Recent Trends and Developments to Valorize Sheep and Goat Cheese Whey for Small and Medium-Size Enterprises.

Sheep and goat milk are mainly used for cheese manufacture in small livestock farms, giving rise to a large volume of whey. Sheep and goat cheese whey possess excellent and specific functional and nutritional characteristics. The valorization of these valuable by-products through physicochemical or biotechnological processes compatible with artisanal production are important in terms of sustainability, i.e., economic, social, and environmental impacts. The main challenges for whey processing in small and medium-size enterprises (SMEs) are the lack of equipment, construction and information as well as the small amounts of cheese whey generated from these plants. Membrane technology can be convenient to produce valuable by-products for small dairy plants in the presence of enough investment cost and whey amount. Biotechnological treatments covering anaerobic digestion systems and fermentation processes are advantageous for SMEs over physicochemical methods on investment cost. In these processes, efficient microorganisms are able to produce high-value natural products, biofuels, and biopolymers. Anaerobic digestion is a suitable method for goat and sheep cheese whey valorization in SMEs due to the small volumes. Additionally, bioconversion into fermented beverages is a good choice for cheese whey valorization in SMEs because of its low operational and equipment cost.