Conventional Extraction Methods Research Articles

Environmentally Friendly Techniques for the Recovery of Polyphenols from Food By-Products and Their Impact on Polyphenol Oxidase: A Critical Review

Even though food by-products have many negative financial and environmental impacts, they contain a considerable quantity of precious bioactive compounds such as polyphenols. The recovery of these compounds from food wastes could diminish their adverse effects in different aspects. For doing this, various nonthermal and conventional methods are used. Since conventional extraction methods may cause plenty of problems, due to their heat production and extreme need for energy and solvent, many novel technologies such as microwave, ultrasound, cold plasma, pulsed electric field, pressurized liquid, and ohmic heating technology have been regarded as alternatives assisting the extraction process. This paper highlights the competence of mild technologies in the recovery of polyphenols from food by-products, the effect of these technologies on polyphenol oxidase, and the application of the recovered polyphenols in the food industry.

Novel Approaches in Green Extraction for Natural Medicines

Green extraction is based on discovery and design of extraction process which will reduce unit operation, reduce energy consumption, reduce time consumption, reduce organic solvent use, alternate solvent with water or agro-solvent and ensure safe and high-quality extract. In this study the conventional extraction methods and various green extraction methods were compared. Both these studies on extraction process were done in the past, in this review those studies were compared. From this we can know that which method is suitable for extraction which will not harmful for the environment, promote the health of patient, produce by-product or co-product instead of waste.

High-quality instant black tea manufactured using fresh tea leaves by two-stage submerged enzymatic processing

Repeated thermal treatment could impair the flavor of instant black tea (IBT) as the volatile compounds and characteristic constituents dramatically vary during the manufacturing process. Utilization of fresh leaves as raw material in IBT manufacture at low temperature may become an alternative to conventional extraction methods. This study aimed to improve the quality of IBT using fresh tea leaves by a two-stage enzymatic processing. The influence of combined enzymatic oxidation and extraction conditions for maximal extractable flavour (taste and aroma) characteristics from fresh tea leaves were investigated. The changes of aroma profiles and chemical constituents including theaflavins (TFs), thearubigins (TRs), theabrownines (TBs) and TRs/TFs ratio in converted tea brews under two-stage enzyme catalyzed fermentation and extraction conditions were further compared between different treatments, based on which the optimised conditions were determined. During the two-stage enzymatic processing, 75 kinds of volatile compounds were identified in all processed samples, and the contents of TFs, TRs, TBs and TRs/TFs ratio could be optimized by adjusting different procedures and parameters. The overall properties of final product were compared with two types of commercial IBT. High quality IBT with desired properties and antioxidant activity can be manufactured using fresh tea leaves by two-stage enzymatic processing approach.

An Edible Oil Enriched with Lycopene from Pink Guava (Psidium guajava L.) Using Different Mechanical Treatments.

According to the regulations of the United States Food and Drug Administration (FDA), organic solvents should be limited in pharmaceutical and food products due to their inherent toxicity. For this reason, this short paper proposes different mechanical treatments to extract lycopene without organic solvents to produce an edible sunflower oil (SFO) enriched with lycopene from fresh pink guavas (Psidium guajava L.) (FPGs). The methodology involves the use of SFO and a combination of mechanical treatments: a waring blender (WB), WB+ high-shear mixing (HSM) and WB+ ultrafine friction grinding (UFFG). The solid:solvent (FPG:SFO) ratios used in all the techniques were 1:5, 1:10 and 1:20. The results from optical microscopy and UV–vis spectroscopy showed a correlation between the concentration of lycopene in SFO, vegetable tissue diameters and FPG:SFO ratio. The highest lycopene concentration, 18.215 ± 1.834 mg/g FPG, was achieved in WB + UFFG with an FPG:SFO ratio of 1:20. The yield of this treatment was 66% in comparison to the conventional extraction method. The maximal lycopene concentration achieved in this work was significantly higher than the values reported by other authors, using high-pressure homogenization for tomato peel and several solvents such as water, SFO, ethyl lactate and acetone.

MS-IDF: A Software Tool for Nontargeted Identification of Endogenous Metabolites after Chemical Isotope Labeling Based on a Narrow Mass Defect Filter.

