Аңдатпа
Background and Objective: This study assessed the potential of incorporating high-protein dairy ingredients into ice cream recipes in response to increasing consumer interest in high-protein foods with improved nutritional benefits. The goal was to assess the functional and compositional characteristics of protein ingredients derived from skim milk, which could play a critical role in creating low-fat ice cream that meets sensory expectations. Material and Methods: Various milk-based protein ingredients, including milk protein concentrate, rennet casein, acid casein, sodium caseinate, calcium caseinate, and micellar casein concentrate, have been analyzed for their protein content, ash content, amino acid profiles, and functional characteristics such as water-binding and viscosity-building capacities. This comprehensive assessment was conducted to assess their potential to replicate the creamy texture of traditional ice creams. Results and Conclusion: The protein content of the ingredients varied from 82.5–92.7%, with acid casein and sodium caseinate showing the highest levels. This high protein content contributed to excellent water-binding and viscosity-building characteristics, which are critical for replicating the creamy texture of ice creams. Rennet casein and sodium caseinate included higher ash contents, which could affect the ice creams' mineral content and overall flavor profile. Although milk protein concentrate, sodium caseinate, and micellar casein concentrate lacked certain essential amino acids, they included biological values of over 50%, thereby enhancing the nutritional quality of low-fat ice cream formulations. The potential of these high-protein dairy ingredients to significantly affect the development of healthier ice cream products with desirable sensory and physicochemical characteristics cannot be exaggerated. Incorporating these ingredients into low-fat ice cream offers a promising approach to creating further nutritious products. Conflict of interest: The authors declare no conflict of interest. 1. Introduction Ice cream is one of the most famous frozen desserts used in most countries. According to the FDA (2014), ice cream should contain more than 10% milk fat or 10% non-fat milk solids [1]. If fat content limitations are modified in recipes, high-protein dairy-based ingredients can be used instead of milk fat. Modern technologies in the dairy industry, including microfiltration (MF), ultrafiltration (UF), nanofiltration (NF), and ion exchange (IE), have made it possible to achieve a wide range of high-protein ingredients with specific functional and technological characteristics that can optimize composition and technological aspects of food production [2,3]. In addition to the functionality of dairy-based ingredients for food uses (water binding and viscosity building; emulsification; flavor enhancement; gelling and heat setting; whipping, foaming, aeration, and so on), milk proteins include excellent nutritional value [4]. Due to their distinctive physiological characteristics, high protein ingredients are vital compounds of functional and specialized foods for various age groups, ranging from infant formulations to elderly nutrition [5,6]. Research worldwide verifies the benefits of high-protein diets in weight management, glycemic index regulation, bone health maintenance, muscle loss prevention, and sarcopenia risk [7‒9]. Moreover, modern trends in healthy eating guide consumers to consume foods with high protein content. In 2020, foods with high protein content accounted for nearly 50% of the consumer market [10]. Increased consumer demand for high-protein foods derives innovation in industrial production, addressing the diversity of dairy ingredients and knowledge of their functional characteristics and nutritional values [11]. Expansion of the range of products with increased protein contents is associated with the priority criteria for consumers to choose food products, including attractive organoleptic characteristics, low-calorie contents, health benefits, and safety. Thus, ice creams with decreased fat due to increased protein content should include specified organoleptic characteristics and high biological values [12, 13]. This study collected data on high-protein dairy-based ingredients and technological aspects of their production, as well as functional and technological characteristics that could affect quality indicators of low-fat ice creams. It also compared their nutritional values, focusing on amino acid composition. 