Combined effect of chitosan and bovine serum albumin/whey protein isolate on the characteristics and stability of shrimp oil‐in‐water emulsion

Abstract

The effect of bovine serum albumin (BSA) or whey protein isolate (WPI) at various concentrations (0.5%, 1.5%, and 3%; w/v) on the properties of shrimp oil-in-water emulsion was investigated. Both proteins at 1.5% showed the highest emulsifying properties. Moreover, the combined impact of chitosan (CS) at different levels (0.25%, 0.50%, 0.75%, and 1%; w/v) and 1.5% BSA or 1.5% WPI on emulsion properties was also studied. For the same protein used, those stabilized by BSA and WPI in conjunction with CS solution at 0.5% and 0.25% had the highest emulsion stability index, respectively. During storage for 28 days, the BSA-CSstabilized emulsion had higher turbidity, a*, b* but the lowest L* values compared to the WPI-CS counterpart (p < 0.05). Emulsion stabilized by the BSA-CS complex showed higher stability, as witnessed by lower d 32 and d 43 and lower flocculation factor and coalescence index, but it had a lower negative charge than those stabilized by the WPI-CS complex (p < 0.05). Oil droplets of the BSA-CS-stabilized emulsion showed a lower extent of size enlargement after storage. Rheological studies revealed viscous, shear-thinning, and non-Newtonian behavior of emulsions. Overall, emulsion stabilized by the BSA-CS complex had higher stability than that stabilized by the WPI-CS complex, and the former could maintain the stability of pigment in shrimp oil to some extent. K E Y W O R D Sbovine serum albumin, chitosan, emulsion, hepatopancreas, shrimp oil, whey protein isolate Practical Application: Oil from shrimp hepatopancreas is a rich source of both astaxanthin and polyunsaturated fatty acids with health benefits. It can be used for the preparation of food emulsion, such as mayonnaise, with nutraceutical properties. However, emulsion stability determines the quality of the emulsion.The use of protein (bovine serum albumin) in conjunction with polysaccharides, especially chitosan at appropriate concentrations, was proven to improve shrimp oil-in-water emulsion during extended storage. Additionally, chitosan can act as an antioxidant to prevent the degradation of astaxanthin to some extent. This finding could be potentially beneficial to produce emulsion with high stability using protein-chitosan complexes.

Changes in Emulsifying and Physical Properties of Shrimp Oil/Soybean Oil‐in‐Water Emulsion Stabilized by Fish Myofibrillar Protein during the Storage

“…[ 21 ] In our previous study, a similar trend in EAI was attained in SO/SBO‐in‐water emulsion using bovine serum albumin as emulsifier. [ 10 ]…”

“…[21] In our previous study, a similar trend in EAI was attained in SO/SBO-in-water emulsion using bovine serum albumin as emulsifier. [10] ESI was increased with augmenting FMP concentrations (p < 0.05) (Figure 1B). This coincided with other proteins such as milk and corn germ flour protein used to stabilize the emulsion.…”

“…[ 21 ] SO/SBO mixture (30:70, v/v) was used to lower the fishy odor. [ 10 ] Ten mL of SO/SBO mixture was homogenized with FMP solutions (30 mL) having various concentrations (15, 30, and 45 mg mL −1 ) in polystyrene tube at 13 500 rpm for 5 min with the 30 s of break after every minute. The freshly prepared emulsion was subjected to further analyses.…”

“…[9] To minimize such undesirable odor, SO was blended with soybean oil (SBO) at a ratio of 30:70 v/v before use. [10] Emulsions with small diameter of droplets (0.1-100 μm) have been used in food, pharmaceutical, and cosmetic industries. [6,11] Food industries heavily rely on emulsions to produce numerous products such as salad dressing, mayonnaise, etc.…”

“…[ 9 ] To minimize such undesirable odor, SO was blended with soybean oil (SBO) at a ratio of 30:70 v/v before use. [ 10 ]…”