Extraction of orange pectin based on the interaction between sodium caseinate and pectin

Properties of lime peel pectin as mainly influenced by ethanol and protein-based purification methods

BACKGROUND

Lime peel, obtained from juice factory waste, is considered as a source of pectin. Lime peel pectin samples, extracted by three extraction procedures of 90 °C heating for 120 min, 90 °C heating for 90 min and then 32 min of ultrasound, and 80 °C heating for 60 min and then 22 min of ultrasound, and purified by two methods using ethanol and sodium caseinate (SC), were prepared and characterized.

RESULTS

The results showed that the purification method significantly affected the lime pectin samples properties. Pectin samples purified with SC had a transparent and film-like appearance, whereas the ethanol-purified pectin samples showed an amorphous and opaque appearance. Pectin samples purified with ethanol showed higher extraction recovery (approximately 20%), whereas the lowest pectin yield was observed for the purification with SC (approximately 10%). Although SC purification did not enhance the pectin yield, it diminished the level of 'non-pectin' components and resulted in purer pectin. The bands at 1045-1076 cm-1 , relating to neutral sugars, had higher intensities in ethanol-purified pectin samples, indicating their higher sugar contents. Also the samples purified with SC exhibited more thermal stability, probably as a result of the presence of protein in their structure.

CONCLUSION

In the present study, under the same or varying extraction conditions, the most important element distinguishing pectins in terms of appearance, physicochemical, thermal and Fourier transform infrared characteristics was the type of purification method. Purification with SC may result in pectins with more non-esterified galacturonic acids from the homogalacturonan fraction. © 2023 Society of Chemical Industry.

An efficient method for improving the stability of Monascus pigments using ionic gelation

BACKGROUND

Monascus pigments (Mps) are easily impacted by heating, pH and light, resulting in degradation. In this study, Mps were encapsulated by the ionic gelation method with sodium alginate (SA) and sodium caseinate (SC), as well as CaCl2 as a crosslinker. The encapsulated Mps SA/SC in four proportions (SA/SC: 1/4, 2/3, 3/2, 4/1, w/w). Then, the encapsulation efficiency and particle size of the SA/SC-Mps system were evaluated to obtain the optimal embedding conditions. Finally, the effects of heating, pH, light and storage on the stability of non-capsulated Mps and encapsulated Mps were assessed.

RESULTS

SA/SC = 2/3 (AC2) had higher encapsulation efficiency (74.30%) of Mps and relatively small particle size (2.02 mm). The AC2 gel beads were chosen for further investigating the stability of encapsulated Mps to heating, pH, light and storage. Heat stability experiments showed that the degradation of Mps followed first-order kinetics, and the encapsulated Mps had lower degradation rates than non-capsulated Mps. Encapsulation could reduce the effect of pH on Mps. The effects of ultraviolet light on the stability of Mps were considered, and showed that the retention efficiency of encapsulated Mps was 22.01% higher than that of non-capsulated Mps on the seventh day. Finally, storage stability was also evaluated under dark refrigerated conditions for 30 days, and the results indicated that encapsulation could reduce the degradation of Mps.

CONCLUSION

This study has proved that AC2 gel beads can improve the stability of Mps. Thus, the ionic gelation method is a promising encapsulation method to improve the stability of Mps. © 2023 Society of Chemical Industry.

Physicochemical, structural and in vitro gastrointestinal tract release properties of ι-carrageenan/sodium caseinate synbiotic microgels produced by double-crosslinking with calcium ions and transglutaminase

The aim of this study was to develop ι-carrageenan (ιC)/sodium caseinate (NaCas) synbiotic microgels loading Lacticasebacillus paracasei produced by double-crosslinking with calcium ions and different concentrations (0, 5, 10, and 15 U/g protein) of transglutaminase (TGase). The synbiotic microgels were coated/filled with pectic oligosaccharide (POS). Field emission scanning electron microscope (FE-SEM) and X-ray diffraction (XRD) analyses indicated that L. paracasei was successfully microencapsulated in synbiotic microgels. In Fourier transform infrared (FT-IR) analysis, the new formation of covalent and ionic crosslinking was observed in double-crosslinked synbiotic microgels. The encapsulation efficiency of L. paracasei was significantly increased from 87.82 to 97.68 % by increasing the concentration of TGase from 0 to 15 U/g protein, respectively. After exposure to simulated gastric fluid for 2 h and simulated intestinal fluid for 4 h, the survival rate of L. paracasei was significantly increased as the concentration of TGase increased.

