**2. Natural by-product and waste compositions and properties**

### **2.1 Whey protein**

The dairy industry is characterized by a broad group of food products, such as milk, milk powder, butter, yoghurts, cream and cheese, but it is also a big source of solid and liquid by-products, but among those, whey is the one produced at the highest volumes in cheese industry. The world production of by-products in dairy industry is around 4–11 million tonnes per year, but Europe is the worldwide leader in cheese production and consequently the largest whey producer [1, 2]. This has a big environmental impact if they are disposed as wastes, so strategies to reuse these by-products are important, and there is a community pressure in this sense. Traditionally, some years ago, whey is used to be disposed of, but with environmental concerns and legislation to be implemented, the reuse appears with a prominent role [2]. Whey is considered one of the major pollutant byproducts because of its high biological and chemical oxygen demands [2]. Whey is composed of 85–90% water, 10–15% lactose (carbohydrates), soluble vitamins, minerals (e.g. calcium, phosphorus, sodium and so on) and proteins (e.g. β-lactoglobulin, α-lactalbumin, bovine serum albumin (BSA), immunoglobulins and others) [1, 2]. Lactose is the main component, being responsible for most of the biological and chemical oxygen demands [2]. However, lactose and other nutrients essential for microbial growth confer whey a potential to produce several bioproducts. Whey proteins award health benefits such as high nutritional value, easy digestion and assimilation, which are interesting for the food industry too. It can be used for biotransformation feeds, bioproteins, prebiotics, and bioactive peptides after fermentation or enzymatic hydrolysis. On the other hand, the reduced-lactose whey, demineralized whey, and whey protein concentrates or isolates are used for food, cosmetic and pharmaceutical industries, especially for thier emulsifying, thickening, gelling, foaming and water-binding properties. More specific, these proteins of natural origin and with emulsifying capacity are used in the formulation of creams and shampoos as substitutes for synthetic surfactants. The whey protein hydrolysate also has this type of application for hair products. Another property of whey protein consists of gel formation, being used to produce protective films and coatings. These proteins, as they have low permeability to water vapour, are used in paper coating, providing good appearance and printability. β-Lactoglobulin and α-lactalbumin can be used as moisturizing and antiwrinkle agents. Lactoferrin is a good iron chelator, preventing the formation of free radicals. In the 1990s, whey protein, in the form of iron proteinate, was also used as an antianemic preparation [3]. Moreover, this by-product can be reused not only for its technological properties but also for its biological properties in terms of the body's benefits.

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**Table 1.**

chemicals.

**2.2 Agro-industrial wastes**

*Innovation of Textiles through Natural By-Products and Wastes*

food, fuel health, pharmaceuticals, biomaterials and others.

bioactive glasses with potential applications in bone tissue engineering.

These biomaterials have been explored for tissue engineering applications due to their chemical and biological properties, such as the ability to retain water, easy transport/entrapment of nutrients or cells, controlled biodegradability, mechanical properties and biocompatibility [5]. However, the field of action of whey is much wider and applied to other industries as an eco-friendly alternative to conventional

Agro-industrial wastes include several different wastes from the food and agriculture industries. The amount of wastes from the food and forestry-based industries produced in the European Union (EU) is estimated to be in the order of 900 million tonnes per year. However, a large part of these wastes are considered low-value input materials instead of wastes, like sawdust that can be used to make products such as fibreboard or leaves and stalks of plants that can have other agricultural uses such as animal bedding [6]. If these wastes are released to the environment without a proper disposal procedure, they may worsen the environmental pollution and cause harmful effects on human and animal health. **Table 1** shows the

Recently, these wastes have been the focus of much attention due to their huge potential for exploration, not only for their wide availability and diversity but also for their intrinsic properties and functionalities, which make them an increasingly

**(Mtonnes/year)**

Paper industry 17.5 12.3 Wood industry 8 5.6 Food and garden industries 37.6 26.3 Crop wastes 122 139 Forestry wastes 40 40

**2030 availability (Mtonnes/year)**

estimated sustainable availability of agro-industrial wastes.

**Wastes Current availability** 

*Agro-industrial wastes and wastes produced in the EU [6].*

Due to its biological and chemical properties, whey has several applications, depending on the biotechnological method applied to reuse this by-product. It can be used to obtain chemical products to produce functional formulations and for

Whey has been used in the food industry to produce functional food and drinks as an innovative product with health benefits. For example, whey can be used in dairy beverages: unfermented or fermented, probiotic, refreshing soft, alcoholic, diet and high protein sport [2]. Whey is also one of the main sources of the bioactive peptides that can be used as nutritional supplements because of its structure, rapid absorption and biological properties (antihypertensive activities and antioxidant properties). On the other hand, whey protein has been explored in the food industry in edible film or coating development for food preservation, for its biochemical properties, such as its edible nature and intrinsic biodegradability, suitable mechanical barrier, flexibility and the capacity to incorporate functional compounds [4]. The improvement of knowledge has also allowed the development of biomaterials from whey, for example, to produce biodegradable capsules for drug delivery. The whey protein isolates (WPI) have been used for bone regeneration to produce

*DOI: http://dx.doi.org/10.5772/intechopen.93011*

*Waste in Textile and Leather Sectors*

business models.