Chemical isotope labeling liquid chromatography mass spectrometry (LC-MS) is an emerging metabolomic strategy for the quantification and characterization of small molecular compounds in biological samples. However, its subsequent data analysis is not straightforward due to a large amount of data produced and interference of biological matrices. In order to improve the efficiency of searching and identification of target endogenous metabolites, a new software tool for nontargeted metabolomics data processing called MS-IDF was developed based on the principle of a narrow mass defect filter. The developed tool provided two function modules, including IsoFinder and MDFinder. The IsoFinder function module applied a conventional peak extraction method by using a fixed mass differences between the heavy and light labels and by the alignment of chromatographic retention time (RT). On the other hand, MDFinder was designed to incorporate the accurate mass defect differences between or among stable isotopes in the peak extraction process. By setting an appropriate filter interval, the target metabolites can be efficiently screened out while eliminating interference. Notably, the present results showed that the efficiency in compound identification using the new MDFinder module was nearly doubled as compared to the conventional IsoFinder method (an increase from 259 to 423 compounds). The Matlab codes of the developed MS-IDF software are available from github at https://github.com/jydong2018/MS_IDF. Based on the MS-IDF software tool, a novel and effective approach from nontargeted to targeted metabolomics research was developed and applied to the exploration of potential primary amine biomarkers in patients with schizophrenia. With this approach, potential biomarkers, including N,N-dimethylglycine, S-adenosine-l-methionine, dl-homocysteine, and spermidine, were discovered.

Evaluation of Serological and Molecular Method for Detection of Xylella Fastidiosa Associated with Olive Quick Decline

Sampling was carried out monthly for five months (March to July) on different host plants known to be infected by X. fastidiosa in previous surveys in order to evaluate the efficiency of a patented “sap extraction method” for favoring the detection of X. fastidiosa. Regarding the bacterium isolation, “sap extraction” showed to be more performing than conventional ones for olive, N. oleander and P. myrtifolia. The study confirmed that the best period for the bacterium isolation was from the end of spring to early summer. Regarding the use of Sap extraction for diagnostic purposes, slight differences were related to the type of explants used in ELISA and RT-LAMP. Likely, the surface sterilization of plant material may decrease the concentration of the bacterium in Sap extraction. In ELISA, Sap extraction looks less sensitive and has a slower reaction kinetics compared to conventional extraction method, while RT-LAMP applied with Sap Extraction looks better than conventional ones. Concerning RT-LAMP, the numbers of comparative tests should be increased. From the preliminary results of this study, it would appear that the “sap extraction method” is more effective than the conventional one for the isolation of different fungal species.

Development and evaluation of a molecular based protocol for detection and quantification of Cryptosporidium spp. in wastewater

Infections caused by protozoan parasites are a major public health concern globally. These infections are commonly diagnosed during water-borne outbreaks, necessitating accurate and highly sensitive detection procedures to assure public health protection. Current molecular techniques are challenged by several factors, such as low parasite concentration, inefficient DNA extraction methods, and inhibitors in environmental samples. This study focused on the development and validation of a molecular protocol for DNA extraction, efficient protozoan (oo)cyst recovery and quantification of protozoan parasites from wastewater using droplet digital polymerase chain reaction (ddPCR). Five DNA extraction methods, including commercial kits, custom phenol-chloroform, and in-house modified methods, were evaluated. The efficiency of each method was assessed via spectrophotometric analysis and ddPCR amplification using specific primers. Lastly, the developed protocol was evaluated for the detection and quantification of Cryptosporidium parvum in wastewater from different regions in South Africa. The conventional phenol-chloroform extraction method yielded the highest DNA concentration of 223 (±0.71) ng/μl and detected the highest number of Cryptosporidium parvum (1807 (±0.30) copies/ddPCR reaction) compared to other methods evaluated in this study. Additionally, the phenol-chloroform method demonstrated high sensitivity in extracting DNA from as few as one cyst/L of Cryptosporidium parvum, corresponding to 5.93 copies/ddPCR reaction. It was also observed that analysis of both the filtered supernatant and pellets after centrifugation improves the recovery efficiency of oocysts from wastewater by 10.5%, resulting in a total recovery of 64.1%. This optimized protocol was successfully applied to measure protozoan concentration in wastewater from different regions in South Africa. The improved DNA extraction and quantification method proposed in this study would be effective in monitoring protozoan concentration in the environment, which will help in instituting mitigation measures to reduce water-borne infections.

