Development of an Accelerated Stability Model to Estimate Purple Corn Cob Extract Powder (Moradyn) Shelf-Life

Insight into the interaction between tannin acid and bovine serum albumin from a spectroscopic and molecular docking perspective

In this study, the interaction mechanism of bovine serum albumin (BSA) with tannic acid (TA) was investigated by spectroscopic and computational approaches and further validated using circular dichroism (CD), differential scanning calorimetry (DSC) and molecular docking techniques. The fluorescence spectra showed that TA bound to BSA and underwent static quenching at a single binding site, which was consistent with the molecular docking results. And the fluorescence quenching of BSA by TA was dose-dependent. Thermodynamic analysis indicated that hydrophobic forces dominated the interaction of BSA with TA. The results of circular dichroism showed that the secondary structure of BSA was slightly changed after coupling with TA. Differential scanning calorimetry showed that the interaction between BSA and TA improved the stability of the BSA-TA complex, and the melting temperature increased to 86.67 °C and the enthalpy increased to 264.1 J g^-1 when the ratio of TA to BSA was 1.2 : 1. Molecular docking techniques revealed specific amino acid binding sites for the BSA-TA complex with a docking energy of -12.9 kcal mol^-1, which means the TA is non-covalently bound to the BSA active site.

A New Polysaccharide Carrier Isolated from Camelina Cake: Structural Characterization, Rheological Behavior, and Its Influence on Purple Corn Cob Extract's Bioaccessibility

A polysaccharide fraction obtained from camelina cake (CCP), selected as a carrier to encapsulate purple corn cob extract (MCE), was investigated. A wide population of carbohydrate polymers (with a polydispersivity index of 3.26 ± 0.07 and an average molecular weight of about 139.749 × 103 ± 4.392 × 10³ g/mol) with a gel-like behavior and a thixotropic feature characterized the fraction. MCE-CCP combinations (50–50 and 25–75, w/w), selected based on CCP encapsulation efficiency, were tested for their stability and MCE polyphenols’ bioaccessibility during digestion (monitored using an in vitro static procedure). During the oral and gastric phases of the digestion process, CCP gradually swelled and totally released MCE polyphenols. MCE-CCP50 had the fastest release. Moreover, anthocyanins were still detectable during the duodenal phase, in both MCE-CCP ingredients. Furthermore, CCP (5 mg/mL) exerted in vitro potential hypocholesterolemic activity via bile salts binding during digestion.

Selection and Optimization of an Innovative Polysaccharide-Based Carrier to Improve Anthocyanins Stability in Purple Corn Cob Extracts

The extraction process of alcohol-insoluble polysaccharides from exhausted Moradyn cob (Zea mays L. cv. Moradyn) (EMCP), camelina cake (Camelina sativa L. Crantz) (CCP), and common bean seeds (Phaseolus vulgaris L.) (CBP) was investigated and optimized by Response Surface Methodology. Each fraction was tested at different core/carrier ratios in the encapsulation of Moradyn cob extract (MCE), a rich source of antioxidant anthocyanins, and the obtained ingredients were screened for their encapsulation efficiency (EE%) and extraction process sustainability. The ingredients containing 50% and 75% CCP had EE% higher than 60% and 80%, respectively, and were selected for further studies. Preliminary structural analysis indicated CCP was mostly composed of neutral polysaccharides and proteins in a random-coiled conformation, which was also unchanged in the ingredients. CCP-stabilizing properties were tested, applying an innovative stress testing protocol. CCP strongly improved MCE anthocyanins solid-state stability (25 °C, 30% RH), and therefore it could be an innovative anthocyanins carrier system.