Impacts of high hydrostatic pressure processing on the structure and properties of pectin

Characterizations of Pectin from Choerospondias axillaris Fruit Pulp: Comparison of Different Extraction Methods

Generally, the extraction method has a great influence on the quality of pectin. However, there is little study on the effect of extraction method on the properties of Choerospondias axillaris fruit pulp pectin (CAPP). Accordingly, the physicochemical, structural, and functional properties of CAPP extracted by hot water (HWE), hydrochloric acid (HAE), ultrasound (UAE), and ultrahigh pressure (UPE) were investigated. Among these four CAPPs, UPE had the highest yield (15.79%) and GalA content (60.44%). UAE showed the most abundant side chains and RG-I region (55.12%). The lowest molecular weight (233.13 kDa) and yield (8.64%) were found in HAE. Though HWE exhibited better yield than HAE, its Mw was the highest. Different from physicochemical characteristics, the extraction method had a small effect on the structure of CAPP. The crystalline structure and functional group composition of different CAPPs were similar, while the surface structure of UAE and UPE had irregular circular holes in comparison with HWE and HAE. Furthermore, the extraction method also showed a great impact on the function. Compared with HWE and HAE, UAE and UPE presented better thermal stability and emulsifying properties. Meanwhile, HAE and UAE showed better antioxidant ability and prebiotic properties among these four CAPPs. The above results indicated that UAE showed better yield and functional properties. Hence, ultrasound extraction could be used as an effective method to extract CAPP.

Reducing the oil absorption and oil deterioration in fried apple slices by ultrasound integrated in infrared frying

The effects of integrated ultrasonic infrared frying (USIF) on the oil absorption of apple slices and the oil deterioration were studied with frequency of 28 and 40 kHz, respectively. Results showed that the heat transfer and moisture migration was accelerated by the integrated ultrasound in IF. The soluble Gal-A content and esterification degree of pectin was increased, the damages of pectin crystal structure and chemical structure in side chain was aggravated. These damages to pectin were intensified with higher frequency (40 kHz) of ultrasound. Lower retention of phenols was found in USIF apple slices, but the flavonoids content had no significant change compared to CF samples. USIF samples showed a smoother morphology, and the pore volume and porosity were reduced by ultrasonication applied with 28 kHz but increased with 40 kHz. The largest volume fraction of pores was changed from 100-250 μm in IF to 0.02-10 μm and 10-100 μm by the integrated ultrasound at 28 kHz and 40 kHz samples, respectively. The total oil uptake in USIF samples was reduced by 24.9 %-33.2 % compared to the conventional fried (CF) samples, and achieved the lowest with the frequency of 40 kHz. The surficial and structural oil were also decreased by 39.2 %-51.3 % and 20.9 %-32.3 %, respectively. The peroxide value, acid value, carbonyl value, polar component, and the saturated fatty acids ratio of oil in repeated frying for 16 h was reduced in USIF, especially with ultrasonication 40 kHz. These results indicate that USIF is a promising method for producing novel low-oil apple fries.

Elucidation of the structural changes of hemicellulose and cellulose in sunflower seed during roasting

This study evaluated the structural changes in hemicellulose and cellulose from sunflower seeds before and after roasting at 160°C, 190°C, and 220°C. Sugar composition, molecular weight, Fourier transform infrared spectrometry, thermogravimetric, and NMR analyses were utilized to determine the structural properties of these polysaccharides and detect the volatile compounds. The results showed that roasting destroyed the microstructure of these hemicelluloses and cellulose. Glucose and arabinose of hemicellulose were more easily degraded than other sugars during roasting. The galacturonic acid content increased from 7.8% to 46.66% after roasting. The hemicellulose obtained at 220°C had a backbone of D-xylose residues with a β-(1→4)-linkage. The molecular weight of cellulosic polysaccharides decreased with the increase of roasting temperature. The crystallinity increased from 28.92% to 31.86% revealing that mainly the amorphous regions of cellulosic polysaccharides were destroyed by roasting. After roasting, the volatile compounds of these polysaccharides were rich in furfural, which was produced by caramelization and the Maillard reaction, contributing to the characteristic aroma of roasted sunflower seeds. This study provides some information on the relationship between structural changes of polysaccharides and the formation of flavor during roasting sunflower seeds.

