Progress in vegetable proteins isolation techniques: A review

Abstract

Novel vegetable proteins, like those extracted from abundant raw materials (grass) or agri-food by-products and waste streams (oilseed meals), are expected to be used as replacers for animal-derived proteins, due to higher production efficiency, reduced life cycle environmental impact and possibility to meet consumers' dietary or cultural preferences. Although having a versatile functionality (emulsifying, foaming, gelling, texturizing agents), application of proteins is limited since their properties highly depend on their structure and composition, environmental factors (pH, ionic strength, presence of other micro-and macro-molecules in food matrices) and isolation method and conditions. The objective of this article is to review the current techniques used to isolate the proteins from vegetable raw materials and comment on the influence of extraction method and conditions (pH, ionic strength, extraction media temperature, extraction time, etc.) on protein properties (yield, purity, appearance, solubility, denaturation degree, emulsification efficiency, etc.). The utilization of novel technologies such as ultrasound assisted extraction, electro-activation technique and approaches (enzyme-assisted extraction) to improve protein extraction yield or functionality was also discussed.

Bioprocessing of Functional Ingredients from Flaxseed

“…Several novel technologies have also been discovered for protein extraction. These methods increases the yield, functionality and production sustainability of protein [ 60 ]. Novel technologies include ultrasound assisted extraction, electro-activation technique, pressurized low polarity water extraction, pulse–electric field technique, high voltage electrical discharge and complete or limited enzymatic (proteases) hydrolysis-assisted extraction.…”

“…Micellization, as an isolation technique helps in the preservation of native state of protein and removal of non–protein components [ 60 ]. Protein precipitate by ‘salting out’ at different salt concentrations.…”

“…The most commonly used salt is ammonium sulfate, due to its high solubility, minimal cost and lack of buffering capacity relative to other salts [ 66 ]. Micellization involves protein extraction with salt solution, usually in an ice bucket, followed by removal of insoluble material by centrifugation, recovery of precipitates by centrifugation, diafiltration to remove excess salts and final recovery by centrifugation [ 60 , 66 ]. Proteins extracted by micellization have low phytic acid and pentosans levels, higher enthalpies (meaning high structural order), and are lightly coloured [ 60 ].…”

Vegetable Additives in Food Packaging Polymeric Materials

“…Soy Protein, hydrolyzed proteins (wheat gluten, wheat gliadin), zein, polypeptides -Alkaline extraction followed by protein precipitation at isoelectric pH; -protein extraction with salt solution, followed by precipitation from a salt extract by ultrafiltration, diafiltration membranes or dilution in cold water (micellization) [29]; and -novel techniques, such as ultrasound assisted extraction, enzyme-assisted extraction in the form of proteases and/or carbohydrolases [29].…”

Hydrolyzed hemp seed proteins as bioactive peptides

“…During the food processing, the occurrence of biologicalspecific waste is inevitable. The disposal of food waste is difficult due to its biological instability, potentially pathogenic nature, high water content, potentially rapid autoxidation and very high enzymatic activity.High risk of environmental pollution caused by the uncontrolled release of food by-products has led to the necessity of reducing the amount of waste through development of various bioprocesses toconvert the starting material tonovel food products.Numerous recent studies have shown that food industry by-products represent rich source of proteins and other nutraceuticals (Hadnađev et al, 2017;Rodrigues et al, 2012).…”