High Methoxyl Pectin Research Articles

Production and Characterisation of Pectin from Cocoa Bean Shells

Cocoa bean shells constitute the major waste generated from the industrial processing of cocoa beans. The shells contain about 9% of pectin and extracting it would be of economic and ecological importance. However, limited knowledge on the characteristics of the pectin from cocoa bean shells and the extraction conditions, which would yield pectin of good quality and sufficient quantity, restrict the possible use of the shells as a source of commercial pectin. The objective of this study was to extract and characterise pectin from cocoa bean shells, with focus on finding the optimum extraction conditions. The conventional hot dilute acid extraction method was used. 12 M hydrochloric acid was used to acidify water to pH 1.0, 1.5, 2.0, 2.5, 3.0, 3.5 and 4.0. Extractions were carried out at temperatures of 60, 70, and 80 °C, for different times of 0.5, 1, and 2 h. The effects of each of the conditions on yield and other properties of pectin were evaluated. Depending on the conditions under which cocoa bean shells were treated, both high methoxyl and low methoxyl pectins were extracted. At the optimum conditions of pH 3.5, extraction time of 2 h and 80 °C extraction temperature, high methoxyl pectin was obtained. The yield was 4.7%, the degree of esterification was 68.9% and the anhydrouronic acid content was 71.2%. While the methoxyl content was 8.6%, the equivalent mass was found to be 805.8 g/eq. Moisture and ash contents were 6.7 and 10.3%, respectively, and the pH of the pectin hydrocolloid was 3.7. Fourier Transform Infrared (FT-IR) spectra confirmed the presence of functional groups found in the pectin structure. The intrinsic viscosity varied between 0.075–0.088 m3/kg and the molecular mass ranged from 23,470 - 42,384 g/mol. The results revealed that the shells are a viable source for commercial pectin, while necessary investigations focusing on the gelling, thickening, emulsifying, texturing, and stabilising potentials of the pectin from cocoa bean shells would inform of the areas of application

Phase separation and formation of sodium caseinate/pectin complex coacervates: effects of pH on the complexation

BackgroundThe electrostatic interactions between polysaccharides and proteins are an interesting field in the complex coacervation. PH and mixing ratio have major effect on the complexation and the coacervates structure. Hence, it is necessary to find the optimum pH and mixing ratio of the coacervates as well as understanding the thermal, mechanical, and structural characterization of the coacervates. Thus, structural changes of the complexes of sodium caseinate (NaCas) and high methoxyl pectin as a function of pH (2.00–7.00), biopolymer ratios (1:1, 2:1, 4:1, and 8:1), and total biopolymer concentration (0.1, 0.2, and 0.4% w/v) were evaluated by light scattering and ζ-potential measurements. The phase separation behavior of the NaCas/HMP coacervate and its kinetics turbidity were also investigated via monitoring the turbidity profiles. Moreover, the thermal, rheological and structural behavior of the coacervates was evaluated at the selected pH values.ResultsThe highest turbidity, particle size, and viscosity were achieved at pHmax = 3.30 and formation or dissociation around the pHmax was confirmed by particle size and FTIR. The optimum condition for the coacervation of NaCas and HMP was obtained at ratio 4:1 and 0.4% w/v. Thermal and mechanical stability of the NaCas/HMP coacervates was improved at pH 3.30. By increasing the total concentration of biopolymers, the NaCas/pectin ratio shifted to higher pH values. Furthermore, the maximum coacervate yield was achieved at 39.8% w/w at a ratio of 4:1 of NaCas/HMP and a total biopolymer concentration of 0.4% w/v.ConclusionPhase separation behavior of the coacervates exhibited the optimum pH in coacervation between NaCas and HMP. Furthermore, the rheological, thermal and structural stability of the coacervates were improved in comparison with the single biopolymers.Graphical

Green Carbon Dots as Additives of Biopolymer Films for Preserving from Oxidation of Oil-Based Products.

