Extraction, composition, and functional properties of dried alfalfa (Medicago sativa L.) leaf protein

Abstract

It is technically feasible to extract protein with desirable emulsifying and heat stability properties from dried alfalfa leaves; however, the dried form may not be a practical starting material for protein production, given the difficulty of achieving high yields and high-purity protein product. © 2016 Society of Chemical Industry.

Plant RuBisCo: An Underutilized Protein for Food Applications

“…For instance, Martin et al (Martin et al, ) obtained an almost 100% pure and a highly soluble RuBisCo isolate by combining anion‐exchange and size‐exclusion chromatography. pH precipitation (alkali solubilization and acid‐induced precipitation) is a common practice for extracting plant proteins, although the protein recovery was reported to be lower than 50% for alfalfa leaves and solubility of the acid‐precipitated proteins was considerably compromised (Hojilla‐Evangelista et al, ). However, plant leaf proteins extracted in an alkali environment or acid‐extracted proteins that were redissolved at neutral pH before analysis showed excellent solubility in water (Lamsal et al, ; Zhong et al, ).…”

“…Additionally, proteins concentrated by ultrafiltration, which were at pH 7.0 before analysis, followed the same trend as the resolubilized proteins and showed a peak of solubility of 90/100 g at pH 9.0. Hojilla‐Evangelista et al () reported a limited solubility for dried alfalfa leaf protein concentrate in the pH range 2.0–10.0, with the lowest solubility observed at pH 4.0 (2/100 g) and the highest solubility at pH 5.5–10.0 (50/100 g). In this study, proteins were extracted by alkali solubilization and acid‐induced precipitation, and the observed results are, therefore, in line with the behavior observed by Lamsal et al () for acid‐extracted proteins.…”

“…The emulsifying activity of RuBisCo was reported to be lower than that of bovine serum albumin and soy protein (Barbeau & Kinsella, ), but higher than that of egg‐white protein (Lamsal et al, ). Hojilla‐Evangelista et al () reported high emulsifying capacities and emulsion stabilities for dried alfalfa leaf proteins. The emulsification properties were further found to increase with pH values, a behavior that may be related to protein unfolding and the subsequent increased oil–water interface that occurs at alkaline pH (Fennema, ).…”

“…Removal of unwanted compounds such as phenols, chlorophyll, and off‐flavor compounds is the arduous step during RuBisCo extraction. Various extraction and purification procedures have been reported for tobacco, spinach, alfalfa, beet leaves, and algae (Hojilla‐Evangelista, Selling, Hatfield, & Digman, ; Martin, Nieuwland, & De Jong, ; Merodio & Sabater, ; Schwenzfeier, Wierenga, & Gruppen, ; Sheen & Sheen, ), and these methods are often adapted for the specific RuBisCo source. Extraction processes greatly influence the solubility, denaturation state, and composition of protein isolates, which in turn influence the functional properties relevant for food applications, such as gelation, foaming, and emulsion properties (Lamsal, Koegel, & Gunasekaran, ).…”

Sugar beet leaves for functional ingredients

“…neutral pH, low temperature). Protein extraction from dried alfalfa leaves leads to lower yields and less purity than from fresh leaves (Hojilla-Evangelista et al, 2016). Reaching higher yields would require harsh conditions such as using highly alkaline pH (pH14), as described for dried tea leaves (Zhang et al, 2014).…”