**Adjusting Bioactive Functions of Dairy Products via Processing Processing**

**Adjusting Bioactive Functions of Dairy Products via** 

DOI: 10.5772/intechopen.72927

Katrin A. Kopf-Bolanz Katrin A. Kopf-Bolanz Additional information is available at the end of the chapter

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/intechopen.72927

#### **Abstract**

Milk is known for its high nutrient content that helps to maintain important body functions. In this regard, bioactive peptides that are encrypted in milk proteins and get released during processing and/or digestion might play a role. These peptides are able to inhibit enzymes, influence cell growth, or target specific receptors. The peptide profile that arises after protein digestion in the jejunum before the absorption into the blood takes place includes these bioactive peptides. The composition of the peptide profile is influenced strongly via processing and a modification in processing might target specific functionalities. Thermal, chemical, biochemical, and physical treatments affect protein digestion mainly by changing the protein structure for example via denaturation or protease actions. Parameters influencing this are external ones, like the matrix of the product, and internal ones, like specific enzyme deficiencies. However, considering all the important aspects that are involved, there might be the possibility in the future to adjust a bioactive function via processing.

**Keywords:** bioactive peptides, processing, bioavailability, bioactive function, dairy products

#### **1. Introduction**

Dairy products are appreciated for their high nutritional value [1]. Not only the high contents of protein, vitamins, and minerals determine the positive health effect of dairy products. Hidden components called bioactive peptides, encrypted in parent milk proteins, exhibit special functions that might influence our well-being. So far peptides with antihypertensive, anti-oxidative, anti-thrombotic, anticancer, immune-modulatory, antimicrobial, cholesterollowering, antidiabetic, mineral-binding, opioid and satiety properties were identified. These peptides occur directly in the dairy products after processing and are resistant to digestion enzymes or they are encrypted in dairy proteins and get released during digestion.

Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons

Interestingly, the processing method of the dairy products can influence the number and sequence of the resulting peptides after digestion and therefore also the content of bioactive peptides. Heat treatment, chemical and biochemical, and physical treatment can influence the bioactive functionality transmitted by the selected dairy product. In the future, it might be possible to target a wished bioactive function via processing. This book chapter just deals with the effects exhibited by bioactive peptides. However, also other milk components are affected by processing and can exhibit bioactive functions, e.g. effects on the lipids, minerals, and vitamins. Furthermore, the addition of certain bioactive ingredients to dairy products is also not discussed in this chapter. The focus is given to the possible effects transmitted via bioactive peptides and the effect of processing on the peptide profile.

These are the ways to produce bioactive peptides that can be afterwards purified and used as ingredients for manufacturers of functional foods. However, also the more natural way of processing via hydrolysis by proteolytic microorganisms can be an approach to enrich a specific bioactive function in a product. Bioactive peptides have been discovered not only in dairy products, but also in meat, eggs, fish, and other marine organisms and also in plant

Adjusting Bioactive Functions of Dairy Products via Processing

http://dx.doi.org/10.5772/intechopen.72927

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The production of bioactive peptides for use as additives can be done by enzymatic hydrolysis or microbial fermentation [7]. Enzymatic hydrolysis applies digestion enzymes. Mostly trypsin, a pancreatic proteinase is used, but also chymotrypsin, pepsin thermolysin, pancreatin, elastase, carboxypeptidase or a proline-specific endopeptidase can deliver bioactive peptides. Additionally, proteases from bacteria, fungi, and plants also showed interesting properties [7]. Microbial fermentation uses bacteria or yeast that exhibit proteolytic activity to generate peptides. They are grown and added in their exponential phase to the protein of interest. The degree of hydrolysis is then dependent on the strain and its proteolytic activity. In both ways, a purification of the peptides is necessary. This can be for example reached by centrifugation methods, freeze drying, desalting, and membrane filtration techniques [8]. Examples are the production of caseinophosphopeptides from α-s-casein with an immobilized trypsin in a fluidized bed bioreactor [9] and a combination of diafiltration and anionexchange chromatography [10]. The peptide additives can be added to a product of interest to generate a functional food. For this purpose, also the stability of the peptides with regard to pH, temperature, and food matrix has to be considered. Furthermore, the more natural way to enhance dairy products with bioactive peptides is to directly add a bacterial culture to the dairy product and generate a fermented product containing bioactive peptides. This is the general processing method applied already for each fermented dairy product. If protein is not taken out, all dairy products result in a high quantity of bioactive peptides that might be absorbed in the small intestine. For the functionality of these peptides, the selection of bacteria strains is important to aim for a specific bioactive function via processing

The possible, so far detected, functionalities of bioactive peptides are summarized in **Figure 2**.

sources like certain grains, legumes, pulses, and oilseeds [4–6].

(see Section 3).

**Figure 2.** Possible functionalities of bioactive peptides.