The deterioration of oil-based products during processing, distribution and storage has a major negative impact on the industry from an economic point of view. The spoilage of oil is mainly due to its oxidation which can be triggered by various factors, such as UV light, heating or the presence of impurities that result in the formation of radical species. In this context, several packaging alternatives have recently been developed with the aim to protect and extend the shelf life of oil-based products. This work aimed to study the antioxidant properties of bio-polymer-based films (BPFs) obtained from high methoxylated pectin (HMP) and sodium caseinate (CAS) and enriched with different concentrations of green carbon dots (gCDs), 0.25%, 0.50 and 1% w/w, obtained from apple pomace (APCDs) and rosemary powder (RCDs). The resulting films (gCDs-BPFs) have shown that the presence of gCDs not only modified the surface roughness of the films, but also positively affected their antioxidant properties. The addition of gCDs enhanced the radical inhibiting capacity of the raw BPFs by 42 and 62% for the films containing 1% RCDs and 1% APCDs, respectively. As a proof of the concept, two oil samples (edible and cosmetic) were treated with the obtained antioxidant films, and the results demonstrated that in both types of samples the oxidation process was minimized during the five days of the experiment. These results are promising and suggest that the antioxidant bio-polymer-based films could be excellent candidates for further production of active packaging.

Compound treatment of thiolated citrus high-methoxyl pectin and sodium phosphate dibasic anhydrous improved gluten network structure

The effects of pectin or thiolated pectin alone and combined with sodium phosphate dibasic anhydrous (Na2HPO4) on the performances of gluten were studied. Results showed that compared with pectin treated gluten, the thiols of thiolated pectin treated gluten increased by 8.7 times. Analysis of the extensibility and rheological properties revealed that pectin reduced gluten strength, whereas thiolated pectin improved the strength and viscoelasticity of gluten, especially with the assistance of Na2HPO4. Furthermore, thiolated pectin and Na2HPO4 compound increased enthalpy (ΔH, from 150.42 to 168.60 J/g) and decreased Imax (from 5255.33 to 2775.33) markedly, indicating gluten aggregation. The highest β-sheet (76.47%) and the lowest α-helix/β-sheet ratio (0.11) were found in gluten treated with thiolated pectin and Na2HPO4 and suggested gluten stability was enhanced. SEM observation confirmed that thiolated pectin and Na2HPO4 compound strengthened the gluten structure. These results are of great significance for the supplementation of pectin in wheat products.

Fabrication and characterization of gelatin-EGCG-pectin ternary complex: formation mechanism, emulsion stability, and structure.

Protein-polyphenol-polysaccharide ternary complex particles have better emulsion interfacial stability compared to protein-polysaccharide binary complexes. However, knowledge is scarce when it comes to the fabrication of protein-polyphenol-polysaccharide ternary complexes as interfacial stabilizers and the interactions between the three substances. In the present work, ternary complexes were prepared using gelatin, high methoxyl pectin, and epigallocatechin gallate (EGCG) as raw materials. The effect of different influencing factors on the formation process of ternary complexes was investigated by varying different parameters. physicochemical stability, emulsifying properties, and structural characteristics were analyzed. The ternary complex had a smaller particle size (275 nm) and polydispersity index (0.112) when the mass concentration ratio of gelatin to high methoxyl pectin was 9:1, addition of EGCG was 0.05%, pH value was 3.0, and ionic strength was 10 mmol L-1 . Meanwhile, the complex had the highest emulsifying stability index (691.75 min) and emulsifying activity index (22.96 m2 g-1 ). Scanning electron microscopical observation demonstrated that the addition of EGCG promoted the dispersion of ternary complex more uniformly, and effectively reduced the agglomeration phenomenon. The discrepancy in fluorescence intensity suggested that interactions between EGCG and gelatin occurred, which altered the protein spatial conformation of gelatin. Fourier transform infrared spectroscopic analysis elucidated that hydrogen bond interaction was the primary non-covalent interaction between EGCG and gelatin-high methoxyl pectin binary complex. The aforementioned results purposed to provide some theoretical reference and basis for the rational design of stable protein-polyphenol-polysaccharide ternary complexes. © 2022 Society of Chemical Industry.

