The Experts below are selected from a list of 786 Experts worldwide ranked by ideXlab platform
Andrea Lazzeri - One of the best experts on this subject based on the ideXlab platform.
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thermal mechanical viscoelastic and morphological properties of poly lactic acid based biocomposites with Potato Pulp powder treated with waxes
Materials, 2019Co-Authors: Maria Cristina Righetti, Patrizia Cinelli, Norma Mallegni, Carlo Andrea Massa, Laura Aliotta, Andrea LazzeriAbstract:The thermal, mechanical and viscoelastic properties of biocomposites of poly(lactic acid) (PLA) with 20 wt.% of Potato Pulp powder were investigated. The Potato Pulp powder utilized is a byproduct from the production and extraction of starch. The results showed that the Potato Pulp powder does not act as reinforcement, but as filler for PLA, due to an unfavorable aspect ratio and the irregular shape of the particles. In order to improve the mechanical response of the PLA/Potato Pulp powder biocomposites, surface treatment of the Potato Pulp particles with bio-based and petroleum-based waxes was investigated. This treatment was found to improve the properties of the biocomposites, enhancing the adhesion between the PLA based polymeric matrix and the Potato Pulp fibers. The best result is obtained with a petroleum-based wax, but also the bio-based waxes lead to good mechanical properties of the biocomposite. Thus, the addition to PLA of Potato Pulp powder, treated with waxes, appears a method able to (i) utilize and valorize an abundant agro-food biomass such as Potato Pulp, according to the principles of circular economy, (ii) favor the production of articles with properties valuable for practical applications, and (iii) reduce the cost of the final products, considering the relatively high cost of PLA.
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thermal and mechanical properties of biocomposites made of poly 3 hydroxybutyrate co 3 hydroxyvalerate and Potato Pulp powder
Polymers, 2019Co-Authors: Maria Cristina Righetti, Patrizia Cinelli, Norma Mallegni, Andreas Stabler, Andrea LazzeriAbstract:The thermal and mechanical properties of biocomposites of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) containing 5 wt % of valerate units, with 20 wt % of Potato Pulp powder were investigated in order (i) to obtain information on possible miscibility/compatibility between the biopolymers and the Potato Pulp, and (ii) to quantify how the addition of this filler modifies the properties of the polymeric material. The Potato Pulp powder utilized is a residue of processing for the production and extraction of starch. The final aim of this study is the preparation of PHBV based materials with reduced cost, thanks to biomass valorization, in agreement with the circular economy policy, as result of the incorporation of agricultural organic waste. The results showed that the Potato Pulp powder does not act as reinforcement, but rather as filler for the PHBV polymeric matrix. A moderate loss in mechanical properties is detected (decrease in elastic modulus, tensile strength and elongation at break), which regardless still meets the technical requirements indicated for rigid packaging production. In order to improve the mechanical response of the PHBV/Potato Pulp powder biocomposites, surface treatment of the Potato Pulp powder with bio-based and petroleum-based waxes was investigated. Good enhancement of the mechanical properties was achieved with the natural carnauba and bee waxes.
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thermal mechanical and rheological properties of biocomposites made of poly lactic acid and Potato Pulp powder
International Journal of Molecular Sciences, 2019Co-Authors: Maria Cristina Righetti, Patrizia Cinelli, Norma Mallegni, Carlo Andrea Massa, Simona Bronco, Andreas Stabler, Andrea LazzeriAbstract:The thermal, mechanical, and rheological properties of biocomposites of poly(lactic acid) (PLA) with Potato Pulp powder were investigated in order to (1) quantify how the addition of this filler modifies the structure of the polymeric material and (2) to obtain information on the possible miscibility and compatibility between PLA and the Potato Pulp. The Potato Pulp powder utilized is a residue of the processing for the production and extraction of starch. The study was conducted by analyzing the effect of the Potato Pulp concentration on the thermal, mechanical, and rheological properties of the biocomposites. The results showed that the Potato Pulp powder does not act as reinforcement but as filler for the PLA polymeric matrix. A progressive decrease in elastic modulus, tensile strength, and elongation at break was observed with increasing the Potato Pulp percentage. This moderate loss of mechanical properties, however, still meets the technical requirements indicated for the production of rigid packaging items. The incorporation of Potato Pulp powder to PLA offers the possibility to reduce the cost of the final products and promotes a circular economy approach for the valorization of agro-food waste biomass.
