Gunvantsinh Rathod

Milk whey proteins, which are derived from skim milk through membrane filtration, exhibit valuable functional properties when transformed into a fibrillar form. This conversion enhances their suitability for various applications, including thickening, gelling, emulsification, and foaming. However, reported fibrillation methods have longer heating times, which may not be economical for the dairy industry. To address these challenges, the current study was undertaken with the objective of reducing the time required for fibril formation. In this study, 2% milk whey protein isolate (mWPI) solution at pH 2 was heated with static and stirring heating conditions at 80 °C for 20 h to convert milk whey proteins into fibrils. Fibrils were observed using the thioflavin T value, transmission electron microscopy, Tricine SDS-PAGE, rheology, and protein oxidation. Results suggest that stirring heating conditions with 14 h heating time produced fibrils with good morphology compared to static heating, showing a 6 h reduction compared to an earlier reported 80 °C for 20 h heating time. Also, stirring heating produced a uniform and homogeneous fibril solution compared to the static heating method. Gentle stirring during heating can also help to scale up fibril production in an industrial setup. The fibrillation method with processing intervention will help to produce fibrils with enhanced functionality at the pilot and industrial scales.

Commercial manufacturing of dairy products involves the addition of dairy ingredients (such as nonfat dry milk and milk protein concentrates) as well as non-dairy additives (such as gums, stabilizers, emulsifiers, and texture modifiers) to get the best product appearance, maintain the product quality, and extend shelf-life. Though these non-dairy additives are not harmful, consumers do not prefer them in dairy food formulations. Therefore, the dairy industry is working on improving the inherent functionality of dairy ingredients using different processes. Recently, fibrillation emerged as a new technique to convert globular proteins such as whey proteins into fibrils, which provide enhanced viscosity, foaming, and emulsification capacity. Therefore, skim milk was subjected to microfiltration followed by ultrafiltration of microfiltration permeate to fractionate whey proteins. Then, whey proteins were selectively fibrillated and mixed back with other streams of microfiltration and ultrafiltration to get fibrillated skim milk. Fibrillated skim milk was spray-dried to get fibrillated nonfat dry milk (NDM). Visible whey protein fibrils were observed in reconstituted fibrillated NDM which showed survival of fibrils in fibrillated NDM. Fibrillated NDM showed significantly (P <0.05) higher viscosity than control NDM. Fibrillated NDM also showed higher emulsification capacity, foaming capacity, and stability than the control NDM but lower gel strength. Considering the improved functionality of fibrillated NDM, they can be used in product formulations such as ice cream mix where the thickening of a solution, good emulsification, and foaming properties are required.

Consumer focus on health and wellness is driving the growth in high-protein dairy beverages. The review discusses shelf-stable ready-to-drink beverages that are primarily dominated by sports nutrition and the "better for you" beverage categories. Both of these categories tend to have a "high in protein" claim. Because of their functionality, sensorial attributes, and protein quality, dairy protein ingredients are the ingredients of choice to meet protein claims. Due to the higher protein content of the beverages, the functionality of dairy protein ingredients plays a critical role in final product quality and stability. In the United States, Food and Drug Administration regulations classify shelf-stable foods into acid/acidified and low-acid foods. The differentiation is based on pH and water activity (a_w). In the context of shelf-stable high-protein dairy beverages, any beverage with a_w of >0.85 and with a finished equilibrium pH of >4.6 is classified as low acid. Beverages to which acids or acid foods are added and have a finished equilibrium pH of ≤4.6 and a_w >0.85 are classified as acidified food. Acid foods have a natural pH of ≤4.6. The final pH requirement of these shelf-stable products will affect the type of dairy protein used in these applications. In acidified dairy protein beverages, the go-to ingredient is whey protein. In low-acid beverages, the protein ingredients of choice are milk protein ingredients (with a casein-to-whey protein ratio of 80:20, as found in typical bovine milk) and casein-enriched ingredients. Rendering the product shelf-stable depends on whether the product is classified as acidified or low acid. Low-acid, shelf-stable beverages, in general, have 2 manufacturing options: retort and UHT processing, followed by hermetic sealing. Pasteurization is the standard processing choice for shelf-stable acidified beverages, followed by hot fill. Because of differences in pH and heat loads during the manufacture of high-protein dairy beverages, the functionality of protein ingredients will play an essential role in determining the final beverage quality. Two of the most important functional properties of dairy protein ingredients that have a role in producing these beverages are solubility and heat stability. This review elucidates the physicochemical properties of dairy protein ingredients for low- and high-acid shelf-stable dairy protein applications, analytical techniques to characterize protein ingredients, beverage processing conditions, and quality defects observed.

