Aquafaba is a viscous juice from canned chickpea that, when stirred vigorously, produces a relatively stable white froth or foam. The primary research goal is to identify the components of aquafaba that contribute viscosifying/thickening properties using nuclear magnetic resonance (NMR), ultrafiltration, electrophoresis, and peptide mass fingerprinting.
Chickpea and other pulses are commonly sold as canned products packed in a thick solution or a brine. This solution has recently been shown to produce stable foams and emulsions, and can act as a thickener. Recently interest in this product has been enhanced through the internet where it is proposed that this solution, now called aquafaba by a growing community, can be used a replacement for egg and milk protein. As aquafaba is both new and being developed by an internet based community little is known of its composition or properties. Aquafaba was recovered from 10 commercial canned chickpea products and correlations among aquafaba composition, density, viscosity and foaming properties were investigated. Proton NMR was used to characterize aquafaba composition before and after ultrafiltration through membranes with different molecular weight cut offs (MWCOs of 3, 10, or 50 kDa). A protocol for electrophoresis, and peptide mass fingerprinting is also presented. Those methods provided valuable information regarding components responsible for aquafaba functional properties. This information will allow the development of practices to produce standard commercial aquafaba products and may help consumers select products of superior or consistent utility.
Increasingly vegetarian products are being developed that mimic the properties of meat, milk, and eggs. The functional properties of pulses are important in their current uses in food applications and their properties are being explored in the development of replacements for animal protein. For example, dairy alternatives sales were $8.80 Billion USD in 2015 and this market is growing rapidly. This market is projected to grow to $35.06 billion by 2024. Moreover, the upward trend in demand for plant-based milk substitutes is, in part, a result of consumer health concerns regarding cholesterol, antibiotics, and growth hormones often used in milk production1. Similarly, vegetable protein and hydrocolloid egg replacer markets are rapidly expanding and a compound annual growth rate of 5.8% is expected for these materials over the next 8 years with sales of $1.5 billion USD expected in 20262. A growing number of consumers prefer vegan protein sources, allergen reduced diets and reduced carbon footprint for food products. Demand for pulse-based products, especially from lentil, chickpea, and faba bean are steadily growing due to the high protein content, dietary fiber and low saturated fat content of pulses3. Pulses also contain phytochemicals with potentially beneficial biological activity4.
Commercial entities, scientists and private individuals have taken different approaches to communicate the quality properties of chickpea based egg and milk replacements. Gugger et al.5 produced a milk-like product from high starch grains including adzuki bean and chickpea. In their described methods the proponents attempted to show that their product is unique and different from "aquafaba"6. In another commercial approach elucidated by Tetrick et al.7 a plant-based egg substitute was developed. Their patent application describes methods of combining pulse flour with known thickeners that emulate the function of egg white in baked materials. Typical formulae include 80-90% pulse flour and 10-20% thickening additives.
Peer reviewed literature also indicates the functionality possible with chickpea and has demonstrated that albumin protein fractions obtained from kabuli and desi chickpea flour have good emulsification properties. They have also found a significant effect of chickpea source on the albumin yield and performance8.
After the initial internet report describing "aquafaba" by French chef Joël Roessel, an open source movement is showing the utility of aquafaba as a replacement of egg white and dairy protein in many food applications. There are many highly viewed webpages and YouTube videos showing the incorporation of aquafaba in foods that emulate the qualities of ice cream, meringue, cheese, mayonnaise, scrambled eggs, and whipped cream. Most pioneers providing open source aquafaba applications (recipes) obtain their material by straining canned chickpeas and using the liquid in their recipes. These individuals are mostly not trained scientists. Video comments sections indicate that the respondents have copied the recipes and some have failed to replicate the successes of the aquafaba advocates.
All three approaches (corporate, scientific and open source) to developing egg and milk replacements have merit but are missing an important dimension. Applied scientists, basic scientists and individuals promulgating pulse-based products have incompletely characterized and standardized their input material. Standardization of a product for a specific use is a normal industrial practice. Chickpea cultivars have not been standardized for aquafaba quality and industrial canning practices are standardized to produce consistent chickpeas not aquafaba.
Based on studies of other commodities, it is predictable that both genotype and environment will contribute to pulse aquafaba quality. It is known that both genotype and environment affect kabuli chickpea canning properties9. Typically, genotypic effects are large between related species and smaller within members of a species. Variation in physical and chemical properties can be minimized through identity preservation that allows the selection of cultivars with desired properties. Environmental effects can also be large and are managed by quality evaluation and blending to standard performance in specific tests10.
