Influence of Cardboard Pretreatment on the Determination of Starch Content by the Enzymatic Method

We determined the amount of starch by the enzymatic method in different samples of corrugated cardboard, including the sample produced of primary semi-finished products and corrugated cardboard made of 100 % waste paper. For starch enzymatic degradation, it is necessary to extract it from the corrugated board structure, since the processes of compression and keratinization of pulp fibers reduce the availability of starch for extraction. Enzymatic treatment requires the use of a complex amylolytic preparation for complete hydrolysis of starch to glucose. We were able to determine, respectively, 70 and 84 % of starch obtained from primary semi-finished products by mechanical methods, such as defibrillation in water and degradation in a liquid nitrogen medium, and added at the production stage of corrugated cardboard. It was shown that extraction with alkaline agents was necessary for more complete extraction of starch from corrugated cardboard. The influence of alkaline treatment on the characteristics of fibers of waste paper fractions obtained at the Sukhonsky Cardboard and Paper Mill has been analyzed. The fibers swell in alkali, resulting in an increase in fiber width and its shortening, as well as a decrease in crystallinity, which can be a positive opportunity for more complete starch extraction. Fiber swelling and crystallinity reduction are more intensive for the short fiber fraction compared to the long fiber fraction. When determining starch in corrugated cardboard using the standard method SCAN-P 91:09 SСAN-W 13:09 it was not possible to detect all the starch added at the production stage of corrugated cardboard from primary semi-finished products. Also the processing conditions of this methodology lead to degradation of the partially hydrolyzed starch. The most complete extraction of starch from corrugated cardboard was achieved by two stages of alkaline extraction under the following conditions: 5 % NaOH, temperature of 20 °C, the duration of each extraction – 2 h. Under these processing conditions it was possible to determine all the starch (22.8 kg/t) in the corrugated cardboard produced of primary semi-finished products with known consumption of starch; the starch content in the corrugated cardboard produced of 100 % waste paper was 48.2 kg/t. For citation: Khadyko I.A., Novozhilov E.V., Chukhchin D.G. Influence of Cardboard Pretreatment on the Determination of Starch Content by the Enzymatic Method. Lesnoy Zhurnal [Russian Forestry Journal], 2021, no. 5, pp. 150–162. DOI: 10.37482/0536-1036-2021-5-150-162

Coffee Silver Skin: Chemical Characterization with Special Consideration of Dietary Fiber and Heat-Induced Contaminants

Coffee silver skin is produced in large amounts as a by-product during the coffee roasting process. In this study, coffee silver skin of the species Coffea arabica L. and Coffea canephora Pierre ex A. Froehner as well as silver skin pellets produced in the coffee industry were characterized with respect to both nutritional value and potential heat-induced contaminants. Enzymatic-gravimetric/chromatographic determination of the dietary fiber content showed values ranging from 59 to 67 g/100 g with a comparably high portion of soluble fiber, whereas low molecular weight soluble fiber was not detected. Compositional and methylation analysis indicated the presence of cellulose and xylans in the insoluble dietary fiber fraction, whereas pectic polysaccharides dominate the soluble dietary fiber fraction. The protein content as determined by the Kjeldahl method was in the range of 18 to 22 g/100 g, and all essential amino acids were present in coffee silver skin; whereas fat contents were low, high ash contents were determined. Elemental analysis by inductively coupled plasma mass spectrometry (ICP-MS) showed the presence of macroelements in large amounts, whereas toxic mineral elements were only detected in trace amounts or being absent. Acrylamide was quantified with levels of 24–161 µg/kg. Although 5-hydroxymethylfurfural was detected, its concentration was below the limit of determination. Furfuryl alcohol was not detected.

Italian Ryegrass (Lolium multiflorum Lam.) Fiber Fraction Content and Dry Matter Digestibility Following Biostimulant Application against the Background of Varied Nitrogen Regime

An experiment was conducted to determine the effect of an application of biostimulants, against the background of varied nitrogen regime, on the share of neutral detergent fraction (NDF), acid detergent fraction (ADF), and acid detergent lignin (ADL) in the crude fiber fraction of Italian ryegrass as well as its digestibility. A field experiment was arranged as a randomized subblock design (split-plot) with three replicates at the Siedlce Experimental Unit of the University of Natural Sciences and Humanities in Poland in 2013. The following factors were examined: type of biostimulant: Algex, Tytanit, Asahi SL and a control; nitrogen application rate: 0 (control); 120 and 180 kg·ha−1. There were confirmed positive effects resulting from an application of biostimulants in Italian ryegrass cultivation. There was confirmed the assumed hypothesis that an application of both natural and synthetic biostimulants will make it possible to improve the feeding value of grasses by reducing the fiber fraction. Particular attention should be paid to the biostimulant Algex whose application in Italian ryegrass cultivation produced the most beneficial response in terms of the share of NDF, ADF, and ADL fractions, which resulted in the greatest increase in the plant dry matter digestibility. Increasing nitrogen rates significantly reduced the quantity of analyzed fiber fractions, and increased grass digestibility.

