Processing and formulation technology of nutritional and functional food products by utilizing cheese and/or paneer whey: A critical review

2.1 Cultured buttermilk and lassi

Buttermilk is produced as a byproduct and is considered a functional food because of its emulsifying power, which is attributed to the polar lipids and milk fat globule membrane components (Gebreselassie et al., 2016; Rose et al., 2023; Jakopović et al., 2023). There are different ways to categorize buttermilk, such as traditional or conventional buttermilk, or cultured buttermilk. Churning is a process that effectively separates the white butter from the curd, leaving behind a liquid known as cultured buttermilk. This technique has been extensively studied and documented by various researchers (Gebreselassie et al., 2016; Mudgil et al., 2016; Rose et al., 2023; Jakopović et al., 2023). Manufacturing curd, homogenizing curd, and diluting with water are all essential steps in the commercial production of cultured buttermilk in India. Buttermilk is a highly nutritious and beneficial beverage due to its rich content of phospholipids and essential nutrients (Gebreselassie et al., 2016; Rose et al., 2023; Jakopović et al., 2023). Consuming cultured buttermilk in the diet has been found to have several benefits, including improved digestion, increased immunity, and reduced cholesterol levels in the blood (Devi, 2010; Nirgude et al., 2013; Rose et al., 2023). Cultured buttermilk is a widely recognized fermented dairy product that has been studied for its potential health benefits. It is known by various names, such as “Chhash” in South Asian countries and certain states in India (Devi, 2010; Pushpangadan et al., 2012; Ghanshyambhai et al., 2015; Rose et al., 2023). With its delightful flavor and impressive array of health advantages, buttermilk has gained significant popularity among consumers and is an essential ingredient in various Ayurvedic formulations (Devi, 2010; Pushpangadan et al., 2012; Rose et al., 2023; Jakopović et al., 2023).

Lassi is a well-known and widely enjoyed fermented milk beverage that is often consumed during the summer months for its refreshing qualities. It is made from dahi, as described in several studies (Kedaree et al., 2021a, b; Datir et al., 2022). This beverage is widely consumed during the summer season in cold drink shops and restaurants across India, especially in the northern region (Kedaree et al., 2021a, b). Lassi is a fermented milk product prepared using specific strains of lactic acid bacteria (LAB) as starter cultures. It is then mixed with water, sugar, salt, and optional flavoring ingredients, along with spices like cumin seeds and coriander leaves (Betoret et al., 2011; Kedaree et al., 2021a, b; Datir et al., 2022). Lassi can be categorized into two types: salty Lassi and sweet Lassi, depending on the ingredients used (Mollet and Rowland, 2002). In addition to the regular classification of lassi, there exists a unique variation known as Bhang lassi. This particular type of lassi is made utilizing the plant leaf extract of Cannabis spp., and is commonly consumed during the Holi and Shivaratri festivals in India (Kedaree et al., 2021a, b; Datir et al., 2022). Lassi offers numerous health benefits similar to yogurt or curd. It aids in reducing acidity in the stomach, promoting the growth of advantageous bacteria in the gastrointestinal (GI) tract, boosting immunity, aiding digestion, and maintaining internal organ temperature during hot summers (Mollet and Rowland, 2002; Betoret et al., 2011). Therefore, there has been a shift in consumer perceptions regarding foods and dietary habits. Many peoples now recognize the significant impact that these foods can have on their health (Mollet and Rowland, 2002; Betoret et al., 2011).

Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus were combined in equal proportions (i.e. 1:1) to produce cultured buttermilk. Half of the milk in this preparation was replaced with paneer whey for curd production. To enhance the sensory quality, salt (0.5 %) and spices (0.4 %) were incorporated into the buttermilk production process. The resulting buttermilk had a shelf life of up to 4 days, as reported by Maheta et al. (2015). In 2003, researcher prepared lassi by using dahi made from neutralized fresh paneer whey and buffalo milk (Mittal, 2003). Yogurt was made by adding a specific amount of stabilizer at 60 °C, mixing, and pasteurizing at 80 °C. Following cooling to 30 °C, the mixture received a 1 % starting culture and was left to incubate for 14–16 h. The lassi was produced by mixing sugar syrup and flavoring, followed by homogenizing and cooling the mixture to 4 °C before consumption. After a sensory assessment by a panel of expert judges, the product scored 7.83 out of 9.0 on the Hedonic scale, indicating a high level of acceptability. The suitability of lassi depends on the interplay of environmental factors and chemical processes that take place during its making. Undesirable flavors in food, like milk, were caused by processes involving different unit operations. Factors such as heat and solids transfers, oxidable compounds, and oxygen exposure have been associated with causing off-flavoring in foods (Zhang et al., 2012; Park et al., 2016; Smith et al., 2016; Amit et al., 2017). The bitterness and metallic taste are a result of proteolysis in cheese whey, involving proteases and chymosin in fluid whey necessary for coagulating the curd (Amiri et al., 2021; Ardö, 2021). Eliminating chymosin and proteolysis in dairy processing can assist in minimizing off-flavoring. For instance, lassi, a cultured milk product, includes carbohydrates, fat, minerals, and organic acids, especially lactic acid from the curdling process. This typically leads to acid whey, known for its sour aroma and taste (Smith et al., 2016). However, by incorporating syrup and low methoxy pectin as a protein stabilizer during processing, the sour attribute can be masked effectively. Consequently, paneer whey-based lassi, in its current formulation, is not only a feasible way to reduce environmental pollution caused by whey, but it also provides an opportunity to generate economic value and provide consumers with an end-product that is of good quality and has a minimal off-flavor.