There are many genetically distinct cultivars of chickpea in commercial production. For examples, the University of Saskatchewan Crop Development Centre, a major source of commercial chickpea germplasm, has released 23 chickpea cultivars since 1980 of which 6 are currently recommended for cultivation in Canada. While scientific manuscripts often describe the cultivar used in a study, the patents and internet pages that were surveyed did not indicate the cultivar used or the provenance of the chickpeas. The standardization of cultivars and handling could help users increase their success in using chickpea but this information is not available on canned chickpea products.
The objective of this research is to determine the aquafaba components that contribute foaming properties. Here,the rheological properties of aquafaba from commercial chickpea brands were compared and the chemical properties were studied by NMR, electrophoresis, and peptide mass fingerprinting. To our knowledge, this is the first research which describes the chemical composition and the functional properties of the aquafaba viscosifier components.
In this research, we have found that chickpea aquafaba from different commercial sources produces foams that vary in both properties (volume and stability of foam) and chemical composition. There was a positive correlation between aquafaba viscosity and moisture content. Foam volume increase (Vf100) was not related to these parameters. Additives such as salt and disodium EDTA might suppress viscosity and foam stability as aquafaba from chickpea canned with these additives had lower viscosity and produced foams…
The authors have nothing to disclose.
This research was supported by the Institute of International Education's Scholar Rescue Fund (IIE-SRF).
Freeze Dryer | |||
Stoppering Tray Dryer | Labconco Inc. | 7948040 | |
Mixer | |||
Stainless steel hand mixer | Loblaws | PC2200MR | |
Viscosity Measurement | |||
Shell cup No. 2 | Norcross Corp. | ||
Color Measurement | |||
Colorflex HunterLab spectrophotometer | Hunter Associates Laboratory Inc. | ||
Protein and Carbon Contents | |||
Elemental analyzer | LECO Corp. | CN628 | |
NMR Spectrometry | |||
Spectrafuge 24D | Labnet International Inc. | ||
Syringe filters | VWR International | CA28145-497 | 25 mm, with 0.45 µm PTFE membrane |
Deuterium oxide | Cambridge Isotope Laboratories Inc. | 7789-20-0 | |
3-(trimethylsilyl)propionic-2,2,3,3-d4 acid sodium salt | Sigma-Aldrich | 169913-1G | |
Bruker Avance 500 MHz NMR spectrometer | Bruker BioSpin | ||
TopSpin 3.2 software | Bruker BioSpin GmbH | ||
Electrophoresis | |||
Regenerated cellulose membrane | Millipore Corp. | 3, 10, 50 kDa (MWCO) | |
Centrifugal filter unit | Millipore Corp. | ||
Benchtop centrifuge | Allegra X-22R, Beckman Coulter Canada Inc. | ||
Mixer Mill MM 300 bead mill | F. Kurt Retsch GmbH & Co. KG | ||
Eppendorf centrifuge 5417C | Eppendorf | ||
Phosphate buffered saline, pH 7.4 | Sigma-Aldrich | P3813-10PAK | |
Tris-HCl buffer pH 7.4 | Sigma-Aldrich | T6789-10PAK | |
PageRuler Prestained Protein Ladder | Fisher Scientific | ||
Mini-Protein Tetra Cell system | BioRad | ||
Peptide Mass Fingerprinting | |||
Thermo-Savant SpeedVac | BioSurplus | Centrifugal vacuum evaporator | |
Trypsin buffer | 20 µL trypsin in 1 mM hydrochloric acid and 200 mM NH4HCO3 | ||
Iodoacetamide | Sigma-Aldrich | I1149-5 g | |
Trifluoroacetic acid | Fluka | BB360P050 | |
Acetonitrile | Fisher Scientific | L14734 | |
Formic acid | Sigma-Aldrich | 33015-500mL | |
Mass spectrometry vial | Agilent Technologies Canada Ltd. | ||
Agilent 6550 iFunnel quadrupole time-of-flight mass spectrometer | Agilent Technologies Canada Ltd. | Agilent 1260 series LC instrument and Agilent Chip Cube LC-MS interface | |
HPLC-Chip II: G4240-62030 Polaris-HR-Chip_3C18 | 360 nL enrichment column and 75 µm × 150 mm analytical column, both packed with Polaris C18-A, 180Å, 3 µm stationary phase. | ||
Agilent MassHunter Qualitative Analysis Software | Agilent Technologies Canada Ltd. | ||
SpectrumMill data extractors | Agilent Technologies Canada Ltd. |