Development of a combined differential DNA/RNA co-extraction protocol and its application in forensic casework

In forensic casework, a broad range of extraction techniques is available, and the type of case will decide on the extraction method. Generally, in sexual assault cases, either the presence of semen is questioned (foremost in victim samplings), or the presence of body fluids such as vaginal mucosa or saliva (mostly in samples taken from the suspect). To analyze the semen component, differential extraction (DE) procedures are helpful as spermatozoa DNA gets specifically extracted in a distinct fraction. To assess which body fluid is present, messenger RNA (mRNA) profiling has emerged as one the best methods especially for body fluids encountered in forensic sexual assault cases. mRNA profiling requires the use of DNA/RNA co-extraction methods. In common sexual assault cases, mRNA typing is requested whilst semen may also be present, possibly in surplus amounts. This drove the development of a combined DNA/RNA/DE extraction method that yields DNA and RNA of both the sperm fraction as well as the non-sperm fraction. For the validation of the developed method, its performance was successfully assessed against conventional extraction methods, a range of relevant body fluids and stains up to 1 month old. The developed protocol was implemented for use in casework and is now part of the regular casework workflow in our laboratory.

Tree stem extraction from TLS point-cloud data of natural forests based on geometric features and DBSCAN

Conventional methods for tree stem extraction from point-cloud data of natural forests suffer from problems of low accuracy and poor universality. In this article, an enhanced method is proposed for tree stem extraction from point-cloud data collected by terrestrial laser scanning (TLS). First, principal component analysis is used to calculate the eigenvalues and eigenvectors of the point-cloud data, and an information entropy criterion is minimized in order to achieve the best neighbourhood scale selection. Then, three-dimensional spatial geometric forest features are combined with the Z-axis component of the normal vector. These geometric features are used for rough extraction of tree stem points, while a large number of non-stem points is filtered out by thresholding. Finally, the DBSCAN algorithm is used to achieve accurate extraction of tree stem points. The proposed method for tree stem detection and extraction is experimentally evaluated in the case of two representative natural forest plots of Pinus densata Mast. and Picea asperata Mast. in the Shangri-La City in China. All stem points in these two plots were detected and extracted with a reference method to create a ground-truth dataset. Correlation analysis was carried out between the stem points extracted by the proposed and reference methods for the two plots. This analysis resulted in an R2 value of 0.990 for the Pinus densata Mast. sample plot, and an R2 value of 0.982 for the Picea asperata Mast. sample plot which has a more complex growth environment.

Olive byproducts and their bioactive compounds as a valuable source for food packaging applications.

Among the most important agro-industrial activities in the Mediterranean basin, olive oil production has a high impact on the economy of many Mediterranean countries. However, olive oil extraction generates huge quantities of byproducts, including leaves, pomace residues, stones and wastewater, which have severe environmental impacts mainly because of their phytotoxicity and great organic content. Olive oil byproducts are regarded as inexpensive and abundant raw materials rich in bioactive compounds with high and varied health-related activities. Several phenolic compounds and terpenoids were recovered from olive byproducts using different conventional and advanced extraction methods due to their potential to be used in food, packaging, pharmaceutical, and cosmetic industries. Recently, the use of olive byproducts and their functional compounds to enhance the functional properties of packaging systems was investigated as a sustainable strategy for food preservation, fostering the sustainability of the olive-oil chain, and promoting circular economy. In this framework, the main goals of this review are to summarize the main bioactive compounds in olive byproducts, to review the main advancements in their extraction, purification, and characterization, and finally to discuss their applications in food packaging systems as well as safety-related aspects.

