Preparation of environment-friendly pectin from sugar beet pulp and assessment of its emulsifying capacity

Ferulated Pectins and Ferulated Arabinoxylans Mixed Gel for Saccharomyces boulardii Entrapment in Electrosprayed Microbeads

Ferulated polysaccharides such as pectin and arabinoxylan form covalent gels which are attractive for drug delivery or cell immobilization. Saccharomyces boulardii is a probiotic yeast known for providing humans with health benefits; however, its application is limited by viability loss under environmental stress. In this study, ferulated pectin from sugar beet solid waste (SBWP) and ferulated arabinoxylan from maize bioethanol waste (AX) were used to form a covalent mixed gel, which was in turn used to entrap S. boulardii (2.08 × 10⁸ cells/mL) in microbeads using electrospray. SBWP presented a low degree of esterification (30%), which allowed gelation through Ca²⁺, making it possible to reduce microbead aggregation and coalescence by curing the particles in a 2% CaCl₂ cross-linking solution. SBWP/AX and SBWP/AX+ S. boulardii microbeads presented a diameter of 214 and 344 µm, respectively, and a covalent cross-linking content (dimers di-FA and trimer tri-FA of ferulic acid) of 1.15 mg/g polysaccharide. The 8-5′, 8-O-4′and 5-5′di-FA isomers proportions were 79%, 18%, and 3%, respectively. Confocal laser scanning microscopy images of propidium iodide-stained yeasts confirmed cell viability before and after microbeads preparation by electrospray. SBWP/AX capability to entrap S. boulardii would represent an alternative for probiotic immobilization in tailored biomaterials and an opportunity for sustainable waste upcycling to value-added products.

Eco-friendly extraction and physicochemical properties of pectin from jackfruit peel waste with subcritical water

BACKGROUND

Water is generally considered to be a safe and green solvent suitable for use in natural product extraction. In this study, an eco-friendly subcritical water method was used to extract pectin from waste jackfruit peel (JFP-S), which was compared with pectin obtained by the traditional citric acid method (JFP-C).

RESULTS

The extraction process was optimized using response surface methodology (RSM), and the optimum process parameters were as follows: extraction temperature 138 °C, extraction time 9.15 min, liquid / solid (L/S) ratio 17.03 mL g^-1 . Under these conditions, the pectin yield was 149.6 g kg^-1 (dry basis). Pectin obtained from the two extraction methods displayed a high degree of esterification and the monosaccharide composition was consistent. The galacturonic acid content of JFP-S and JFP-C was 52.27% and 56.99%, respectively. JFP-S had more hairy regions and side chains than JFP-C. The molecular weight of JFP-S was 113.3 kDa, which was significantly lower than that of JFP-C (174.3 kDa). Fourier-transform infrared spectroscopy (FTIR) indicated that two samples had similar pectin typical absorption peaks. According to differential scanning calorimetry (DSC), both JFP-S and JFP-C had relatively good thermal stability. JFP-S demonstrated lower apparent viscosity and elasticity than JFP-C. Meanwhile, the G' and G'' moduli of JFP-S were lower, which found expression in the gel textural characterization of the samples.

CONCLUSION

This work showed that the subcritical water method is an efficient, time-saving, and eco-friendly technology for the extraction of pectin from jackfruit peel compared with the traditional citric acid method. The physicochemical properties of pectin could be changed during subcritical water extraction. © 2019 Society of Chemical Industry.

Pectin and Neutral Monosaccharides Production during the Simultaneous Hydrothermal Extraction of Waste Biomass from Refining of Sugar-Optimization with the Use of Doehlert Design

We propose a one-stage hydrothermal extraction of sugar beet pulp leading to effective co-production of pectin and neutral monosaccharides with a relatively high yield and satisfactory purity without the presence of an acidic catalyst. The optimal experimental design methodology was used for modelling and optimizing the yield of pectin and neutral monosaccharides. In good agreement with experimental results (R² = 0.955), the model predicts an optimal yield of pectin (approx. 121.1 g kg⁻¹ ± 0.47 g kg⁻¹) at a temperature and time of about 118.1 °C and 21.5 min, respectively. The highest yield of the sum of neutral monosaccharides (approx. 82.6 g kg⁻¹ ± 0.72 g kg⁻¹) was obtained at about 116.2 °C and 26.4 min (R² = 0.976). The obtained results are suitable for industrial upscaling and may provide an incentive to implement a new, environmentally friendly, simple, and effective method for treating waste product from the sugar refining industry, which has proved onerous until now.

Synergistic Effect of Laccase and Sugar Beet Pectin on the Properties of Concentrated Protein Emulsions and Its Application in Concentrated Coconut Milk

Concentrated coconut milk (CCM), a raw material from coconut products, is extremely unstable because of its high oil content (>30%). In this study, three model emulsions-primary emulsions stabilized by coconut proteins only, secondary emulsions stabilized by the conjugation of sugar beet pectin (SBP) and coconut protein, and laccase-treated secondary emulsions-were prepared to investigate the effects of different factors (coconut proteins, coconut proteins + SBP, laccase-treated emulsions) on the stability of model emulsions and the application of this method to real CCM. The stability of the emulsions was evaluated based on their interfacial tension, zeta potential, particle size distribution, rheological properties, and the assembly formation of SBP and coconut protein at the oil⁻water interface. Results showed that addition of SBP or laccase can increase the viscosity and reduce the interfacial tension of the emulsion, and the effect was concentration dependent. Zeta potential of the emulsion decreased with the increase of protein (from -16 to -32 mV) and addition of SBP (from -32 to -46 mV), and it was reduced when laccase was added (from -9.5 to -6.0 mV). The secondary emulsion exhibited the narrowest particle size distribution (from 0.1 to 20 μm); however, laccase-catalyzed secondary emulsions showed the best storage stability and no layering when the laccase content reached 10 U/100 g. Confocal laser scanning microscopy (CLSM) revealed that protein was adsorbed on the oil⁻water interface and SBP distributed in the continuous phase could undergo oxidative crosslinking by laccase. These results show that the stability of the concentrated emulsion can be effectively improved by adding SBP and laccase.