Whey proteins in milk are globular proteins that can be converted into fibrils to enhance functional properties such gelation, emulsification, and foaming. A model fibrillated milk protein concentrate (MPC) was developed by mixing micellar casein concentrate (MCC) with fibrillated milk whey proteins. Similarly, a control model MPC was obtained by mixing MCC with milk whey proteins. The resulting fibrillated model MPC and control model MPC contained 5% protein and a ratio of casein to whey proteins similar to milk. The objective of the current study was to understand the rheological characteristics of fibrillated and control model MPC during acid gelation, using Förster resonance energy transfer (FRET) to assess small amplitude oscillation and casein-whey protein interaction. The results from the FRET index images showed greater interactions between caseins and whey proteins in fibrillated model MPC compared with the moderate and uniform interactions in control model MPC gels. Rheological study showed that the maximum storage modulus of acid gel of fibrillated model MPC was 546.9 ± 15.5 Pa, which was significantly higher than acid gel made from control model MPC (336.9 ± 11.3 Pa), indicating that fibrillated model MPC produced a firmer gel. Therefore, it can be concluded that acid gel produced from fibrillated model MPC was stronger than control model MPC. Selective fibrillation of the whey protein fraction in MPC can be used to improve gelation characteristics of acid gel type products.

Milk protein concentrate (MPC) is a preferred ingredient to provide nutritional and functional benefits in various dairy and food products. Altering the protein configuration and protein-protein interactions in MPC can provide a novel functionality and may open doors for new applications. The fibrilization process converts the globular structure of whey proteins to fibrils and consequently increases viscosity and water holding capacity compared with the native protein structure. The objective of the current work was to selectively convert the whey proteins in MPC as fibrils. For this purpose, simulated control model MPC was prepared by combining solutions of micellar casein concentrate (MCC) and milk whey protein isolate (mWPI) to give casein and whey protein in an 80:20 ratio. The mWPI solution was converted to fibrils by heating at low pH, neutralized, and combined with MCC solution similar to control model MPC and termed "fibrillated model MPC." Thioflavin T fluorescence value, transmission electron microscopy, and gel electrophoresis confirmed the fibril formation and their survival after neutralization and mixing with MCC. Further, the fibrillated mWPI showed significantly higher viscosity and consistency coefficient than nonfibrillated mWPI. Similarly, fibrillated model MPC showed significantly higher viscosity and consistency coefficient compared with control model MPC. Hence, the fibrillated model MPC can be used as ingredient to increase viscosity. Heat coagulation time was found to be significantly higher for control model MPC compared with fibrillated model MPC.

Fish oil is a rich source of omega 3 fatty acids, an essential fatty acid, vital for the functioning of the human body. But the undesirable flavour is an inherent limitation of fish oil which reduces its acceptability. Masking its fish flavour can increase acceptability of fish oil. The present study was focused on double encapsulation of fish oil to mask its distinct flavour. Fish oil was emulsified using soya lecithin where emulsifier to fat ratio was kept 1:4. The emulsion droplets were in the size range of 172.9 ± 1.7 to 238.2 ± 33.8 nm. The emulsion was mixed with whey protein—sodium alginate solution and converted to beads by dropwise extrusion in calcium chloride solution. Droplets were converted to soft gel beads containing fish oil. The encapsulation efficiency was 89.3%. Fish oil flavour was perceived from the dried beads. Hence, beads were further coated with high melting fat using pan coater and flavoured for making beads palatable to use as an oral supplement. Beads were free-flowing and light yellowish in colour. Beads coated with high melting fat and vanilla flavour scored more in the sensory evaluation by panelists. Beads were kept in airtight pack and stored under refrigeration.