为探究豆腐柴果胶的结构特征,以热水为萃取剂提取豆腐柴果胶(water-soluble pectin,WSP),通过分级醇沉分离收集到纯度较高的组分(water-soluble pectin with 50%~55% ethanol-induced precipitation,WSP-55),结合傅里叶变换红外光谱、高效凝胶排阻色谱(high-performance size exclusion chromatography,HPSEC)、高效阴离子交换色谱、气质联用仪、核磁共振波谱(nuclear magnetic resonance spectroscopy,NMR)等仪器对豆腐柴果胶的分子结构进行解析。HPSEC结果表明,WSP-55的相对分子质量为139 kDa。结合红外、甲基化分析表明,WSP-55为含有丰富的同型半乳糖醛酸聚糖(homogalacturonan,HG)结构域和少量鼠李半乳糖醛酸聚糖I型(rhamnogalacturonan-Ⅰ,RG-I)结构域的低酯果胶。NMR结果分析显示,WSP-55的→4)-α-GalpA-(1→和→4)-α-GalpA-6-O-Me-(1→以4∶1的摩尔比组成HG结构域,RG-I结构域的主链结构则由重复单元[→2)-α-Rhap-(1→4)-α-GalpA-(1→]n构成,Araf糖残基和Galp糖残基位于RG-I的侧链。该研究将为豆腐柴果胶构效关系的研究奠定基础,并为其在食品及生物医药等多个领域的有效应用提供理论支撑。
To investigate the structural characteristics of pectin from Premna microphylla Turcz (PMTP), hot water was used to extract water-soluble pectin (WSP).Following gradual ethanol precipitation, high-purity water-soluble pectin with 50%-55% ethanol-induced precipitation (WSP-55) was collected.The molecular structure of WSP-55 was analyzed using Fourier transform infrared spectroscopy (FT-IR), high-performance size exclusion chromatography (HPSEC), high-performance anion exchange chromatography-pulsed amperometric detector, gas chromatography-mass spectrometry, nuclear magnetic resonance spectroscopy (NMR).HPSEC results showed that the relative molecular weight of WSP-55 was 139 kDa.Combined with FT-IR and methylation analysis, WSP-55 was a low-methoxyl pectin containing abundant homogalacturonan (HG) domain and a small amount of rhamnogalacturonan-I (RG-I) domain.The results of NMR analysis showed that the HG domain of WSP-55 consisted of a molar ratio of 4∶1 of →4)-α-GalpA-(1→ and →4)-α-GalpA-6-O-Me-(1→, while the main chain structure of the RG-I domain was composed of the repeating unit[→2)-α-Rhap-(1→4)-α-GalpA-(1→]n, with the Araf and Galp sugar residues were found on the side chain of RG-I.This study would lay a foundation for the study of the structure-activity relationship of PMTP and provide theoretical support for its effective application in the biomedical and food industries.
[1] CAFFALL K H, MOHNEN D.The structure, function, and biosynthesis of plant cell wall pectic polysaccharides[J].Carbohydrate Research, 2009, 344(14):1879-1900.
[2] REICHEMBACH L H, LÚCIA DE OLIVEIRA PETKOWICZ C.Pectins from alternative sources and uses beyond sweets and jellies:An overview[J].Food Hydrocolloids, 2021, 118:106824.
[3] YOO S H, LEE B H, LEE H, et al.Structural characteristics of pumpkin pectin extracted by microwave heating[J].Journal of Food Science, 2012, 77(11):C1169-C1173.
[4] SILA D N, VAN BUGGENHOUT S, DUVETTER T, et al.Pectins in processed fruits and vegetables:Part Ⅱ—Structure-function relationships[J].Comprehensive Reviews in Food Science and Food Safety, 2009, 8(2):86-104.
[5] MELLINAS C, RAMOS M, JIMÉNEZ A, et al.Recent trends in the use of pectin from agro-waste residues as a natural-based biopolymer for food packaging applications[J].Materials, 2020, 13(3):673.
[6] MÜLLER-MAATSCH J, BENCIVENNI M, CALIGIANI A, et al.Pectin content and composition from different food waste streams[J].Food Chemistry, 2016, 201:37-45.
[7] CHEN J, LIANG R H, LIU W, et al.Extraction of pectin from Premna microphylla Turcz leaves and its physicochemical properties[J].Carbohydrate Polymers, 2014, 102:376-384.