Structural characteristics and gel properties of pectin from citrus physiological premature fruit drop

This study is the first to extract and characterize pectin from citrus physiological premature fruit drop. The extraction yield of pectin reached 4.4 % by acid hydrolysis method. The degree of methoxy-esterification (DM) of citrus physiological premature fruit drop pectin (CPDP) was 15.27 %, indicating it was low-methoxylated pectin (LMP). The monosaccharide composition and molar mass test results showed CPDP was a highly branched macromolecular polysaccharide (β: 0.02, Mw: 2.006 × 10⁵ g/mol) with rich rhamnogalacturonan I domain (50.40 %) and long arabinose and galactose side chain (32.02 %). Based on the fact that CPDP is LMP, Ca²⁺ was used to induce CPDP to form gels. Textural and rheological tests showed that the gel strength and storage modulus of CPDP were higher than commercial citrus pectin (CP) used in this paper due to the lower DM and rich neutral sugar side chains of CPDP. Scanning electron microscope (SEM) results showed CPDP had stable gel network structure.

Microwave-assisted extraction of pectin from jackfruit rags: Optimization, physicochemical properties and antibacterial activities

While fruit biowastes pose an environmental hazard, they can be utilized as a source of beneficial biopolymers such as pectin. However, conventional extraction techniques require long processing time with low, impure yields, and microwave assisted extraction (MAE) can suffer from these drawbacks. Here, MAE was applied to extract pectin from jackfruit rags and compared with conventional heating reflux extraction (HRE). Response surface methodology was adopted to optimize pectin yield, based on pH (1.0-2.0), solid-liquid ratio (1:20-1:30), time (5-90 min), and temperature (60-95 °C). Pectin extraction by MAE required lower temperatures (65.99 °C) and shorter reaction times (10.56 min). Pectin HRE resulted in a product with amorphous structures and rough surfaces, while pectin-MAE was high crystalline with smooth surfaces. Although both pectin samples showed shear-thinning behavior, pectin-MAE exhibited higher antioxidant and antibacterial activities. Therefore, microwave assisted extraction was an efficient method to extract pectin from jackfruit rags.

Physicochemical properties and prebiotic activities of polysaccharides from Zizyphus jujube based on different extraction techniques

Zizyphus jujube polysaccharide was extracted with hot water, ultrahigh pressure, deep eutectic solvent (DES) and ultrahigh pressure-assisted DES. Comparative analyses were conducted on the yield, physicochemical properties and prebiotic activity of four polysaccharides (JP-H, JP-U, JP-D and JP-UD). The yield of JP-UD (10.42 %) was 3.3 times that of JP-H (3.12 %), and its sugar content was the highest. JP-UD possessed the lowest Mw, while JP-H possessed the highest. Four JPs were acidic pyranose and mainly composed of galacturonic acid, arabinose and galactose. NMR results demonstrated that they contained not only similar glycosidic linkage but also the specific glycosidic linkage of →4)-α-D-Glcp-(l→ appeared in JP-U and JP-UD, the esterified units of GalA and CONH₂ group appeared in JP-D and JP-UD, and the Terminal β-D-Galp and →4)-α-GalpA-(1→ appeared in JP-UD. JPs showed different proliferation effects on four lactobacillus strains, among which JP-UD exhibited the strongest prebiotic activity. Zizyphus jujube polysaccharides have great potential for application in the functional food and medical industry.

