Proteolytic regulation of the extent of dietary proteins with skin grape proanthocyanidin and anthocyanidin's interactions

Abstract

During technological processing, proanthocyanidins and anthocyanidins could be partly lost due to the complexation phenomena, affecting food and beverage nutritional properties, organoleptic properties and health-promoting potentials. A common issue is encountered when processing food and beverage which is binding of phenolics to dietary proteins. The present investigation aims at evaluating the proteolysis contribution, using pure protease (Pepsin, 3000 units g À1 ), to protein-anthocyanidin and protein-proanthocyanidin interactions. Bovine serum albumin (BSA), ovalbumin (OVA) and casein (CAS) dietary protein models were used. High-performance liquid chromatography coupled to diode array detector (HPLC-DAD) and size exclusion chromatography analyses proved that pepsin treatment significantly (P > 0.05) decreased the ratio of flavonoids' interaction with tested proteins . The proteolysis reduced anthocyanidin interactions with CAS, OVA and BSA by 64.88%, 57.37% and 42.87% respectively. Similarly, proanthocyanidins interaction with CAS, OVA and BSA were reduced by 34.23%, 13.74% and 2.39% respectively. This study provides the basis to develop innovative technologies to limit protein-flavonoid complexation during food and beverage processing.

Toward the enrichment of dietary proanthocyanidins: In vitro investigation of their concentration‐dependent complexation with β‐casein

“…The extraction procedure has to be as cautious as possible. Several studies highlighted the proper utilization of acetone to separate high molecular weight phenolics, especially tannins (Ben Abdallah et al., 2018). Using this method, data obtained showed that total polyphenol content of the pomegranate and persimmon skin purified extract was, respectively, 82.49 ± 3.21 and 19.92 ± 0.96 mg GAE/g DW starting material (Figure 1).…”

“…This was not the case in our finding; but, in contrast, obtained results (Table 1) illustrated a decrease of absorbance at 280 nm, therefore, deduced as a decrease of proanthocyanidins. Additionally, we excluded in a previous work (Ben Abdallah et al., 2018) the hypothesis of any matching protein significant detection, given that the entirety tyrosine and tryptophan percentage content of casein did not exceed 6.3%. This level is judged insufficient to support eventual contributing role those two aromatic amino acids to the recorded absorbance at 280 nm wavelength.…”

“…Respecting the molar ratio of polyphenols/casein of 2.59:1, as indicated by (Ben Abdallah et al., 2018), β‐casein was added, to 3 ml tubes containing separately the persimmon and pomegranate peel extracts previously dissolved in a model solution (12% acidulated ethanol at pH 3.6 with trifluoroacetic acid) to obtain a final concentration varied in the medium from 0.008, 0.017, 0.028 to 0.035 mg (CE) of PA in the reaction medium in order to elucidate how this variation will influence protein–flavonoid interaction. A range of trials were carried out, and these contents have been revealed to be adequate for showing PA–β‐casein complexation, simultaneously, for both extracts.…”

“…Total polyphenolic content (TPC) was evaluated spectrometrically following the Folin–Ciocalteu colorimetric method reported by Ben Abdallah et al. (2018). The assay was carried out by mixing 50 μl of deionized water, 50 μl of extract, and 400 μl of Folin–Ciocalteu reagent (10%).…”

“…Our previous studies (Bautista-Ortín et al, 2016;Ben Abdallah et al, 2018) indicate that use of enzymes formulations regulated the extent of proanthocyanidin' interaction with tested dietary proteins or cell wall polysaccharides. Similarly, a first perception proposes that the variation of proanthocyanidins concentration could include a similar effect on the interaction intensity of proanthocyanidin with milk proteins.…”