Follow the plan – Producer Producer
As a producer of fresh cut basil, what is your main production goal? It is most likely to produce a quality crop with the highest possible yield while minimizing production time and input costs. Similar to production, basil is sold in bulk, so yield equals profitability. We know that we can direct the growth, development and yield of plants to achieve our goals by manipulating environmental parameters such as light intensity, quality and photoperiod, as well as temperature and carbon dioxide concentration. However, the quality parameters of the crops must also be preserved. The quality of basil includes many parameters including its appearance (color, blemishes, turgor or wilting, etc.), leaf / stem ratio, leaf size, shelf life, aroma and flavor. Without a great aroma and flavor, basil wouldn’t be any different from lettuce.
We often think of flavor as just a taste, but it’s actually a combination of taste and aroma. Take the example of basil: what is the characteristic smell that you associate with basil? How does that compare to his taste? It’s a good example of how taste and aroma work together. It also helps illustrate how volatile compounds, or compounds that may be suspended in the air, are integral to the quality of some crops.
When we study the flavor of basil, we need to quantify specific compounds. How do we decide which ones to focus on? There are many compounds that make up the signature flavor of basil, but we’ll focus on four compounds that contribute the most: Eugenol, Methyl Cavicol, 1,8 Cineole, and Linalool (Fig. 1). Eugenol and methyl chavicol are the main aromatic compounds in cloves and anise, respectively, contributing to the clove and anise aroma of basil. 1.8 cineole, also known as eucalyptol, contributes a eucalyptus-like flavor and is a main component of eucalyptus. Finally, linalool brings in a flavor that is described as “spicy floral” in the literature, but we think it smells like Fruit Loops. Together, these compounds, along with several others, make up the basil flavor profile we love.
Light = Flavor
How do our production practices influence the flavor of basil and the concentration of these compounds? We grew ‘Nufar’ sweet basil plants in a grow room at 100, 200, 400 or 600 µmol m-2S-1 for 16 hours each day to create daily light integrals of 6, 12, 23 or 35 mol-2·D-1. After two weeks, we harvested the seedlings. Overall, the concentrations of three of the four compounds tended to increase as light intensity increased (2).
The bigger question is, how has the change in the light environment impacted consumer perception and preferences? After all, while lab testing is important, at the end of the day what really matters is whether a customer likes the look and taste of the product. We conducted a sensory panel where samples were prepared, randomized and delivered one at a time with water and crackers to consumer panelists through a sliding door (3). The panelists answered a series of questions regarding their perception of the basil they consumed. What we found was that the overall rating (green line) was highest when young basil was grown below 200 µmol m-2S-1 compared to lower or higher light intensities (Figure 4). But why is this the case? The trends in plant color, texture and flavor reflect the general trend in taste. Panelists described a darker green coloration of leaves grown at lower light intensities than those grown at 400 or 600 µmol m-2S-1 of light (purple line). While plants grown below 600 µmol m-2S-1 appeared normal when harvested, bruising occurred when the leaves were gently rinsed for consumption (4). In addition, the texture (blue line) of leaves grown under 600 µmol m-2S-1 has been more frequently described as “faded” or “fluffy”. Apart from the differences in discoloration and texture, the flavor (red line) has greatly contributed to the overall appreciation of consumers. Basil cultivated at 100 µmol m-2S-1 did not have a strong flavor, but those grown below 200 µmol m-2S-1 had the characteristic basil flavor expected by panelists. However, as the light intensity increased to 400 and 600 µmol m-2S-1, the flavor was too intense. Panelists described basil grown at high intensities as “bitter” and “spicier”.
We often think of flavor as just a taste, but it’s actually a combination of taste and aroma.
Aromatic preferences (yellow line) had an interesting trend where plants grown under 100 µmol m-2S-1 had the lowest rating because the aroma was not strong enough. When the light intensity has increased from 200 to 600 µmol m-2S-1, the flavor preference stabilized because it is more difficult to saturate the flavor in a large room compared to a sample having too strong a flavor.
Additionally, participants preferred the larger leaf size (pink line) of plants grown under higher light intensities. Again, these were two week seedlings; plants grown under 100 µmol m-2S-1 had fairly small leaves. The good thing about small leaves, as some panelists suggested, is that whole leaves can be used to garnish a dish.
What implications does this knowledge have for production?
There are some limitations to this study. Young basil plants have been used in the analysis and sensory study of consumers, where basil is often transplanted and grown longer before harvest. Additionally, the panelists tasted the basil as a whole leaf, not in pasta, caprese salad, or any other delicious dish. However, there are still important lessons to be learned from this work. We know that light intensity has a big impact on the concentration of aromatic compounds in basil, and we know that consumers can tell the difference. If the basil you’re growing isn’t tasty enough, consider adding more light. If it’s too tasty, consider shading the crop. Keep in mind that changing the light environment will not only influence flavor, but also yield. Additionally, for greenhouse grown basil, slight differences between the seasons can influence the flavor and overall quality of your harvest. To produce a crop with a consistency of flavor all year round, additional lighting or shading will likely be necessary. Finally, if your goal is to produce basil for different purposes, the “light” level is an effective tool to manipulate to produce basil with low flavor intensity for fresh consumption, such as in caprese salads, and basil at high flavor. flavor for freshly processed foods. , like pesto.