2.2 Dahi

Earlier, dahi (i.e. Curd) was made by fermenting boiled milk of cow or buffalo with lactic cultures like L. lactis spp. lactis, L. lactis spp. cremoris, and L. diacetylactis. These cultures could be used alone or in combination (Rathi et al., 2015). Curd, also known as Indian dahi, is manufactured by fermenting milk with LAB. The milk undergoes a series of specific processes, including heat treatment, homogenization, and cooling, to create the ideal conditions for the introduction of bacteria or starter culture. Under optimal conditions of temperature and moisture, the bacteria have the ability to undergo lactose fermentation, resulting to the formation of lactic acid. The milk proteins undergo a process of coagulation and solidification, resulting in the formation of curd, commonly known as Indian dahi. During fermentation, a clear liquid known as acetaldehyde is also made, which adds to the distinctive taste of the curd (Indian dahi). It is commonly included in daily diets due to its potential to provide vitamin B-complex including riboflavin (vitamin B₂) and folic acid (vitamin B₉) (Sarkar et al., 2015). Dahi contains a high amount of LAB and has been found to have a probiotic effect. This can be beneficial for maintaining intestinal health and managing diarrhea in children (Sharma and Lal, 1997; Sarkar et al., 2015). In addition, misti dahi is referred to by other names such as misti doi, payodhi, and lal dahi. This is a conventional sweetened fermented milk product that is quite popular in the eastern region of India, particularly in West Bengal, Bihar, and Assam. The product is made through a process known as lactic acid fermentation, which involves the fermentation of sweetened milk. Misti dahi is considered a significant dessert during ceremonial events in both rural and urban Bengal. The product is typically found in a variety of sizes, contained within earthen pots. A high-quality misti dahi exhibits distinct visual attributes such as a rich brown color, a solid yet yielding texture, a velvety smoothness, and a delightful caramelized taste. Misti dahi is best made using buffalo milk because of its high fat content, resulting in a rich and creamy product with a delightful texture. Due to its high protein content, buffalo milk forms a firm coagulum that effectively prevents whey separation during storage and transportation.

2.3 Lactose fermented beverage

It is worth noting that lactose is the main carbohydrate found in dairy products. This particular disaccharide is a unique combination of glucose and galactose, exclusively present in the milk of mammals (Schaafsma, 2008; Kanurić et al., 2018). Lactose plays a vital role in the formation of the neural system and the growth of skin, bone skeleton, and cartilage in infants. In addition, it aids in the prevention of conditions like rickets and saprodontia (Emmett and Rogers, 1997; Kanurić et al., 2018). The process of lactose fermentation by LAB is a frequent happening in the production of different fermented dairy products. Specifically, lactose serves as the primary energy source for the bacteria in the starter culture (Kanurić et al., 2018).

Utilizing a cost-effective and simple fermentation method, along with enriching with fruit juices and carbonation, cheese or paneer whey can be effectively used to produce beverages, as demonstrated by various studies (Dilipkumar and Yashi, 2014; Patel et al., 2017; Rizzolo and Cortellino, 2018; Silva e Alves et al., 2018; Ahmed and Bajwa, 2019; Kaur et al., 2019). From an economic standpoint, producing whey as a beverage on a large scale is beneficial. The findings from the research demonstrate that whey can be successfully used to produce fermented carbonated beverages (Pereira et al., 2015; Panghal et al., 2017; Ranavaya et al., 2019). Transforming the entire paneer whey into a refreshing carbonated health drink with a sensory score above 8.01 for overall acceptance can help address environmental pollution concerns (Kakan et al, 2018; Pandey et al., 2019). According to reports, the beverage has been stated to have a shelf-life of one week (Shaik, 2013; Baba et al., 2016). Utilizing paneer whey in manufacturing fermented milks might also help to minimize the adverse environmental impact of whey (Raghavendra et al., 2017). When it comes to dairy products, incorporating whey and stabilizing ingredients in yogurt, dahi, cultured buttermilk, or lassi can enhance texture and minimize whey syneresis while the product is stored (Mittal, 2003; Kelly, 2019).