The physicochemical properties and the release of sodium caseinate/ polysaccharide gum chlorophyll multiple-layer particles by rotary side-spray fluid bed technology

Multiple-layer coating technology has widely applied to the quality modification of bioactive ingredients nowadays. This research used a rotary side-spray fluid bed to manufacture chlorophyll multiple-layer particles to adjust control release characteristics. The chlorophyll extracts were coated with sodium alginate (A1) and sodium caseinate (CA1) as the primary layer on sugar spheres and the product yield was 96.98 and 96.71%, respectively. The content of chlorophyll a and b (μg/g) were 41.04 and 13.20 in A1, 47.40 and 13.68 in CA1. The Fourier-transform infrared spectroscopy confirmed the bonding change and increase stability. The CA1 was coated with sodium alginate (CA-A), sodium carboxymethylcellulose (CA-C) and xanthan gum (CA-X) as the secondary layer, which can increase coated integrity, shell strength and thermal stability. The simulated gastrointestinal fluid showed 30.11% release in the stomach and 94.27% in the intestine, which improved release control characteristics. Increased retention rate and color stability in the storage test.

Effect of bentonite and calcium chloride on apple wine

BACKGROUND

Apple wine is a popular alcoholic beverage for its nutrition and fresh taste. However, the methanol existing in apple wine restricts its quality. Unfortunately, there are no methods to reduce the methanol content in fruit wine. To this end, bentonite (B), calcium chloride (CC) and their combination (B&CC) were added into apple juice in this study. The treated juice (0) and supernatant obtained by standing the juice at 25 °C for 24 h were fermented at 25 °C and 10 °C, respectively.

RESULTS

Bentonite was an excellent methanol interrupter, a pectin retainer and a wine quality defender both at 25 and 10 °C. The lowest methanol content of 1.41 mg L^-1 and higher pectin content of 84.74 mg L^-1 were reached in the finished wine by B0 at 10 °C. Calcium chloride decreased pectin content, elevated methanol content and changed the profile of individual organic acids. In fact, the wine by B&CC0 at 25 °C showed dramatic changes in individual organic acids. The content of l-malic acid and succinic acid was only 2.22% and 6.29% of the control, respectively, while the lactic acid content was 17.72 times that of the control.

CONCLUSIONS

It is suggested that B0 and fermented at 10 °C was the most effective way to decrease methanol content, retain pectin content and defend wine quality. © 2021 Society of Chemical Industry.

Characterization and prebiotic properties of pectin polysaccharide from Clausena lansium (Lour.) Skeels fruit

Pectins have proven to be advantageous for human health as they regulate beneficial microbial communities and enhance immunity. The fruit of Clausena lansium (Lour.) Skeels (Wampee), also referred to as "treasure in fruit", is rich in pectin polysaccharides. In this study, a homogalacturonan-type pectin (CCP2) with a molecular weight of 8.9 × 10⁴ Da and degree of esterification of 42.86% was isolated from Wampee fruit. The gut microbiota regulation and phagocytosis-enhancing properties of CCP2 were examined in vivo and in vitro, respectively. Oral administration of CCP2 dramatically decreased the abundance of Bacteroidetes and increased the abundance of Firmicutes in intestinal bacteria in mice. The content of short-chain fatty acids in the feces also significantly improved. Moreover, CCP2 exhibited excellent phagocytosis-enhancing activities on RAW 264.7 macrophages. These results suggested that CCP2 could be a potential gut microbiota regulator and phagocytosis-enhancer, which could be used in food products to promote health through beneficial manipulation of gut microbiota.

Effect of centrifugal pre-treatment on flavor change of cloudy orange juice: Interaction between pectin and aroma release

Cloud loss of orange juice could be effectively inhibited by centrifugal treatment, but it can induce flavor changes, which become a new challenge for the industry. This work aims to investigate the effect of centrifugation on flavor changes in orange juice and explore its possible mechanism. Taste- and aroma-related attributes were analyzed, and pectin was characterized. Results indicated that pH (4.00), total soluble solid (9.67 °Brix), titratable acidity (0.42%), sucrose (44%), fructose (29%), and glucose (27%) were less affected by centrifugation (P > 0.05). However, aroma compounds significantly changed (P < 0.05), where terpenes and alcohols tended to be distributed in pulp and serum after centrifugation, respectively. Pearson correlation analysis showed that aroma compound distribution induced by centrifugation was highly related to chelator-solubilized pectin fraction and sodium carbonate-solubilized pectin fraction (|R| > 0.9). In general, centrifugation clearly changed aroma of orange juice, which was mainly affected by pectin characteristics.