Impact of pectin and whey minerals solubilized by lime juice on calcium bioaccessibility in yogurt based snacks

Pectin is used in dairy products to improve texture, but it may also affect calcium absorption. The influence of pectins with different degrees of esterification on calcium bioaccessibility in yogurt snacks enriched with or without whey mineral concentrates and lime juice was quantified using a three-step in vitro digestion including electrochemical determination of free and complex bound calcium. Calcium from whey minerals became bioaccessible under intestinal conditions when combined with lime juice, as a consequence of a large fraction of complex bound calcium by citrate. Pectin improved the texture of the snacks but lowered the calcium bioaccessibility by 6%–16% depending on the degree of esterification through endothermic binding of calcium to carboxylate groups of pectins as evidenced by higher yield stress of the snack bases. Decreasing degree of esterification and increasing blockiness promoted calcium binding, as indicated by the estimated binding sites and association constants. Increasing temperature from 25 °C to 37 °C and pH from 4 to 7 (intestinal conditions) also increased the interactions between calcium and pectins. For low methoxyl pectin, the complex binding of calcium to pectin carboxylates was found more evident than binding to citrate from the lime juice reducing calcium bioaccessibility. For high methoxyl pectin with fewer binding sites, citrate binding kept calcium available for uptake through intestinal digestion. A balanced formulation with whey minerals, lime juice and calcium-insensitive high methoxyl pectin yielded crispy yogurt snacks with high calcium bioaccessibility, which provides a new perspective to design dairy products with high nutritional value. • Pectin improves hardness and crispness of freeze-dried yogurt snacks. • Whey minerals with lime juice increase Ca bioaccessibility by citrate binding. • LM and to a lesser degree of HM pectin decreases Ca bioaccessibility. • LM pectin reduces calcium binding to citrate decreasing Ca bioaccessibility. • HM pectin and whey minerals lead to crispy snacks and high Ca bioaccessibility.

Stability of acidified milk drinks: Comparison of high hydrostatic pressure (HHP) and thermal treatments

There is a search for effective stabiliser activity and alternative pasteurisation techniques for acidified milk drinks (AMD). In the present study, AMD were prepared at three different pH (4.0, 4.5 and 5.0) and high methoxyl pectin (HMP) levels (0.2, 0.5 and 0.8%) by thermal (75 °C, 15 min) and high hydrostatic pressure (HHP) (100, 300 and 500 MPa, 5 min) treatments. To achieve minimum steric stability, 0.5% HMP was required. HMP at 0.5%, pH 4.0 and 4.5, produced high protein solubility (60–70%), low storage sedimentation (10–15%) and mean particle size values in the range of 1.70–3.00 μm for all samples. Heat treatment induced lower particle size variation than HHP treatment. Heat-treated samples also showed lower Turbiscan stability index (TSI) values and smaller delta backscattering (ΔBS) variations. Nonetheless, HHP could replace heat treatment at 0.5% HMP concentration and pH 4.0–4.5.

Pectin extraction from garlic waste under dual acid condition

AbstractA novel approach for the extraction of pectin from garlic waste (peel, stem, and straw) was accomplished under dual acid solution conditions including two organic (citric acid [CA] and acetic acid [AA]), two inorganic (hydrochloric acid [HCl] and sulfuric acid [H2SO4]) and six different mixtures of these acids (CA‐HCl, CA‐H2SO4, CA‐AA, AA‐H2SO4, AA‐HCl, and HCl‐H2SO4) with 1/30 (v/w) solid–liquid ratio at 90°C in 90 min extraction duration. The effects of acid mixture on the yields and physicochemical properties of the extracted pectins from garlic waste were investigated. Applying different acid mixtures during the extraction process allowed to obtain pectin samples with controlled physicochemical properties and higher yields. The maximum pectin yield of 22.4% was observed in the extraction condition carried out HCl‐H2SO4 (1/3 v/v) mixture. Extractions carried out under dual acid mixtures showed higher Gal‐A contents compared with the conditions where organic or inorganic acids were used alone. The extracted pectin samples were generally composed of high methoxyl pectin and their methoxyl contents are observed to be close to that of commercial citrus pectin. FT‐IR spectra results of the extracted samples from garlic waste confirmed the pectin structure compared with the FT‐IR spectrum of commercial citrus pectin. Results indicate that organic–inorganic dual acid mixtures could be used as an efficient extraction media for the controlled physicochemical properties and higher yields of pectin extraction. Considering that about 3.7 million tons of garlic waste is annually produced worldwide, it could be very beneficial to obtain pectin from these wastes as a useful product for the industry.Practical applicationsGarlic waste was converted into a valuable product for the industry and used as an alternative pectin source. Applying organic–inorganic dual acid mixtures during the pectin extraction process from garlic waste allowed to obtain pectin samples with controlled physicochemical properties and higher yields. Extracted pectin samples showed higher Gal‐A contents compared with the conditions where organic or inorganic acids used alone. Obtained pectins were generally composed of high methoxyl pectins and their methoxyl contents are observed to be close to that of the commercial citrus pectin.

