Effects of different crosslinking agents on properties of agar/sodium alginate composite films
-
摘要: 琼胶和海藻酸钠是从海藻中提取的亲水性胶体,具有良好的成膜性和生物降解性。为提高琼胶/海藻酸钠复合膜的应用性能,以琼胶、海藻酸钠为成膜基料,甘油为增塑剂,阿魏酸、单宁酸、柠檬酸和丁二酸为交联剂,采用溶液浇筑法制备了琼胶/海藻酸钠复合膜,通过测定复合膜的机械性能、耐水性、阻湿性、不透明度、傅里叶变换红外光谱 (FT-IR) 和微观结构,研究了4种交联剂对复合膜性能的影响。结果表明,4种交联剂均显著提高了复合膜的拉伸强度、耐水性和阻湿性 (P<0.05),但显著降低了膜的透明度 (P<0.05),且当阿魏酸和单宁酸添加量为5%、柠檬酸和丁二酸为10%时,交联剂对复合膜的改善作用最好。4种交联剂中,柠檬酸交联膜的性能最好,当添加量为10%时,其拉伸强度为46.98 MPa,断裂伸长率为17.87%,水溶性为24.17%,溶胀率为38%,水蒸气透过率为0.51 g·mm·(m2·h·kPa)−1。FT-IR分析显示,柠檬酸和丁二酸通过与琼胶和海藻酸钠分子中的羟基 (−OH) 发生酯化反应,改善复合膜的性能,阿魏酸和单宁酸通过与琼胶和海藻酸钠形成分子间氢键实现交联。扫描电镜分析结果表明,琼胶和海藻酸钠的相容性良好,交联剂可使复合膜截面更加致密、光滑。因此,适量添加4种交联剂可不同程度地改善琼胶/海藻酸钠复合膜的理化性能,为包装薄膜的制备及应用提供科学参考。Abstract: Agar and sodium alginate are hydrophilic colloids extracted from algae, with good film-forming and biodegradability. In order to improve the application performance of agar/sodium alginate composite membrane, we used agar and sodium alginate as film-forming base material, glycerol as plasticizer, ferulic acid, tannin acid, citric acid and succinic acid as crosslinking agents to prepare the agar/sodium alginate composite films by solution casting method. Then we studied the effects of four crosslinking agents on the properties of the composite films based on the mechanical properties, water resistance, moisture resistance, opacity, fourier transform infrared spectroscopy (FT-IR) and microstructure of the composite films. The results show that the four crosslinking agents improved the tensile strength, water resistance and moisture resistance of the composite films significantly (P<0.05), but reduced the transparency significantly (P<0.05). The crosslinking agents had the best improvement effect on the composite films with additions of ferulic acid and tannin acid of 5%, citric acid and succinic acid of 10%. Among the four crosslinking agents, citric acid cross-linked film had the best performance, and when the addition of citric acid was 10%, each index reached the optimal value [The tensile strength was 46.98 MPa; the elongation at break was 17.87%; the water solubility was 24.17%; the swelling ratio was 38%; the water vapor permeability (WVP) was 0.51 g·mm·(m2·h·KPa)−1]. FT-IR analysis shows that citric acid and succinic acid improved the properties of the composite films by esterifying with −OH of agar and sodium alginate, and ferulic acid or tannin acid achieved crosslinking by forming intermolecular hydrogen bonds with agar and sodium alginate. Scanning electron microscopy (SEM) analysis shows that agar and sodium alginate had good compatibility, and the cross section of composite film became denser and smoother with the addition of crosslinking agents. Therefore, moderate addition of crosslinking agent to agar/sodium alginate composite films can improve the physical and chemical properties of composite films at different degrees, which provides scientific references for the preparation and application of packaging films.
-
Key words:
- Agar /
- Sodium alginate /
- Crosslinking agent /
- Edible film
-
图 1 不同交联剂对复合膜拉伸强度、断裂伸长率、水蒸气透过率水溶性和溶胀率的影响
注:图1-d和1-e中同种交联剂不同小写字母间存在显著性差异 (P<0.05)。
Figure 1. Effects of different crosslinking agents on tensile strength, elongation at break, water vapor permeability, water solubility, and swelling ratio of composite films
Note: For the same crosslinking agent, different letters indicate significant differences (P<0.05).