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effect of Potato Pulp filler on the mechanical properties and water vapor transmission rate of thermoplastic wpi pbs blends
Polymer-plastics Technology and Engineering, 2016Co-Authors: Markus Schmid, Andreas Stabler, Carola Herbst, Kerstin Muller, Daniel Schlemmer, Maria Beatrice Coltelli, Andrea LazzeriAbstract:ABSTRACTOne strategy for improving the cost efficiency as well as techno-functional properties of bio based plastics is the incorporation of natural fillers. In this study, Potato Pulp was used as a compound additive in different concentrations in extruded biopolymer blends based on glycerol/water plasticized whey protein isolate and polybutylene succinate. The main goal of this work was to determine the influence of Potato Pulp on the thermoplastic process as well as on the techno-functional properties of whey protein isolate/polybutylene succinate blends. When increasing the Potato Pulp concentration the elongation at break decreased, Young's modulus increased and the tensile strength was not affected.
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Effect of Potato Pulp Filler on the Mechanical Properties and Water Vapor Transmission Rate of Thermoplastic WPI/PBS Blends
Polymer-plastics Technology and Engineering, 2015Co-Authors: Markus Schmid, Andreas Stabler, Carola Herbst, Kerstin Muller, Daniel Schlemmer, Maria Beatrice Coltelli, Andrea LazzeriAbstract:ABSTRACTOne strategy for improving the cost efficiency as well as techno-functional properties of bio based plastics is the incorporation of natural fillers. In this study, Potato Pulp was used as a compound additive in different concentrations in extruded biopolymer blends based on glycerol/water plasticized whey protein isolate and polybutylene succinate. The main goal of this work was to determine the influence of Potato Pulp on the thermoplastic process as well as on the techno-functional properties of whey protein isolate/polybutylene succinate blends. When increasing the Potato Pulp concentration the elongation at break decreased, Young's modulus increased and the tensile strength was not affected.
Zhengbiao Gu - One of the best experts on this subject based on the ideXlab platform.
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study on rapid drying and spoilage prevention of Potato Pulp using solid state fermentation with aspergillus aculeatus
Bioresource Technology, 2020Co-Authors: Liyao Zhao, Li Cheng, Yan Hong, Yu Deng, Zhaofeng Li, Caiming Li, Zhengbiao GuAbstract:Abstract Effects of solid-state fermentation on rapid drying and spoilage prevention of Potato Pulp were evaluated. Pectin hydrolyzing and antibacterial ability of pectinase-secreting Aspergillus aculeatus and Bacillus subtilis were compared. A. aculeatus grew better in Potato Pulp, with highest pectinase yield of 342.71 ± 5.09 U/mL and rapid pH reduction to 3.76 ± 0.01. Next generation sequencing showed that the abundance of genera Candida and Enterobacter, which probably caused undesirable fermentation and spoilage, were significantly reduced after inoculation with A. aculeatus. In addition, fermentation with A. aculeatus significantly reduced water holding capacity from 16.63 ± 0.36 g/g to 7.78 ± 0.12 g/g, which resulted in lower viscosity and water binding capacity, and concomitantly significantly decreased moisture content from 76.05 ± 0.24% to 12.95 ± 0.19% after filtration and airflow drying. These results suggested that solid-state fermentation might be a promising technology for efficient processing and utilization of Potato Pulp.