Extraction and characterization of a pectin from sea buckthorn peel.

Sea buckthorn peel is the by-product of the sea buckthorn processing, which contains many bioactive compounds. In this paper, sea buckthorn high methoxyl pectin (SBHMP) was obtained, with a yield of 8% and a light-colored. The SBHMP was a high methoxyl with a degree of esterification of 57.75% and uronic acid content of 65.35%. The structural and morphological characterization of SBHMP were analyzed by high-performance liquid chromatography, Fourier-transform infrared spectroscopy, and scanning electron microscopy. Results showed that SBHMP presented a sheet and layered stacked morphological, and was mainly composed of galacturonic acid, arabinose, galactose, rhamnose, and mannose, which indicated that SBHMP mainly consisted of homogalacturonan (HG) and rhamnogalacturonan-I (RG-I) type pectin polysaccharides. In addition, SBHMP also presented significant gel, thickening, and emulsifying properties. The results exhibited that SBHMP could form jelly-like gels under acid and high sucrose conditions, presenting a shear-thinning behavior and increasing apparent viscosity with the enhancement of pectin and sucrose contents. Besides, SBHMP could form oil-in-water emulsions with pectin concentrations of 1.0–3.0%. When the SBHMP concentrations were 2.0 and 3.0%, the emulsions were stable during 7 days of storage. Findings in this paper demonstrated the potential of SBHMP to be a food thickener and emulsifier and support the in-depth utilization of sea buckthorn by-products.

Dilatational rheology-property relationships of β-lactoglobulin /high methoxyl pectin mixtures in aqueous foams

Interface rheology and macroscopic properties of aqueous β-lactoglobulin (BLG)/High methoxyl pectin (HMP) mixtures at different concentrations of pectin by using dynamic foam analyzer and their molecular properties interfaces as their major structural element were investigated. HMP decreased surface tension to some extend and along with BLG showed unique air-water interface and foam stability. BLG at 15 μM was mixed with HMP at two regimes of concentrations, low and high. The surface tension was decreased in the low regime of HMP and then reached a plateau in the high regime. The maximum surface pressure was obtained at 150 μM of pectin (ratio 1:10 protein to polysaccharide). The CMC, the surface excess (Г), and the molecular area (A) of HMP were ∼150 μM, 2.76 μmol/m2 and 0.60, respectively. Similarly, the highest diffusion rate was achieved at 150 μM HMP. The diffusion rate (Kdiff) penetration rate (Kp), and rearrangement rate (Kr) of BLG/HMP were increased as the pectin concentration was increased. There was a reverse relation between the γ and the E′ of the film layer at the interface. Consequently, the lowest γ and the highest dilatational elasticity were achieved at ∼150 μM. BLG/HMP mixtures revealed a synergistic effect at the air-water interface and in the bulk solution can favorably influence foam stability. There was a positive relationship between the surface pressure, foam rheology and foam stability which can be useful in the foam systems developed by BLG and pectin. The foam stability confirmed that BLG/HMP can stabilize air-water interface due to the coacervation at the interface which improve the foam stability.

High Methoxyl Pectin and Sodium Caseinate Film Matrix Reinforced with Green Carbon Quantum Dots: Rheological and Mechanical Studies.