Extraction of keratin from sheep wool fibres using aqueous ionic liquids assisted probe sonication technology

Wool derived keratin is a potential biopolymer that can play a vital role as a cheap, sustainable, renewable source of material for designing various speciality products in the field of biomedicine. Unlike conventional methods for keratin extraction, the use of eco-friendly, a recyclable solvent like ionic liquids opens a new perspective for the processing of natural raw materials from livestock industries. In this research work, we develop a technique for rapid dissolution of keratin in ionic liquid assisted by probe sonication without any heating from an external source. The whole process of keratin extraction was optimized concerning the type of ionic liquid, sonication time, initial loading of the sample, and acoustic power of probe sonicator. The properties of regenerated keratin were studied further by using various analytical techniques such as Scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) analysis, thermogravimetric analysis (TGA), Nuclear magnetic resonance (NMR) spectroscopic analysis, Sodium dodecyl sulphate -polyacrylamide gel electrophoresis (SDS-PAGE). FTIR analysis showed the protein secondary structure and TGA analysis further revealed improved thermal properties of regenerated keratin when compared to raw untreated wool. The presence of intermediate filament derived low sulphur keratin along with some fraction of matrix protein in regenerated keratin was confirmed by SDS – PAGE analysis. Thus, further efforts are required to implement this technique at larger industrial scale to make this whole process of keratin extraction economical, quick, and environmentally friendly.

Extraction of sweeteners from Stevia rebaudiana by semicontinuous percolation of untreated leaves and leaves pretreated with ethanol

Untreated leaves (UL) and leaves pretreated with ethanol (PL) of the Stevia UEM-13 variety were extracted by a percolation method using boiling water as solvent (1/40). Five extractive cycles were performed for each starting material. The total recovery of sweeteners was 91.64% for UL and 93.80% for PL. In the first extractive cycle the value of insoluble impurities was estimated at 55.44% for UL and 63.12% for PL, therefore the purity levels of the extracts from the first cycle could, respectively, be increased from 25.68% to 81.12% and from 24.14% to 87.26% by employing an additional microfiltration step. It was extracted enough sweeteners from 5 g of both Stevia leaves to sweeten a liter of coffee, and preliminary sensory tests showed that, unlike the coffee prepared with UL, the coffee prepared with pretreated leaves did not have an unpleasant herbaceous taste. Novelty impact statement A simple conventional extraction method by semicontinuous percolation with boiling water as solvent, which allows steviol glycoside recovery levels above 90%; Obtaining minimally processed extracts that can be easily purified by membrane separation methods, without the use of flocculation and carbonation agents; Development of a conventional extraction method that allows obtaining minimally processed extracts, without herbaceous flavor, from Stevia leaves pretreated with ethanol, which can be used directly as a sweetener in beverages and foods.

Effect of Hilbert-Huang transform on classification of PCG signals using machine learning

Heartbeat sounds are biological signals used in the early diagnosis of cardiovascular diseases. Digital heartbeat sound recordings, called phonocardiogram (PCG), are used in the determination and automatic classification of possible heart diseases. Healthy and pathological PCG signals are non-stationary signals and conventional feature extraction methods are insufficient in classifying these signals. In this study, PCG signals in healthy and four pathological categories are decomposed into intrinsic mode functions (IMFs) by Hilbert-Huang transform. Mel-frequency cepstral coefficient (MFCC) features were extracted from each mode to investigate the effect of the modes obtained by Hilbert-Huang transform on the classification of PCG signals. Genetic algorithm was used as feature selection method and k-nearest neighbor (KNN), multilayer perceptron (MLP), support vector machine (SVM) and deep neural network (DNN) machine learning methods were used as classifier. We have implemented multi classifications of five PCG classes (healthy, aortic stenosis, mitral stenosis, mitral regurgitation and mitral valve prolapse) by using 5-fold cross validation and 10 × 5-fold cross validation Data Analysis Protocol (DAP) framework. The results show that the DNN model provides the highest classification performance with 98.9% precision, 98.7% recall, 98.8% F1-score and 98.9% accuracy using 5-fold cross validation, and Matthews correlation coefficient of 0.981 using the DAP method.

Chemical composition and mineral content of Black Borgoña (Vitis labrusca L.) grapes, pomace and seeds, and effects of conventional and non-conventional extraction methods on their antioxidant properties

Grape pomace and seeds, good source of functional compounds such as polyphenols, are waste by-products generated during wine making. Extraction is a very important step for later use of polyphenols. Herein we investigated the effects of conventional (CSE) and non-conventional extraction methods (subcritical water extraction (SWE) and pressurized ethanol extraction (PEE) on extraction yield, total phenolic content (TPC) and antioxidant capacity (AC) of Black Borgoña (Vitis labrusca L.) grape, pomace and seeds. Chemical composition showed the greatest amount of protein and lipids in pomace and seeds. Calcium was present in a high concentration in seeds (137.24 mg/100 g DM). PEE samples retained the highest TPC among all the extraction methods for grape, pomace and seeds with 21.42 ± 0.43, 54.36 ± 3.37 and 56.5 ± 3.81 mg GAE/g DM, respectively. The highest AC was determined by FRAP in seeds, 431.16 ± 37.71 µmol TE/g DM, followed by 329.04 ± 13.3 µmol TE/g DM in pomace when PEE was used. Significant correlations between antioxidant capacity and total phenolics were observed for all samples. This study demonstrated that non-conventional green method PEE is an efficient method to achieve the highest TPC and AC of Black Borgoña grape, pomace and seeds.