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characterization of physicochemical properties of cellulose from Potato Pulp and their effects on enzymatic hydrolysis by cellulase
International Journal of Biological Macromolecules, 2019Co-Authors: Li Cheng, Yan Hong, Zhaofeng Li, Zhengbiao Gu, Xiaohui Hu, Caiming LiAbstract:Abstract In this work, cellulose was extracted from Potato Pulp, a low-efficiently utilized by-product from Potato starch industry, by a combined alkali and sodium sulfite treatment. Its physicochemical properties were characterized and compared with cellulose from corn stalk. The yield and purity of cellulose from Potato Pulp were determined to be 24.74% and 81.34% respectively. Cellulose from Potato Pulp had more loosened and porous structure, lower crystallinity index and larger specific surface area (SSA) compared with cellulose from corn stalk. It also provided the highest accessibility to cellulase (5.7 mg protein/g glucan) and had the highest enzymatic digestibility (with glucose yield of 88.46%). Maximum adsorption capacity (Wmax) and equilibrium constant (K) were obtained by fitting the adsorption data with the Langmuir adsorption isotherm, suggesting that cellulose from Potato Pulp had the highest cellulase adsorption efficiency. The data further indicated that the presence of non-cellulosic components, especially for pectin, appeared to have a considerable effect on the hydrolysis by cellulase due to non-productive adsorption. State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue Wuxi 214122, Jiangsu Province, People's Republic of China.
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enzyme assisted fermentation of Potato Pulp an effective way to reduce water holding capacity and improve drying efficiency
Food Chemistry, 2018Co-Authors: Jing Du, Li Cheng, Yan Hong, Yu Deng, Zhaofeng Li, Caiming Li, Zhengbiao GuAbstract:Abstract The effects of an enzyme-assisted fermentation technique on the water holding capacity (WHC) and drying characteristics of Potato Pulp were investigated. Potato Pulp was fermented with Lactobacillus plantarum to increase the content of organic acids, reduce the pH of the Pulp and assist in enhancing the enzymatic hydrolysis. Removal of pectin and cellulose reduced the WHC of Potato Pulp from 16.84 to 6.83 and 9.64 g/g, respectively. Drying characteristics were determined using the air-drying process, which indicated that pectinase-assisted fermentation could remove pectin from Potato Pulp and shorten the air-drying time from 240 to 140 min, while cellulase had an opposite effect on the drying rate. This result was also confirmed by low field nuclear magnetic resonance (LF-NMR), which showed more mobile water and less bonded water in pectin-removed Potato Pulp samples.
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characterisation of physicochemical and functional properties of soluble dietary fibre from Potato Pulp obtained by enzyme assisted extraction
International Journal of Biological Macromolecules, 2017Co-Authors: Li Cheng, Yan Hong, Zhaofeng Li, Caiming Li, Xianmei Zhang, Zhengbiao GuAbstract:In this study, enzyme-assisted methodology was applied with the aim to optimise the efficiency of soluble dietary fibre (SDF) extraction from Potato Pulp. The yields of SDF pretreated by cellulase, xylanase, and a cellulase/xylanase mixture were 31.9% (w/w), 25.7% (w/w), and 39.7% (w/w) respectively. When comparing single enzyme pretreatment with combined enzymatic treatment, we observed differences in properties related to molecular weight and viscosity. SDF obtained by xylanase pretreatment rendered better results for glucose dialysis retardation index (32.98%, w/w), amylase inhibitory effect (56.2%), and pancreatic lipase inhibitory activity (55.33%), while combined enzymatic pretreatment exhibited better effect in properties related to exposure of functional groups and specific surface area, including sodium cholate binding capacity (72.2%) and hydroxyl radical scavenging activity (87.57%). Our results indicated that enzymatic pretreatment, which could effectively hydrolyse cellulose and hemicellulose components, could not only benefit the yield of SDF, but also enhance its physiological and functional properties.
Andreas Stabler - One of the best experts on this subject based on the ideXlab platform.
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thermal and mechanical properties of biocomposites made of poly 3 hydroxybutyrate co 3 hydroxyvalerate and Potato Pulp powder
Polymers, 2019Co-Authors: Maria Cristina Righetti, Patrizia Cinelli, Norma Mallegni, Andreas Stabler, Andrea LazzeriAbstract:The thermal and mechanical properties of biocomposites of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) containing 5 wt % of valerate units, with 20 wt % of Potato Pulp powder were investigated in order (i) to obtain information on possible miscibility/compatibility between the biopolymers and the Potato Pulp, and (ii) to quantify how the addition of this filler modifies the properties of the polymeric material. The Potato Pulp powder utilized is a residue of processing for the production and extraction of starch. The final aim of this study is the preparation of PHBV based materials with reduced cost, thanks to biomass valorization, in agreement with the circular economy policy, as result of the incorporation of agricultural organic waste. The results showed that the Potato Pulp powder does not act as reinforcement, but rather as filler for the PHBV polymeric matrix. A moderate loss in mechanical properties is detected (decrease in elastic modulus, tensile strength and elongation at break), which regardless still meets the technical requirements indicated for rigid packaging production. In order to improve the mechanical response of the PHBV/Potato Pulp powder biocomposites, surface treatment of the Potato Pulp powder with bio-based and petroleum-based waxes was investigated. Good enhancement of the mechanical properties was achieved with the natural carnauba and bee waxes.