3.1 Paneer whey supplemented milk bread

“Paneer Whey Supplemented Milk Bread” combines the technical aspects of paneer whey with the scientific benefits of milk in a delightful bread recipe (Kakan et al., 2016, 2018). This cutting-edge loaf combines the residual whey from paneer production with fresh milk, resulting in a tender and delectable bread with a subtle tang (Kakan et al., 2018). The addition of paneer whey enhances the nutritional composition of the bread, enriching it with essential protein, vitamins, and minerals (Kakan et al., 2016, 2018; Dobhal et al., 2024). Indulge in the warmth of this bread, mixed perfectly with butter or transformed into delectable sandwiches and toast. Not only does it satisfy the way it tastes, but it also helps minimize food waste and provides a wholesome homemade essential (Kakan et al., 2018). People try it for a unique twist on traditional bread recipes that are celebrated for sustainability and flavor.

Adding paneer whey to bread led to a slight rise in total solids, ash, and total protein content. As the level of paneer whey was elevated, the moisture and pH values showed a decrease (Kakan et al, 2018; Paul et al, 2019). When 300gm of flour was used, various amounts of paneer whey were added, ranging from 45 to 180 mL. It was observed that as the quantity of paneer whey increased, the moisture and pH values decreased. The overall solid, ash, and protein content of the bread remained relatively stable. In a study by Paul et al. (2019), they explored the utilization of paneer whey as a diluent in the production of multigrain bread. Their findings revealed that incorporating whey led to enhanced crust browning along with a higher total solid content. Adding whey did not impact the texture quality due to the high temperature of over 160 °C and the total solids content of 15 %. The results remained largely consistent with the control multigrain bread; however, incorporating whey into the process resulted in the characteristic browning linked to the Maillard reaction. When adding paneer whey to milk bread, it's crucial to closely monitor the baking temperature to achieve the desired properties in the final product. According to Paul et al. (2019), milk bread enriched with paneer whey can be produced with a creamy hue to avoid the Maillard reaction above 180 °C. Technologically, the multigrain dough made by adding concentrated paneer‐whey (15, 20, and 25 % TS) was found to have a firmer and stickier texture, but less gummy compared to dough made with water. Concentrated whey was discovered to slow down the proofing rate of dough (Paul et al., 2019).

As per a study by Iuga and colleagues (2020), the dough's elasticity decreased when acid whey was used, while an increase in elasticity was noted when milk was used, compared to the control. In addition, the study by Iuga et al. (2020) discovered that the samples with up to 25 % acid whey exhibited an increase in resistance to dough deformation. However, this resistance decreased when water was substituted with more than 25 % milk. Using paneer whey instead of water not only enhanced the nutritional properties of the milk breads, but it also had economic benefits for dairy plants. It helped reduce the expenses of treating effluent and played a role in addressing pollution problems resulting from whey drainage (Kakan et al, 2018).

3.2 Jam and jelly with the addition of paneer whey

Paneer whey-based jam and jelly provide a fascinating variation on conventional fruit preserves, delivering a combination of unique flavors and health advantages (Wasnik, 2016; Raj et al., 2017). Paneer whey adds a delicate tanginess to jams and jellies, elevating their flavor with a touch of acidity (Wasnik and Changade, 2015; Wasnik, 2016). The distinct flavor profile of this product enhances the sweetness of the fruits, resulting in a harmonious blend of flavors (Raj et al., 2017). In addition, paneer whey contains a high amount of protein, vitamins, and minerals, which can enhance the nutritional value of jams and jellies. Integrating whey into these preserves not only elevates their flavor but also boosts their nutritional content, providing a healthier choice for consumption (Raj et al., 2017; Kumari and Rani, 2019). Furthermore, the addition of paneer whey in the production of jam and jelly contributes to the reduction of food waste by repurposing a byproduct of cheese-making (Raj et al., 2017; Kumari and Rani, 2019; Tsermoula et al., 2021). This practice emphasizes the importance of optimizing resources and reducing environmental impact, which ultimately leads to a more sustainable and environmentally-friendly food system. In addition, paneer whey-based jam and jelly have a wide range of culinary uses. They can be spread on toast, used as a topping for pancakes or waffles, filled into pastries, or even added to salad dressings and marinades (Wasnik and Changade, 2015; Wasnik, 2016; Raj et al., 2017; Kumari and Rani, 2019). Their adaptability makes them a flexible ingredient for both sweet and savory dishes.

