Production of nutraceutics from chestnut burs by hydrolytic treatment

Ellagitannin Content in Extracts of the Chestnut Wood Aesculus

The chestnut tree (Castanea sativa Mill.) is a widespread plant in Europe, rich in high-value compounds, which can be divided mainly into monomeric polyphenols and tannins. These compounds exhibit various biological activities, such as antioxidant, as well as anticarcinogenic and antimicrobial properties. Chestnut wood (CW) extracts were prepared using different extraction techniques, process conditions, solvents, and their mixtures. This work aimed to test various extraction techniques and determine the optimal solvent for isolating enriched fractions of vescalagin, castalagin, vescalin, and castalin from CW residues. Supercritical CO2 extraction with a more polar cosolvent was applied at different pressures, which influenced solvent density. According to the results, the proportions of the components strongly depended on the solvent system used for the extraction. In addition, HPLC-DAD was used for semiqualitative purposes to detect vescalagin, castalagin, vescalin, and castalin. The developed valorization protocol allows efficient fractionation and recovery of the polyphenolic components of CW through a sustainable approach that also evaluates pre-industrial scaling-up.

Utilization of Cumbeba (Tacinga inamoena) Residue: Drying Kinetics and Effect of Process Conditions on Antioxidant Bioactive Compounds

The residue generated from the processing of Tacinga inamoena (cumbeba) fruit pulp represents a large amount of material that is discarded without proper application. Despite that, it is a raw material that is source of ascorbic acid, carotenoids and phenolic compounds, which are valued in nutraceutical diets for allegedly combating free radicals generated in metabolism. This research paper presents a study focused on the mathematical modeling of drying kinetics and the effect of the process on the level of bioactive of cumbeba residue. The experiments of cumbeba residue drying (untreated or whole residue (WR), crushed residue (CR) and residue in the form of foam (FR)) were carried out in a fixed-bed dryer at four air temperatures (50, 60, 70 and 80 °C). Effective water diffusivity (Deff) was determined by the inverse method and its dependence on temperature was described by an Arrhenius-type equation. It was observed that, regardless of the type of pretreatment, the increase in air temperature resulted in higher rate of water removal. The Midilli model showed better simulation of cumbeba residue drying kinetics than the other models tested within the experimental temperature range studied. Effective water diffusivity (Deff) ranged from 6.4890 to 11.1900 × 10-6 m2/s, 2.9285 to 12.754 × 10-9 m2/s and 1.5393 × 10-8 to 12.4270 × 10-6 m2/s with activation energy of 22.3078, 46.7115 and 58.0736 kJ/mol within the temperature range of 50-80 °C obtained for the whole cumbeba, crushed cumbeba and cumbeba residue in the form of foam, respectively. In relation to bioactive compounds, it was observed that for a fixed temperature the whole residue had higher retention of bioactive compounds, especially phenolic compounds, whereas the crushed residue and the residue in the form of foam had intermediate and lower levels, respectively. This study provides evidence that cumbeba residue in its whole form can be used for the recovery of natural antioxidant bioactive compounds, mainly phenolic compounds, with the possibility of application in the food and pharmaceutical industries.

Subcritical Water Extraction of Chestnut Bark and Optimization of Process Parameters

The aim of the work was the optimization of the subcritical water extraction process of chestnut bark using Box–Behnken response surface methodology. The influence of process parameters, such as temperature, extraction time and solvent-solid ratio, on extraction yield, yield of the main compounds, total phenol content, total tannin content and antioxidant activity has been investigated. The identified compounds were ellagic and gallic acids, ellagitannins (vescalagin, castalagin, 1-o-galloyl castalagin, vescalin and castalin), sugars (maltose, glucose, fructose and arabinose) and sugar derivatives (5-HMF, furfural and levulinic acid). Finally, the optimal process conditions for obtaining the bark extract highly rich in ellagic acid and with satisfactory levels of total phenols and total tannins have been determined.

Content of Phenolic Compounds and Antioxidant Activity of New Gluten-Free Pasta with the Addition of Chestnut Flour

Chestnut fruit abounds in carbohydrates, proteins, unsaturated fatty acids, fiber, polyphenolic compounds, as well as vitamins and micronutrients, that are behind the health-promoting properties of this plant. The purpose of the discussed research was to obtain innovative gluten-free pasta from rice and field bean flour enriched with a various addition of chestnut flour. Regarding the studied pasta, the following were determined: the content of free phenolic acids, total polyphenols, and antioxidant properties. Chromatographic analysis (HPLC-ESI-MS/MS (high-performance liquid chromatography-electrospray ionization tandem mass spectrometry)) revealed a wide variety of phenolic acids. In a sample with 20% and higher content of chestnut flour, as many as 13 acids were detected. Isoferulic acid prevailed. The total content of free phenolic acids and total polyphenols increased along with the increasing chestnut content. Moreover, in most cases, the content of individual acids increased with the addition of chestnut flour. Besides, the antioxidant activity was positively correlated with the addition of chestnut fruit flour, the content of free phenolic acids, and total polyphenols. Our research has demonstrated that our innovative gluten-free pasta, with the addition of chestnut flour, has a potential to be a source of polyphenolic compounds, including free phenolic acids, that are valuable for human health.