**2.1 Whey protein**

the development of functional textiles on a large scale. By-products and wastes from different sources and industries such as proteins, vegetable, agroforestry, furniture, food, footwear and automotive industries are often used as biomass or sent to landfills. However, due to the interest in by-products as a substituent for the commercially aggressive chemicals used in the textile industry, research on the valorization of these materials has remarkably increased. In this sense, several studies were carried out to enhance the performance attributes of textile goods through finishing, coating and dipping technologies with by-products and residues, thus creating an opportunity for the establishment of partnerships and circular economy

**2. Natural by-product and waste compositions and properties**

The dairy industry is characterized by a broad group of food products, such as milk, milk powder, butter, yoghurts, cream and cheese, but it is also a big source of solid and liquid by-products, but among those, whey is the one produced at the highest volumes in cheese industry. The world production of by-products in dairy industry is around 4–11 million tonnes per year, but Europe is the worldwide leader in cheese production and consequently the largest whey producer [1, 2]. This has a big environmental impact if they are disposed as wastes, so strategies to reuse these by-products are important, and there is a community pressure in this sense. Traditionally, some years ago, whey is used to be disposed of, but with environmental concerns and legislation to be implemented, the reuse appears with a prominent role [2]. Whey is considered one of the major pollutant byproducts because of its high biological and chemical oxygen demands [2]. Whey is composed of 85–90% water, 10–15% lactose (carbohydrates), soluble vitamins, minerals (e.g. calcium, phosphorus, sodium and so on) and proteins (e.g. β-lactoglobulin, α-lactalbumin, bovine serum albumin (BSA), immunoglobulins and others) [1, 2]. Lactose is the main component, being responsible for most of the biological and chemical oxygen demands [2]. However, lactose and other nutrients essential for microbial growth confer whey a potential to produce several bioproducts. Whey proteins award health benefits such as high nutritional value, easy digestion and assimilation, which are interesting for the food industry too. It can be used for biotransformation feeds, bioproteins, prebiotics, and bioactive peptides after fermentation or enzymatic hydrolysis. On the other hand, the reduced-lactose whey, demineralized whey, and whey protein concentrates or isolates are used for food, cosmetic and pharmaceutical industries, especially for thier emulsifying, thickening, gelling, foaming and water-binding properties. More specific, these proteins of natural origin and with emulsifying capacity are used in the formulation of creams and shampoos as substitutes for synthetic surfactants. The whey protein hydrolysate also has this type of application for hair products. Another property of whey protein consists of gel formation, being used to produce protective films and coatings. These proteins, as they have low permeability to water vapour, are used in paper coating, providing good appearance and printability. β-Lactoglobulin and α-lactalbumin can be used as moisturizing and antiwrinkle agents. Lactoferrin is a good iron chelator, preventing the formation of free radicals. In the 1990s, whey protein, in the form of iron proteinate, was also used as an antianemic preparation [3]. Moreover, this by-product can be reused not only for its technological properties but also for its biological properties in

**106**

terms of the body's benefits.

Due to its biological and chemical properties, whey has several applications, depending on the biotechnological method applied to reuse this by-product. It can be used to obtain chemical products to produce functional formulations and for food, fuel health, pharmaceuticals, biomaterials and others.

Whey has been used in the food industry to produce functional food and drinks as an innovative product with health benefits. For example, whey can be used in dairy beverages: unfermented or fermented, probiotic, refreshing soft, alcoholic, diet and high protein sport [2]. Whey is also one of the main sources of the bioactive peptides that can be used as nutritional supplements because of its structure, rapid absorption and biological properties (antihypertensive activities and antioxidant properties). On the other hand, whey protein has been explored in the food industry in edible film or coating development for food preservation, for its biochemical properties, such as its edible nature and intrinsic biodegradability, suitable mechanical barrier, flexibility and the capacity to incorporate functional compounds [4].

The improvement of knowledge has also allowed the development of biomaterials from whey, for example, to produce biodegradable capsules for drug delivery. The whey protein isolates (WPI) have been used for bone regeneration to produce bioactive glasses with potential applications in bone tissue engineering.

These biomaterials have been explored for tissue engineering applications due to their chemical and biological properties, such as the ability to retain water, easy transport/entrapment of nutrients or cells, controlled biodegradability, mechanical properties and biocompatibility [5]. However, the field of action of whey is much wider and applied to other industries as an eco-friendly alternative to conventional chemicals.
