Emulsifying Properties of Sericin Obtained from Hot Water Degumming Process

Abstract

Sericin is a protein present in the silkworm cocoon of Bombyx mori. Although usually discarded during the silk degumming process, which causes environmental impact and high costs of wastewater treatment, this protein possesses properties that are particularly useful to the food industry. This work was carried out to determine the amino acid profile and evaluate the antioxidant and emulsifier capacity of sericin. The main amino acids present in sericin are glycine, serine and aspartic acid. The high-molecular-weight fractions of this protein have antioxidant activity. Furthermore, due to the predominant hydrophilic character of its amino acids, it acts as an emulsifier. The emulsions prepared with 1.0% of sericin were stable for 24 h. All emulsions showed pseudoplastic behavior and great internal strength, according to the rheological analysis. Thus, sericin can be used as an additive in emulsified products providing antioxidant properties in these products. PRACTICAL APPLICATIONSThe present work provides an application as emulsifier to sericin, which is normally discarded during the silk process. This protein prevents phase separation in emulsions and provides antioxidant activity to the formed emulsion, besides being a natural product. The resulting emulsions prepared with high concentration of sericin have high viscosity, and therefore sericin can be used in the production of mayonnaise and creams. It can also be used, in lower concentrations, in salad dressing for example, resulting in a lower viscosity product.

The rheological properties of native sericin

“…Large quantities of sericin solution are produced industrially from wastewater in the cocoon degumming process [43][44][45] and find uses in the food [46][47][48], cosmetic [32,[49][50][51][52], biomedical [53][54][55][56][57], and health supplement industries [58].…”

“…Nevertheless, the combination of high temperature, pressure, and solvents typically used affects the quality of the sericin produced through changes to its conformation or molecular weight [32,35,57,63,[73][74][75][76]Therefore, while these industrially derived sericins represent promising advances in their respective fields, and a significant waste reduction in traditional silk industries [32,60,61,74,77], the mechanical [78][79][80][81] and rheological [35,47,78,79,[82][83][84] sericin characterisation undertaken in these studies cannot be considered truly representative of the natural system.…”

Amino Acid Profile and Biological Properties of Silk Cocoon as Affected by Water and Enzyme Extraction

“…However, it has been shown that this protein presents interesting properties, which may allow its application in several fields. Due to its moisturizing and anti-wrinkling abilities, sericin is an interesting compound to the cosmetic industry [ 3 , 4 ]. Additionally, sericin has been studied for its biomedical purposes, such as a biomaterial and for drug delivery [ 5 , 6 , 7 , 8 ], mainly because it has been reported to be immunologically inert [ 6 ].…”

Extraction and antioxidant activity of sericin, a protein from silk

“…However, it has been shown that this protein presents interesting properties which may allow its application in several fields. Due to its moisturizing and anti-wrinkling abilities, sericin is an interesting compound to the cosmetic industry (Sothornvit et al, 2010;Züge et al, 2017). Additionally, sericin has been studied with biomedical purposes, as biomaterial and drug delivery (Cao & Zhang, 2016;Lamboni et al, 2015;Srnivas et al, 2014;Suktham et al, 2018), mainly because it was reported to be immunologically inert (Lamboni et al, 2015).…”