Unveiling the impact of high-pressure processing on anthocyanin-protein/polysaccharide interactions: A comprehensive review

Anthocyanins, natural plant pigments responsible for the vibrant hues in fruits, vegetables, and flowers, boast antioxidant properties with potential human health benefits. However, their susceptibility to degradation under conditions such as heat, light, and pH fluctuations necessitates strategies to safeguard their stability. Recent investigations have focused on exploring the interactions between anthocyanins and biomacromolecules, specifically proteins and polysaccharides, with the aim of enhancing their resilience. Notably, proteins like soy protein isolate and whey protein, alongside polysaccharides such as pectin, starch, and chitosan, have exhibited promising affinities with anthocyanins, thereby enhancing their stability and functional attributes. High-pressure processing (HPP), emerging as a non-thermal technology, has garnered attention for its potential to modulate these interactions. The application of high pressure can impact the structural features and stability of anthocyanin-protein/polysaccharide complexes, thereby altering their functionalities. However, caution must be exercised, as excessively high pressures may yield adverse effects. Consequently, while HPP holds promise in upholding anthocyanin stability, further exploration is warranted to elucidate its efficacy across diverse anthocyanin variants, macromolecular partners, pressure regimes, and their effects within real food matrices.

Comparison on emulsifying and emulgelling properties of low methoxyl pectin with varied degree of methoxylation from different de-esterification methods

Low methoxyl pectin (LMP) with different degree of methoxylation (DM, 40-50 %, 20-30 % and 5-10 %) were prepared from commercially available citrus pectin using high hydrostatic pressure assisted enzymatic (HHP-pectin) and traditional alkaline (A-pectin) de-esterification method. The results showed that both de-esterification methods and DM exhibited LMPs with varied physicochemical, structural, and functional properties. As the DM decreased, LMP showed a decrease in molecular weight (Mw), while an increase in negative charges and rhamnogalacturonan I (RG-I) ratio, accompanied with better emulsion stability, emulsion gel strength and water-holding properties. Relative to A-pectin, HHP-pectin had higher Mw and lower RG-I side chain ratio, contributing to its better thermal stability, apparent viscosity, and emulgelling properties. HHP-pectin with lower DM (5-10 %) showed superior thickening, emulsifying and emulgelling properties, while that with higher DM (40-45 %) had superior thermal stability, which provided alternative for de-esterification and targeted structural modification of pectin.

Mechanisms of persimmon pectin methyl esterase activation by high pressure processing based on chemical experiments and molecular dynamics simulations

High pressure processing (HPP) was found to have a kinase effect on persimmon pectin methyl esterase (PME), while the mechanism remains unclear. In this study, chemical experiments and molecular dynamics (MD) simulations were used to reveal its mechanisms. Persimmon PME was first extracted and purified using ion exchange columns with 81.89% purity. After 500 MPa/5 min, PME activity increased 11.3%, the α-helix and β-folding decreased 10.8% and 6.1% compared to the 0.1 MPa group, respectively. MD results showed that HPP decreased the volume, increased the number of hydrogen bonds between PME and pectin. Under high pressure, Asp-157, Asp-136 and Gln-135 in the enzyme activity center remained stable, while the positions of Arg-225 and Gln-113 changed a lot. The conformation of the substrate binding channel also changed. The secondary structure and volume changes of the HPP-treated PME affected the active center and substrate channels, ultimately altering the activity.

