Seasonal Variation of Health-Promoting Bioactives in Broccoli and Methyl-Jasmonate Pre-Harvest Treatments to Enhance Their Contents.

Inma Navarro-González,Javier García-Alonso,Rocío González-Barrio,Mª Jesús Periago-Castón,Nieves Baenas,Vanesa Nuñez-Gómez,Diego A. Moreno

doi:10.3390/foods9101371

Abstract

Broccoli is a source of bioactive compounds that provide an important nutritional value. The content of these compounds can vary depending on agronomic and environmental conditions, as well as on elicitation. In this study, three crop trials were carried out to evaluate the effects of the cultivation season, the application of different dosages of methyl-jasmonate (MeJA) on the overall quality and on the total content of bioactive compounds of ‘Parthenon’ broccoli cultivated under the field conditions of southeastern Spain. Color parameters, chlorophyll content, total phenolic compounds, total flavonoids and antioxidant activity were measured to evaluate the overall quality. Moreover, individual carotenoids, phenolic compounds and glucosinolates were evaluated by high performance liquid chromatography with diode array detection (HPLC-DAD) and high performance liquid chromatography equipped with diode array detector coupled to mass spectrometer using electro spray ionization (HPLC-DAD-ESI/MSn). The content of total carotenoids, phenolic compounds and glucosinolates were higher in autumn compared with spring, showing increases of 2.8-fold, 2-fold and 1.2-fold, respectively. Moreover, a double application of MeJA increased the contents of total carotenoids, phenolic compounds and glucosinolates by 22%, 32% and 39%, respectively, relative to the untreated samples. Considering our results, the controlled and timely application of 250 µM MeJA to the aerial parts of the plants four days before harvest, on two consecutive days, seems to be a valid agronomic strategy to improve the health-promoting capacity of Parthenon broccoli, without compromising its overall quality.

Highlights

The Brassica family is a group of vegetables widely consumed around the world, including cabbages, cauliflower, Brussels sprouts, radishes and broccoli (Brassica oleracea L. var. italica) among others [1]
Chlorophyll content determines the intensity of the green color of broccoli, which is important to overall quality and consumer acceptability, and likelihood of purchase
The hue angle (h*) was significantly higher in the samples of broccoli plants cultivated in autumn than in the spring samples, showing their greener color; the L* value was higher in the samples harvested in spring, which could be due to the yellowing process

Summary

Introduction

The Brassica family is a group of vegetables widely consumed around the world, including cabbages, cauliflower, Brussels sprouts, radishes and broccoli (Brassica oleracea L. var. italica) among others [1]. The Brassica family is a group of vegetables widely consumed around the world, including cabbages, cauliflower, Brussels sprouts, radishes and broccoli The consumption of broccoli has undergone a significant rise, with a positive effect on the agricultural economy, in the Murcia region (southeastern Spain), which is the region with the greatest production of broccoli in Europe [2,3]. This rise in consumption is related to increased adherence to healthier diets by European consumers, since this family of vegetables, and broccoli, Foods 2020, 9, 1371; doi:10.3390/foods9101371 www.mdpi.com/journal/foods. Carotenoids, one of the characteristic groups of compounds in broccoli, are natural pigments derived from the isoprenoid pathway, and are formed of a C40 backbone that differs according to the specific carotenoid being considered [7]

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