Pougoue Ngueukam Annick Arcelle, Klang Mathilde Julie, Zokou Ronice, Teboukeu Boungo Gires, Djikeng Tonfack Fabrice, Azeez Barakat Koyinsola, Womeni Hilaire Macaire, Tsopmo Apollinaire
Biochemistry, Food Sciences, Nutrition and Medicinal Plants Research Unit, Department of Biochemistry, Faculty of Science, University of Dschang, Dschang P.O. Box 6, Cameroon.
Department of Biochemistry, Faculty of Science, University of Bamenda, Bambili P.O. Box 39, Cameroon.
Foods. 2023 Sep 20;12(18):3498. doi: 10.3390/foods12183498.
This study determined for the first time the structure of the peptides (i.e., peptidomics) in soy protein hydrolysates and elucidated their effects on an oil's oxidative stability during frying cycles. The oil investigated was palm olein during 0, 4, 8, and 12 frying cycles of plantain banana chips. Proteins were extracted and hydrolyzed with two proteases. Trypsin hydrolysate (HTRY) exhibited higher anti-radical activity (DPPH, 70.2%) than the control (unhydrolyzed proteins, 33.49%) and pepsin hydrolysate (HPEP, 46.1%) at 200 µg/mL. HPEP however showed a 4.6-fold greater reduction of ferric ions (FRAP) while also possessing a higher peroxyl radical scavenging ability (716 ± 30 µM Trolox Eq/g) than HTRY (38.5 ± 35 µM Trolox Eq/g). During oil oxidative stability tests, HPEP improved the oxidative stability of the palm olein oil after 8 and 12 frying cycles, characterized by lower concentrations of hydroperoxides, and carbonyl and volatile compounds. HTRY however exerteda pro-oxidant activity. Structural data from SDS-PAGE and tandem mass spectrometry showed that the mechanism for the greater activity of the pepsin hydrolysate occurred due to unique structural features and a higher percentage of short-chain peptides. This was justified by a 25, 31, and 48% higher contents of tryptophan, histidine, and methionine, respectively (important amino acids with hydrogen atom transfer and electron-donating capacities) in the peptides identified in the pepsin hydrolysate.
本研究首次确定了大豆蛋白水解物中肽的结构（即肽组学），并阐明了它们在油炸过程中对油脂氧化稳定性的影响。所研究的油脂是用于油炸大蕉薯片的0、4、8和12个循环的棕榈油精。蛋白质用两种蛋白酶进行提取和水解。在200µg/mL时，胰蛋白酶水解物（HTRY）表现出比对照（未水解蛋白质，33.49%）和胃蛋白酶水解物（HPEP，46.1%）更高的抗自由基活性（DPPH，70.2%）。然而，HPEP显示出铁离子还原能力（FRAP）高4.6倍，同时也具有比HTRY（38.5±35µM Trolox当量/g）更高的过氧自由基清除能力（716±30µM Trolox当量/g）。在油脂氧化稳定性测试中，HPEP在8和12个油炸循环后提高了棕榈油精的氧化稳定性，其特征是氢过氧化物、羰基和挥发性化合物的浓度较低。然而，HTRY表现出促氧化活性。SDS-PAGE和串联质谱的结构数据表明，胃蛋白酶水解物活性更高的机制是由于其独特的结构特征和更高比例的短链肽。这可以通过胃蛋白酶水解物中鉴定出的肽中色氨酸、组氨酸和蛋氨酸的含量分别高出25%、31%和48%（具有氢原子转移和供电子能力的重要氨基酸）来证明。
