The research was presented last week at the American Chemical Society conference
One of the best-selling fruits in the world, the tomato, will be at the center of the Tomatina festival taking place today in Valencia, Spain. As part of the Tomatina festival, a tomato war is held with the participation of tens of thousands of people. The festival is held every year towards the end of August, and the tomato war seals it, on the last Wednesday of the month. Visitors to the festival throw ripe tomatoes at each other. Unless these tomatoes are picked that morning and go directly to the festival participants, they will almost certainly lack the most important ingredient - the aroma.
It turns out that the process of transporting the tomato from the picking to the consumer, in many places around the world, causes the loss of the strong aroma of the fruit. Tomato lovers will be happy to read about a study from which it appears that restructuring a few small steps in the process of transporting tomatoes from the farmer to the vegetable seller and from there to the consumer, may significantly improve the taste of the tomato. This is according to a study by researchers at the US Department of Agriculture, which was presented last week (August 19) at the 250th meeting of the American Chemical Society held in Boston.
"Ideally, tomatoes should be picked ripe in their growing positions on the farm" says the lead researcher, Dr. Jinha Bai, a plant physiology researcher from the US Department of Agriculture. "But this is not always possible due to the process of selling the tomatoes, during which the tomatoes are stored and transported long distances."
To prevent the tomatoes from ripening too much before they reach the store, the growers pick them when they are still green, in the packing process they use ethylene gas to make the fruit ripen, and then store and transport them at a low temperature.
The problem is that cooling the tomatoes impairs their flavor, Bai says. In an effort to improve the quality of the taste, Bai and his staff developed a slightly different method. "To produce a tastier tomato, we added hot water before the ethylene treatment." he explains. "We discovered that this simple pretreatment prevents the loss of flavor during cooling."
The researchers, from the U.S. Department of Agriculture's Agricultural Research Service and the University of Florida, dipped Florida-grown tomatoes in hot water (about 50 degrees Celsius) for five minutes and then cooled the fruit to temperatures between 5 and 12 degrees Celsius, the temperature range used to transport agricultural produce. After the tomatoes ripened, the researchers tested their taste and smell.
They discovered that the fruits treated with hot water have a higher level of the compounds that cause the characteristic smell of the tomato (6-methyl-5-hepten-2-one, 2-methylbutanal and 2-phenylethanol) compared to tomatoes that were not heated and they were also tastier . According to Dr. Bai, "refrigeration suppresses the production of compounds containing oxygen, nitrogen and sulfur, including alcohols and aldehydes, including 13 compounds that are important for obtaining the aroma of the tomato." However, treatment with hot water causes them to produce higher concentrations of compounds that contribute to the aroma, and they do so despite the cooling that follows immediately.
The researchers monitor the aroma compounds at several points in time - when the tomato was still green, immediately after the picking and shipping process and when they were partially ripe. This is to expand the database that today relies only on measuring the ingredients in fully ripe tomatoes, and this is to help develop a better transportation process.
Bai says that the method he developed together with his colleagues to solve the problem of preserving the smell is cheap. "Most post-harvest treatments sacrifice the smell to avoid damage or spoilage. Our method can be implemented in the existing commercial system without risking decay," he added.
The researchers also tried other methods in addition to the hot water such as growing the green tomatoes in an environment containing methyl silicate - also known as an essential oil, an antifungal agent recognized as safe by the US Food and Drug Administration.
They also managed to preserve the tomato charge using another method. In this process they harvested the tomatoes at a later stage than farmers harvest today, when they were half green and half red rather than when they were still fully green. The researchers treated them using the gas methyl chlorophene (methylcyclopropene) which is also a gas approved for use. They refined the treatment with the aim of making the fruit more forgiving of cell death and yeast when stored at high temperatures. In this way, they were able to skip the cooling step and thus preserve the taste.
When the researchers determine whether one method is better than the other, they will contact the food processing companies and check their interest in implementing the techniques," says Bai.
Video clip of the broadcast of the press conference where the study was presented, Boston, August 19, 2015
More of the topic in Hayadan:
- The genome sequences of the cultivated tomato and the wild tomato were deciphered
- Scientists from the Hebrew University and the USA have discovered a gene in the tomato that increases the yield of the plant by 60% and improves its quality
- Scientists have succeeded, for the first time, in improving the taste of the tomato significantly, using methods of genetic engineering
