# Techno-Functional Properties and Recent Advances in the Manufacturing of Whey Beverages: A Review
## 4. Whey-Based Beverages
### Fermented Whey-Based Beverages  
The production of fermented whey beverages is another relatively attractive method of utilising all whey. Due to its high lactose content, whey serves as a suitable medium for the cultivation of lactic acid bacteria, yeasts, or kefir cultures. During fermentation, the breakdown of lactose, peptides, and fats occurs through the action of microbial enzymes, leading to the formation of lactic acid, alcohols, and other sensory-active compounds. These compounds can contribute to the specific organoleptic profile of the beverages while extending their shelf life. Examples include acetaldehyde, ethyl acetate, isoamyl alcohol, isobutanol, 1-propanol, isopentyl alcohol, and 1-hexanol, which have been identified using high-performance liquid chromatography [16; 54; 55; 56; 57]. Lactic acid bacteria (_Pediococcus pentosaceus_, _Lactiplantiobacillus plantarum_) used in the production of fermented whey beverages are capable of inhibiting pathogenic bacteria. As a result, these beverages may help reduce cholesterol levels and increase antioxidant activity [58]. In the work of [PERSON] et al. [59], hydrolys collagen (0.30%, 0.50%, 0.75%, and 1%) was added to fermented whey beverages. Specifically, fermentation was carried out using lactic acid bacteria (_Lactizesibacillus rhamnosus_, _Lactoobacillus delbruveckii_ subsp. _bulgaricus_, _Lactobacillus delbruveckii_, and _Streptococcus thermophilus_). Beverages with the addition of 1% hydrolys collagen were found to contain 9.75 \(\pm\) 0.20 g/L of protein. Moreover, as the concentration of hydrolys collagen increased, the viscosity of the beverages also rose significantly. Furthermore, the beverages enriched with hydrolys collagen demonstrated antimicrobial properties, as no undesirable pathogenic microbiota were detected. In addition to these benefits, the nutritional value of the beverages due to the high protein concentration and no changes in the fat and lactose concentrations were also enhanced. Furthermore, the in vitro bioavailability of hydrolys collagen exhibited elevated absorption rates attributable to its low molecular weight. Furthermore, [PERSON] and [PERSON] [60] examined the commercial potential of whey beverages combined with 25% and 50% semi-skimmed milk addition and fermented using yogurt cultures. The study also compared unfermented and fermented whey-based beverages. The culture contained lactic acid bacteria, specifically _Streptococcus thermophilus_ and _Lactobacillus delbruveckii_ subsp. _bulgaricus_. No significant changes in acidity were observed between samples fermented for 3 or 4 h; however, a significant difference was identified between whey drink samples with and without milk addition. Based on the results, the fermentation by yoghurt culture did not yield statistically significant enhancements in the organoleptic properties of the whey drink; however, the incorporation of milk emerged as the primary factor affecting not only the overall sensory quality of the whey drinks but also their flavour, appearance, colour, viscosity, and homogeneity. [PERSON] et al. [61] produced whey beverages with different concentrations of cactus pear (10, 20, and 30%) and kiwi (10 and 20%) juice fermented with _Lactiplantiobacillus plantarum_. The quality, viability of microorganisms, and organoleptic properties of the beverage were monitored over a period of 20 days. The concentration or type of the fruit component did not have a significant effect on the viability of _Lactiplantiobacillus plantarum_. Duringferentation, the pH value of the model samples decreased. After 20 days of the experiment, the beverages exhibited higher antioxidant activity and an increased content of phenolic compounds. Based on the sensory analysis, the samples with a 30% fruit component addition were rated as the best. [PERSON] et al. [62] focused on the production of probiotic beverages using WPC derived from cow, sheep, and goat milk.