Effect of pasteurization processing and storage conditions on softening of acidified chili pepper: Pectin and it related enzymes

The softening of acidified chili peppers induced by processing and storage has become a major challenge for the food industry. This study aims to explore the impact of pasteurization techniques, thermal processing (TP), high-pressure processing (HPP), addition of sodium metabisulfite (SMS), and storage conditions (25 °C, 37 °C, and 42 °C for 30 days) on the texture-related properties of acidified chili pepper. The results showed that the textural properties of samples were destructed by TP (the hardness of samples decreased by 19.43 %) but were less affected by HPP and SMS. Compared with processing, storage temperature had a more dominant impact on texture and pectin characteristics. With increased storage temperature, water-solubilized pectin fraction content increased (increased by 160.99 %, 136.74 %, and 13.01 % in TP, HPP, and SMS-stored groups, respectively), but sodium carbonate-solubilized pectin fraction content decreased (decreased by 29.84 %, 26.81 %, and 8.60 % in TP-, HPP-, and SMS-stored groups, respectively), especially in TP-stored groups. Multivariate data analysis showed that softening was more closely related to pectin conversion induced by acid hydrolysis and pectinase depolymerization. This finding offers new perspectives for the production of acidified chili pepper.

Modification methods, biological activities and applications of pectin: A review

Pectin is a complex and functionally rich natural plant polysaccharide that is widely used in food, medical, and cosmetic industries. It can be modified to improve its properties and expand its applications. Modification methods for natural pectin can be divided into physical, chemical, enzymatic, and compound methods. Different modification methods can result in modified pectins (MPs) exhibiting different physicochemical properties and biological activities. The objectives of this paper were to review the various pectin modification methods explored over the last decade, compare their differences, summarize the impact of different modification methods on the biological activity and physicochemical properties of pectin, and describe the applications of MPs in food and pharmaceutical fields. Finally, suggestions and perspectives for the development of MPs are discussed. This review offers a theoretical reference for the rational and efficient processing of pectin and the expansion of its applications.

Fabrication of Whey Protein Isolate-Pectin Nanoparticles by Thermal Treatment: Effect of Dynamic High-Pressure Treatment

This study investigated the impact of dynamic high-pressure (DHP) treatment on the ability of whey protein isolate (WPI) to form associative complexes with pectin and to form aggregate particles after their subsequent heat treatment. Light scattering showed that DHP treatments disrupted preexisting WPI aggregates and assembled pectin chains. Complexes formed from WPI/pectin mixtures at pH 4.5 were an order of magnitude smaller when formed after DHP treatment, regardless of the degree of esterification. WPI/pectin complexes formed after DHP treatment were more stable against subsequent pH neutralization than complexes formed without DHP treatment, and WPI/high-methoxyl pectin (HMP) complexes had greater stability than WPI/low-methoxyl pectin (LMP) complexes. WPI/pectin particles prepared by thermal treatment of complexes at pH 4.5 were also smaller when prepared after DHP treatment. WPI/HMP particles were stable to subsequent pH neutralization, while WPI/LMP particles became larger after neutralization.

Characterize the physicochemical properties and microstructure of pectin from high-pressure and thermal processed cloudy hawthorn (Crataegus pinnatifida) juice based on acid heating extraction

Physicochemical properties and morphological features of pectin in high-pressure-processing (JHPP) and thermal-processing (JTP) treated cloudy hawthorn juice were investigated based on acid heating extraction. Pectin from hawthorn juice was identified as low methoxy pectin (41.77%), which was significantly reduced to 34.56%-39.51% from JHPP, while pectin esterification degree (DE) from JTP increased to 45.58%, which can also be confirmed by Fourier transform infrared spectroscopy. In comparison to control, pectin linearity of JHPP and JTP significantly decreased with more highly branched-chains. However, no significate difference was observed in thermostability, crystallinity and main functional groups. Interestingly, a large number of aggregations was observed in JHPP pectin, and the intermodular distance of JTP pectin was enhanced, which was consistent with the results of viscosity, molecular weight and DE. These findings provided insights into utilization of hawthorn pectin and application of high-pressure processing (HPP) for improving quality property of fruit products by pectin modification.