[8] ZHAN Z J, TANG L, SHAN W G.A new triterpene glycoside from Premna microphylla[J].Chemistry of Natural Compounds, 2009, 45(2):197-199.
[9] LU J K, LI J J, JIN R C, et al.Extraction and characterization of pectin from Premna microphylla Turcz leaves[J].International Journal of Biological Macromolecules, 2019, 131:323-328.
[10] DUAN H, WANG W, LI Y X, et al.Identification of phytochemicals and antioxidant activity of Premna microphylla Turcz.stem through UPLC-LTQ-Orbitrap-MS[J].Food Chemistry, 2022, 373:131482.
[11] WANG D Y, XU S Y.Two new xanthones from Premna microphylla[J].Natural Product Research, 2003, 17(1):75-77.
[12] 胡予, 张攀, 陈信, 等.不同月份豆腐柴叶果胶理化性质差异研究[J].食品工业科技, 2020, 41(1):38-43, 49.
HU Y, ZHANG P, CHEN X, et al.Study on the difference of the physicochemical properties of pectin from Premna microphylla Turcz leaves in different months[J].Science and Technology of Food Industry, 2020, 41(1):38-43, 49.
[13] CHEN Y Y, LIU X, LEI X J, et al.Premna microphylla Turcz pectin protected UVB-induced skin aging in BALB/c-nu mice via Nrf2 pathway[J].International Journal of Biological Macromolecules, 2022, 215:12-22.
[14] SU Y D, CHEN Y, QIN Y T, et al.Pectin extracted from Premna microphylla Turcz for preparation of a “sandwich” multi-property sensor film involved with deep eutectic solvent[J].International Journal of Biological Macromolecules, 2023, 253:127171.
[15] KANG J, HUANG-FU Z Y, TIAN X N, et al.Arabinoxylan of varied structural features distinctively affects the functional and in vitro digestibility of wheat starch[J].Food Hydrocolloids, 2023, 140:108615.
[16] DUBOIS M, GILLES K A, HAMILTON J K, et al.Colorimetric method for determination of sugars and related substances[J].Analytical Chemistry, 1956, 28(3):350-356.
[17] BRADFORD M M.A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding[J].Analytical Biochemistry, 1976, 72(1-2):248-254.
[18] BLUMENKRANTZ N, ASBOE-HANSEN G.New method for quantitative determination of uronic acids[J].Analytical Biochemistry, 1973, 54(2):484-489.
[19] SINGTHONG J, CUI S W, NINGSANOND S, et al.Structural characterization, degree of esterification and some gelling properties of Krueo Ma Noy (Cissampelos pareira) pectin[J].Carbohydrate Polymers, 2004, 58(4):391-400.
[20] GUO Q B, DU J H, JIANG Y, et al.Pectic polysaccharides from hawthorn:Physicochemical and partial structural characterization[J].Food Hydrocolloids, 2019, 90:146-153.
[21] ZHU J X, CHEN Z Y, CHEN L, et al.Comparison and structural characterization of polysaccharides from natural and artificial Se-enriched green tea[J].International Journal of Biological Macromolecules, 2019, 130:388-398.
[22] WOOD P, WEISZ J, BLACKWELL B.Structural studies of (1→3), (1→4)-β-D-glucans by13C-nuclear magnetic resonance spectroscopy and by rapid analysis of cellulose-like regions using high-performance anion-exchange chromatography of oligosaccharides released by lichenase[J].Cereal Chemistry, 1994, 71:301-307.
[23] MOHNEN D.Pectin structure and biosynthesis[J].Current Opinion in Plant Biology, 2008, 11(3):266-277.
[24] AL-AMOUDI R H, TAYLAN O, KUTLU G, et al.Characterization of chemical, molecular, thermal and rheological properties of medlar pectin extracted at optimum conditions as determined by Box-Behnken and ANFIS models[J].Food Chemistry, 2019, 271:650-662.
[25] LIU D, TANG W, HUANG X J, et al.Structural characteristic of pectin-glucuronoxylan complex from Dolichos lablab L.hull[J].Carbohydrate Polymers, 2022, 298:120023.
[26] SHAKHMATOV E G, MAKAROVA E N, BELYY V A.Structural studies of biologically active pectin-containing polysaccharides of pomegranate Punica granatum[J].International Journal of Biological Macromolecules, 2019, 122:29-36.
