The Hydrolysis Mechanism of Inulin and Its Hydrolysate in the Reaction Field by the Hot Compressed Water

Abstract

Aiming to produce functional oligosaccharides such as diD -fructose dianhydrides (DFAs) from inulin in subcritical water (the hot compressed water), the hydrolysis mechanism of inulin was investigated. The hydrolysis of inulin was conducted in carbon dioxide-the hot compressed water (CO 2-HCW) created with a batch-type reactor (temperature: 100 150 , pressure: 3.0 5.0 MPa). The inulin hydrolysate prepared with CO 2-HCW were determined by electrospray ionization mass spectrometry and UV-Vis spectroscopy. The results showed that inulin is hydrolyzed to monosaccharides, disaccharides, fructooligosaccharides , and DFAs with CO 2-HCW. The hydronium ion concentration ([H ϩ ]) formed in CO 2-HCW was approximately estimated 100-fold higher than [H ϩ ] created in the hot compressed water without CO 2. High [H ϩ ] is believed to be one of the factors that contributes to the hydrolysis of inulin Ͻ150. The generation of 5hydroxymethylfurfural (HMF) occurred by intramolecular dehydration of fructose was suppressed due to low temperature process (Ͻ150). CO 2-HCW is one of the means to convert inulin into DFAs while suppressing the generation of HMF.

Valorization of spent black tea by recovery of antioxidant polyphenolic compounds: Subcritical solvent extraction and microencapsulation

“…Of these techniques, subcritical solvent extraction (SSE) is a greener and faster method (Munir, Kheirkhah, Baroutian, Quek, & Young, 2018), which uses a pressurized liquid kept below its critical point (374°C for water) and above its boiling point (100°C for water). These conditions allow fluids to remain in a liquid state due to the applied pressure and it creates low polar water with equivalent to organic solvents at ambient temperature (Shimizu, Ushiyama, & Itoh, 2019; Zhang, Baroutian, Munir, & Young, 2017; Zhang & Wolf 2019). This technique facilitates rapid extraction without the loss or changing the chemical integrity of thermolabile compounds (Essien, Young, & Baroutian, 2020).…”

Effect of temperature on the hydrolysis of levan treated with compressed hot water fluids

“…Levan hydrolysis was performed as reported previously by Shimizu et al (2019) and Yoshioka and Shimizu (2014) in a batch‐type reactor equipped with a pressure‐resistant vessel made from SUS‐316 stainless steel and an inner container made from Teflon equipped with a type‐K thermocouple and a pressure gauge. Levan (0.02 g), ultrapure water (10 ml), and a magnetic stir bar were placed into the inner container, and the vessel was pressurized to the appropriate pressure with nitrogen gas.…”

“…Thus, a deep understanding of the hydrolysis mechanisms and fine control of the reaction conditions are necessary (Vaquerizo et al, 2018). Previous work has examined the use of compressed hot water in the hydrolysis of fructans like inulin (Itoh & Shimizu, 2014; Shimizu, Ushiyama, & Itoh, 2019); however, the use of this reagent in the hydrolysis of levan has not (to our knowledge) been documented previously. In the present study, compressed hot water fluids were applied to levans from two different bacterial sources.…”

GH172 difructose dianhydride I synthase: A two-stepped journey via glycosylation and cyclization using QM/MM metadynamics

“…4 In Japan, the interest in producing such functional oligosaccharides from plants inspired the investigation of the hydrolytic mechanism of the inulin present in chicory by hot compressed water, resulting in fructose and DFAs. 5 Given the combinatorial possibilities, five different DFAs are obtained: four α-D-Fruf -X-β -D-Fruf are DFA I (X = 1,2':2,1'), DFA III (X = 1,2':2,3'), DFA IV (X = 2,6':6,2'), DFA V (X = 1,2':2,6'), and one β -D-Fruf -Y-β -D-Fruf is DFA II (Y = 1,2':2,3'). 6 The enzymatic obtention of these molecules 7 is important for both health and economy, so these molecules are beneficial for human welfare.…”