Xylitol

Pomelo was purchased from Lvhang Fruit Co., Ltd. (Zhangjiajie, China). PL 64 (PEO₁₃-PPO₃₀-PEO₁₃, average molecular weight ≈ 2900 g/mol), choline chloride (ChCl, ≥99%), betaine (Bet, ≥98%), xylitol (Xyl, ≥99%), L-(-)-proline (Pro, ≥99%), tetraethylammonium chloride (N₂₂₂₂Cl, ≥98%), tetrabutylammonium chloride (N₄₄₄₄Cl, ≥95%), tetraethylammonium bromide (N₂₂₂₂Br, ≥98%), tetrapropylammonium bromide (N₃₃₃₃Br, ≥98%), tetrabutylammonium bromide (N₄₄₄₄Br, ≥99%), and D-(+)-maltose monohydrate (Mal, ≥99%) were provided by Adamas Reagent Co., Ltd. (Shanghai, China). Glycerol (Gly, ≥99%), D-(+)-glucose (Glu, ≥99.7%), oxalic acid dihydrate (OA, ≥99%), ethanol (≥99.7%), citric acid (CA, ≥99.5%), phosphoric acid (PA, ≥85%), ethyl acetate (EA, ≥99.5%), potassium phosphate dibasic trihydrate (K₂HPO₄·3H₂O, ≥99%) were purchased from Greagent Reagent Co., Ltd. (Shanghai, China). Neo (99.69%) and Nar (99.88%) were purchased from RefMedic Biotech Co., Ltd. (Chengdu, China). Other reagents were analytically pure and used without further treatment.

All the solvents or reagents used were of HPLC or analytical grade. Ethanol, FeCl₃·6H₂O, HCl, K₂S₂O_8, and acetic acid were purchased from Titan Scientific Co., Ltd. (Shanghai, China). Gallic acid was purchased from Energy-Chemical Co., Ltd. (Shanghai, China). ChCl and xylitol were obtained from Adamas Co., Ltd. (Shanghai, China). Na₂CO₃ was purchased from Sinopharm Chemical Reagent (Shanghai, China). D-sorbitol, glucose, maleic acid, malonic acid, malic acid, sucrose, and Folin–Ciocalteu’s phenol reagent were all obtained from Macklin Biochemical Co., Ltd. (Shanghai, China). Citric acid, ethylene glycol (EG), and 1,2-propanediol (PD) were purchased from TCI Shanghai (Shanghai, China). Lactic acid and sodium acetate were purchased from Shanghai Lingfeng Chemical Reagent Co., Ltd. (Shanghai, China). Glycerol was purchased from MP Biomedicals Co., Ltd. (Shanghai, China). 2, 4, 6-Tri(2-pyridyl)-s-triazine (TPTZ), [2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS), and 1,1-diphenyl-2-picrylhydrazyl (DPPH) were purchased from Sigma Aldrich (St. Louis, MO, USA). Commercial standards of catechins [(−)-EC, (−)-EGC, (−)-ECG, and (−)-EGCG, purity ≥ 98%] were purchased from Chengdu RefMedic Biotech Co., Ltd. (Chengdu, China).

Sodium borohydride (NaBH₄, 98%, Aldrich), methanol (CH₃OH, 99%, Aldrich), ethylene glycol (C₂H₆O₂, 99%, Aldrich), glycerol (C₃H₈O₃, 99%, Aldrich), erythritol (C₄H₁₀O₄, 99%, Adamas), xylitol (C₅H₁₂O₅, 99%, Adamas), sorbitol (C₆H₁₄O₆, 99%, Adamas), mannitol (C₆H₁₄O₆, 99%, Adamas) and sodium metaborate (NaB(OH)₄·2H₂O, 99%, Adamas) were all analytical grade and used without further purification.