PH-Responsive epitope-imprinted magnetic nanoparticles for selective separation and extraction of chlorogenic acid and caffeic acid in traditional Chinese medicines.

Chlorogenic acid and caffeic acid often coexist in traditional Chinese medicines (TCMs) and play roles as antioxidation, antiviral, antitumor and anti-inflammatory agents. Due to their low content and the presence of structural analogues, they cannot be effectively separated by conventional extraction methods. Molecularly imprinted polymers, as synthesized receptors with antibody-like binding properties, have significant advantages in separating structural analogues. However, the harsh imprinting conditions easily induced the degradation of chlorogenic acid. Therefore, caffeic acid was used as an epitope template to replace chlorogenic acid for imprinting. Boronic acid-functionalized magnetic nanoparticles (MNPs) were selected as substrates, which could not only facilitate the immobilization and removal of the templates by pH regulation, but also achieve rapid separation under an external magnetic field. Tetraethyl orthosilicate was selected as an imprinting monomer which allowed for precise control of the thickness of the imprinting layer by adjusting the imprinting time. The prepared epitope-imprinted MNPs showed excellent specificity, in combination with high performance liquid chromatography, have been successfully applied to the selective separation and detection of chlorogenic acid and caffeic acid in TCMs.

Effective solvents for proteins recovery from microalgae

From an industrial perspective, the exploitation of microalgae as protein source is of great economical and commercial interest due to several attractive characteristics. However, the protein extraction efficiency is limited by the multiple layers of rigid and thick cell walls that are enriched with recalcitrant structure of cellulose. Therefore, an efficient method of cell disruption is necessary to disintegrate the cell wall and promote the release of protein contents. The conventional methods for downstream processing, e.g. disruption, isolation, extraction, concentration and purification, are energy-intensive and costly because they typically compose of several operational units. To reduce the overall process cost and establish an economical feasible process for the large-scale production of microalgae derived products, a more cost-effective and ecofriendly technique in downstream processing is in critical demand. One of the main challenges for protein extraction from microalgae cells is the recalcitrant structure of microalgae cell wall. This work aims to provide a guideline on the selection of the solvent to facilitate the proteins release during the cell disruption process. The influences of various solvent types (methanol, ethanol, 1-propanol and water) were evaluated and compared based on the protein yields. It was found that water solvent released the highest protein concentration from microalgae compared to the other tested solvents.

A comparative study on conventional and non-conventional extraction methodologies for yield, quality and antibacterial investigation of Moringa oleifera Lam.

The impact of different extraction methods such as soaking, soxhlet, Ultrasound-Assisted Extraction (UAE) and Microwave-Assisted Extraction (MAE) using ethanol as a green solvent on the percentage of extraction yield (EY), total phenol content (TPC), total flavonoid content (TFC), antioxidant activity (RSA%) and the antibacterial effect was studied. Unknown phytochemicals present in the moringa leaf extract from different methods were identified using Gas chromatography-Mass spectrometry (GC-MS) and identified phytocompounds present in the moringa leaf extract ranging from twenty-eight compounds to thirty-four compounds from different extraction methods. On comparing the conventional and nonconventional methods of extraction, the quantity and quality of extracted moringa biomolecules were found to be high in terms of extraction yield (21.79 ± 0.10%), TPC (144.52 ± 3.44 QE mg/g), TFC (22.93 ± 0.28 GA mg/g) and antioxidant activity (84.15 ± 1.14%) in UAE followed by MAE in lesser time compared to conventional methods. Moringa leaf extract from UAE, showed a maximum zone of inhibition (56.25 ± 0.35 mm) against E. coli at higher concentrations. Based on the research results, UAE and MAE could be novel extraction methods for various industrial sectors with a wide range of nutrients and bioactivity. In future, these extracted compounds might be further purified, characterized and fortified with other food products to mitigate malnutrition.