Proteins undergo denaturation during jam processing, leading to the removal of whey proteins (Brodkorb et al., 2016). Considering the lower protein levels in fruit pulps used in jam, whey can be incorporated as an economical protein source to enhance its nutritional content. Replacing papaya jam with 10 % whey led to a satisfactory formulation with improved texture, suitable for a jam-like product (Raj et al., 2017). By incorporating paneer whey, there was a noticeable rise in the acidity (pH), total solids, and ash levels. The water content of the jam contained a significant amount of protein and reduced sugar levels. Protein concentrations in different samples were 0.92 %, 3.15 %, and 4.23 % for T0 (control jam), T1, and T2, respectively (Raj et al., 2017). Moreover, a study showed that whey can be successfully substituted in jam, enhancing its nutritional, physiochemical, and textural properties while maintaining its sensory attributes. Moreover, the research paved the way for effectively utilizing paneer whey, a plentiful byproduct of the Indian dairy industry.

The jelly confection was developed using paneer whey, offering a promising alternative for utilizing 100 % of the whey, particularly during the manufacturing process (Wasnik and Changade, 2015). Several combinations of paneer whey and water that were developed in various ratios: 00:100 (T1), 25:75 (T2), 50:50 (T3), 75:25 (T4), and 100:00 (T5). They were then heated to 77–82 °C with color, flavor, and citric acid added at 0.1, 0.2, and 1.0 %, respectively. High methoxyl pectin at 1.5 % and ground sucrose at 47.5 % were combined and concentrated to 65 °Brix to produce a jelly confection (Wasnik and Changade, 2015). As the paneer whey content increased, the total protein content also increased. Following a 30-day storage period, the moisture content reduced with the rise in paneer whey volume. Based on the research by Wasnik and Changade (2015), paneer whey has the potential to fully substitute water in making jelly confections without significantly altering the sensory attributes, as indicated by the non-significant changes in sensory scores. As the levels of paneer whey increased, the nutrient contents in the treatments showed improvement. This will help dairy plant operations reduce costs by lowering the expense of effluent treatment and will contribute to solving pollution issues caused by whey drainage (Wasnik and Changade, 2015). The addition of whey to sweetened formulation not only increases the protein and mineral contents, but it also reduces the amount of other sugar that is required to be added in the product because it also contains some amount of sugar in its composition. This is despite the fact that there are not enough studies in the literature that address the employment of whey in the production of jelly and jam. de Almeida Marques et al. (2016) developed cookies without added sugar that matched the taste of regular cookies by replacing wheat with whey protein concentrate. To preserve the sensory qualities of traditional cookies with acceptance rates of 70 % or higher, a combination of 54.0 g of WPC/100 g and 33.4 g of margarine/100 g is recommended (de Almeida Marques et al., 2016). Moreover, the limited solubility of acidic whey proteins combined with conjugation in the presence of reducing carbohydrates could lead to the development of heat-stable networks, solid gelification, viscosity increase, and turbidity to maintain desirable textural characteristics (Wijayanti et al., 2014; Brodkorb et al., 2016).

In a nutshell, paneer whey-based jam and jelly provide a tasty and healthy choice that embraces the exploration of new flavors, sustainable practices, and culinary ingenuity.

3.3 Rusk and soup with the addition of paneer whey

Paneer whey concentrated to 30 % total solids can be utilized instead of water as a diluent in making rusks and soup sticks. These products remained unchanged at 30 °C for 9 days without any loss in sensory qualities (Mallik and Kulkarni, 2010). After analyzing the costs, it was found that whey-incorporated Rusks were priced at Rupees 44.24 per kg, whereas the control was priced at Indian Rupees 46.70 per kg. Similarly, whey-incorporated Soup sticks were priced at Rupees 46.18 per kg compared to Rupees 48.50 per kg for the control. Concentrated paneer whey can effectively substitute water in the production of rusks and soup sticks without compromising the sensory characteristics. In a study conducted by Parjane et al. (2010), a tomato soup was developed using a ratio of 1:3 tomato pulp to chhana whey. The soup received a satisfactory rating of 7.73 on a 9-point Hedonic scale for overall acceptance. Various studies have explored the utilization of liquid whey in different soup recipes. For instance, corn flour soup, vegetable soup, and mushroom whey soup powder have been developed using liquid whey as an ingredient (Singh et al., 2003; Verma et al., 2010; David and Prashant, 2014; Rai et al., 2014). An ice candy was produced successfully by utilizing direct liquid whey (Raval, 2014; Chavan et al., 2020). Additional information about the studies can be found in Table 5.

