Characterization of concentrated second cheese whey

The residual deproteinized whey known as second cheese whey or “Sorelho”, is a byproduct obtained from whey cheese manufacture. It is commonly obtained in small/medium scale cheese plants and, although it has little to no commercial value, it is produced in relatively high volumes, which results in a complex disposal process. Therefore, the objective of this work was to characterize the nutritional composition of two concentrated deproteinized wheys (sheep and goat), obtained through ultrafiltration/diafiltration with a 10 kDa membrane followed by freezedrying. From the nutritional standpoint, it was possible to observe that after ultrafiltration, samples were mostly comprised of protein 75-58% (w/w). Samples also exhibited a low mineral and lactose contents (1.7-3.9% (w/w) and 0.93 -69%(w/w), respectively). The fatty acid composition profile was predominantly composed of short- and medium chain fatty acids including butyric, caproic and caprylic acids, with long chain fatty acids, such as palmitoleic, rumenic, trans vaccenic, docosapentaenoic and docosahexaenoic acids being also detected in both goat and sheep Sorelho, but in the goat Sorelho the concentration was bigger of these fatty acids. When regarding the amino acids identified aspartic acid, glutamic acid, alanine and tyrosine were the most predominant amino acids found in the sheep Sorelho while in the goat Sorelho aspartic acid, glutamic acid, asparagine, threonine and valine were prevalent. Overall, these results provide some insights into Sorelhos’ potential usage as source of bioactive compounds for posterior incorporation into foods.