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thermal mechanical and rheological properties of biocomposites made of poly lactic acid and Potato Pulp powder
International Journal of Molecular Sciences, 2019Co-Authors: Maria Cristina Righetti, Patrizia Cinelli, Norma Mallegni, Carlo Andrea Massa, Simona Bronco, Andreas Stabler, Andrea LazzeriAbstract:The thermal, mechanical, and rheological properties of biocomposites of poly(lactic acid) (PLA) with Potato Pulp powder were investigated in order to (1) quantify how the addition of this filler modifies the structure of the polymeric material and (2) to obtain information on the possible miscibility and compatibility between PLA and the Potato Pulp. The Potato Pulp powder utilized is a residue of the processing for the production and extraction of starch. The study was conducted by analyzing the effect of the Potato Pulp concentration on the thermal, mechanical, and rheological properties of the biocomposites. The results showed that the Potato Pulp powder does not act as reinforcement but as filler for the PLA polymeric matrix. A progressive decrease in elastic modulus, tensile strength, and elongation at break was observed with increasing the Potato Pulp percentage. This moderate loss of mechanical properties, however, still meets the technical requirements indicated for the production of rigid packaging items. The incorporation of Potato Pulp powder to PLA offers the possibility to reduce the cost of the final products and promotes a circular economy approach for the valorization of agro-food waste biomass.
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effect of Potato Pulp filler on the mechanical properties and water vapor transmission rate of thermoplastic wpi pbs blends
Polymer-plastics Technology and Engineering, 2016Co-Authors: Markus Schmid, Andreas Stabler, Carola Herbst, Kerstin Muller, Daniel Schlemmer, Maria Beatrice Coltelli, Andrea LazzeriAbstract:ABSTRACTOne strategy for improving the cost efficiency as well as techno-functional properties of bio based plastics is the incorporation of natural fillers. In this study, Potato Pulp was used as a compound additive in different concentrations in extruded biopolymer blends based on glycerol/water plasticized whey protein isolate and polybutylene succinate. The main goal of this work was to determine the influence of Potato Pulp on the thermoplastic process as well as on the techno-functional properties of whey protein isolate/polybutylene succinate blends. When increasing the Potato Pulp concentration the elongation at break decreased, Young's modulus increased and the tensile strength was not affected.
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Effect of Potato Pulp Filler on the Mechanical Properties and Water Vapor Transmission Rate of Thermoplastic WPI/PBS Blends
Polymer-plastics Technology and Engineering, 2015Co-Authors: Markus Schmid, Andreas Stabler, Carola Herbst, Kerstin Muller, Daniel Schlemmer, Maria Beatrice Coltelli, Andrea LazzeriAbstract:ABSTRACTOne strategy for improving the cost efficiency as well as techno-functional properties of bio based plastics is the incorporation of natural fillers. In this study, Potato Pulp was used as a compound additive in different concentrations in extruded biopolymer blends based on glycerol/water plasticized whey protein isolate and polybutylene succinate. The main goal of this work was to determine the influence of Potato Pulp on the thermoplastic process as well as on the techno-functional properties of whey protein isolate/polybutylene succinate blends. When increasing the Potato Pulp concentration the elongation at break decreased, Young's modulus increased and the tensile strength was not affected.
Maria Cristina Righetti - One of the best experts on this subject based on the ideXlab platform.