4.1 Acido whey

The whey from the paneer is utilized to produce this beverage, which is both invigorating and delicious. Paneer whey was pasteurized at 72 °C for 15 min, and then cooled before adding a culture of L. acidophilus (1 %) and fermenting at 37 °C for 24 h. Flavoring the food with sugar and citrus enhances its appeal during refrigeration. The end result exhibited an acidity level of 0.8–0.9 % (L. acidophilus). When stored in refrigerated conditions, the product's shelf life was approximated to be two to three weeks. A patent was granted for the process of producing Acidowhey by Gandhi D.N. in 1989 (Gandhi, 1989). Acidowhey is a non-alcoholic whey beverage produced by fermenting whey with the beneficial bacteria L. acidophilus and L. bulgaricus, as described by Hati et al. (2013). Additional whey-derived beverages were also documented by Hati and colleagues, including whevit, soups made from whey, whey-based lassi, and more (Hati et al., 2013).

4.2 Electrolyte whey drink

Paneer whey contains lower lactose content and higher concentrations of minerals like chloride (Cl), salt, calcium (Ca), and magnesium (Mg) compared to cheese whey (Goyal and Gandhi, 2009). To produce a top-notch electrolytic drink, it is essential to keep mineral and lactose levels at a minimum (Gandhi, 1989). It has been demonstrated that paneer whey is better suited for producing beverages or electrolyte drinks to replenish lost minerals in the body.

4.3 Whey-based fruit juice

Researchers have formulated a variety of fruit juice-based whey beverages, including fermented, nonfermented, and carbonated, prepared either utilizing paneer whey or cheese whey. For the production of Whey-based Kinnow juice concentrate (WKJP), a specific formula was utilized which included 40 % kinnow juice, 53 % paneer whey, 7 % sugar, 0.05 % pectin, and 0.15 % carboxymethylcellulose. The concentrate obtained showed a pH of 4.5. For over six months, the metalized polyester pouches were kept at a temperature of 25 °C (Khamrui and Pal, 2003). Acid whey, whey powder, and whey protein concentrate are different types of whey that can be effectively incorporated into beverages. Storing whey-based mango juice led to a significant increase in the juice's acidity (0D 0.405 % and 30D 0.435 %). After 30 days of refrigerator storage, the acceptance ratings of the whey protein concentrate-based mango beverage dry mix (WPCMB) were found to be satisfactory (Chavan et al., 2015). The optimal combination was 77.24 g of whey/mango pulp, 8.65 g of fructose (totaling 100 g). Singh and Kumar (1997) found that a blend of 15 % mango pulp (25 °Brix), 77 % paneer whey concentrate (37 %, TS), and 8 % sugar was the most suitable for producing whey-mango concentrate. Over a period of 90 days in storage, a kinnow-whey beverage that was sonicated for 15 min at 20 kHz showed better acceptability and lower microbial growth compared to samples that were thermally treated or contained preservatives (Siddique et al., 2023).

4.4 Carbonated whey-based lemon beverages

Paneer whey is a key element in a lemon-based beverage developed by Singh et al. (2014). When developing this beverage, a combination of sugar, lemon juice, and lemon flavoring was used to achieve a total acceptability score of 7.8 on the 9-point Hedonic scale. Whey, lemon juice (4.5 %), sugar (10.1 %), ginger juice (1 %), and salt were mixed to produce a carbonated lemon whey beverage of acceptable quality (0.6 %). The whey beverage can be stored in the refrigerator for a maximum of 49 days at a temperature of 4 ± 1 °C. The price was Rupees 5.33 for every 200 mL of whey beverage (Patel et al., 2017). Utilizing this product in the dairy sector, particularly in the production of chhana and paneer, can help decrease waste disposal and increase revenue from whey. Famous fermented milk dish popular in India, Shrikhand, has acidic whey which was used to make carbonated whey fruit beverages (Dilipkumar and Yashi, 2014).