FUCOIDAN FROM Sargassum plagiophyllum BY MICROWAVE ASSISTED EXTRACTION IN COMPARISON WITH CONVENTIONAL METHODS

Sargassum is a brown seaweed rich in fucoidan which is a sulfated polysaccharide. This study aims to examine the conventional and microwave-assisted extraction (MAE) methods to optimize fucoidan extraction from Sargassum plagiophyllum with 0.1 M HCl and water solvents. The extraction of fucoidan was conducted in two different methods, conventional (C) and MAE (M) methods. Microwave-assisted extraction was performed at 450, 600, and 700 W microwave power for five minutes, then the extracted fucoidan was determined for its sulfate and fucose contents, as well as antioxidant activities. In both the conventional (CAwe) and MAE methods (MAfa7), the maximum yields of fucoidan crude extract produced in 0.1 M HCl solvent were 19.10 and 19.20%, respectively. The highest sulfate (MAfa7; 6.14%), and fucose content (MAaf7; 5.95 mg/100g) were found in the HCl solvent using the MAE method. Based on the results, the MAE approach with HCl solvent was a more efficient technology for extracting fucoidan from S. plagiophyllum than the conventional method.

Enhancing extraction of proanthocyanidins from Chinese quince fruit by ball-milling and enzyme hydrolysis: yield, structure, and bioactivities

Chinese quince fruits are rich in proanthocyanidins (PAs), which have antioxidant properties. This work describes a method to isolate PAs from Chinese quince fruits by a combination of ball-milling and enzyme hydrolysis pretreatments. The yield, total PA and total phenolic contents, structural characteristics, antioxidant activity, and α-amylase inhibitory activity of different pretreated PA samples were determined and analyzed. Among them, the ball-milling combined with multi-enzyme (cellulase, xylanase, and pectinase) hydrolysis pretreated sample (BEP-4) was the most outstanding. The yield of BEP-4 could be improved up to 7.72%, which was 2.51 times higher than that of the conventional organic solvent extraction method (3.02%). It had the highest total phenols and PAs content of 750.98 ± 6.95 and 948.72 ± 3.50 mg/g extract, respectively. The thermal stability and molecular weight (9610 Da) of BEP-4 were lower than other fractions. BEP-4 contained a high proportion of PC structure (98.35%) and flavan-3-ol content (87.88%). It also had the highest antioxidant capacity with IC50 values of 131.45 ± 0.97, 22.66 ± 0.32, 134.05 ± 0.71, and 182.07 ± 0.28 μg/mL for DPPH, ABTS, hydroxyl radical scavenging capacity, and α-amylase inhibiting capacity, respectively. These investigations provide a new, efficient way to isolate PAs from Chinese quince fruits, and reveal that Chinese quince fruits may be a good source of antioxidants, worthy of further development.

A comparative study of conventional and supercritical carbon dioxide extraction methods for the recovery of bioactive compound from Lion’s Mane mushroom (Hericium erinaceus)

Lion’s Mane mushroom (Hericium erinaceus), LM, is a medicinal mushroom which has various bioactive compounds within its fruiting bodies. However, during the cultivation, a large amount of the irregular-shape LM (Ir-LM) was generated. This mushroom type was considered a mushroom by-product. In this study, conventional solvent extraction (Maceration) and supercritical fluid extraction using carbon dioxide (SCFE-CO2) were performed to compare the recovery of ergosterol, hericenone C, and hericene A content from Reg-LM and Ir-LM fruiting bodies. Furthermore, two extraction conditions (40°C at 200 bar and 70°C at 350 bar) were conducted for the SCFE-CO2technique. The results showed that SCFE-CO2methods produced a higher recovery of ergosterol and hericenone C as compared to the Maceration techniques. SCFE-CO2extracts were determined for their antioxidant activities. The DPPH radical scavenging activity of the extract from 70°C at 350 bar was significantly higher (p < 0.05) than the extract obtained from 40°C at 200 bar. The results revealed the use of green technology supercritical fluid extraction using carbon dioxide to recover bioactive compounds from mushroom by-products and apply for high-value added products.