Effects of Salts on Structural, Physicochemical and Rheological Properties of Low-Methoxyl Pectin/Sodium Caseinate Complex

The addition of salts is an effective way to improve the properties of polysaccharide/protein complexes for use in foods. However, there is no comparative study on the effects of different ions on the complex system of low methoxyl pectin (LMP)/ sodium caseinate (CAS) complex. The effects of different concentrations of three salt ions (Na⁺, K⁺, Ca²⁺) on the physicochemical and rheological properties of the LMP/CAS complex were determined in this study, and the structure of LMP/CAS complex was characterized. The results showed that the addition of these three salt ions affected zeta potential, particle size, and turbidity of the LMP/CAS complex, and lead the LMP/CAS complex to form a more regular and uniform network structure, which helped improve its stability, solubility, and rheological properties. The particle size and turbidity value of the complex achieved with Ca²⁺ were higher than those obtained using Na⁺ and K⁺. Moreover, the secondary structure of the proteins in the complex changed to adding high concentrations of Ca²⁺. Our study provides valuable information for the application of the LMP/CAS complex in the food industry.

Combination of Coagulation-Flocculation-Decantation and Ozonation Processes for Winery Wastewater Treatment

This research assessed a novel treatment process of winery wastewater, through the application of a chemical-based process aiming to decrease the high organic carbon content, which represents a difficulty for wastewater treatment plants and a public health problem. Firstly, a coagulation–flocculation–decantation process (CFD process) was optimized by a simplex lattice design. Afterwards, the efficiency of a UV-C/ferrous iron/ozone system was assessed for organic carbon removal in winery wastewater. This system was applied alone and in combination with the CFD process (as a pre- and post-treatment). The coagulation–flocculation–decantation process, with a mixture of 0.48 g/L potassium caseinate and 0.52 g/L bentonite at pH 4.0, achieved 98.3, 97.6, and 87.8% removals of turbidity, total suspended solids, and total polyphenols, respectively. For the ozonation process, the required pH and ferrous iron concentration (Fe²⁺) were crucial variables in treatment optimization. With the application of the best operational conditions (pH = 4.0, [Fe²⁺] = 1.0 mM), the UV-C/ferrous iron/ozone system achieved 63.2% total organic carbon (TOC) removal and an energy consumption of 1843 kWh∙m⁻³∙order⁻¹. The combination of CFD and ozonation processes increased the TOC removal to 66.1 and 65.5%, respectively, for the ozone/ferrous iron/UV-C/CFD and CFD/ozone/ferrous iron/UV-C systems. In addition, the germination index of several seeds was assessed and excellent values (>80%) were observed, which revealed the reduction in phytotoxicity. In conclusion, the combination of CFD and UV-C/ferrous iron/ozone processes is efficient for WW treatment.

Development and Characterization of Functional Starch-Based Films Incorporating Free or Microencapsulated Spent Black Tea Extract