表 1 不同交联剂对复合膜不透明度的影响
Table 1. Effect of different crosslinking agents on opacity of composite films
交联剂添加量Crosslinking agent
addition/%复合膜不透明度Opacity of composite films 阿魏酸FA 单宁酸TA 柠檬酸CA 丁二酸SA 0 1.18±0.01f 1.18±0.01f 1.18±0.01d 1.18±0.01e 3 1.22±0.01e 1.84±0.02e 1.20±0.02d 1.20±0.01de 5 1.30±0.02d 2.64±0.03d 1.27±0.03c 1.23±0.01cd 7 1.39±0.01c 2.93±0.06c 1.31±0.02b 1.24±0.02bc 10 1.46±0.01b 3.14±0.02b 1.34±0.02b 1.27±0.03ab 15 1.59±0.01a 3.65±0.10a 1.41±0.03a 1.29±0.01a 注:同列不同字母表示差异显著 (P<0.05)。 Note: Different letters within the same column indicate significant differences (P<0.05). -
[1] 赵换英, 李智超, 曹志鹏, 等. 海藻酸钠复合膜的制备及性能研究[J]. 山东理工大学学报 (自然科学版), 2021, 35(2): 68-72. [2] 陈淑花, 岳丽春, 张晶, 等. 壳聚糖接枝物与琼脂复合膜的制备及性能研究[J]. 包装工程, 2021, 42(1): 77-82. doi: 10.19554/j.cnki.1001-3563.2021.01.010 [3] MOSTAFAVI F S, ZAEIM D. Agar-based edible films for food packaging applications: a review[J]. Int J Biol Macromol, 2020, 159: 1165-1176. doi: 10.1016/j.ijbiomac.2020.05.123 [4] SEDAYU B B, CRAN M J, BIGGER S W. A review of property enhancement techniques for carrageenan-based films and coatings[J]. Carbohydr Polym, 2019, 216: 287-302. doi: 10.1016/j.carbpol.2019.04.021 [5] HOU X B, XUE Z X, XIA Y Z. Preparation of a novel agar/sodium alginate fire-retardancy film[J]. Mater Lett, 2018, 233: 274-277. doi: 10.1016/j.matlet.2018.09.026 [6] ABDOLLAHI M, DAMIRCHI S, SHAFAFI M, et al. Carboxymethyl cellulose-agar biocomposite film activated with summer savory essential oil as an antimicrobial agent[J]. Int J Biol Macromol, 2019, 126: 561-568. doi: 10.1016/j.ijbiomac.2018.12.115 [7] RUKMANIKRISHNAN B, RAJASEKHARAN S K, LEE J, et al. Biocompatible agar/xanthan gum composite films: thermal, mechanical, UV, and water barrier properties[J]. Polym Adv Technol, 2019, 30(11): 2750-2758. doi: 10.1002/pat.4706 [8] 王可, 宋义虎. 交联剂改性小麦醇溶蛋白/壳聚糖复合膜的制备与性能[J]. 材料科学与工程学报, 2013, 31(1): 78-83. doi: 10.14136/j.cnki.issn1673-2812.2013.01.031 [9] URANGA J, NGUYEN B T, SI T T, et al. The effect of cross-linking with citric acid on the properties of agar/fish gelatin films[J]. Polymers, 2020, 12(2): 291. doi: 10.3390/polym12020291 [10] 庄晓雯, 赵芸, 陈春梅, 等. Fe3+-H+交联型防紫外线海藻纤维膜的性能研究及表征[J]. 食品工业科技, 2021: 1-14. [11] BELAY M, TYEB S, RATHORE K, et al. Synergistic effect of bacterial cellulose reinforcement and succinic acid crosslinking on the properties of agar[J]. Int J Biol Macromol, 2020, 165: 3115-3122. doi: 10.1016/j.ijbiomac.2020.10.144 [12] 孙晗, 傅俊曦, 谢春阳, 等. 秋葵多糖-壳聚糖复合可食膜制备及其结构表征[J]. 吉林农业大学学报, 2021: 1-11. [13] WANG X J, GUO C F, HAO W H, et al. Development and characterization of agar-based edible films reinforced with nano-bacterial cellulose[J]. Int J Biol Macromol, 2018, 118(PtA): 722-730. [14] KURT A, KAHYAOGLU T. Characterization of a new biodegradable edible film made from salep glucomannan[J]. Carbohydr Polym, 2014, 104: 50-58. doi: 10.1016/j.carbpol.2014.01.003 [15] SUKHIJA S, SINGH S, RIAR C S. Analyzing the effect of whey protein concentrate and psyllium husk on various characteristics of biodegradable film from lotus (Nelumbo nucifera) rhizome starch[J]. Food Hydrocoll, 2016, 60: 128-137. doi: 10.1016/j.foodhyd.2016.03.023 [16] CAO N, FU Y H, HE J H. Mechanical properties of gelatin films cross-linked, respectively, by ferulic acid and tannin acid[J]. Food Hydrocoll, 2007, 21(4): 575-584. doi: 10.1016/j.foodhyd.2006.07.001 [17] YERRAMATHI B B, KOLA M, MUNIRAJ B A, et al. Structural studies and bioactivity of sodium alginate edible films fabricated through ferulic acid crosslinking mechanism[J]. J Food Eng, 2021, 301: 11. [18] 贾超, 王利强, 卢立新, 等. 阿魏酸对马铃薯淀粉基复合膜性能的影响[J]. 