potatoes, they are still rich in nutrients,” she said.

Cilembu sweet potatoes also contain fiber, which acts as a natural prebiotic, as well as beta-carotene and antioxidants beneficial for health. Therefore, consuming roasted Cilembu sweet potatoes is still recommended as part of a healthy diet. (dr) (IAAS/LAN)