Study of organoleptic and rheological properties of chocolate mousse incorporating sodium caseinate and gelatin

Introduction: Proteins are widely used in food industry because it has functional properties such as formation and stabilization of foam systems. These molecules had surface-active properties. They rapidly adsorb at interface during the foaming processes and form a film around gas bubbles. The bulk properties has important role in the stabilization foam system. It has been shown that protein adsorption is influenced by molecular properties, such as size, shape, surface hydrophobicity, conformation, and charge and conditions in the bulk solution, such as bulk concentration, pH and ionic strength. The foaming properties depend on many intrinsic factors (size, structure of protein, hydrophobicity, surface potential, charge, etc.); and environmental and processing factors (protein concentration, pH, temperature, addition of other ingredients, etc.) Foams are colloidal systems in which gas phase dispersed in an aqueous continuous phase. Foaming operation is usually devoted to produce lighter products, modify the appearance and the texture of food products, therefore, it be used to production new products adapted to consumer choice and needs, using air as a zero-cost component. Microstructure has fundamental role in foam properties. At foam based products, bubble size is of most importance at the foam properties, because it influences on texture, the mouth-feel and the stability of the aerated product. Many food products have aerated structure. In these foods, the gas phases, forms small bubbles that modify microstructure and mouth feel properties of product. Aerated desserts have shown a great market potential, which is dependent on consumer behavior, interested in lighter and healthier products. Food products based on foam structure such as chocolate mousse have good marketing; therefore deep knowledge about their properties is important. Mousse is an aerated dessert with stabilized foamy structure which little attention has been paid to industrial production. Although, the most popular mousse flavor is chocolate, orange, lemon and strawberry have good marketability. Materials and method: This study follows two important objectives; first, the effect of different amount of gelatin concentration and sodium caseinate on rheological, physical and sensory properties of chocolate mousse is investigated. Then, the relationship this parameters was discussed on the basis of laboratory results using PCA method. Chocolate mousse was include of, Gelatin(Bangladesh, type B, bloom 160-180), Cacao powder(Cargill Co., Netherlands), Whipped cream(Mahrang sahar shargh CO., Iran 27% fat), Sugar(Fariman, Iran) and Sodium caseinate (Milad, Iran). Chocolate mousse samples were prepared with different amount of gelatin (1, 2 and 3 gr) and sodium caseinate (1, 2 and 3 gr) concentrations. Gelatin was first dissolved in hot water. Next, cacao powder and sugar were stirred in hot water and added to whipped cream agitated by Gosonic home mixer with speed 5400 RPM for 3 minutes. Then, Sodium caseinate was mixed in distilled water for 2 minutes and added to mixture prepared. Finally, mousse was placed in refrigerator after stirring with gelatin solution. The samples were stored in a refrigerator for 24 hours. Results and Discussion: In this work, physical, sensorial and rheological properties of chocolate mousse were investigated. Rheological measurements were carried out using a rotational viscometer (Bohlin Model Visco 88, Bohlin Instruments, UK) equipped with a heating circulator (Julabo, Model F12-MCand, Julabo Labortechnik, Germany) and C30 spindle. All the experiments were performed at 25°C±0.2. A pre shearing of 10-15 s at 14.1 s was applied to all samples. Sample flow was measured by registering the shear stress/ shear rate data at an increasing trend from 14.1 to 300 s. To describe the time independent flow behavior, the experimental data (shear stress-shear rate) were fitted by Herschel- Bulkley, Bingham, power law, and Casson models. Sensorial properties were tested at the same optical condition and environmental temperature. Chocolate mousses were evaluated using hedonic analysis procedures by a sensory panel of ten assessors, who had been selected and trained. Sensorial properties were evaluated based on 1 to 9 scores. The gas hold-up was calculated by comparing the density of the aerated chocolate with the gas-free density of solid chocolate. PCA method was used for determination of the relation of sensory attributes and main component. Conclusion: Results showed that chocolate mousse incorporating 2 gr gelatin and 3 gr sodium caseinate had the best sensory properties. According to the R2 (R2>0/99) and RMSE values, it is obvious that the Power-law models can properly describe non-newtonian flow behavior of samples. Behavior index (n) and consistency coefficient (k) were obtained from fitting power-law model. Consistency coefficient was high in the sample containing 3 gr gelatin and 3 gr sodium caseinate. Density values decreased with increase in protein content and decrease in gelatin content. Based on PCA results, total acceptance of samples was severely related to the smoothness, jelly and melting rate attributes.