Zinc-binding capacity of yak casein hydrolysate and the zinc-releasing characteristics of casein hydrolysate-zinc complexes.
Zinc-binding capacity of yak casein hydrolysate and the zinc-releasing characteristics of casein hydrolysate-zinc complexes.
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DOI：
10.3168/jds.2010-3900
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发表时间：
2011-06
影响因子：
3.5
通讯作者：
Xianlong Wang;J. Zhou;P. Tong;X. Mao
中科院分区：
文献类型：
--
作者：
Xianlong Wang;J. Zhou;P. Tong;X. Mao
影响饲粮锌生物利用度的因素很多，导致锌在某些食物系统中的利用度偏低和锌营养缺乏。然而，一些蛋白质或多肽可以与锌形成复合物，增加锌在肠道中的吸收和生物利用度。本研究的目的是测定牦牛酪蛋白水解物（YCH）的锌结合活性，并考察其在模拟肠道环境中的稳定性、溶解度和透析性。研究了用alcalase， pepsin, trypsin, Flavozyme （Novo Nordisk Biochem Inc., Franklinton， NC）或木瓜蛋白酶制备的YCH的锌结合活性。紫外-可见光谱和傅里叶变换红外光谱也发现了Zn和YCH之间形成配合物的证据。结果表明，与胃蛋白酶、黄酶和木瓜蛋白酶相比，alcalase和胰蛋白酶制备的YCH具有最高的锌结合能力。alcalase得到的6 h YCH显示出最高的zn结合能力。与天然牦牛酪蛋白相比，在肠道碱性pH范围内，YCH的锌结合活性显著降低，但其溶解度和透析性显著提高。这一点很重要，因为高溶解度和透析性与更好的生物利用度有关。紫外可见光谱和傅里叶变换红外光谱显示，在模拟肠道条件下，YCH的一些位点可以与锌离子结合形成配合物，使锌更易于溶解和透析。因此，YCH-Zn配合物可能具有提高Zn生物利用度的潜力。
Many factors affect the bioavailability of dietary Zn, which leads to its low availability in some food systems and Zn nutrient deficiency. However, some proteins or peptides can form complexes with Zn and increase its absorption and bioavailability in intestinal conditions. The purpose of this work was to determine the Zn-binding activity of yak casein hydrolysate (YCH) and examine its stability, solubility, and dialyzability in a simulated intestinal environment. The Zn-binding activity of YCH, prepared using alcalase, pepsin, trypsin, Flavozyme (Novo Nordisk Biochem Inc., Franklinton, NC), or papain, was investigated. Evidence for the formation of complexes between Zn and YCH also were detected by UV-visible spectroscopy and Fourier transform infrared spectroscopy. Results were that YCH prepared with alcalase and trypsin possessed the highest Zn-binding capacity compared with YCH prepared with pepsin, Flavozyme, or papain. The 6-h YCH obtained with alcalase showed the highest Zn-binding capacity. Compared with native yak casein, the Zn-binding activity of YCH was significantly lower, but its solubility and dialyzability were markedly higher under intestinal basic pH ranges. This is important because high solubility and dialyzability is associated with better bioavailability. Both UV-visible spectroscopy and Fourier transform infrared spectroscopy spectra indicated that some sites of YCH can bind with Zn ions and form complexes that make Zn more soluble and dialyzable under simulated intestinal conditions. Therefore, YCH-Zn complexes may have potential to improve Zn bioavailability.