Optimization of the Recovery of Secondary Metabolites from Defatted Brassica carinata Meal and Its Effects on the Extractability and Functional Properties of Proteins.

V P Thinh Nguyen,Irina Ioannou,Jon D Stewart,Florent Allais

doi:10.3390/foods11030429

V P Thinh Nguyen, Irina Ioannou + Show 2 more

Open Access

https://doi.org/10.3390/foods11030429

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Abstract

The sustainable extraction of secondary metabolites from Brassica agro-industrial by-products often involves the use of high concentrations of ethanol, and/or high temperatures, which tends to decrease the efficiency of protein extraction (yield, profile, etc.). To understand the limits of the combination of these two extraction processes, aqueous ethanol extraction of secondary metabolites (e.g., phenolic compounds and glucosinolates) from Brassica carinata defatted meal was optimized using Response Surface Methodology. The validated models predicted that aqueous ethanol extraction of defatted Carinata meal, with a low aqueous EtOH concentration (22% EtOH) at moderate Te (50 °C), enables the efficient recovery of secondary metabolites (sinapine = 9.12 ± 0.05 mg/gDM, sinigrin = 86.54 ± 3.18 µmol/gDM) while maintaining good protein extractability (59.8 ± 2.1%) from successive alkaline extractions. The evaluation of functional properties of the resulting protein isolates revealed that aqueous extraction, under optimized conditions, improves foaming activity while preserving emulsion ability.

Highlights

Cultivated in the Ethiopian highlands and adjoining areas of East African and Mediterranean regions for food purposes, Brassica carinata is considered a nonfood oilseed crop in the United States due to its high erucic acid-rich oil content, which is suitable for aviation biofuel production [1]
The aqueous ethanol (AE) extraction was performed prior to the alkaline extraction to avoid the amalgam extraction of proteins along with secondary metabolites, which would require a more complicated downstream separation are reported in Figures S1 and S2 (Supplementary Materials)
Optimization of AE extraction of Carinata meal with aqueous ethanol resulted in validated models based on selected factors and responses

Summary

Introduction

Cultivated in the Ethiopian highlands and adjoining areas of East African and Mediterranean regions for food purposes, Brassica carinata (referred as Carinata) is considered a nonfood oilseed crop in the United States due to its high erucic acid-rich oil content, which is suitable for aviation biofuel production [1]. The main purpose of such cultivations is to support bio-fuel production, the residual meal still contains valuable components, such as proteins and secondary metabolites [3,4]. The therapeutic benefits of these co-product molecules have often been mentioned (e.g., antioxidant, antibacterial, anticancer) [7,14,15,16], they exhibit anti-nutritional activities at high concentrations, and thereby decrease the nutritional value of meal or protein extracts [7,17]. An additional separation step is, required to remove secondary metabolites from protein extracts. Such a separation process must have a high separation efficiency, without altering the extractability or functional properties of the proteins

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Conclusion