Dietary fiber modification: structure, physicochemical properties, bioactivities, and application-a review

There is increasing attention on the modification of dietary fiber (DF), since its effective improvement on properties and functions of DF. Modification of DF can change their structure and functions to enhance their bioactivities, and endow them with huge application potential in the field of food and nutrition. Here, we classified and explained the different modification methods of DF, especially dietary polysaccharides. Different modification methods exert variable effects on the chemical structure of DF such as molecular weight, monosaccharide composition, functional groups, chain structure, and conformation. Moreover, we have discussed the change in physicochemical properties and biological activities of DF, resulting from alterations in the chemical structure of DF, along with a few applications of modified DF. Finally, we have summarized the modified effects of DF. This review will provide a foundation for further studies on DF modification and promote the future application of DF in food products.

The Preparation and Potential Bioactivities of Modified Pectins: A Review

Pectins are complex polysaccharides that are widely found in plant cells and have a variety of bioactivities. However, the high molecular weights (Mw) and complex structures of natural pectins mean that they are difficult for organisms to absorb and utilize, limiting their beneficial effects. The modification of pectins is considered to be an effective method for improving the structural characteristics and promoting the bioactivities of pectins, and even adding new bioactivities to natural pectins. This article reviews the modification methods, including chemical, physical, and enzymatic methods, for natural pectins from the perspective of their basic information, influencing factors, and product identification. Furthermore, the changes caused by modifications to the bioactivities of pectins are elucidated, including their anti-coagulant, anti-oxidant, anti-tumor, immunomodulatory, anti-inflammatory, hypoglycemic, and anti-bacterial activities and the ability to regulate the intestinal environment. Finally, suggestions and perspectives regarding the development of pectin modification are provided.

Inhibition effect of high hydrostatic pressure combined with epigallocatechin gallate treatments on pectin methylesterase in orange juice and model system

High hydrostatic pressure (HHP) is currently the most successful non-thermal processing technology for commercial applications, but with a drawback that it is difficult to effectively inactivate the pectin methylesterase (PME), which is critical to the stability of orange juice. In this study, the PME inhibition and mechanism by HHP (600 MPa/10 min) combined with epigallocatechin gallate (HHP-EGCG) treatment were investigated. Firstly, the HHP-EGCG treatment showed enhancement effect on PME inhibition in orange juice, and the samples maintained higher content of water soluble pectin and exhibited higher suspension stability than the HHP treated samples during 13 days of refrigerated storage. Secondly, after HHP-EGCG treatment, further synergistic effect was observed in the phosphate buffer system, and the greatest secondary structure transformation and fluorescence quenching of PME occurred. Finally, molecule docking suggested that EGCG could interact with the active sites of PME, and transmission electron microscope results revealed further aggregation of PME under HHP-EGCG treatment.

Extraction of Pectin from Satsuma Mandarin Peel: A Comparison of High Hydrostatic Pressure and Conventional Extractions in Different Acids

Satsuma mandarin peel pectin was extracted by high hydrostatic pressure-assisted citric acid (HHPCP) or hydrochloric acid (HHPHP), and the physiochemical, structural, rheological and emulsifying characteristics were compared to those from conventional citric acid (CCP) and hydrochloric acid (CHP). Results showed that HHP and citric acid could both increase the pectin yield, and HHPCP had the highest yield (18.99%). Structural characterization, including NMR and FTIR, demonstrated that HHPHP showed higher Mw than the other pectins. The viscosity of the pectin treated with HHP was higher than that obtained with the conventional method, with HHPHP exhibiting significantly higher viscosity. Interestingly, all the pectin emulsions showed small particle mean diameters (D_4,3 being 0.2–1.3 μm) and extremely good emulsifying stability with centrifugation and 30-day storage assays, all being 100%. Satsuma mandarin peel could become a highly promising pectin source with good emulsifying properties, and HHP-assisted acid could be a more efficient method for pectin extraction.