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thermal mechanical viscoelastic and morphological properties of poly lactic acid based biocomposites with Potato Pulp powder treated with waxes
Materials, 2019Co-Authors: Maria Cristina Righetti, Patrizia Cinelli, Norma Mallegni, Carlo Andrea Massa, Laura Aliotta, Andrea LazzeriAbstract:The thermal, mechanical and viscoelastic properties of biocomposites of poly(lactic acid) (PLA) with 20 wt.% of Potato Pulp powder were investigated. The Potato Pulp powder utilized is a byproduct from the production and extraction of starch. The results showed that the Potato Pulp powder does not act as reinforcement, but as filler for PLA, due to an unfavorable aspect ratio and the irregular shape of the particles. In order to improve the mechanical response of the PLA/Potato Pulp powder biocomposites, surface treatment of the Potato Pulp particles with bio-based and petroleum-based waxes was investigated. This treatment was found to improve the properties of the biocomposites, enhancing the adhesion between the PLA based polymeric matrix and the Potato Pulp fibers. The best result is obtained with a petroleum-based wax, but also the bio-based waxes lead to good mechanical properties of the biocomposite. Thus, the addition to PLA of Potato Pulp powder, treated with waxes, appears a method able to (i) utilize and valorize an abundant agro-food biomass such as Potato Pulp, according to the principles of circular economy, (ii) favor the production of articles with properties valuable for practical applications, and (iii) reduce the cost of the final products, considering the relatively high cost of PLA.
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thermal and mechanical properties of biocomposites made of poly 3 hydroxybutyrate co 3 hydroxyvalerate and Potato Pulp powder
Polymers, 2019Co-Authors: Maria Cristina Righetti, Patrizia Cinelli, Norma Mallegni, Andreas Stabler, Andrea LazzeriAbstract:The thermal and mechanical properties of biocomposites of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) containing 5 wt % of valerate units, with 20 wt % of Potato Pulp powder were investigated in order (i) to obtain information on possible miscibility/compatibility between the biopolymers and the Potato Pulp, and (ii) to quantify how the addition of this filler modifies the properties of the polymeric material. The Potato Pulp powder utilized is a residue of processing for the production and extraction of starch. The final aim of this study is the preparation of PHBV based materials with reduced cost, thanks to biomass valorization, in agreement with the circular economy policy, as result of the incorporation of agricultural organic waste. The results showed that the Potato Pulp powder does not act as reinforcement, but rather as filler for the PHBV polymeric matrix. A moderate loss in mechanical properties is detected (decrease in elastic modulus, tensile strength and elongation at break), which regardless still meets the technical requirements indicated for rigid packaging production. In order to improve the mechanical response of the PHBV/Potato Pulp powder biocomposites, surface treatment of the Potato Pulp powder with bio-based and petroleum-based waxes was investigated. Good enhancement of the mechanical properties was achieved with the natural carnauba and bee waxes.
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thermal mechanical and rheological properties of biocomposites made of poly lactic acid and Potato Pulp powder
International Journal of Molecular Sciences, 2019Co-Authors: Maria Cristina Righetti, Patrizia Cinelli, Norma Mallegni, Carlo Andrea Massa, Simona Bronco, Andreas Stabler, Andrea LazzeriAbstract:The thermal, mechanical, and rheological properties of biocomposites of poly(lactic acid) (PLA) with Potato Pulp powder were investigated in order to (1) quantify how the addition of this filler modifies the structure of the polymeric material and (2) to obtain information on the possible miscibility and compatibility between PLA and the Potato Pulp. The Potato Pulp powder utilized is a residue of the processing for the production and extraction of starch. The study was conducted by analyzing the effect of the Potato Pulp concentration on the thermal, mechanical, and rheological properties of the biocomposites. The results showed that the Potato Pulp powder does not act as reinforcement but as filler for the PLA polymeric matrix. A progressive decrease in elastic modulus, tensile strength, and elongation at break was observed with increasing the Potato Pulp percentage. This moderate loss of mechanical properties, however, still meets the technical requirements indicated for the production of rigid packaging items. The incorporation of Potato Pulp powder to PLA offers the possibility to reduce the cost of the final products and promotes a circular economy approach for the valorization of agro-food waste biomass.
Anne S Meyer - One of the best experts on this subject based on the ideXlab platform.