Nowadays, proteins and polysaccharides play a fundamental role in the manufacturing of biocompatible materials applied in food packaging. The resulting films have, however, limits associated with the resistance to mechanical stress; therefore, it is important to reinforce the initial mixture with additives that promote the development of stronger molecular links. Carbon dots (CDs) are excellent candidates for this purpose due to the presence of surface functional groups that determine the formation of numerous intramolecular bonds between the charged biopolymers. The present research aims to evaluate the effect of CDs on the mechanical properties of biopolymer films obtained from sodium caseinate (CAS), high methoxyl pectin (HMP) and glycerol used as plasticizers. Green carbon dots (gCDs) were obtained from natural organic sources by green synthesis. The effects of gCDs on the flow behavior and viscoelastic properties of mixed biopolymer dispersions and the thermophysical properties of the corresponded films were evaluated by steady and unsteady shear rheological measurements and differential scanning calorimetry (DSC) tests, respectively. The dynamic mechanical measurements were realized taking into account the parameters of temperature and relative humidity. The results indicate a significant change in the viscosity of the protein–polysaccharide dispersions and the thermomechanical properties of the corresponding film samples reinforced with higher amounts of gCDs.

Fabrication of phenylalanine amidated pectin using ultra-low temperature enzymatic method and its hydrogel properties in drug sustained release application

In this study, pectin was modified with phenylalanine by ultra-low temperature enzymatic method to improve its gel properties. The grafting ratio of phenylalanine amidated pectin was studied under different reaction conditions. The highest value (29.21 %) was reached a reaction temperature of −5 °C and time of 12 h. Further analysis indicated that phenylalanine and high methoxyl pectin combined at the solid-liquid two phase interface under the catalysis of papain to form phenylalanine amidated pectin. Moreover, the physicochemical properties of pectin hydrogel and its feasibility as a sustained-release drug carrier were discussed. The results showed that phenylalanine amidated pectin can form hydrogel with a certain strength under acidic conditions, and there is no need to add a lot of soluble solids and divalent cations. Besides, the phenylalanine amidated pectin hydrogel as a sustained release carrier of drugs showed more sustained and complete drug release.

The Development of a Pectin-Based Food Ink from Locally Sourced Durian Rind Waste for Possible Use as a 3D Printable Food Material

Durian (Durio zibethinus) is a popular seasonal fruit in Southeast Asia. Pectin can be extracted from the rind. Pectin is an excellent source of fibre and is available in two forms: high and low methoxyl pectin. Both of these types of substances can be employed as gelling agents. As such, the purpose of this research is to partially characterise durian pectin in order to facilitate the development of a pectin-based edible ink formulation. Four formulations of pectin-based food ink were developed and evaluated using a rheometer to determine the viscoelastic properties, a Fourier transform infrared (FTIR) to determine the chemical functional groups available, and thermogravimetric analysis to determine the thermal stability using durian rind waste pectin and commercial pectin. The results indicated that durian pectin contains a low amount of methoxyl (LM) at 2.48 ± 0.31%, which is appropriate for the development of food ink, whereas commercial pectin has a high methoxyl (HM) content of 28.72 ± 0.47%. With viscosities of 31759.20 Pa/s and 7482.62 Pa/s, formulations 3 and 4 of LM pectin exhibited the highest viscoelastic properties. The third and fourth formulations of HM pectin, as well as the third and fourth formulations of LM pectin, contain components that include the alcohol, carbonyl compound, and carbonyl group are found in both pectin granules. The LM pectin formulation 2 offers the highest thermal stability (32.00% residual weight) and the lowest weight loss percentage (57.15%). Due to its capacity to form gel, the LM result demonstrated potential for use in the formulation of edible ink. Additionally, it can be used as a polymeric crosslinker in conjunction with other materials.

Formulation and characterization of microcapsules encapsulating carvacrol using complex coacervation crosslinked with tannic acid

Carvacrol-loaded microcapsules were developed based on coacervation complexes of whey protein isolate (WPI) and high methoxyl pectin (HMP), followed by cross-linking with tannic acid (TA). Optimal pH and WPI-HMP ratios for complex coacervation were found to be 4.1 and 5:1, respectively. Coacervation complexes were used to encapsulate carvacrol. Optimum conditions for achieving morphology and encapsulation efficiency were found for wall materials with a concentration of 2% (w/v), a wall/core ratio of 1:2 (w: w), and a homogenization speed of 15,000 rpm. The optimized formulation of microcapsules has an encapsulation efficiency of 77.48 ± 0.03% for carvacrol and a size of 1.08 μm. The addition of tannic acid (TA) decreased particle size and had no other influence on the morphological properties of microcapsules. Additionally, Fourier transform infrared spectroscopy (FTIR) indicated that coacervates were formed through the electrostatic interactions between WPI and HMP and the main force between TA and coacervates is hydrogen bonding. The addition of HMP to WPI and the presence of TA both decreased the content of tryptophan residues. Carvacrol microcapsules crosslinked with TA demonstrated better stability and antioxidant properties, showing potential for encapsulation of bioactive substances.