Antioxidant polyphenols in black tea residue are an underused source of bioactive compounds. Microencapsulation can turn them into a valuable functional ingredient for different food applications. This study investigated the potential of using spent black tea extract (SBT) as an active ingredient in food packaging. Free or microencapsulated forms of SBT, using a pectin-sodium caseinate mixture as a wall material, were incorporated in a cassava starch matrix and films developed by casting. The effect of incorporating SBT at different polyphenol contents (0.17% and 0.34%) on the structural, physical, and antioxidant properties of the films, the migration of active compounds into different food simulants and their performance at preventing lipid oxidation were evaluated. The results showed that adding free SBT modified the film structure by forming hydrogen bonds with starch, creating a less elastic film with antioxidant activity (173 and 587 µg(GAE)/g film). Incorporating microencapsulated SBT improved the mechanical properties of active films and preserved their antioxidant activity (276 and 627 µg(GAE)/g film). Encapsulates significantly enhanced the release of antioxidant polyphenols into both aqueous and fatty food simulants. Both types of active film exhibited better barrier properties against UV light and water vapour than the control starch film and delayed lipid oxidation up to 35 d. This study revealed that starch film incorporating microencapsulated SBT can be used as a functional food packaging to protect fatty foods from oxidation.

Pectin in biomedical and drug delivery applications: A review

Natural macromolecules have attracted increasing attention due to their biocompatibility, low toxicity, and biodegradability. Pectin is one of the few polysaccharides with biomedical activity, consequently a candidate in biomedical and drug delivery Applications. Rhamnogalacturonan-II, a smaller component in pectin, plays a major role in biomedical activities. The ubiquitous presence of hydroxyl and carboxyl groups in pectin contribute to their hydrophilicity and, hence, to the favorable biocompatibility, low toxicity, and biodegradability. However, pure pectin-based materials present undesirable swelling and corrosion properties. The hydrophilic groups, via coordination, electrophilic addition, esterification, transesterification reactions, can contribute to pectin's physicochemical properties. Here the properties, extraction, and modification of pectin, which are fundamental to biomedical and drug delivery applications, are reviewed. Moreover, the synthesis, properties, and performance of pectin-based hybrid materials, composite materials, and emulsions are elaborated. The comprehensive review presented here can provide valuable information on pectin and its biomedical and drug delivery applications.

Quality of reduced-fat meat emulsion: effect of pre-emulsified duck skin and hydrocolloids

This study explored the impact of reduced-fat meat emulsion with pre-emulsified duck skin and hydrocolloids on physicochemical properties such as cooking loss, emulsion stability, apparent viscosity, protein solubility, and texture profile analysis. Six different reduced-fat meat emulsions were produced: control (pork back fat), T1 (duck skin, DS), T2 (pre-emulsified with duck skin, PDS), T3 (PDS + 2% carrageenan), T4 (PDS + 2% alginate), T5 (PDS + 2% pectin), and T6 (PDS + 2% guar gum). Moisture content, protein content, yellowness, and apparent viscosity of reduced-fat emulsion with PDS and hydrocolloids were all higher (P < 0.05) than control. Cooking loss and emulsion stability of T4 and T6 were lower (P < 0.05) than the control values. Cooking loss and total fluid separation were greatest (P < 0.05) for T5. Fat content of reduced-fat emulsion with PDS was lower (P < 0.05) than that of the control. Meat emulsion comprising PDS with alginate resulted in superior physicochemical properties compared to the other reduced-fat meat emulsion.

Electrostatic complexation of β-lactoglobulin aggregates with κ-carrageenan and the resulting emulsifying and foaming properties

The electrostatic complexation of protein and polysaccharide and the functional properties of the complexes are significantly affected by the structure of protein aggregates and are important in the development of new food ingredients. In this work, natural globular β-lactoglobulin (NGBLG), β-lactoglobulin nanoparticles (BLGNP), and β-lactoglobulin fibrils (BLGF) were prepared and complexed with κ-carrageenan (κ-car). Phase diagrams of the NGBLG-, BLGNP-, and BLGF-κ-car systems were established and divided into 4 regions: mixed soluble polymers (I), intramolecular soluble complex (II), intermolecular soluble complex (III), and intermolecular insoluble complex (IV). Aggregation shifted the boundaries of regions III and IV of BLGF- or BLGNP-κ-car to lower pH and higher protein aggregates/κ-car weight ratio (r), especially for BLGF-κ-car. The emulsifying and foaming properties of the 3 mixed systems were investigated in regions I and II. Complexes in region II had significantly better emulsifying properties than the corresponding mixtures in region I and the pure protein aggregates. Interestingly, phase separation resulted in different effects on the foaming properties of the 3 BLG-κ-car complexes, in which BLGF-κ-car complexation in region II decreased the foaming properties in region I but the complexation of NGBLG-κ-car and BLGNP-κ-car in region II increased the foaming properties. The BLGF-κ-car complex in regions I and II provided the best emulsifying and foaming properties. Interfacial data both on oil-water and air-water interfaces overall explained the emulsifying and foaming properties of the complexes.

