Enzyme assisted extraction of protein from mallow leaf (<i>Malva sylvestris</i> L.) for production of alternative protein concentrate

The tendency to consume the plant-based protein is gradually increasing with the increase of the world population. Although the leaf proteins are the sustainable protein sources, the protein isolation from them is difficult due to plants structure. The objective of this study was to evaluate the mallow leaf as an alternative protein source, to increase the protein efficiency with enzyme assisted extraction and to determine their functional properties for industrial food production. The optimum conditions for the enzymes were found as 5.6 pH value, 52.5 C, 75 min and 7% enzyme concentration for Pectinex UF, 7 pH value, 48 C, 75.5 min and 7% enzyme concentration for Pectinex Ultra SP-L by response surface methodology. The effect of precipitation methods, isoelectric (IP), ammonium sulfate (ASP) and isoelectric-ammonium sulfate (IASP), on efficiency and functional properties of plant proteins was investigated. The protein contents of IP, ASP and IASP were 40, 65.5 and 61.7%, respectively. Despite the lowest protein content, IP (97% at pH 7.5) has the highest solubility than ASP (95% at pH 7.5) and IASP (94.4% at pH 8.5). The highest foaming capacity at pH 6 was determined as 133.3, 90.9 and 80%, respectively, for IP, ASP and IASP. Also, IP has the highest emulsion activity and stability than ASP and IASP. All these evaluations, mallow leaf can be used for protein isolation, but its economic dimension should be investigated through more comprehensive studies.