Efficacy of Food Proteins as Carriers for Flavonoids

Abstract

Enrichment of flavonoids in food is often limited by their off-tastes, which might be counteracted by the use of food proteins as carriers of flavonoids. Various milk proteins, egg proteins, and gelatin hydrolysates were compared for their binding characteristics to two flavan-3-ols. Among the proteins tested for their affinities toward epigallocatechin gallate (EGCG), β-casein and gelatin hydrolysates, in particular fish gelatin, were found to be the most promising carriers with an affinity on the order of 10(4) M(-1). A flexible open structure of proteins, as present in random coil proteins, was found to be important. The saturation of binding observed at high flavonoid/protein ratios was used to estimate the maximal binding capacity of each protein. To reach a daily intake of EGCG that has been associated with positive health effects, only 519 mg of gelatin B and 787 mg of β-casein were required to complex EGCG on the basis of their maximal binding capacity. When the absence of turbidity is taken into account, β-casein prevails as carrier. Three selected proteins were further investigated for their binding potential of representative flavonoids differing in their C-ring structure. An increase in hydrophobicity of flavonoids was related to a higher affinity for proteins, and the presence of a gallic acid ester on the C-ring showed an overall higher affinity.

Adsorption of isoflavones onto PVPP in the presence of a soy matrix

“…The interaction of polyphenols with proteins depends on many parameters: the conformation and structure of the protein, the exact structure of the polyphenol and its amount and position of hydroxyl groups, the medium in which the association takes place, and the pH amongst others [9,15,17,21]. In the reported cases of interactions of proteins with isoflavones, it cannot be excluded that the isoflavones that partition into the protein fraction solely coprecipitate due to their low solubility in water.…”

“…This becomes important considering that soy protein having a globular structure is less prone to bind polyphenols than proteins that have lost part of their conformation. The isoflavone structure and soy protein specifically are not expected to interact strongly [21], but the denaturation state of the proteins may be an important factor in this case.…”

Whey Protein Complexes with Green Tea Polyphenols: Antimicrobial, Osteoblast-Stimulatory, and Antioxidant Activities

“…This was to be expected, given that previous studies have reported the binding efficiency of whey proteins with green tea catechins [Keppler et al, 2015]. For example, galloylated catechins, such as EGCG and ECG, were found to react most strongly with the protein and exhibited good antioxidative capacity [Bohin et al, 2012]. Due to the nature of the noncovalent reaction, the catechins bound to the protein are always in equilibrium with unbound catechins.…”

The behaviour of green tea catechins in a full-fat milk system under conditions mimicking the cheesemaking process

“…In light of this, EGCG has been reported to have the strongest affinity for milk proteins in comparison with other catechins including C Kanakis et al 2011;Bohin et al 2012;Rashidinejad et al 2015). Other researchers suggest that food proteins can be efficiently used as carriers for catechins (Dufour & Dangles 2005;Bohin et al 2012), or help reduce the stringency of catechins in particular food products (Bohin et al 2012).…”