Towards green chemicals and edible coatings from barks and peels with near critical extraction of suberin

peer reviewedDue to their complex structures, industrial suberoligneous by-products such as barks and peels remain poorly exploited. In this study, we demonstrated the efficient extraction of suberin from barks (11.3%) and peels (20.85%) via supercritical and near-supercritical transesterification without the need for catalysts. When applied in non-isocyanate polyurethane (NIPU) foams, suberinic extracts allowed the increase of the biomass content by up to 20% and facilitated the foaming process by improving pre-curing viscosity. When sprayed on fruits, the suberinic extracts effectively reduced the water loss rate by 25%, extending the shelf-life of the produce. A life cycle analysis for the latter application confirmed the competitive potential of our process against plastic sealing. This work uncovers the potential of suberoligneous biomass (SBM) to provide sustainable solutions to emerging societal challenges

Highlighting a New Morphospecies within the Dialium Genus Using Leaves and Wood Traits

peer reviewedDuring inventories of lesser-known timber species in eastern Gabon, a new Dialium morphospecies was discovered. To discriminate it from the two other 2–5 leaflets Dialium species, 25 leaf traits were measured on 45 trees (16 Dialium pachyphyllum, 14 Dialium lopense, 15 Dialium sp. nov.). Nine wood chemical traits, as well as infrared spectra, were also examined on harvestable trees (four Dialium pachyphyllum and four Dialium sp. nov.). This study revealed seven discriminant leaf traits that allowed to create a field identification key. Nine significant differences (five in sapwood and four in heartwood) in terms of wood composition were highlighted. The use of the PLS-DA technique on FT-IR wood spectra allowed to accurately identify the new morphospecies. These results provide strong support for describing a new species in this genus. Implications for sustainable management of its populations are also discussed.Essence à Haut Potentiel de Valorisation (EHPva

Dosage de l'asparagine par spectrophotométrie au sein d'une matrice complexe

In this study we show, on 15 wheat varieties, the ability to assay the asparagine content in a complex matrix such as wheat flour by a simple spectrophotometric assay. This method is easier, faster and cheaper than conventional chromatography analysis and allow to discriminate quickly which materials has high or low level of this amino acid. Asparagine is an amino acid present in free form in the food biomass and has the property of reacting with the free sugars during the Maillard reactions that occur during baking at temperatures above 120°C. The Acrylamide resulting from this reaction chain has been identified as reprotoxic, genotoxic and carcinogenic in animals since 1986. The present method allowed us to identify wheat varieties with significantly lower or higher asparagine contents (α=0.05). Therefore, this method can be used to identify wheat varieties or other plants with low asparagine content to use preferentially in products designed for food

Identification de variétés de blé à faible potentiel d'acrylamide

Maillard reactions are responsible for the formation of many compounds in food that have been baked at temperatures above 120°C1. Some of these compounds are sought for their contribution to the organoleptic qualities of food but others, such as acrylamide, have been identified since 1986 as reprotoxic, genotoxic and carcinogenic in animals2. Synthesized from a chain reaction between free sugars and free asparagine, acrylamide has been found in many food such as products prepared from wheat flour1,3,4. The correlation between the amount of free sugars and free asparagine in raw food with the acrylamide content in the baked food has been well documented5. For this reason we compared the levels of 15 wheat varieties and identified wheat varieties with significantly lower level (=0.05) in acrylamide precursors. Those varieties could therefore be used preferentially in products intended for food

Suberin isolation : A better way to valorize potato peels

The present study describes a cost-effective method to enzymatically isolate suberin from potato peels. Over the 2 800 000 tons of potatoes harvested annually in Belgium, two-thirds enters into the food industry[1]. Potato peels are the most abundant byproducts of the processing and accounts for 10 to 15% of the processed potatoes amount[1]. Due to its content in water, starch and protein, this byproduct has been historically used in animal feed[1]. This use only adds a limited commercial value and exploitation of suberin and suberin-associated waxes, which are major components of potato peels[2], has so far been limited. Suberin is a waxy polymer known to be an important part in cork[3] and that is expected to have a wide variety of applications such as paints, inks[4], glues, biosourced materials[3],[4], rubbers and even in cosmetics. Today, suberin applications are mainly limited by the resilience of cork that makes suberin extraction too expensive and polluting to be commercially viable. With the proposed method only three days were required to isolate the suberin-rich fraction from potato peels by using a cocktail of cellulase and pectinase. After filtration, microscopic observation of the suberin-riche fraction after staining with Sudan red 7B shown that only the suberized portions of the cell matrix were left undigested. The isolated suberin can then be used as a raw material or be depolymerized to conform to a specifics application. This method represents a reliable, easy and cost-effective way to isolate suberin for potential commercial and industrial applications

Development of a sustainable method for the extraction of suberin-related compounds from biomass using supercritical transesterification

