Peeling a banana often includes finding thin, fibrous strands clinging to the fruit’s flesh, which many people instinctively pull off and discard. These structures are a common source of curiosity, often appearing as leftover packaging rather than an intentional part of the fruit. Understanding their function reveals a sophisticated internal transportation system necessary for the banana’s development. These pieces have a specific scientific name and a highly specialized purpose.
What the “Strings” Are Called
The white, stringy bits found on a banana are scientifically known as phloem bundles. These structures are a type of vascular tissue, making them part of the plant’s internal plumbing system. Phloem is present in all vascular plants, forming a network of living cells that extend throughout the entire organism. In the banana, these bundles run longitudinally, lining the space just beneath the peel.
Phloem is primarily responsible for the transport of organic compounds, particularly sugars produced during photosynthesis. These cells are the conduits that move the energy source from where it is made to where it is needed. Because of this specialized role, they possess a more rigid structure compared to the surrounding soft, edible fruit pulp.
Their Biological Purpose
These phloem bundles serve as the primary delivery system for nutrients into the developing fruit. As the banana grows, the plant produces sugars and other organic molecules in its leaves through photosynthesis. This nutrient-rich sap must be distributed to every part of the plant, including the sugar-storing fruit. The phloem bundles act like miniature pipelines, channeling these compounds from the main stem through the peel and into the banana flesh.
Without this system, the banana would not be able to accumulate the sugars, starches, and micronutrients that make it a desirable food source. The bundles are structurally reinforced to withstand the pressure of constant, long-distance transport. While plants also contain xylem, which transports water, the phloem tissue remains clearly visible in the mature fruit, emphasizing its role in sugar distribution. Their presence ensures that the fruit receives all the necessary building blocks to fully ripen and develop its characteristic sweetness.
Why They Are Safe to Eat
Despite their different appearance and texture, phloem bundles are completely safe to consume. They are composed of the same general plant materials as the rest of the banana and pose no health risk, though they are often discarded due to personal preference. Their stringy texture is due to their composition of complex fibers, which are necessary for the structural integrity required for their transport function.
These bundles contain a higher concentration of fiber compared to the soft fruit pulp. This difference in fiber density gives them a tougher, chewier mouthfeel than the smooth flesh. Eating the phloem bundles simply adds extra dietary fiber to the snack. They tend to cling more tightly and be more noticeable on less-ripe bananas, separating more easily from a fully ripened fruit.