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Selection of Bacillus species for targeted in situ release of prebiotic galacto-rhamnogalacturonan from Potato Pulp in piglets
Applied Microbiology and Biotechnology, 2017Co-Authors: Carsten Jers, Mikael L. Strube, Mette D. Cantor, Bea K. K. Nielsen, Ole B. Sørensen, Mette Boye, Anne S MeyerAbstract:We have previously shown that galacto-rhamnogalacturonan fibers can be enzymatically extracted from Potato Pulp and that these fibers have potential for exerting a prebiotic effect in piglets. The spore-forming Bacillus species are widely used as probiotics in feed supplements for pigs. In this study, we evaluated the option for further functionalizing Bacillus feed supplements by selecting strains possessing the enzymes required for extraction of the potentially prebiotic fibers. We established that it would require production and secretion of pectin lyase and/or polygalacturonase but no or limited secretion of galactanase and β-galactosidase. By screening a library of 158 Bacillus species isolated from feces and soil, we demonstrated that especially strains of Bacillus amyloliquefaciens , Bacillus subtilis , and Bacillus mojavensis have the necessary enzyme profile and thus the capability to degrade polygalacturonan. Using an in vitro porcine gastrointestinal model system, we revealed that specifically strains of B. mojavensis were able to efficiently release galacto-rhamnogalacturonan from Potato Pulp under simulated gastrointestinal conditions. The work thus demonstrated the feasibility of producing prebiotic fibers via a feed containing Bacillus spores and Potato Pulp and identified candidates for future in vivo evaluation in piglets.
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in situ prebiotics enzymatic release of galacto rhamnogalacturonan from Potato Pulp in vivo in the gastrointestinal tract of the weaning piglet
AMB Express, 2015Co-Authors: Mikael Lenz Strube, Anne S Meyer, Tim Kare Jensen, Mette BoyeAbstract:Prebiotics may be efficient for prevention of intestinal infections in humans and animals by increasing the levels of beneficial bacteria and thereby improving gut health. Using purified prebiotics may however not be cost-effective in the livestock production industry. Instead, prebiotic fibres may be released directly in the gastro-intestinal tract by feeding enzymes with a suitable substrate and allowing the prebiotics to be produced in situ. Using low doses, 0.03 % enzyme-to-substrate ratio, of the enzymes pectin lyase and polygalacturonase in combination with Potato Pulp, a low-value industrial by-product, we show that high molecular weight galacto-rhamnogalacturonan can be solubilized in the stomach of weaning piglets. The release of this fiber is in the order of 22–38 % of the theoretical amount, achieved within 20 min. The catalysis takes place mainly in the stomach of the animal and is then followed by distribution through the small intestines. To our knowledge, this is the first paper describing targeted production of prebiotics in an animal model.
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time of harvest affects the yield of soluble polysaccharides extracted enzymatically from Potato Pulp
Food and Bioproducts Processing, 2015Co-Authors: Helle Christine Ravn, Ole Bandsholm Sorensen, Anne S MeyerAbstract:Abstract Potato Pulp is a co-processing product from Potato starch production. The Pulp mainly consists of the tuber cell walls, which are rich in pectin and cellulose. The Potato Pulp pectin is dominated by galactan branched rhamnogalacturonan 1 which after enzymatic solubilization has shown promising properties as bifidogenic prebiotic fibers. The Potato starch processing campaign is based on processing of fresh Potatoes (in Denmark the campaign lasts from September to December). This study examines the effect of time of harvest and processing during the campaign on the yield of enzymatically solubilized Potato polysaccharides applying a recently developed enzymatic process using 1.0% (w/w) [enzyme/substrate (E/S)] pectin lyase from Aspergillus nidulans and 1.0% (w/w) [E/S] polygalacturonase from A. aculeatus at 60 °C, 100 mM citric acid, pH 6.0 for 1 min. Seven samples drawn within the Potato starch campaign of 2011 were characterized: the yields of enzymatically solubilized Potato polysaccharides and the solubilized galactan proportion increased during the Potato starch campaign. The data thus suggest that Potato Pulp produced late in the campaign would be preferable for upgrading to the bifidogenic fibers; this outcome may be the result of an inherent effect of the higher maturity of the Potatoes late in the campaign.