Suberin is a biopolyester which has a unique molecular diversity in long chain aliphatic molecules such as omega-hydroxyacids, alpha,omega-dicarboxyacids and their derivatives carrying functionnalities1. However, the use of suberin as a source of building blocks on an industrial scale for the development of new products and materials is hampered by the chemical resilience of suberin. Of all the methods that have been developed to depolymerize and extract suberin, transesterification is one of the most effective methods. However, it has the drawbacks of requiring a catalyst, of being sensitive to water and free fatty acids and of requiring a long purification thereafter. This work is based on the development of a SCTE (supercritical transesterification) method which offers the advantages of being tolerant to the presence of water and free fatty acids while being catalyst-free2. As a result, SCTE allowed to successfully extracting suberin from potato peels, cassava peels and oak bark in less than 1 hour with a high selectivity thus limiting the need for purification. The results also show that by adjusting the duration of the treatment it is possible to obtain a total or partial depolymerization depending on the desired final product. SCTE is therefore a promising method to obtain suberin monomer mixture at a large scale. (1) Gandini, A.; Neto, C. P.; Silvestre, A. J. D. Suberin: A Promising Renewable Resource for Novel Macromolecular Materials. Prog. Polym. Sci 2006, 31, 878–892. https://doi.org/10.1016/j.progpolymsci.2006.07.004. (2) Karki, S.; Sanjel, N.; Poudel, J.; Choi, J. H.; Oh, S. C. Supercritical Transesterification of Waste Vegetable Oil: Characteristic Comparison of Ethanol and Methanol as Solvents. Appl. Sci. 2017, 7 (6). https://doi.org/10.3390/app7060632

Lignocellulosic fibres surface interactions in enzymatic reaction using data-mining

peer reviewedLignocellulosic fibres modification focused so far essentially on the resulting material properties to create functional fibres instead of determining the reaction influencing parameters. Using a data-mining algorithm, surface chemical composition of the fibres after modifications was compared to multiple signals. A 24 h reaction at either 25 °C or 60 °C, pH5 was conducted in presence of trans-ferulic acid, laccase, and lignocellulosic fibres (flax, hemp, or cellulose) having different chemical surface composition. Dimers and trimers were detected in variable concentrations in the reaction filtrate and extractive. At 25 °C, crystalline cellulose, amorphous cellulose, xylans, mannans, and lignins were well correlated to specific reaction products while at 60 °C, only lignins and xylan were found correlated to reaction products. Fibres surface composition affected the extractive profile. Lignocellulosic surface composition influence on the product formed was unveiled using a data mining approach. This study presents a way to unveil non-evident chemical interface interaction in reactions

A method for rapid and homogenous initiation of post-harvest physiological deterioration in cassava storage roots identifies Indonesian cultivars with improved shelf-life performance

Abstract Cassava is the most cultivated and consumed root crop in the world. One of the major constraints to the cassava value chain is the short shelf life of cassava storage roots which is primarily due to the so-called post-harvest physiological deterioration (PPD). The identification of natural sources of PPD tolerance represents a key approach to mitigating PPD losses by generating farmer- and industry-preferred cassava cultivars with prolonged shelf life. In the present study, a PPD assessment method was developed to screen for PPD tolerance in the cassava germplasm. The proposed PPD assessment method displayed a reduced rate of microbial infection and allowed a rapid and homogenous development of typical PPD symptoms in the cassava storage roots. We successfully used the PPD assessment method in combination with an image-based PPD scoring method to identify and characterize PPD tolerance in 28 cassava cultivars from the Indonesian cassava germplasm. Our analysis showed a significant and positive correlation between PPD score and dry matter content (r = 0.589–0.664, p-value < 0.001). Analysis of additional root parameters showed a significant and positive correlation between PPD scores at 2 days post-harvest (dph) and root length (r = 0.388, p-value < 0.05). Our analysis identified at least 4 cultivars displaying a significantly delayed onset of PPD symptoms as compared to the other selected cultivars. The availability of cassava cultivars contrasting for tolerance to PPD will be particularly instrumental to understanding the molecular mechanisms associated with delayed PPD in cassava roots

Nonconventional enzymatic method to determine free asparagine level in whole-grain wheat

A new enzymatic methodology is herein proposed to measure free asparagine content in wheat grains and to predict their potential for Maillard reaction products. Our model estimates the acrylamide levels generated during the industrial heat treatment of whole-grain wheat based on free asparagine and glucose measurements. We selected fifteen wheat varieties currently grown in Belgium as benchmark for the present study. While conventional chromatographic methods require a long and tedious multi-step sample preparation, the proposed method takes advantage of being simple and quick. Statistical analysis of free asparagine content indicates that selected wheat varieties can be classified into seven content levels from 0.0149% to 0.0216% of the dry matter. Based on our analysis, the varieties KWS Ozon, Benchmark and Pionier appears to be the most suitable for thermal processing (i.e. cooking applications)