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β-Lactoglobulin hydrolysates (βlgHs) were generated using elastase at enzyme-to-substrate ratios (E:S) of 0.5, 1.0 and 1.5% in order to reach target degree of hydrolysis (DH) values of 9 and 13%. The impact of different E:S during manufacture on hydrolysates having similar DHs was assessed. Samples with similar DHs generated with different E:S showed comparable molecular mass distribution profiles and in vitro dipeptidyl peptidase IV (DPP-IV) inhibitory activities (p>0.05). Liquid-chromatography tandem mass spectrometry (LC-MS/MS) analysis showed that 62 and 84% of the peptides identified were common within hydrolysates having a similar DH of 9 or 13%, respectively. Differences in the peptides identified within hydrolysates having similar DHs may be due to E:S dependent modifications in specificity and enzyme kinetics. Overall, this study showed that reduction in E:S while targeting the development of a similar DH for βlgHs may be employed to reduce the cost of hydrolysate production without having an adverse impact on the bioactivity and physicochemical properties studied herein., (Copyright © 2017. Published by Elsevier Ltd.)

The dairy protein β-lactoglobulin (βlg) is known to form a complex with fatty acids (FA). Due to industrial processing, βlg is often in its non-native form in food products, which can modify the FA/βlg complex properties. We investigated the interaction of bovine βlg, in selected structural forms (native βlg, a covalent dimer and as nanoparticles), with linoleate (C18:2). Using fluorescence and Isothermal Titration Calorimetry, linoleate was found to bind βlg at two different binding sites. Regardless of the structural state of βlg, association constants remained in the same order of magnitude. However, the stoichiometry increased up to 6-fold for nanoparticles, compared to that of native βlg. The impact of these structural changes on linoleate uptake in vitro was measured by cytotoxicity assays on Caco-2 cells. The order of cytotoxicity of linoleate was as follows: free>complexed to dimers>complexed to nanoparticles>complexed to native βlg. Therefore, the in vitro cytotoxicity of linoleate could be modulated by altering the state of βlg aggregation, which in turn affects its binding capacity to the FA., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

The dairy protein β-lactoglobulin (BLG) is known to bind fatty acids such as the salt of the essential longchain fatty acid linoleic acid (cis,cis-9,12-octadecadienoic acid, n-6, 18:2). The aim of the current study was to investigate how bovine BLG-linoleate complexes, of various stoichiometry, affect the enzymatic digestion of BLG and the intracellular transport of linoleate into enterocyte-like monolayers. Duodenal and gastric digestions of the complexes indicated that BLG was hydrolyzed more rapidly when complexed with linoleate. Digested as well as undigested BLG-linoleate complexes reduced intracellular linoleate transport as compared with free linoleate. To investigate whether enteroendocrine cells perceive linoleate differently when part of a complex, the ability of linoleate to increase production or secretion of the enteroendocrine satiety hormone, cholecystokinin, was measured. Cholecystokinin mRNA levels were different when linoleate was presented to the cells alone or as part of a protein complex. In conclusion, understanding interactions between linoleate and BLG could help to formulate foods with targeted fatty acid bioaccessibility and, therefore, aid in the development of food matrices with optimal bioactive efficacy., (Copyright © 2013 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

The dairy protein β-lactoglobulin (βlg) is known to bind hydrophobic ligands such as fatty acids. In the present work, we investigated the biological activity in vitro of linoleate once complexed to bovine βlg. Binding of linoleate (C18:2) to bovine βlg was achieved by heating at 60 °C for 30 min at pH 7.4, resulting in a linoleate/βlg molar binding stoichiometry of 1.1, 2.1, and 3.4. Two types of binding sites were determined by ITC titrations. Binding of linoleate induced the formation of covalent dimers and trimers of βlg. The LD(50) on Caco-2 cells after 24 h was 58 μM linoleate. However, cell viability was unaffected when 200 μM linoleate was presented to the Caco-2 cells as part of the βlg complex. The Caco-2 cells did not increase mRNA transcript levels of long chain fatty acid transport genes, FATP4 and FABPpm, or increase levels of the cAMP signal, in response to the presence of 50 μM linoleate alone or as part of the βlg complex. Therefore, it is proposed that βlg can act as a molecular carrier and alter the bioaccessibility of linoleate/linoleic acid.