Date of Award
Master of Science
Food Science and Human Nutrition
Food Science and Technology
Lester A. Wilson
Greenhouse herb producers may use artificial lighting to supplement the natural light available to their crops. High-pressure sodium (HPS) lights are the most common supplemental lighting systems employed in such operations, but light-emitting diode (LED) lighting is increasing in popularity because of its energy efficiency, customizability, and environmental friendliness. LED lights can be customized to emit specific proportions of light wavelengths, but many herb producers do not know how these “light recipes” affect their crops, specifically their crops’ aroma. This research utilized consumer sensory difference panels and flash gas chromatograph-electronic nose (GC-EN) analysis to evaluate the aroma of fresh basil, parsley, and dill herbs after cultivation under one of three supplemental light treatments: HPS, LED with a high proportion of blue to red diodes (high blue LED), or LED with a low proportion of blue to red diodes (low blue LED).
Consumer sensory panels using triangle difference tests found that consumers could not determine the difference between herbs grown under HPS and high blue LED. Preliminary work suggests a similar result for HPS and low blue LED, but further research is required to confirm this. GC-EN analysis revealed no significant chemical differences between lighting treatments among basil or parsley. Subtle chemical differences were uncovered in dill GC-EN data, especially when nonpolar and mid-polar column data were examined separately to prevent false correlation from multiple detections of a single compound. Consistent with literature findings, linear discriminant analysis of these data subsets revealed that multiple volatile compounds in dill are affected by the supplemental lighting wavelengths available to the herb.
In the scope of this study, there appears to be no overall aroma difference between herbs grown under HPS light and those grown under LED light, but more research must be conducted to confirm and expand upon these findings. Future research including sensory preference tests, descriptive analyses, GC-olfactometry, and GC-MS studies will make research like this more practical for herb farmers.
Anne Kalyn Seely
Seely, Anne Kalyn, "Determining aroma differences among basil, parsley, and dill grown under varied supplemental light wavelengths using consumer sensory and flash gas chromatograph-electronic nose analyses" (2017). Graduate Theses and Dissertations. 16211.