Structure-activity relationship of Citrus segment membrane RG-I pectin against Galectin-3: The galactan is not the only important factor

Rhamnogalacturonan I (RG-I) pectin are regarded as strong galectin-3 (Gal-3) antagonist because of galactan sidechains. The present study focused on discussing the effects of more structural regions in pectin on the anti-Gal-3 activity. The water-soluble pectin (WSP) recovered from citrus canning processing water was categorized as RG-I pectin. The controlled enzymatic hydrolysis was employed to sequentially remove the α-1,5-arabinan, homogalaturonan and β-1,4-galactan in WSP. The Gal-3-binding affinity KD (kd/ka) of WSP and debranched pectins were calculated to be 0.32 μM, 0.48 μM, 0.56 μM and 1.93 μM. Moreover, based on the more sensitive cell line (MCF-7) model, the IC₃₀ value of WSP was lower than these of modified pectins, indicating decreased anti-Gal-3 activity. Our results suggested that the total amount of neutral sugar sidechains, the length of arabinan and cooperation between HG and RG-I played important roles in the anti-Gal-3 activity of WSP, not the Gal/Ara ratio or RG-I/HG ratio. These results provided a new insight into structure-activity relationship of citrus segment membrane RG-I as a galectin-3 antagonist and a new functional food.

Determination of pectin content in orange peels by near infrared hyperspectral imaging

Pectin has several purposes in the food and pharmaceutical industry making its quantification important for further extraction. Current techniques for pectin quantification require its extraction using chemicals and producing residues. Determination of pectin content in orange peels was investigated using near infrared hyperspectral imaging (NIR-HSI). Hyperspectral images from orange peel (140 samples) with different amounts of pectin were acquired in the range of 900-2500 nm, and the spectra was used for calibration models using multivariate statistical analyses. Principal component analysis (PCA) and linear discriminant analysis (LDA) showed better results considering three groups: low (0-5%), intermediate (10-40%) and high (50-100%) pectin content. Partial least squares regression (PLSR) models based on full spectra showed higher precision (R2 > 0.93) than those based on few selected wavelengths (R2 between 0.92 and 0.94). The results demonstrate the potential of NIR-HSI to quantify pectin content in orange peels, providing a valuable technique for orange producers and processing industries.

Comparison between irradiating and autoclaving citrus wastes as substrate for solid-state fermentation by Aspergillus aculeatus

Agricultural or food processing wastes cause serious environmental burden and economic losses. Solid-state fermentation using these wastes is an attractive option to valorize these wastes. However, conventional autoclaving of substrate may degrade nutrients and generate toxins. Unsterilization of the substrate will cause undesired microbial contamination. Therefore, we compared irradiation with autoclaving to treat citrus wastes as substrate for solid-state fermentation by Aspergillus aculeatus. By comparing microbial growth, enzymes tested and medium consumption, irradiated substrate had higher biomass and extracellular protein, more sugar consumption and higher enzyme production than those with autoclaved substrate. Irradiation prevented the generation of cell-inhibiting components such as 5-hydroxymethylfurfural (5-HMF) whereas preserved the flavonoids well that are often enzyme inducers. These findings suggest that irradiation of agricultural and food processing wastes as substrate has advantages over autoclaving for solid-state fermentation. SIGNIFICANCE AND IMPACT OF THE STUDY: This study proposes irradiation as an alternative to sterilize agricultural residues rich in nutrients and thermosensitive compounds, such as citrus wastes for fungal solid-state fermentation and production of enzymes.