Conditions Governing Food Protein Amyloid Fibril Formation. Part II: Milk and Legume Proteins

Abstract

Both intrinsic and extrinsic factors impact amyloid formation of food proteins. We here review the impact of various conditions and food constituents on amyloid fibrillation of milk and legume proteins. Much less is known about casein and legume protein amyloid‐like fibril formation than about that of whey proteins such as β‐lactoglobulin, α‐lactalbumin, and bovine serum albumin. Proteins of both sources are often studied after heating under strong acidic (pH < 3) conditions. The latter induces changes in protein conformation and often peptide hydrolysis. At higher pH values, alcohols, chaotropic and/or reducing agents induce the conformational changes required to enhance fibrillation. Different types of food proteins can impact each other's fibrillation. Also, the presence of other food constituents can enhance or reduce it. No general conclusions on the mechanisms or impact of different food constituents on food proteins can be made. Optimal conditions for AF formation, that is, heating for several days at low pH, are rare in food processing. However, this does not exclude the possibility of AF formation in food products. For example, slow cooking of hydrolyzed proteins may enhance it. Future research should focus on the prevalence of AFs in complex food systems or model systems relevant for food processing.

Conditions Governing Food Protein Amyloid Fibril Formation—Part I: Egg and Cereal Proteins

“…The OVA peptides LAMVYL, MVLVNAIVFK, and FLFCIK can form AFs on their own when heated at 80°C and pH 7.5. For more information on prediction algorithms as a tool to identify regions of protein sequences with high β-aggregation propensity, the interested reader is referred to the review of Jansens et al (2019).…”

“…AFs have unique technofunctional properties (Jansens et al, 2019). The presence and morphology of fibrillar structures have been related with foaming and emulsifying properties (Blijdenstein, Veerman, & van der Linden, 2004; Kroes-Nijboer, Venema, & van der Linden, 2012).…”

“…These nuclei, that is, seeds, contain amino acid sequences that promote ordered protein aggregation and end up in the fibril core (such sequences are hence referred to as amyloid core peptides). Seeding is particularly interesting since it holds promise for tailoring aggregation, and hence, protein technofunctionality (Jansens et al, 2019).…”

“…During heating, both protein sources impact each other's protein network formation and product quality (Lambrecht, Deleu, Rombouts, & Delcour, 2018). An overview of the current knowledge on amyloid formation of egg and cereal proteins will help further research of food proteins as will an accompanying paper dealing with AF formation from dairy and legume proteins (Lambrecht et al, 2019). Knowledge on the exact conditions and mechanisms of AF formation, their technofunctionality, and impact on human health is necessary.…”

“…Knowledge on the exact conditions and mechanisms of AF formation, their technofunctionality, and impact on human health is necessary. The significance of AF formation in food systems for technofunctional properties and nutritional quality has recently been discussed by Jansens et al (2019). In this review, all conditions that are known to induce fibril formation with hen egg, wheat, maize, and rice proteins are listed and the mechanisms and resulting fibril morphology are described.…”