Analyzing the Interaction between Anthocyanins and Native or Heat-Treated Whey Proteins Using Infrared Spectroscopy

Abstract

The color stability of anthocyanins (ACN) has been shown to be improved by interaction with whey proteins (WP). In this study, we explore the ACN–WP interaction using Fourier transform infrared spectroscopy (IR). ACN from purple corn, grape, and black carrot (50 μM) were evaluated. IR spectra (4000–700 cm−1) were collected for native and preheated (40–80 °C) WP (5 mg/mL) and ACN–WP mixtures at pH 7.4. Soft independent modeling of class analogy was used to analyze the IR data. The WP secondary structure changed after heat treatments and after interaction with ACN. As expected, the WP α-helices decreased, and β-sheet increased after heat treatment. The intensities of the WP amide I and II bands decreased after ACN addition, revealing a decrease in the WP α-helix content. Higher preheating temperatures (70–80 °C) resulted in a more disordered WP structure that favored stronger WP–ACN interactions related to amide III changes. Addition of ACN stabilized WP structure due to heat denaturation, but different ACN structures had different binding affinities with WP. WP structure had less change after interaction with ACN with simpler structures. These results increase our understanding of ACN–WP interactions, providing a potential strategy to extend anthocyanin color stability by WP addition.

Studying Liquid-Infused Surfaces with Affordable Surface Features Infiltrated with Various Lubricants from Corrosion, Biofouling, and Fluid Drag Viewpoints

“…The PBS solution was fabricated by adding 8 g of sodium chloride, 0.2 g of potassium chloride, 1.44 g of sodium phosphate dibasic, and 0.245 g of potassium phosphate monobasic to an appropriate volume of water. The final volume of this solution was 1 L, and its pH was adjusted to 7.4 by adding hydrochloric acid dropwise . Next, the withdrawn samples were ultrasonically washed in the 10 mL PBS solution for 30 min at room temperature to collect the bacteria attached to the samples.…”

“…The final volume of this solution was 1 L, and its pH was adjusted to 7.4 by adding hydrochloric acid dropwise. 52 Next, the withdrawn samples were ultrasonically washed in the 10 mL PBS solution for 30 min at room temperature to collect the bacteria attached to the samples. The bacteria attached to the substrate were dispersed in the PBS solution at this stage.…”

Effect of Preheating Whey Protein Concentrate on the Stability of Purple Sweet Potato Anthocyanins

“…Ren et al (2022) used FTIR to investigate the WP-ANs interaction. The WP structure became more disordered at higher preheating temperatures (70–80 °C), which introduced a stronger WP-ANs interactions owing to amide III alterations [ 20 ]. However, information on how preheating conditions affect WPC-ANs interactions is still lacking.…”

Magnetic Resonance and Vibrational Spectroscopy and Imaging in Food Analysis

“…The infrared spectroscopy and imaging papers are as follows: Aykas et al [8] develop a rapid, accurate method to detect acrylamide content in par-frozen French fries using a portable Infrared spectrometer. Ren et al [9] use Fourier transform infrared spectroscopy to study the stability and interactions of anthocyanins and whey proteins.…”