Assessment of nutritional and metabolic profiles of pea shoots: The new ready-to-eat baby-leaf vegetable

Pea-shoots are a new option as ready-to-eat baby-leaf vegetable. However, data about the nutritional composition and the shelf-life stability of these leaves, especially their phytonutrient composition is scarce. In this work, the macronutrient, micronutrient and phytonutrients profile of minimally processed pea shoots were evaluated at the beginning and at the end of a 10-day storage period. Several physicochemical characteristics (color, pH, total soluble solids, and total titratable acidity) were also monitored. Standard AOAC methods were applied in the nutritional value evaluation, while chromatographic methods with UV-vis and mass detection were used to analyze free forms of vitamins (HPLC-DAD-ESI-MS/MS), carotenoids (HPLC-DAD-APCI-MSn) and flavonoid compounds (HPLC-DAD-ESI-MSn). Atomic absorption spectrometry (HR-CS-AAS) was employed to characterize the mineral content of the leaves. As expected, pea leaves had a high water (91.5%) and low fat (0.3%) and carbohydrate (1.9%) contents, being a good source of dietary fiber (2.1%). Pea shoots showed a high content of vitamins C, E and A, potassium and phosphorous compared to other ready-to-eat green leafy vegetables. The carotenoid profile revealed a high content of β-carotene and lutein, typical from green leafy vegetables. The leaves had a mean flavonoid content of 329mg/100g of fresh product, mainly composed by glycosylated quercetin and kaempferol derivatives. Pea shoots kept their fresh appearance during the storage being color maintained throughout the shelf-life. The nutritional composition was in general stable during storage, showing some significant (p<0.05) variation in certain water-soluble vitamins. © 2014 Elsevier Ltd.

Joana Santos is thankful to FCT for the PhD grant SFRH/BD/66476/2009 financed by POPH-QREN and subsidized by ESF and MCTES. M.H. would like to thank MICINN for a “Ramón y Cajal” research contract. This work had been supported by Fundação para a Ciência e Tecnologia through project no. PEst-C/EQB/LA0006/2013 and NORTE-07-0124-FEDER-000069 – Food Science. The authors thank Iberian Salads S.A for the vegetable samples used in this study and also to Drª. Ana Paula Vale from ESA-Instituto Politécnico de Viana do Castelo for the help provided in the dietary fiber determinations.

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