4.5 Whey-based alcoholic beverage

Utilizing Kluyveromyces fragilis and Saccharomyces lactis, whey has been employed in the production of beer, wine, and sparkling “whey champagne” with specific yeast strains (Oliveira et al., 2019). These food products are characterized by their low alcohol concentration, which is less than 1.5 %. Whey provides a rich source of lactose, minerals, and nutrients. Nevertheless, fat negatively affects beer foam and is considered an unwanted element (Jeličić et al., 2008). When incorporating whey into a beverage, it is crucial to maintain a balance between clarity, stability, shelf life, and protein content to ensure its market success and effectiveness in enhancing human performance and recovery upon consumption (da Rosa Camargo et al., 2020). Typically, whey is used in two main types of beverages: those with acidified and neutral pH levels. The beverage's quality and stability depend on the pH level and type of whey utilized in the formulation. Consider this: when developing an acidified whey-based beverage, the pH typically falls between 2.8 and 4.0. Interestingly, incorporating whey with a high protein content does not affect the drink's clarity or turbidity negatively. This is due to the remarkable stability and solubility of whey proteins at a pH of around 3.0.. Processing at a neutral pH, specifically with an end-product pH between 4.6–7.5, necessitates specialized processes and stabilization techniques like carboxymethylcellulose, lecithin, dextran, pectin, heat, and more to address protein aggregation, turbidity, and short shelf life issues in this beverage type (Kelly 2019). For instance, the investigation by Singh et al. (2014) reported that incorporating carboxymethylcellulose in carbonated paneer whey-based lemon beverages, along with acidification, produced a high-quality product with a shelf life of 49 days when stored at 4 ± 1 °C. A comparable approach was utilized in the development of acid whey, whey-based fruit juice, and alcoholic beverages.

There is a wide range of whey-based spirits available for consumption worldwide, all emphasizing the dairy or whey relationships. This information is typically provided on the product label and in descriptions that highlight the creamy flavors (Hughes et al., 2018). There is a potential for smaller-scale cheese manufacturers to enhance their products by fermenting and distilling whey to produce ethanol. This process could facilitate the production of a premium end product, like ethanol or spirits. On an industrial scale, the Carbery method is employed to transform whey or whey permeates from dairy manufacturing into ethanol. The process starts with the fermentation of sugars within a substrate by microorganisms to produce ethanol, which is then concentrated through distillation to separate it from other volatile components (Ling 2008; Hughes et al., 2018). According to these findings, dairy whey may be more suitable than other forms of whey for use in the production of alcoholic drinks derived from whey and meant to supply consumers with whey nutrients.

5.1 Biofunctional probiotic whey drinks

Research has shown that fermented whey drinks are an effective way to deliver probiotics, prebiotics, and other beneficial components (Kumari and Vij, 2015; Cordeiro et al., 2019). Thakkar and their team developed a beverage using paneer whey, probiotic bacteria, and orange juice (Thakkar et al., 2018). This unique combination helped to maintain the survival of the probiotic bacteria at specific levels during refrigeration for 28 days. The control group (A) had a survival rate of 6.10 log CFU/mL, while group B2 (60F:40 W) had a survival rate of 7.25 log CFU/mL, which was significantly different (p < 0.05) (Thakkar et al., 2018). A fermented beverage was formulated utilizing paneer whey and L. acidophilus NCDC195, a strain with potential biofunctional properties. The production process started by filtering fresh paneer whey through a muslin cloth to eliminate any leftover casein particles. Damaged particles could reduce solubility and make the beverage more turbid. Typically, the pH was maintained to 6.5 with 0.1 N NaOH, followed by transferring the neutralized whey to designated containers for sterilization (at 121 °C for 10 min) and storage at room temperature. During the preparation of the beverage, it is inoculated with the starter culture (specifically 1 % L. acidophilus NCDC195 in this study) and then incubated at a precise time and temperature (39 °C for 18 h) to undergo fermentation. Upon sensory evaluation, it was found that the whey-based fermented beverage scored above 7.0 on a 9-point Hedonic scale, indicating high acceptability.

Based on a study conducted by Panghal et al. (2017), increasing the concentration of whey in the papaya-based whey drink had a positive effect on its nutritional value. However, it had a negative impact on the taste and microbial quality of the drink. A study conducted by Shende et al. (2022) explored the digestion of an enhanced paneer whey beverage. The researchers discovered that the complex form of zinc (Zn⁺²) in the beverage exhibited significantly higher bio-accessibility (p < 0.05) compared to its free form. According to the study conducted by Shende et al. (2022), it was observed that the concentration of complexed Zn⁺² showed a significant increase with decreased salt levels, elevated pH, and higher spices concentration.

