Thermal degradation of modified pectin samples with varying molecular structure during storage was recently studied at 60 °C and 80% relative humidity (rh) for 28 days. Demethoxylation and depolymerisation were identified as main degradation reactions. The present paper aims on improving the understanding of the different depolymerisation reactions and their interplay with demethoxylation during storage. Therefore, thermal degradaton of acidic and alkaline demethoxylated pectins was studied at a further reduced rh of 40%. The alterations were examined in detail via molecular parameters and were reflected by Differential scanning calorimetry and attenuated total reflectance Fourier-transformation infrared spectroscopy. The impact of thermal degradation on pectin particle structure was studied via particle surface area and microscopy.At low relative humidity (rh) demethoxylation and depolymerisation were reduced, and the formation of brown reaction products, resulting from further decomposition of intermediate uronides and neutral sugars, was restricted. By comparing thermal degradation at different humidity, eliminative decarboxylation was identified as the main depolymerisation reaction.Reduction of rh affected also the alteration of pectin material properties, particle surface reduction was less pronounced. Molecular alterations were stronger in case of acidic demethoxylated samples, and alterations of material properties were higher in case of alkaline demethoxylated samples.

The European Commission funded project Stance4Health (S4H) aims to develop a complete personalised nutrition service. In order to succeed, sources of information on nutritional composition and other characteristics of foods need to be as comprehensive as possible. Food composition tables or databases (FCT/FCDB) are the most commonly used tools for this purpose. The aim of this study is to describe the harmonisation efforts carried out to obtain the Stance4Health FCDB. A total of 10 FCT/FCDB were selected from different countries and organizations. Data were classified using FoodEx2 and INFOODS tagnames to harmonise the information. Hazard analysis and critical control points analysis was applied as the quality control method. Data were processed by spreadsheets and MySQL. S4H’s FCDB is composed of 880 elements, including nutrients and bioactive compounds. A total of 2648 unified foods were used to complete the missing values of the national FCDB used. Recipes and dishes were estimated following EuroFIR standards via linked tables. S4H’s FCDB will be part of the smartphone app developed in the framework of the Stance4Health European project, which will be used in different personalized nutrition intervention studies. S4H FCDB has great perspectives, being one of the most complete in terms of number of harmonized foods, nutrients and bioactive compounds included.

Material properties, gelation and storage stability of demethoxylated pectin samples strongly varied in dependence on the applied modification method. It was assumed that the content of sodium ions and their resulting electrostatic interactions with free carboxyl groups were crucial for these differences. Sodium ions were widely removed by acidic modification but added during alkaline and enzymatic modification using NaOH in a pH-stat method. It was the aim of the present study to investigate the individual impact of sodium ions on pectin properties using samples with similar molecular parameters but different sodium ion content.Sodium enrichment of pectin increased the pectin particle surface and, as a consequence, the pectinwater-interactions. Differences in molecular structure and material properties were reflected in simultaneous thermal analysis; an exothermic starting peak in DSC vanished and pectin pyrolysis was accelerated after sodium ion enrichment. Gel formation was affected by sodium ions. It was delayed in a sugar-acid system by reducing the number of hydrogen bonds and accelerated in a sugar-calcium system by reducing electrostatic repulsion. Sodium ions increased the storage stability of pectin. They were bound to free carboxyl groups (-COONa) and restricted degradation reactions during storage which required these groups, in particular depolymerisation by decarboxylation.

Unhealthy diets represent a major risk for the pathogenesis of metabolic and chronic inflammatory diseases. Improving the quality of diet is important to prevent chronic diseases, and diet-induced modifications of the gut microbiota (GM) community likely play an important role. The EU-funded Stance4Health project aims at performing a randomized clinical trial based on a nutritional intervention program in the context of normal weight and overweight adults as well as children with obesity and gluten-related disorders or allergy/intolerance to cow’s milk. The trial will evaluate the efficacy of a Smart Personalised Nutrition (SPN) service in modifying GM composition and metabolic function and improving consumer empowerment through technology adoption.

Past investigations have shown high browning potential during the caramelization of sugar acids in comparison to reducing sugars. However, no approaches to elucidate the chemical mechanisms have been made. Therefore, this study aims to clarify the reasons for the high browning potential by measuring the mutarotation velocity and the elimination of CO2 during the heat treatment of uronic acids. Performed polarimetric experiments show that the mutarotation velocity of d-galacturonic acid exceeds that of d-galactose by a factor of nearly 4.5. However, the ring opening velocity is not the only parameter that differs between the two carbohydrate structures. Measurements of the release of CO2 of heated d-galacturonic acid at 60 °C show a steady increase, and after 48 h, 6% of degraded d-galacturonic acid has eliminated CO2. CO2 release was also found during the heating of pectin, indicating a decarboxylation reaction during thermal degradation. One of the degradation reactions postulated for the release of CO2 leads to α-ketoglutaraldehyde, which is responsible for the formation of several chromophoric substances.

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