Department of Food Science and Technology, Punjab Agricultural University, Ludhiana, Punjab 141004, India.
Department of Food Science and Technology, Punjab Agricultural University, Ludhiana, Punjab 141004, India.
Food Chem. 2020 Dec 15;333:127503. doi: 10.1016/j.foodchem.2020.127503. Epub 2020 Jul 10.
Protein isolates were prepared from wet heat processed (APIp) and unprocessed alfalfa seeds (APIc) and characterized for composition and functionality at different pH. APIc and APIp exhibited high content of all the essential amino acids. Antinutrient content of APIp was lower in comparison to APIc and marked reduction in the trypsin inhibitor (85.97%) and lectin activity (100%) was observed. Processing did not cause much reduction of bioactive constituents and antioxidant activity of APIp. Alfalfa protein isolates exhibited complex polypeptide banding ranging from molecular weight of 11-75 kDa. APIp exhibited change in the conformation of protein discerned as alteration in interrelated nuances of ATR-FTIR spectra, XRD-pattern, morphology, charge on proteins and reduced solubility in comparison to APIc due to processing. APIp exhibited marked improvement in the functional properties in comparison to APIc discerned as improved hydration, surface active and gelation properties. Highest hydration and surface active properties were exhibited at pH 9.0, even though APIp at pH 7.0 showed fairly similar functional properties as APIc and APIp at pH 9.0. APIp exhibited reduced least gelation concentration in comparison to APIc at pH 7.0 and also engendered gelation at pH 4.0 and 9.0 contrary to APIc.
从湿热加工（APIp）和未加工的紫花苜蓿种子（APIc）中制备蛋白质分离物，并在不同 pH 值下对其组成和功能进行表征。APIc 和 APIp 均含有所有必需氨基酸。与 APIc 相比，APIp 的抗营养因子含量较低，并且观察到胰蛋白酶抑制剂（85.97%）和凝集素活性（100%）明显降低。加工不会导致 APIp 中生物活性成分和抗氧化活性大量减少。紫花苜蓿蛋白质分离物表现出复杂的多肽带，分子量范围从 11-75 kDa。与 APIc 相比，由于加工，APIp 的蛋白质构象发生了变化，这可以从 ATR-FTIR 光谱、XRD 图谱、形态、蛋白质电荷和溶解度降低等方面的细微变化中看出。与 APIc 相比，APIp 的功能特性明显改善，表现为水化、表面活性和胶凝性能的提高。在 pH 值为 9.0 时，APIp 表现出最高的水合和表面活性特性，尽管在 pH 值为 7.0 时，APIp 表现出与 APIc 相当的功能特性，与 APIp 在 pH 值为 9.0 时相似。与 APIc 相比，APIp 在 pH 值为 7.0 时的凝胶浓度最低，并且与 APIc 不同，APIp 在 pH 值为 4.0 和 9.0 时也能引发凝胶化。