The use of whey proteins in food formulation is motivated by their high levels of bioactive proteins such as β-lactoglobulin (β-Lg), α-lactalbumin (α-La), bovine serum albumin (BSA), immunoglobulins (Igs), glycomacropeptide (GMP), and proteose peptone (Sharma, 2019). When utilized as a food additive, β-lactoglobulin has been found to have beneficial impacts on human health. According to a study conducted by Tai et al. (2016), it was discovered that when β-Lg is folded correctly, it can boost human immune responses through a pathway that involves receptors. α-lactalbumin comprises approximately 22 % and 3.5 % of the protein content in human milk and bovine milk, respectively. It has a significant impact on lactose synthesis, which plays a crucial role in determining milk volume. Furthermore, it offers bioactive peptides and essential AAs such as tryptophan, lysine, branched-chain AAs, and sulfur-containing amino acids that are crucial for infant nutrition (Layman et al. 2018). In addition, whey containing bioactive proteins has the potential to act as an antibacterial agent. A study conducted by Kumari and Vij (2015) discovered that the permeate, which contained peptides of 10 and 5 KDa, showed activity against a range of pathogens. These included Gram-negative bacteria such as Salmonella typhi, Shigella dysentriae and Escherichia coli, as well as Gram-positive bacteria like Bacillus cereus, Listeria monocytogenes, and Staphylococcus aureus. The zones of inhibition observed ranged from 17 to 23 mm. In 2015, the quality and shelf life of probiotic drinks formulated with whey and Aloe vera juice were assessed by Sasi Kumar (Sasi Kumar, 2015). Several other researchers have conducted comparable studies (Castro et al., 2013; Kamble et al., 2017).

5.2 Functional whey beverage

The fortification of whey-based beverages with calcium phosphate (Ca₃(PO₄)₂), calcium lactate (C₆H₁₀CaO₆), vitamin D3, and prebiotic dietary fiber was investigated in studies conducted by Algirdasl et al. (2016) and Liutkevičius et al. (2016). A study conducted by Liutkevičius et al. (2016) revealed that the presence of Ca₃(PO₄)₂ resulted in a more significant decline in the overall acceptability of the beverages over time in comparison to C₆H₁₀CaO₆. Upon comparing Ca₃(PO₄)₂ to lactate, researchers found that lactate proved to be more suitable for the food matrix. Consequently, this formulation was chosen for additional investigation (Algirdasl et al., 2016). Following a 21-day period of consuming C₆H₁₀CaO₆, vitamin D3, and prebiotic dietary fiber, there was a notable decrease in LDL-cholesterol and triglyceride concentrations (p < 0.01). According to the study findings, it was expected that these modifications would improve the overall welfare of the individuals involved (Algirdasl et al., 2016).

Exploring the incorporation of prebiotics and fruit flavor into whey-based drinks opens up exciting possibilities for developing novel functional food products on a large scale (Shah and Patel, 2019). In addition, the inclusion of prebiotics enhances the physical, chemical, and functional properties of the whey-based beverage. Furthermore, it also promotes the proliferation of beneficial bacteria. In strawberry-flavored whey-based beverages, researchers have found that the addition of 1.25 g/100 mL of a prebiotic xylooligosaccharide (XOS) can have interesting effects on diabetes, hypertension, and antioxidant properties (Souza et al., 2019).

When developing paneer whey-based iced tea, it was found that samples with 80 % and 100 % whey scored significantly (p < 0.05) better in sensory metrics compared to samples with 50 % whey (Shah et al., 2019). Even more fascinatingly, the enhanced product showed a 25 % antioxidant activity based on the DPPH test and contained 0.6 % protein. In contrast, Baba and colleagues developed a paneer whey beverage by adjusting the ratio of paneer whey (10 % to 30 %) in pineapple juice (Baba et al., 2016). The protein content in both drinks was 0.61 % and 0.86 %, respectively, and both beverages achieved an overall acceptability score of over 8.0 on a 9-point Hedonic scale. The paneer whey-based beverages showed higher levels of protein and minerals compared to the control, suggesting their potential to help address protein-energy malnutrition in children living in underprivileged nations (Baba et al., 2016). In addition, scientists have developed herbal beverages using whey, such as green and black tea (Perasiriyan et al., 2013). A new study presented spicy water made from paneer whey known as Hajma Hajam, containing mint (Mentha aquatica L.) (often known as mentha or pudina, is a member of the Lamiaceae family of plants) along with other ingredients (Ranavaya et al., 2019). When compared to other mixtures, the product with a 50:50 blend of whey and water (pH 3.8–4.2) received the top sensory ratings. Mixing whey with natural herbs like mint or tea within a suitable range, can produce a nutritious drink packed with antioxidants like polyphenols and other beneficial components (Ranavaya et al., 2019; Shah et al., 2019). This enables individuals to enjoy whey without changing its original qualities or increasing expenses.