食品工业科技, 2013, 34(07): 82-85. doi: 10.13386/j.issn1002-0306.2013.07.059 [19] AWADHIYA A, KUMAR D, VERMA V. Crosslinking of agarose bioplastic using citric acid[J]. Carbohydr Polym, 2016, 151: 60-67. doi: 10.1016/j.carbpol.2016.05.040 [20] MATHEW S, ABRAHAM T E. Characterisation of ferulic acid incorporated starch-chitosan blend films[J]. Food Hydrocoll, 2008, 22(5): 826-835. doi: 10.1016/j.foodhyd.2007.03.012 [21] BELAY M, SONKER A K, NAGARALE R K, et al. Synergistic strengthening of composite films by crosslinking graphene oxide reinforcement and poly (vinyl alcohol) with dicarboxylic acids[J]. Polym Int, 2017, 66(12): 1737-1746. doi: 10.1002/pi.5402 [22] ARAGHI M, MOSLEHI Z, MOHAMMADI NAFCHI A, et al. Cold water fish gelatin modification by a natural phenolic cross-linker (ferulic acid and caffeic acid)[J]. Food Sci Nutr, 2015, 3(5): 370-375. doi: 10.1002/fsn3.230 [23] 王跃猛, 刘安军, 李鑫, 等. 姜精油对明胶-CaCO3 可食膜理化及抑菌特性影响的研究[J]. 现代食品科技, 2015, 31(2): 57-62. [24] 孙嘉临, 袁玉娇, 李思琪, 等. 大豆分离蛋白基复合精油可食膜的制备及表征[J]. 中国果菜, 2021, 41(12): 27-36. doi: 10.19590/j.cnki.1008-1038.2021.12.005 [25] INSAWARD A, DUANGMAL K, MAHAWANICH T. Mechanical, optical, and barrier properties of soy protein film as affected by phenolic acid addition[J]. J Agric Food Chem, 2015, 63(43): 9421-9426. doi: 10.1021/jf504016m [26] 俞杨销, 宋功吉, 张子凡, 等. 壳聚糖/明胶/茶多酚复合膜的溶胀溶失性能[J]. 现代纺织技术, 2022, 30(1): 70-77. doi: 10.19398/j.att.202010007 [27] NASEF M M, EL-HEFIAN E A, SAALAH S, et al. Preparation and properties of non-crosslinked and ionically crosslinked chitosan/agar blended hydrogel films[J]. E-J Chem, 2011, 8: S409-S419. doi: 10.1155/2011/513204 [28] NATARAJ D, SAKKARA S, MEENAKSHI H N, et al. Properties and applications of citric acid crosslinked banana fibre-wheat gluten films[J]. Ind Crop Prod, 2018, 124: 265-272. doi: 10.1016/j.indcrop.2018.07.076 [29] THESSRIMUANG N, PRACHAYAWARAKORN J. Characterization and properties of high amylose mung bean starch biodegradable films cross-linked with malic acid or succinic acid[J]. J Polym Environ, 2019, 27(2): 234-244. doi: 10.1007/s10924-018-1340-2 [30] LIGUORI A, URANGA J, PANZAVOLTA S, et al. Electrospinning of fish gelatin solution containing citric acid: an environmentally friendly approach to prepare crosslinked gelatin fibers[J]. Materials, 2019, 12(17): 2808. doi: 10.3390/ma12172808 [31] GUERRERO P, ETXABIDE A, LECETA I, et al. Extraction of agar from Gelidium sesquipedale (Rhodopyta) and surface characterization of agar based films[J]. Carbohydolym, 2014, 99: 491-498. doi: 10.1016/j.carbpol.2013.08.049 [32] COSTA M J, MARQUES A M, PASTRANA L M, et al. Physicochemical properties of alginate-based films: effect of ionic crosslinking and mannuronic and guluronic acid ratio[J]. Food Hydrocoll, 2018, 81: 442-448. doi: 10.1016/j.foodhyd.2018.03.014 [33] SUN L J, SUN J J, CHEN L, et al. Preparation and characterization of chitosan film incorporated with thinned young apple polyphenols as an active packaging material[J]. Carbohydr Polym, 2017, 163: 81-91. doi: 10.1016/j.carbpol.2017.01.016 [34] REDDY N, YANG Y Q. Citric acid cross-linking of starch films[J]. Food Chem, 2010, 118(3): 702-711. doi: 10.1016/j.foodchem.2009.05.050 [35] SHI R, ZHANG Z Z, LIU Q Y, et al. Characterization of citric acid/glycerol co-plasticized thermoplastic starch prepared by melt blending[J]. Carbohydr Polym, 2007, 69(4): 748-755. doi: 10.1016/j.carbpol.2007.02.010 [36] LI K J, ZHU J X, GUAN G L, et al. Preparation of chitosan-sodium alginate films through layer-by-layer assembly and ferulic acid crosslinking: film properties, characterization, and formation mechanism[J]. Int J Biol Macromol, 2019, 122: 485-492. doi: 10.1016/j.ijbiomac.2018.10.188 -