Plant-based foods gain more importance since they play a key role in sustainable, low-meat and healthy diets. In developing countries, these food products, especially legumes and cereals, are important staple foods. Nevertheless, the question arises on how efficient they are to deliver minerals and if it is useful to encourage their consumption to reduce the prevalence of mineral deficiencies? This review paper focuses on the discrepancy between the mineral content and the amount of minerals that can be released and absorbed from plant-based foods during human digestion which can be attributed to several inherent factors such as the presence of mineral antinutrients (phytic acid, polyphenols and dietary fiber) and physical barriers (surrounding macronutrients and cell wall). Further, this review paper summarizes the effects of different processing techniques (milling, soaking, dehulling, fermentation, germination and thermal processing) on mineral bioaccessibility and bioavailability of plant-based foods. The positive impact of these techniques mostly relies on the fact that antinutrients levels are reduced due to removal of fractions rich in antinutrients and/or due to their leaching into the processing liquid.Although processing can have a positive effect, it also can induce leaching out of minerals and a reduced mineral bioaccessibility and bioavailability.

Pectin is an anionic cell wall polysaccharide which is known to interact with divalent cations via its nonmethylesterified galacturonic acid units. Due to its cation‐binding capacity, extracted pectin is frequently used for several purposes, such as a gelling agent in food products or as a biosorbent to remove toxic metals from waste water. Pectin can, however, possess a large variability in molecular structure, which influences its cation‐binding capacity. Besides the pectin structure, several extrinsic factors, such as cation type or pH, have been shown to define the cation binding of pectin. This review paper focuses on the research progress in the field of pectin‐divalent cation interactions and associated functional properties. In addition, it addresses the main research gaps and challenges in order to clearly understand the influence of pectin structural properties on its divalent cation‐binding capacity and associated functionalities. This review reveals that many factors, including pectin molecular structure and extrinsic factors, influence pectin–cation interactions and its associated functionalities, which makes it difficult to predict the pectin–cation‐binding capacity. Despite the limited information available, determination of the cation‐binding capacity of pectins with distinct structural properties using equilibrium adsorption experiments or isothermal titration calorimetry is a promising tool to gain fundamental insights into pectin–cation interactions. These insights can then be used in targeted pectin structural modification, in order to optimize the cation‐binding capacity and to promote pectin–cation interactions, for instance for a structure build‐up in food products without compromising the mineral nutrition value.

The present study aimed at gaining insight into the potential of citrus pectin to bind Fe 2+ , a cation of great importance in a several food products. In particular the role of citrus pectin structural properties, namely the degree of methylesterification (DM) and the absolute degree of blockiness (DBabsratio of non-methylesterified GalA units present in blocks to the total amount of GalA units) on the Fe 2+ adsorption in aqueous solution was explored using adsorption isotherms. Demethylesterification of high DM citrus pectin enzymatically (using plant pectin methylesterase) or chemically (alkaline demethylesterification using NaOH) generated P-and C-pectins, respectively, characterized by comparable DMs but different distributions of nonmethylesterified GalA units (DBabs). Adsorption isotherms of P-and C-pectins in aqueous solutions of various Fe 2+ concentrations revealed that both the DM and DBabs influenced the pectin-Fe 2+ interactions: the lower DM or higher DBabs, the higher the Fe 2+ binding capacity of citrus pectin. The Langmuir adsorption model was used to fit the experimental data for quantification of the maximum adsorption capacity (q G max) and the pectin-Fe 2+ interaction energy (KL) of the P-and C-pectins. It can be concluded that q G max (mol Fe 2+ /mol GalA) was mainly determined by the DM and to a lesser extent by the DBabs while the pectin-Fe 2+ interaction energy was mainly influenced by the DBabs. As a consequence, pectin modification to obtain targeted DM and DBabs allows optimization of its binding capacity and therefore the associated functional properties.

Interactions between citrus pectin and Zn 2+ or Ca 2+ and associated in vitro Zn 2+ bioaccessibility as affected by degree of methylesterification and blockiness,

The present work explored the lipid antioxidant capacity of citrus pectin addition to 5%(w/v) linseed/sunflower oil emulsions stabilized with 0.5%(w/v) Tween 80, as affected by pectin molecular characteristics. The peroxide formation in the emulsions, containing tailored pectin structures, was studied during two weeks of storage at 35°C. Low demethylesterified pectin (≤33%) exhibited a higher antioxidant capacity than high demethylesterified pectin (≥58%), probably due to its higher chelating capacity of pro-oxidative metal ions (Fe), whereas the distribution pattern of methylesters along the pectin chain only slightly affected the antioxidant capacity. Nevertheless, pectin addition to the emulsions caused emulsion destabilization probably due to depletion or bridging effect, independent of the pectin structural characteristics. These results evidence the potential of structurally modified citrus pectin as a natural antioxidant in emulsions. However, optimal conditions for emulsion stability should be carefully selected.