2. Materials and Methods 2.1 Materials Although skim milk is a secondary resource, it is rich in nutrients, particularly protein, allowing it to produce a wide range of high-protein ingredients with increased nutritional values. Samples of high-protein ingredients were made by foreign manufacturers (Lithuania and Australia) and supplied by Unifood, St. Petersburg, Russia [14]. Chemical compounds (Table 1 and Figure 1) and functional-technological characteristics (Table 2) of high-protein dairy-based ingredients were: - Milk protein concentrate (MPC) - Casein such as rennet casein (RC) and acid casein (AC) - Caseinates such as sodium caseinate (SC) and calcium caseinate (CC) - Micellar casein concentrate (MCC) 2.2 Methods 2.2.1 Protein and amino acid analyses [15] The energy values of high-protein ingredients were calculated using coefficients of the energy values of nutrients, such as 3.8 kcal.g-1 for proteins and carbohydrates and 8.9 kcal.g-1 for fats. The National Standard of the Russian Federation (NSRF) 55577-2013 was used to assess the energy values of the high-protein ingredients based on skim milk. This standard is entitled “specialized and functional food products. Information on distinctive features and efficiency” [16]. According to NSRF 55577-2013, a high-protein product must provide at least 20% of the energy value from proteins. To calculate the amino acid score, the content of each essential amino acid of the investigated ingredient was compared with its content in the reference protein (FAO WHO, 2011) by Eq. 1: Where, Аx was the mass fraction of an essential amino acid of the investigated ingredient, g.100g-1 protein, and A was the mass fraction of an essential amino acid in the reference protein, g.100g-1 protein. An amino acid with a scoring rate of less than 100% was called “limiting.” In the presence of several limiting amino acids in the composition of the product/ingredient, the amino acid with the lowest amino acid score was called the “first limiting amino acid.” The biological value of the protein component was assessed using Eqs. 2–4 suggested by Professors I. A. Rogov and N. N. Lipatov, which included coefficients of differences of the amino-acid score (CDAAS, %) and biological value (BC, %). In particular, CDAAS (%) showed the average excess of the amino acid score of essential amino acids, compared to the lowest score of an essential amino acid. Where, ∆DAAS was the difference between the amino-acid score calculated based on Eq. 3 and n was the number of essential amino acids. Where, Ci was the score of “i” th essential amino acid (%), and Cmin was the minimum score of essential amino acids (%). The protein component's biological value (BV) was assessed using Eq. 4. 3. Results and Discussion 3.1 High-protein Composition and Energy Value Analysis of high-protein ingredients derived from skim milk, following NSRF 55577-2013 standards, verifying that all the samples were qualified as high-protein products, contributing more than 20% of their total energy value from protein (Table 3 and Figure 2). Sodium caseinate (SC) varied, offering the highest energy value at 360.4 kcal.100g-1, closely followed by acid casein (AC) at 359.6 kcal.100g-1. Protein contributes over 95% of the total caloric content in most samples, underscoring its significance (Figure 2) [4]. These characteristics make these ingredients excellent candidates for high-protein formulations, particularly in low-fat ice creams, where nutritional value is critical without compromising sensory appeal. SC and AC emerge as the top performers when breaking down the protein content, with protein concentrations reaching 92.7% and 92.0%, respectively. Although lactose and fat contents were minimal, they varied within the samples. For example, SC included the lowest lactose content (0.3%), while RC (rennet casein) included the highest fat content (up to 2.0%) [17]. These differences were more than nutritional details alone, as they affected the functional roles of the ingredients in food products. 3.2 Protein and Amino Acid Composition In addition to total protein content, the amino acid composition of these high-protein ingredients is critical to their nutritional quality. Compared to FAO/WHO 2011 standards, a rich profile of essential amino acids (EAA) is seen (Table 4 and Figure 3). For example, micellar casein (MCC) and milk protein concentrate (MPC) delivered high levels of leucine (9.8 g.100g-1 protein for MCC) and lysine (7.90 g.100g-1 protein for MCC), which are vital for muscle growth and repair [18]. However, RC was limited by its lower lysine content, which decreased its overall biological value (BV) compared to other ingredients (Figure 3). The biological value of these protein ingredients varied significantly. The MCC, MPC, and SC were particularly advantageous, as they lacked limiting amino acids, resulting in biological values of 58.19, 72.23, and 75.35%, respectively. These characteristics make them highly appropriate for enriching the protein content of low-fat ice creams, which aims to enhance nutritional value without losing quality (Table 5) [19,20]. 3.3 Biochemical Pathways and Production Processes The high-protein ingredients analyzed were produced through various biochemical and biotechnological processes such as coagulation, ultrafiltration, and dehydration (Figure 4). These methods included distinct products with specif