Preparation Of Glycosylated Hemp Protein And Its Application In Whipped Aerated Emulsions

The growing global population and the wave of plant-based foods have led to a high priority being placed on proteins of plant origin.Hemp(Cannabis sativa L.)has important nutritional and industrial value,and the hemp protein in it has been well-documented to have good amino acid levels and low allergenicity.However,the poor solubility,emulsification,and other processing properties of hemp proteins had largely limited their full application in complex food systems.Glycosylation modifications with mild reaction conditions and stable resulting products had been confirmed to improve the functional properties and application range of proteins.In this paper,hemp protein was modified with glycosylation and investigated the protein structure and functional properties,and the glycosylated hemp proteins were further applied to whipped aerated emulsions systems to provide a theoretical basis for their practical processing and production in emulsions.Firstly,hemp protein glycosylated with pullulan polysaccharide(HPI-Pullulan)was investigated for its structural characteristics and physicochemical properties.Spectroscopic characterization showed that glycosylation altered the secondary and tertiary structure of hemp protein,and the functional properties of HPI-Pullulan were significantly enhanced compared to HPI.In addition,the Pearson correlation analysis showed a positive correlation between the functional properties and the grafting rate.When glycosylation at 70°C at a ratio of 1:1 between hemp protein and Pullulan polysaccharide for 12 h,the grafting rate reached 27.83±0.80%.In this condition,compared to HPI,HPI-Pullulan with an increase in solubility of 43.37±0.58%,the water-holding capacity increased to 9.59±0.36 g/g,the oil-holding capacity increased to13.73±0.59 g/g,and emulsification raised to 104.64±3.93 m~2/g,the foaming properties were improved to 54.79±1.53%.Overall,glycosylation significantly enhanced the functional properties of the hemp protein.Secondly,the prepared glycosylated hemp protein(HPI-Pullulan)was applied to O/W emulsions to investigate its effect on the structural and stabilizing properties of O/W emulsions.The results showed that HPI-Pullulan significantly reduced the particle size of the emulsions.The HPI-based emulsions showed particle aggregation near the oil droplets under microscopy and HPI-Pullualn significantly ameliorated this phenomenon and resulted in homogeneous and dense oil droplets with significantly improved interfacial properties.The absolute potential value increased from 26.14±2.17 m V to 57.45±0.65 m V,which significantly improved the stability performance of O/W emulsions,and the centrifugal precipitation rate decreased from46.93±2.64%to 32.79±1.32%.Moreover,the rheology showed that the storage modulus(G′)and loss modulus(G′)of HPI-Pullululan were significantly higher compared to HPI emulsions.This indicates that glycosylation can enhance the emulsification of the protein in the emulsion system.Thus,HPI-Pullulan can maintain the stability of the oil-water interface of O/W two-phase emulsions.Finally,the glycosylated hemp protein(HPI-Pullulan)was applied to whipped aerated Emulsions systems to study the application system,replacing the common animal-derived emulsifier casein and the common thickening agent xanthan gum guar gum.In terms of basic evaluation indicators,the whipping time HPI-Pullulan emulsions were significantly reduced and the star stability was significantly increased from 20 min to 40 min,similar to that of the emulsions prepared with casein.At the same time,the glycosylation promoted the whipping aerated result,resulting in a significant increase in the whipped foaming rate from 2.17±0.08to 2.87±0.06 and the foam stability has also been significantly improved.The HPI-Pullulan regulated the fat-globules partial-coalescence rate of the emulsions,resulting in a decrease from80.53±1.33%to 66.87±1.22%,and a decrease in hardness by 36.35±1.38%,which improved the viscosity of the emulsion due to excessive agglomeration of fat globules caused by the HPI.The high viscosity and stiffness of the emulsion caused by the excessive agglomeration of fat globules due to HPI was improved.In addition,the whipped aerated emulsions prepared by HPI-Pullulan had similar textural and rheological properties to that of the casein sample.In summary,this provides a theoretical basis for the use of glycosylated hemp proteins in churned aerated emulsions.