Production of highly purified fractions of α-lactalbumin and β-lactoglobulin from cheese whey using high hydrostatic pressure

Abstract

Despite extensive research on the topic, valorization of dairy by-products remains challenging. Cheese whey is of particular interest because it contains valuable proteins such as α-lactalbumin (α-LA) and β-lactoglobulin (β-LG). However, selective fractionation of these 2 proteins into pure fractions is complex because of their similar molecular weights. In this study, we proposed an innovative protein separation strategy based on coupling high hydrostatic pressure (HHP) with acidification of whey at pH 4.6. We investigated the effect of single-cycle HHP (600 MPa) for 5, 10, and 15 min and multiple-cycle HHP (1-3 cycles of 5 min at 600 MPa) on α-LA and β-LG fractionation from cheese whey at initial pH (control, pH 6.66) and acidified to pH 4.6. All pressurization conditions with acidified whey induced a drastic aggregation of β-LG compared with control whey. The highest degrees of purification (75 and 98%, respectively) and yields (95 and 88%, respectively) of α-LA and β-LG were obtained with the application of single-cycle HHP treatment of acidified whey at pH 4.6 at 600 MPa for 5 min. Our results showed the strong potential of using HHP as an innovative tool for the fractionation of valuable proteins such as α-LA from cheese whey.

Factors affecting the modification of bovine milk proteins in high hydrostatic pressure processing: An updated review

“…Contrasting with the results for β-LG, α-LA was shown to be unaffected by HHP (600 MPa, 5−15 min) at pH values of 4.6 and 6.6 due to the higher rigidity of α-LA (Marciniak et al, 2020). Similarly, for a pure α-LA solution, only acidification at a very low pH (3) had an impact and caused a 25% increase in fluorescence intensity because of the exposure of hydrophobic groups in the molten globule state, whereas pressure processing had no impact on the intensity values.…”

“…However, at a pH of 4.6, β-LG forms octamers (β-LG dimers transform into octamers through carboxylcarboxylate interactions) that are highly sensitive to HHP (Gebhardt et al, 2012;Marciniak et al, 2020). Marciniak et al (2020) observed greater β-LG denaturation and aggregation when whey was acidified at pH 4.6 prior to HHP treatment (600 MPa, 5 min). At that pH, even the least severe HHP (i.e., 1 cycle of 5 min, 600 MPa) was sufficient to unfold the β-LG to its maximum level.…”

“…At an acidic pH close to 3 (where the monomeric state of β-LG was favored and stabilized by solvation), the pressure unfolding of β-LG was highly reversible, and the denatured β-LG was able to regain its native structure after HHP treatment at that pH (Gebhardt et al, 2012;Olsen & Orlien, 2016). However, at a pH of 4.6, β-LG forms octamers (β-LG dimers transform into octamers through carboxylcarboxylate interactions) that are highly sensitive to HHP (Gebhardt et al, 2012;Marciniak et al, 2020). Marciniak et al (2020) observed greater β-LG denaturation and aggregation when whey was acidified at pH 4.6 prior to HHP treatment (600 MPa, 5 min).…”

“…Marciniak et al. (2020) observed greater β‐LG denaturation and aggregation when whey was acidified at pH 4.6 prior to HHP treatment (600 MPa, 5 min). At that pH, even the least severe HHP (i.e., 1 cycle of 5 min, 600 MPa) was sufficient to unfold the β‐LG to its maximum level.…”

HPLC Identification of Mare’s Milk and Its Mix with Cow’s Milk

“…1) Для идентификации видовой принадлежности молока различных видов копытных животных удобно использовать сывороточные белки. Благодаря межвидовым различиям в первичной структуре β-лг, α-ла и сывороточного альбумина их физико-химические свойства будут существенно различаться [27][28][29][30].…”