The purpose of this study was to clarify the effect of surfactant-added oils on the glass transition as a function of water content, fracture behavior, color, and crude oil content of the fried coatings (post-fried wheat flour-water mixture) obtained under various frying conditions (at 150-180 °C for 1.0-4.5 min). Polyglycerol oleic acid esters having hydrophile-lipophile balances of 7.4 (hydrophobic) and 13.3 (hydrophilic) were employed, and canola oils with and without 0.5 % (w/w) surfactants were used for frying. The samples obtained at 170 °C became glassy after frying times of 1.4 min, 1.9 min, and 2.4 min in the hydrophilic surfactant-added oil, hydrophobic surfactant-added oil, and surfactant-free oil, respectively. The glassy samples showed brittle fracture behavior, and the maximum fracture force for the glassy samples obtained using the surfactant-added oils was lower than that obtained using surfactant-free oil. The frying time to obtain glassy samples decreased with increasing frying temperature, and the frying time in the hydrophilic surfactant-added oil was reduced by 60-80 % compared to the surfactant-free oil. When the browning color of the glassy samples obtained for the shortest frying time was compared at each temperature, the samples fried in the hydrophilic surfactant-added oil showed less browning than those fried in the surfactant-free oil due to the reduction of frying time. There were no significant differences in the crude oil content between surfactant-free oil (69.9-105.7 g/100 g-defatted DM, dry matter) and the hydrophilic surfactant-added oil (78.6-115.5 g/100 g-defatted DM) at each frying temperature (except for 150 °C).

Cellouronate, β-1,4-glucuronan, is synthesized from regenerated cellulose via 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) radical-mediated oxidation. Human intestinal bacteria were cultured in a medium containing cellouronate to evaluate its utilization. These experiments showed Bacteroides luhongzhouii to grow well in this medium. Several putative cellouronate lyases belonging to polysaccharide lyase family 38 from B. luhongzhouii were identified. Among these candidate enzymes, BlCUL1, which displayed the most similarity to authentic cellouronate lyases, was heterologously expressed and characterized. The recombinant BlCUL1 (rBlCUL1) showed the highest activity at pH 8.0 and was deactivated by treatment at pH 3.0 for 24 h or heating above 50 °C for 10 min. Moreover, the activity of rBlCUL1 was enhanced in the presence of Mg²⁺, Ca²⁺, or EDTA, but suppressed by Al³⁺ and completely inactivated by Fe³⁺. Analysis of the final reaction mixture generated from the rBlCUL1 mediated degradation of cellouronate revealed an oligomer as the main product, but the monomer was barely detectable. This study is the first to report and characterize a cellouronate lyase from human intestinal bacteria.

Root stubble represents a “hidden” (unrecovered) biomass in agriculture. This study investigated its potential as a source of fermentable sugars using the high-yielding rice cultivar Hokuriku 193. The ripened whole plant was disassembled into panicle, straw, and root stubble. The root stubble was further divided into the aboveground part (AP), basal part (BP), and root part (RP), with AP and BP together accounting for 81.8 % (w/w) of the root stubble. In comparison with the straw, AP contained more starch- and β-1,3-1,4-glucan; BP had more starch and ash; RP had more lignin and ash. The total amount of glucan and xylan in root stubble is equivalent to 61.8 % of that found in straw. Following gas-phase HCl pretreatment and the subsequent enzymatic saccharification, sugar yields from AP and BP exceeded 70 %. These results demonstrate that root stubble has strong potential as a new feedstock for saccharification substituting straw.