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definition and characterization of enzymes for maximal biocatalytic solubilization of prebiotic polysaccharides from Potato Pulp
Enzyme and Microbial Technology, 2011Co-Authors: Lise Vestergaard Thomassen, Dorte Moller Larsen, Jorn Dalgaard Mikkelsen, Anne S MeyerAbstract:Abstract Potato Pulp is a high-volume co-processing product resulting from industrial Potato starch manufacturing. Potato Pulp is particularly rich in pectin, notably galactan branched rhamnogalacturonan I polysaccharides, which are highly bifidogenic when solubilized. The objective of the present study was to characterize and compare four homogalacturonan degrading enzymes capable of catalyzing the required solubilization of these pectinaceous polysaccharides from Potato Pulp in a 1 min reaction. An additional purpose was to assess the influence of the pH and the potential buffer chelating effects on the release of these polysaccharides from the Potato Pulp. The pH and temperature optima of two selected pectin lyases from Emericella nidulans (formerly known as Aspergillus nidulans ) and Aspergillus niger were determined to 8.6 and 4.0, respectively, at ≥100 °C within 1 min of reaction. The optima for the two selected polygalacturonases from E. nidulans and Aspergillus aculeatus were determined to pH 4.4 and 46 °C, and pH 3.7 and ≥80 °C, respectively. The polygalacturonase from A. aculeatus was 4–42 times more heat-resistant at 50 °C than the other enzymes. The difference in pH optima of the pectin lyases and the exceptional thermal stabilities of some of the enzymes are proposed to be related to specific amino acid substitutions, stabilizing hydrogen bonding and structural traits of the enzymes. The K M and V max values ranged from 0.3–0.6 g/L and 0.5–250.5 U/mg protein, respectively. Phosphate buffer induced release of a higher amount of dry matter than Tris–acetate buffer at pH 6, indicating a chelating effect of the phosphate. Moreover, the phosphate had a higher chelating effect at pH 6 than at pH 4. The optimal conditions for a high yield of polysaccharides from Potato Pulp were therefore: 1% (w/w) Potato Pulp treated with 1% (w/w) enzyme/substrate (E/S) pectin lyase from E. nidulans and 1% (w/w) E/S polygalacturonase from A. aculeatus at pH 6.0 and 60 °C for 1 min.
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Maximal release of highly bifidogenic soluble dietary fibers from industrial Potato Pulp by minimal enzymatic treatment
Applied Microbiology and Biotechnology, 2011Co-Authors: Lise V. Thomassen, Jorn Dalgaard Mikkelsen, Louise K. Vigsnæs, Tine R. Licht, Anne S MeyerAbstract:Potato Pulp is a poorly utilized, high-volume co-processing product resulting from industrial Potato starch manufacturing. Potato Pulp mainly consists of the tuber plant cell wall material and is particularly rich in pectin, notably galactan branched rhamnogalacturonan I type pectin which has previously been shown to exhibit promising properties as dietary fiber. The objective of this study was to solubilize dietary fibers from Potato Pulp by a one-step minimal treatment procedure and evaluate the prebiotic potential of the fibers. Statistically designed experiments were conducted to investigate the influence of enzyme type, dosage, substrate level, incubation time, and temperature on the enzyme catalyzed solubilization to define the optimal minimal enzyme treatment for maximal fiber solubilization. The result was a method that within 1 min released 75% [weight/weight (w/w)] dry matter from 1% (w/w) Potato Pulp treated with 1.0% (w/w) [enzyme/substrate (E/S)] pectin lyase from Aspergillus nidulans and 1.0% (w/w) E/S polygalacturonase from Aspergillus aculeatus at pH 6.0 and 60 °C. Molecular size fractionation of the solubilized fibers revealed two major fractions: one fraction rich in galacturonic acid of 10–100 kDa indicating mainly homogalacturonan, and a fraction >100 kDa rich in galactose, presumably mainly made up of β-1,4-galactan chains of rhamnogalacturonan I. When fermented in vitro by microbial communities derived from fecal samples from three healthy human volunteers, both of the solubilized fiber fractions were more bifidogenic than fructo-oligosaccharides (FOS). Notably the fibers having molecular masses of >100 kDa selectively increased the densities of Bifidobacterium spp. and Lactobacillus spp. 2–3 times more than FOS.