Maize Silage Pretreatment via Steam Refining and Subsequent Enzymatic Hydrolysis for the Production of Fermentable Carbohydrates

Maize, also called corn, is one of the most available feedstocks worldwide for lignocellulosic biorefineries. However, a permanent biomass supply over the year is essential for industrial biorefinery application. In that context, ensiling is a well-known agricultural application to produce durable animal feed for the whole year. In this study, ensiled maize was used for steam refining experiments with subsequent enzymatic hydrolysis using the Cellic® CTec2 to test the application possibilities of an ensiled material for the biorefinery purpose of fermentable carbohydrate production. Steam refining was conducted from mild (log R0 = 1.59) to severe conditions (log R0 = 4.12). The yields were determined, and the resulting fractions were characterized. Hereafter, enzymatic hydrolysis of the solid fiber fraction was conducted, and the carbohydrate recovery was calculated. A conversion to monomers of around 50% was found for the mildest pretreatment (log R0 = 1.59). After pretreatment at the highest severity of 4.12, it was possible to achieve a conversion of 100% of the theoretical available carbohydrates. From these results, it is clear that a sufficient pretreatment is necessary to achieve sufficient recovery rates. Thus, it can be concluded that ensiled maize pretreated by steam refining is a suitable and highly available feedstock for lignocellulosic biorefineries. Ultimately, it can be assumed that ensiling is a promising storage method to pave the way for a full-year biomass supply for lignocellulosic biorefinery concepts.

Nutritional Quality And Fiber Fraction Of Complete Feed Silage Based On Sago By-Products, Imperata Cylindrica And Leucaena Leucocephala

This experiment aimed to know nutrition quality and fiber fraction of complete feed silage based on sago by-products, Imperata cylindrica, and Leuchaena leucocephala in different compositions which fermented for three weeks. The study was conducted at the Laboratory of Feed Engineering and Technology, Faculty of Agriculture, University of Pattimura which lasted for three months. The main ingredients used to make silage complete ration in this study consisted of sago pulp, reeds, lamtoro, concentrate and plus coconut water. Complete ration silage fermented using coconut water plus which is a mixture of urea 95% and coconut water 5%. This research conducted by using randomized complete design with five factors of silage compound that are P0 = 60% forages + 40% concentrate (for control) ; P1 = 10% sago by-products + 40% Imperata cylindrical + 10% Leucaena Leucocephala + 40% concentrate ; P2 = 20% sago by-products + 30% Imperata cylindrica + 20 % Leucaena Leucocephala + 30% concentrate ; P3 = 30 % sago by-products + 20% Imperata cylindrica + 30 % Leucaena Leucocephala + 20% consentrate ; dan P4 = 40% sago by-products + 10% Imperata cylindrica + 40% Leucaena Leucocephala + 10% concentrate. Each treatment used four replicates. The variable observed were the percentage of water content, ash, crude protein, crude fat, crude fiber, NDF, ADF, and lignin. The results showed that sago by-products, Imperata cylindrica and Leuchaena leucocephala can be used for basic materials of complete feed silage in ruminants feed because they have no difference quality of nutrition and fiber fraction compared with control P0.

Structural organization in palm stems of Roystonea regia and Archontophoenix alexandrae

Having a high stature subjects palms to the same constraints as trees, but the lack of cambial growth urges them to adopt a different strategy. We aimed to characterize the spatial organization of xylem tissues and their potential functions in two palm stems: a 30 cm diameter at breast height (DBH) royal palm (Roystonea regia) and a 12 cm DBH Alexandra king palm (Archontophoenix alexandrae). Macroscopic and microscopic anatomical characteristics were assessed at five vertical locations and 5–6 radial locations at each height. Over 9600 vessels across the two stems were drawn manually and measured based on histological sections. Vertically, a hydraulic bottleneck was identified at the first meter, and both stems showed conduit tapering from 4 m to the top. Radially, most water transport and mechanical support were achieved within 2–5 cm below the bark. The larger stem diameter of royal palm may have improved its water transport, storage, and potential for mechanical support compared to king palm. There was a strong trade-off between ground parenchyma and the fiber fraction. However, the correlation between theoretical hydraulic conductivity (Kt) and the ground parenchyma fraction, and between Kt and the fiber fraction, shifted from positive or non-significant below the bark, to strongly negative close to the center. These changes reflect the functional sectoriality of the palm stems, which may reduce the constraint of trade-offs between water transport, storage, and mechanical support. To conclude, functional sectoriality may have helped both palm species to withstand the hydraulic and mechanical constraints due to high stature.

A Micromechanical Fatigue Limit Stress Model of Fiber-Reinforced Ceramic-Matrix Composites under Stochastic Overloading Stress

Fatigue limit stress is a key design parameter for the structure fatigue design of composite materials. In this paper, a micromechanical fatigue limit stress model of fiber-reinforced ceramic-matrix composites (CMCs) subjected to stochastic overloading stress is developed. The fatigue limit stress of different carbon fiber-reinforced silicon carbide (C/SiC) composites (i.e., unidirectional (UD), cross-ply (CP), 2D, 2.5D, and 3D C/SiC) is predicted based on the micromechanical fatigue damage models and fatigue failure criterion. Under cyclic fatigue loading, the fatigue damage and fracture under stochastic overloading stress at different applied cycle numbers are characterized using two parameters of fatigue life decreasing rate and broken fiber fraction. The relationships between the fatigue life decreasing rate, stochastic overloading stress level and corresponding occurrence applied cycle number, and broken fiber fraction are analyzed. Under the same stochastic overloading stress level, the fatigue life decreasing rate increases with the occurrence applied cycle of stochastic overloading, and thus, is the highest for the cross-ply C/SiC composite and lowest for the 2.5D C/SiC composite. Among the UD, 2D, and 3D C/SiC composites, at the initial stage of cyclic fatigue loading, under the same stochastic overloading stress, the fatigue life decreasing rate of the 3D C/SiC is the highest; however, with the increasing applied cycle number, the fatigue life decreasing rate of the UD C/SiC composite is the highest. The broken fiber fraction increases when stochastic overloading stress occurs, and the difference of the broken fiber fraction between the fatigue limit stress and stochastic overloading stress level increases with the occurrence applied cycle.