Hydroponic Basil Production: Temperature Influences Volatile Organic Compound Profile, but Not Overall Consumer Preference

Kellie J Walters,Roberto G Lopez

doi:10.3390/horticulturae8010076

Kellie J Walters, Roberto G Lopez

Open Access

https://doi.org/10.3390/horticulturae8010076

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Abstract

Altering the growing temperature during controlled-environment production not only influences crop growth and development, but can also influence volatile organic compound (VOC) production and, subsequently, sensory attributes of culinary herbs. Therefore, the objectives of this study were to (1) quantify the influence of mean daily temperature (MDT) and daily light integral (DLI) on key basil phenylpropanoid and terpenoid concentrations, (2) determine if differences in sensory characteristics due to MDT and DLI influence consumer preference, and (3) identify the sweet basil attributes consumers prefer. Thus, 2-week-old sweet basil ‘Nufar’ seedlings were transplanted into deep-flow hydroponic systems in greenhouses with target MDTs of 23, 26, 29, 32, or 35 °C and DLIs of 7, 9, or 12 mol·m−2·d−1. After three weeks, the two most recently mature leaves were harvested for gas chromatography–mass spectrometry (GC–MS) and consumer sensory analysis. Panel evaluations were conducted through a sliding door with samples served individually while panelists answered Likert scale and open-ended quality attribute and sensory questions. The DLI did not influence VOC concentrations. Increasing MDT from 23 to 36 °C during production increased 1,8 cineole, eugenol, and methyl chavicol concentrations linearly and did not affect linalool concentration. The increases in phenylpropanoid (eugenol and methyl chavicol) were greater than increases in terpenoid (1,8 cineole) concentrations. However, these increases did not impact overall consumer or flavor preference. The MDT during basil production influenced appearance, texture, and color preference of panelists. Taken together, MDT during production influenced both VOC concentrations and textural and visual attribute preference of basil but did not influence overall consumer preference. Therefore, changing the MDT during production can be used to alter plant growth and development without significantly affecting consumer preference.

Highlights

Altering the growing temperature during controlled-environment production influences crop growth and development, but can influence volatile organic compound (VOC)
VOCs quantified, daily light integral (DLI) were pooled for gas chromatography–mass spectrometry (GC–MS) analysis
Eugenol and methyl chavicol concentration increased at similar rates as temperature increased [487 to 499 ng·mg−1 dry mass (DM) per

Summary

Introduction

Altering the growing temperature during controlled-environment production influences crop growth and development, but can influence volatile organic compound (VOC). The increases in phenylpropanoid (eugenol and methyl chavicol) were greater than increases in terpenoid (1,8 cineole) concentrations. These increases did not impact overall consumer or flavor preference. MDT during production influenced both VOC concentrations and textural and visual attribute preference of basil but did not influence overall consumer preference. Producing crops in controlled environments has the potential to improve production efficiencies by precisely manipulating the growing environment to obtain desired yield and quality attributes [2]. This allows us to hypothesize that consumers would prefer basil (Ocimum basilicum) with a more intense flavor

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