Trapping by amylose of the aliphatic chain grafted onto chlorogenic acid: Importance of the graft position

Investigation of Bioactive Complexes of Chitosan and Green Coffee Bean or Artichoke Extracts

The formation of water-insoluble complexes between chitosan (ChS) and caffeoylquinic acid (CQ) derivatives present in artichoke (AE) and green coffee bean (GCBE) extracts was investigated by the equilibrium adsorption method. The UPLC/HPLC analysis revealed that the phenolic compounds accounted for 8.1% and 74.6% of AE and GCBE respectively, and CQ derivatives were the predominant compounds. According to the applied Langmuir adsorption model, anionic compounds present in natural extracts were adsorbed onto the active centers of ChS, i.e., primary amino groups. The driving forces of adsorption were electrostatic interactions between cationic groups of ChS and anionic compounds of natural extracts. Chromatographic analysis revealed that not only CQ derivatives, but also other phenolic compounds of natural extracts were attached to ChS. The release of adsorbed compounds into different media as well as the bioactive properties of complexes were also studied. With the immobilization of bioactives onto ChS, increased and prolonged ABTS^•+ radical scavenging activity and decreased antifungal activity against Fusarium graminearum and Botrytis cinerea were observed compared to those of ChS. The findings of the current study highlight that the adsorption approach could be used to successfully prepare water-insoluble complexes of ChS and components of natural extracts with prolonged antioxidant activity.

Enhancing drying efficiency and quality of seed-used pumpkin using ultrasound, freeze-thawing and blanching pretreatments

Effects of blanching (BL), ultrasound (US) and freeze-thawing (FT) pretreatments prior to far-infrared drying (FIRD) on drying characteristics, water distribution, and quality parameters of seed-used pumpkin (SUP) slices were investigated in this study. US, BL and FT pretreatments significantly accelerated drying rate due to the destruction of cell structure. Modified Page model was the fittest model for predicting the FIRD process. Low field nuclear magnetic resonance (LF-NMR) results revealed that T₂ distribution curves of all pretreated samples moved rapidly to the positive x-axis direction, indicating an increase in the rate of water migration. The color of US-FIRD was closer to fresh SUP. BL-FIRD exhibited the highest free polyphenols content (241.28 ± 1.11 mg GAE/100 g DW) and total carotenoids content (129.69 ± 2.49 μg/ g DW), increasing by 45% and 34% respectively compared to the untreated sample.

Evidence for amylose inclusion complexes with multiple acyl chain lipids using solid-state NMR and theoretical approaches

Amylose is known to form inclusion complexes in the presence of hydrophobic guests. Among lipids, only single-chain fatty acids have been reported as possible guests with the surrounding amylose in a well-defined V-helix conformation. Using experimental ¹³C solid-state NMR, we studied the formation of inclusion complexes between amylose and a variety of multiple-chains lipids of increasing complexity. Molecular dynamics simulations and calculations of ¹³C isotropic chemical shifts using the Density Functional Theory approach were performed to support the interpretation of experimental spectra. We provide unambiguous evidences that amylose forms inclusion complexes with lipids bearing multiple acyl chains. Amylose conformations around these lipids are characterized by {ϕ,ψ} anomeric bond dihedral angles near {115°,105°}. In the ¹³C NMR spectra, this translates into C₁ and C₄ chemical shifts of 102.5 ppm and 81.1 ppm, regardless of the helical conformation of the amylose surrounding the acyl chains.

Starch inclusion complex for the encapsulation and controlled release of bioactive guest compounds

The linear component of starch, especially amylose, is capable of forming inclusion complex (IC) with various small molecules. It could significantly modify the structure and properties of starch, and it could bring beneficial effects when bioactive compounds can be encapsulated. This review discusses the formation and characterization of the starch-guest IC and focuses on the recent developments in the use of starch ICs for the encapsulation and controlled release of bioactive guest compounds. A great number of guest compounds, such as lipids, aroma compounds, pharmaceuticals, and phytochemicals, were studied for their ability to be complexed with starch and/or amylose and some of the formed ICs were evaluated for the chemical stability improvement and the guest release regulation. Starch-guest ICs has a great potential to be a delivery system, as most existing studies demonstrated the enhancement on guest retention and the possibility of controlled release.

Interactions between Phenolic Acids, Proteins, and Carbohydrates-Influence on Dough and Bread Properties

The understanding of interactions between proteins, carbohydrates, and phenolic compounds is becoming increasingly important in food science, as these interactions might significantly affect the functionality of foods. So far, research has focused predominantly on protein-phenolic or carbohydrate-phenolic interactions, separately, but these components might also form other combinations. In plant-based foods, all three components are highly abundant; phenolic acids are the most important phenolic compound subclass. However, their interactions and influences are not yet fully understood. Especially in cereal products, such as bread, being a nutritional basic in human nutrition, interactions of the mentioned compounds are possible and their characterization seems to be a worthwhile target, as the functionality of each of the components might be affected. This review presents the basics of such interactions, with special emphasis on ferulic acid, as the most abundant phenolic acid in nature, and tries to illustrate the possibility of ternary interactions with regard to dough and bread properties. One of the phenomena assigned to such interactions is so-called dry-baking, which is very often observed in rye bread.