5.3 Cultured butter milk with biofunctional properties

Angiotensin-converting enzyme (ACE) inhibition, antioxidant potential, and antimicrobial properties were discovered in beverages developed from different combinations of dahi and fermented paneer whey, as compared to a control sample made from dahi and water (Parekh et al., 2017). The cultured buttermilk produced from fermented paneer whey and dahi (blended with different ratios i.e. 40 % and 60 %, respectively) exhibited enhanced biofunctional properties compared to buttermilk made from different blend fermented paneer whey and dahi (blended with 30 % and 70 %, respectively). Paneer whey was discovered to be useful in the production of cultured buttermilk when combined with fermented paneer whey (Suneeta et al., 2014; Maheta et al., 2015; Paraffin et al., 2019). A study conducted by Parekh et al. (2017) discovered that incorporating fermented paneer whey into cultured buttermilk had a significant positive impact on its biofunctional characteristics. This included improvements in antioxidant and antimicrobial activities.

In addition, the combination of whey-based beverages and fruit fermentations has the potential to be a unique and functional drink option in the market (Pereira et al., 2015). Several compounds found in fruits are commonly combined with whey to enhance their beneficial properties (Baba et al., 2016; Liutkevičius et al., 2016; Raj et al., 2017; Thakkar et al., 2018). Modifying the fruit juice in this whey-based juice beverage can have an effect on its functional properties. Various compounds present in fruits like strawberries (Fragaria ananassa) and blueberries (Vaccinium corymbosum) have shown protective effects against oxidative stress. These compounds include flavanols, catechins, anthocyanins, and phenolic acids (Dhalaria et al. 2020; Kim et al. 2020). Studies conducted by Dhalaria et al. (2020) and Kim et al. (2020) have found that certain substances have the ability to counteract the harmful effects of free radicals and other reactive oxygen species (ROS). Minimizing the development of oxidative stress can help prevent illnesses such as cancer and obesity. The presence of polyphenols, phenolic acids, and flavonoids in apple juice has been found to have a positive impact on cells, potentially reducing the risk of chronic illness (Dias et al., 2021; Guiné et al., 2021; Sobhani et al., 2021). Studies by Dias et al. (2021), Guiné et al. (2021), and Sobhani et al. (2021) have demonstrated the antiproliferative and antioxidative effects of these compounds.

According to a study conducted by Ferreira Wessel and colleagues, it was found that pear juice contains various compounds such as quercetin, hydroxy-cinnamic acids (HCAs), catechins, and other polymeric units (Ferreira Wessel et al., 2016). These compounds possess antioxidant properties and are capable of counteracting free radicals. Various experiments have played a significant role in the advancement and production of whey-based beverages that incorporate a variety of fruit combinations. Several studies have investigated the combined use of sweet rennet-based whey and acid whey, as documented by Smith et al., (2016), Rizzolo and Cortellino (2018), Skryplonek et al. (2019), and Anand and Awasti (2020). A recent study found that Ricotta-Cheese whey has the potential to replace whey in pectin-free beverages like apple, blueberry, and pear (Rizzolo and Cortellino, 2018).

Consumers have a wide range of choices when it comes to finding a nutritious and cost-effective beverage, with energy drinks being one of them. Various flavors are often used to conceal the taste and aroma of energy drinks made from whey. According to a study by Naik et al. (2009), refrigerated watermelon-flavored whey-based energy drinks showed favorable texture, flavor, and color. As per a study conducted by Divya andArchana (2009), it was discovered that a guava-flavored drink containing paneer whey remained safe for consumption even after being stored for 45 days. A study conducted by Kumar and colleagues in 2017 resulted in the development of a nutritious drink made from whey and pineapple juices (Kumar et al., 2017). The drink showed impressive stability over a two-month period. Whey-based fruit beverages and drinks provide a valuable source of energy, nutrition, and beneficial therapeutic properties, making them suitable for a wide range of consumers, from children to seniors. Several studies have also investigated the degree of polymerization (DP) of prebiotic oligosaccharides. In a recent study, Guimaraes and colleagues examined the effects of inulin DP on the physical stability of a soursop-flavored whey beverage (Guimaraes et al., 2020). The aim was to develop a novel prebiotic food product. The researchers observed that samples with inulin DP ≥ 23 demonstrated superior physical stability in comparison to samples with DP ≥ 10.