New research from Florida State University will not only assist you with determining whether your banana bread will be appropriate, but it will also help reduce millions of tons of food waste from the widely grown fruit.
A team of FSU researchers investigated the formation and spread of brown spots on bananas, a surprising example of biological pattern formation. In a research published in Physical Biology, the researchers explained how these spots appear during a two-day window, rapidly expand, but then mysteriously stall, revealing a sharp distinction between brown and the still-yellow peel.
Oliver Steinbock, a professor in the Department of Chemistry and Biochemistry, says the research shows that old bananas have brown spots, but there are also dark yellow areas in between. These areas never really invaded those areas. They just stopped. This is scientifically important because it might be helpful to clarify the mechanisms that trigger the browning.
When oxygen reacts with an enzyme in the fruit peel, brown spots appear on bananas, causing the production of dark pigments. Steinbock and his team wanted to understand how spots appeared and spread, and why they took on dot patterns that are so common for this household staple.
Researchers used time-lapse videos to see how often brown spots formed and how quickly they spread over a week. They used that information to develop a model describing the response speed and the movement of oxygen in the peel. This model has become a tool for understanding the browning process and for future research.
Browning occurs in tiny areas on the peel dubbed stomata, where oxygen can enter, but peels contain many more of these pores than brown spots. The researchers wondered why the reaction appears to be only in certain locations.
Their suggestion is that defective pores permit oxygen to enter. The oxygen spreads from that defect, but the peel responds rapidly, causing the sharp contrast between brown and yellow. If oxygen stops entering the peel, the offending stomata collapse spot expansion abruptly stops.
Steinbock said that the picture that we developed based on our model and our measurements is accurate. But what exactly does it take for this to happen? Is it a rogue pore that misbehaves? Is it a little cluster of stomata? This is a difficult question to answer today.
Farmers cultivated an estimated 117 million tons in 2019, but about 50 million tons ended up as waste. Visually unappealing fruits are a major contributor to the process, making testing and reducing the browning process crucial. Instead of turning overripe fruit into an ingredient for banana bread or storing it in a freezer, consumers often avoid brown bananas in the produce section or throwing them in the trash at home.
The fruit is a vital crop for nations around the globe, making understanding how they ripen even more crucial.
The banana industry is quite a complicated business, according to Steinbock. If you cool them, you slow down the browning, but you mess with the taste. You may spray something onto the surface to reduce the gas exchange, but that will in part alter the taste. It''s not an easy problem.