CAJ | 학술논문

酪蛋白酸钠（sodium caseinate ，SC）所制的可食食品包装膜能有效延缓食品中水份的迁移和扩散以及阻止氧气的氧化等从而对食品起到很好地保鲜和保护作用，由于酪蛋白亲水性较强，使其所制膜阻水性和机械性能均较差，甘油（glycerol ，G）作为添加剂可以增强酪蛋白酸钠膜的韧性和阻水性，为进一步阐明G和SC之间的作用方式及对酪蛋白酸钠结构产生的影响，本实验利用荧光光谱、傅里叶红外光谱和紫外光谱特性对它们的作用方式进行了研究。结果表明：G的加入可以使SC的荧光强度降低，由荧光强度变化速率和甘油的浓度的双对数回归曲线得出了G和SC的结合常数为1.127×103 L?mol－1和结合位点数为1.161，得出G和SC分子之间结合方式为弱化学键；虽然添加G前后SC的红外光谱的吸收峰几乎相同，但吸收强度存在较大差异，说明SC二级结构受到了影响，使得β折叠β-转角结构减少，α螺旋、无规则卷曲、结构显著增多，以及分子间氢键加强；分析紫外光谱得出，G的加入没有改变S C肽键的结构，而是与S C以非共价键的方式结合形成分子质量更大的聚合物并使吸收峰值强度下降。该研究从分子的角度揭示了G和SC分子间的作用方式。
락단백산납（sodium caseinate ，SC）소제적가식식품포장막능유효연완식품중수빈적천이화확산이급조지양기적양화등종이대식품기도흔호지보선화보호작용，유우락단백친수성교강，사기소제막조수성화궤계성능균교차，감유（glycerol ，G）작위첨가제가이증강락단백산납막적인성화조수성，위진일보천명G화SC지간적작용방식급대락단백산납결구산생적영향，본실험이용형광광보、부리협홍외광보화자외광보특성대타문적작용방식진행료연구。결과표명：G적가입가이사SC적형광강도강저，유형광강도변화속솔화감유적농도적쌍대수회귀곡선득출료G화SC적결합상수위1.127×103 L?mol－1화결합위점수위1.161，득출G화SC분자지간결합방식위약화학건；수연첨가G전후SC적홍외광보적흡수봉궤호상동，단흡수강도존재교대차이，설명SC이급결구수도료영향，사득β절첩β-전각결구감소，α라선、무규칙권곡、결구현저증다，이급분자간경건가강；분석자외광보득출，G적가입몰유개변S C태건적결구，이시여S C이비공개건적방식결합형성분자질량경대적취합물병사흡수봉치강도하강。해연구종분자적각도게시료G화SC분자간적작용방식。
Although the immigration of water molecule ,and diffusion and traversing of oxygen can be prevented by the edible film prepared through sodium caseinate ,which plays a good protection role for the food ,the strong hydrophilicity makes its wa-tertightness and mechanical properties become inferior .Because the toughness and water resistance of SC films can be enhanced by glycerol (G) as an additive ,it is necessary to elucidate the interaction between G and SC through the spectral characteristics such as fluorescence spectra ,infrared spectra and UV spectra .The results show that the fluorescence intensity of SC decreases due to the addition of G .The binding constant obtained by the double logarithmic regression curve analysis is 1.127 × 103 L?mol-1 and the number of binding sites reaches 1.161 .It indicates that the weak chemical bond is primary between G and SC mol-ecules ;From IR the absorption peaks of SC are almost the same before and after adding G .However ,there is a certain differ-ence among their absorption intensities .It reveals that the secondary structure of SC is affected ,βfolding length decreases ,αhe-lix ,random coil structure ,βangle structure increases ,and the intermolecular hydrogen bond is strengthened ;From UV the pep-tide bond structure of SC is not changed after the addition of G ,but the polymer with larger molecular weight ,which is formed by non-covalent bond ,makes the peak intensity decrease .The research gives the mode of G and SC from the molecular level .