Effect of κ‐carrageenan/milk protein interaction on rheology and microstructure in dairy emulsion systems with different milk protein types and κ‐carrageenan concentrations

Rheological, Physicochemical, Microbiological, and Aroma Characteristics of Sour Creams Supplemented with Milk Protein Concentrate

Milk protein concentrate (MPC) is widely used to enhance the stability and texture of fermented dairy products. However, most research has focused on yogurt products, and the effects of MPC on sour cream characteristics remain unknown. Therefore, we investigated the effects of different MPC levels (0%, 1%, 2%, and 3% w/w) on the rheological, physicochemical, microbiological, and aroma characteristics of sour creams in this study. We found that MPC supplementation stimulated the growth of lactic acid bacteria (LAB) in sour creams, resulting in higher acidity than that in the control sample due to the lactic acid produced by LAB. Three aroma compounds, acetaldehyde, diacetyl, and acetoin, were detected in all sour cream samples. All sour creams showed shear-thinning behavior (n=0.41-0.50), and the addition of MPC led to an increase in the rheological parameters (η_a,50, K, G', and G″). In particular, sour cream with 3% MPC showed the best elastic property owing to the interaction between denatured whey protein and caseins. In addition, these protein interactions resulted in the formation of a gel network, which enhanced the water-holding capacity and improved the whey separation. These findings revealed that MPC can be used as a supplementary protein to improve the rheological and physicochemical characteristics of sour cream.

Effect of Fluidized Bed Agglomeration on Rheological and Physical Properties of Soy Protein-Enriched Milk Powder for Dietary Supplementation in Sarcopenia

Recently, many elderly people in Korea have been consuming protein-enriched milk powders for dietary supplementation in sarcopenia. In general, protein powders are manufactured using a spray dryer, and their fine particles result in poor instant properties. Fluidized bed agglomeration (FBA) is an effective method for improving the physical properties of protein powders via particle granulation, such as flowability and wettability. Therefore, the effects of FBA on the rheological and physical properties of isolated soy protein (ISP)-enriched skim milk powder (SMP) were investigated in this study. The size of ISP-enriched SMP particles was significantly increased by FBA, leading to changes in the Carr index and Hausner ratio from fair flowability and intermediate cohesiveness to good flowability and low cohesiveness, respectively. The wettability of the granulated particles was also improved by FBA, and they exhibited a shorter wetting time below 10 s. However, a slight color change was observed after the FBA process. These findings contribute to the production of protein-enriched food powders with improved properties.

Effect of Milk Protein Isolate/κ-Carrageenan Conjugates on Rheological and Physical Properties of Whipping Cream: A Comparative Study of Maillard Conjugates and Electrostatic Complexes

With increasing consumer demand for “clean label” products, the use of natural ingredients is required in the food industry. Protein/polysaccharide complexes are considered good alternatives to synthetic emulsifiers and stabilizers for formulating stable emulsion-based foods. Milk protein and carrageenan are widely used to improve the physical properties and stability of dairy food products. In a previous study, milk protein isolate (MPI) was conjugated with κ-carrageenan (κ-Car) in a wet-heating system through the Maillard reaction, and the Maillard conjugates (MC) derived from MPI and κ-Car effectively improved the stability of oil-in-water emulsions. Therefore, MPI/κ-Car conjugates were used in whipping cream as natural emulsifiers in this study, and the physical and rheological properties of whipping creams stabilized using MPI/κ-Car MC and MPI/κ-Car electrostatic complexes (EC) were investigated. The whipping creams stabilized with MPI/κ-Car MC have lower rheological parameters (η_a,50, K, G′, and G″) than those of whipping creams stabilized with MPI/κ-Car EC. Although the overrun value was slightly reduced owing to the addition of MPI/κ-Car MC, the stability of the whipped creams with MC was effectively improved due to enhanced water-holding ability by conjugation.