Effects of high‐pressure pretreatment on acid extraction of pectin from pomelo peel

SummaryTo explore the effects of high‐pressure processing (HPP) pretreatment on pectin extraction from pomelo albedo, the extraction yield, and characteristics of pectin were compared with those obtained via traditional acid (A‐pectin) extraction. Three different pressures (300, 450, and 600 MPa) and holding times (0, 5, and 10 min) were applied to the fresh albedo, followed by acid extraction. The yield, degree of esterification (DE), galacturonic acid (GalA) content, Fourier transform‐infrared (FT‐IR) spectra, and rheological properties of pectin were investigated. By comparison with A‐pectin, the yield increased by more than two and four times at 300 MPa at holding times of 5 and 10 min, respectively. All extracted pectins were high methoxyl pectins (DE of 76.30–87.83%) with high GalA content (62.3–86.60%); however, there were significant decreases in DE and GalA content when pressure was increased to 600 MPa in comparison with A‐pectin. The pressure level and holding time significantly influenced the viscosity of pectin, and HPP‐pectin 300‐5, 450‐10, and 600‐0 exhibited a much higher viscosity than A‐pectin. Consequently, this study demonstrated that HPP pretreatment of fresh albedo can increase extraction yield and/or alter pectin characteristics for further industrial applications.

Pectin Films with Recovered Sunflower Waxes Produced by Electrospraying.

Valorization of by-products obtained from food processing has achieved an important environmental impact. In this research, sunflower wax recovered from oil refining process was incorporated to low and high-methoxyl pectin films produced by electrospraying. Film-forming solutions and wax-added electrosprayed films were physical and structurally evaluated. The addition of sunflower wax to the film-forming solutions reduces conductivity while raising surface tension and density, whereas the type of pectin had a larger impact on viscosity, with the low-methoxyl solution having the highest value. These changes in physical solution properties influenced the film characteristics, observing thicker films with lower water vapor transmission rate (WVTR) when adding wax. Micrographs obtained by scanning electron microscopy (SEM) revealed the presence of wax particles as small spherical shapes, having a good distribution through the sectional area of films. According to X-ray diffraction (XRD), atomic force microscopy (AFM) and mechanical properties analyses, the presence of wax had an impact on the degree of crystallinity, producing a more amorphous and rougher film’s structure, without affecting the elongation percentage and the tensile stress (p>0.05). These results showed that wax addition improves the physical properties of films, while the suitability of using both pectins and the electrospraying technique was demonstrated.

Encapsulation of quercetin in pea protein-high methoxyl pectin nanocomplexes: Formation, stability, antioxidant capacity and in vitro release profile

Quercetin (Que) is a popular polyphenol with various activities. However, its application was limited due to its poor water solubility, stability, and low bioavailability. In this study, pea protein isolate (PPI) and high methoxyl pectin (HMP) complexes were fabricated to encapsulate and protect Que. Soluble PPI-HMP complexes at pH 5 and pH 6 were selected based on phase diagram of the two biopolymers during acidification. Fluorescence quenching experiments indicated that complex at pH 5 showed higher binding affinity towards Que than that at pH 6. Complexes at pH 5 displayed considerably higher encapsulation efficiency and loading ability with Que than those at pH 6. XRD results indicated that Que may be transformed from crystalloid to amorphous state after encapsulation. Photochemical and thermal stabilities of Que were improved by complexing with PPI-HMP nanocomplexes at both pH values. Encapsulation improved the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azinobis (2-ethylbenzothiazoline-6-sulfonate) (ABTS) free radical scavenging ability of Que and complex at pH 6 had higher antioxidative ability. The in vitro release study showed that Que displayed initial burst release followed by sustained release in simulated intestinal fluid and higher percentage of Que was released in complex at pH 6 than at pH 5. Data obtained may provide useful information for fabricating pea protein based effective delivery system for Que.

