Potential of bagasse obtained using hydrothermal liquefaction pre‐treatment as a natural emulsifier

Abstract

Summary Bagasse, a by‐product from raw sugar factories, is conventionally burned for energy production. In this study, bagasse extracts from hydrothermal liquefaction (HTL) treatment (160 °C, 1 MPa and 30 min) with a carbohydrate content of 510.3 mg g−1 and 0.5 mg g−1 of total phenols were applied as emulsifiers in oil‐in‐water (O/W) emulsions. Bagasse extracts from HTL (0.5–4 wt%) lowered the interfacial tension between oil–water interphase from 19.8 to 14.0 mN m−1, owing possibly to the surface‐active hydrophilic carbohydrate‐hydrophobic lignin complexes in the extracts (lignin content: 7.1% w/w). Emulsions stabilised by bagasse extracts from HTL with average droplet size, dav of 0.79 μm were comparable with gum arabic (GA), dav of 2.24 μm after 11 days at 25 °C. Bagasse extracts containing biopolymers have the potential for industrial applications involving emulsion systems; therefore, HTL treatment of bagasse without any solvents can be regarded as an effective tool for producing natural emulsifiers.

Conversion of aqueous extracts from thermochemical treatment of bagasse into functional emulsifiers

“…S2). However, the cooling time was reduced and the liquefaction yield was also lower than reported previously (Vodo et al ., 2020). In this study, the cooling time was reduced to 30 min (Fig.…”

“…Apart from parameters such as temperature, time, pressure, solid to liquid ratio, and sample composition, heating and cooling rates are also important factors in determining the effectiveness of HTL treatment. It was observed that with 0.5 h cooling time achieved, the cooling rate was 4 °C min −1 , 8 times faster than using the fan (Vodo et al ., 2020). The HTL reactor had provision for cooling water circulation that only passed through the top while the temperature of the reactor cell at the bottom would hardly decrease.…”

“…These compounds contribute to the amphiphilic character and reportedly show stabilising capacities against emulsion creaming (Lehtonen et al ., 2018; Mikkonen, 2020). It is hypothesized that the presence of small, linear chain polymers in the P and R portions, containing hemicellulose and lignin derivatives, adsorbs at the oil droplet interface and stabilising O/W emulsion against physical breakdown (Vodo et al ., 2020), that is, by thickening the interfacial layer due to steric hindrance caused by phenolic compounds that are glycosidically bound at the interface and were responsible for flocculation as well (Lehtonen et al ., 2018).…”

“…In this paper, we presented a simple and more streamline approach by directly employing the bagasse extract after HTL treatment, as the aqueous phase in O/W emulsion. That is, the time after HTL treatment to emulsion formation was drastically reduced to <3 h instead of 1–3 days used for evaporation, lyophilisation or centrifugation (Mikkonen et al ., 2016; Vodo et al ., 2020). The separated portions of P and R were an emphasis on understanding the emulsion stability mechanism according to the different cell wall compositions disrupted by HTL treatment.…”

Comprehensive study of α-terpineol-loaded oil-in-water (O/W) nanoemulsion: interfacial property, formulation, physical and chemical stability

“…The dynamic light scattering (DLS) technique using Zetasizer Nano ZS (Malvern Panalytical, Worcestershire, United Kingdom) was applied to determine the particle size and droplet charge, as a protocol adapted from Teo et al (2016) 63 . To avoid multiple scattering effects, for both proceedings, the samples were diluted (1:100) before the analyses 66 . For pH and salt concentration effects, samples were diluted with the same level of pH or ionic strength solution 40 .…”