Green biorefinery for sugar beet pulp valorisation: Microwave hydrothermal processing for pectooligosaccharides recovery and biobutanol production

The complete valorisation of sugar beet pulp (SBP) through pectooligosaccharides (POS) extraction and biobutanol production was studied. A central composite experimental design was planned to optimise the time and temperature of the hydrothermal microwave-assisted extraction. 59.7% of the POS present in the SBP were recovered, and a prehydrolysate with 31.1 g POS/L was obtained under optimal conditions (165 °C and 12 min). The prehydrolysate was further precipitated by ethanol. One-step and stepwise alcohol precipitation were evaluated. The prehydrolysate:ethanol ratio was increased from 1:1–1:3 in the stepwise precipitation, whereas a ratio of 1:2 was used in the one-step precipitation. The pectin fractions differed from each other in their chemical composition. The molecular weight of the pectin fractions ranged from 474 to 523 kDa, and the degree of esterification of all of them was higher than 50%, so they can be considered high methoxyl pectins. On the other hand, the pretreated solid enriched in glucan was subjected to enzymatic hydrolysis with cellulases and fermented by Clostridium beijerinckii, producing 8.3 g butanol/L after 48 h of fermentation (53 kg butanol/t SBP). As this research has demonstrated, SBP is a suitable feedstock for a green biorefinery approach. The fractionation of SBP by hydrothermal treatment avoids using acid and alkaline solvents and allows high POS and biobutanol production yields.

Investigation on esterified pectin as natural hydrate inhibitor on methane hydrate formation

Flow assurance treatment with chemical have become more common as new natural polymers are being develop and are viable for inhibiting hydrate formation in production systems due to its eco-friendly and economical properties. Using high-pressure micro-differential scanning calorimetry (HP-µDSC), the influence of kinetic inhibition on methane gas hydrate formation from synthetic polymer; polycaprolactam (PVCap) and organic polymers (low- and high-methoxylated pectin) was investigated. HP-µDSC was combined with the use of open-ended capillary tubes to counter the stochasticity of hydrate formation which often results in an inconclusive data set without numerous repetitions. By adding the capillary tubes within the cell, more data points on the performance of the inhibitors. Generally, the addition of these inhibitors increased the delay in formation of hydrates compared to the control sample which contained deionized water at 25˚C subcooling and 10 MPa pressure. However, the two types of organic inhibitors, which are distinguished primarily by the functional group ratios (carboxyl and ester), performed in contrast to one another. The results suggest that the presence of higher carboxyl functional groups is affecting the overall polarity (i.e., low-methoxylated pectin) significantly improved the hydrate inhibition at optimum concentration where both high-methoxylated pectin and PVCap; a commercial inhibitor, performed relatively weaker. In comparison with PVCap, high-methoxylated pectin showed comparable trend and slightly better performances at most concentrations; however, the peak structures indicate discernible difference in the formation mechanism. The use of low-methoxylated pectin at optimum concentration may offer inhibition performance up to three times to that of PVCap at high subcooling.

Pectin extraction from lime pomace by cold-active polygalacturonase-assisted method

An Antarctic yeast was cultivated to produce and enzymatic extract with polygalacturonase activity, whose biochemical properties were studied. It assisted pectin extraction from lime pomace at 20 °C. The extract produced by Tausonia pullulans 8E had an optimum temperature of 40 °C and optimum pH of 5.0. At 20 °C, it displayed 54% of relative activity. A good pH-stability and thermostability were observed. Hg+2 and Co+2 inhibited its activity in 40 and 11%, respectively. Pectin was obtained from lime pomace at 20 °C, with 15% of yield after 120 min extraction. Uronic acid (46%) and neutral sugars (53%) were determined. Pectin's molecular weight was estimated in the order of 100,000 g mol−1. By anion-exchange chromatography, pectin-linked and free neutral sugars were observed. The high-methoxyl pectin was used to prepare low-calorie gels. It was demonstrated that this cold-active enzyme allows enzymatic-assisted pectin extraction at 20 °C.