Peptidomics Analysis of Soy Protein Hydrolysates—Antioxidant Properties and Mechanism of their Inhibition of the Oxidation of Palm Olein during Frying Cycles
Annick Arcelle Pougoue Ngueukam,
Mathilde Julie Klang,
Ronice Zokou,
Gires Teboukeu Boungo,
Fabrice Djikeng Tonfack,
Barakat Koyinsola Azeez,
Hilaire Macaire Womeni,
Apollinaire Tsopmo
Affiliations
Annick Arcelle Pougoue Ngueukam
Biochemistry, Food Sciences, Nutrition and Medicinal Plants Research Unit, Department of Biochemistry, Faculty of Science, University of Dschang, Dschang P.O. Box 6, Cameroon
Mathilde Julie Klang
Biochemistry, Food Sciences, Nutrition and Medicinal Plants Research Unit, Department of Biochemistry, Faculty of Science, University of Dschang, Dschang P.O. Box 6, Cameroon
Ronice Zokou
Biochemistry, Food Sciences, Nutrition and Medicinal Plants Research Unit, Department of Biochemistry, Faculty of Science, University of Dschang, Dschang P.O. Box 6, Cameroon
Gires Teboukeu Boungo
Biochemistry, Food Sciences, Nutrition and Medicinal Plants Research Unit, Department of Biochemistry, Faculty of Science, University of Dschang, Dschang P.O. Box 6, Cameroon
Fabrice Djikeng Tonfack
Biochemistry, Food Sciences, Nutrition and Medicinal Plants Research Unit, Department of Biochemistry, Faculty of Science, University of Dschang, Dschang P.O. Box 6, Cameroon
Barakat Koyinsola Azeez
Food Science Program, Department of Chemistry, Institute of Biochemistry, Carleton University, 1125 Colonel by Drive, Ottawa, ON K1S 5B6, Canada
Hilaire Macaire Womeni
Biochemistry, Food Sciences, Nutrition and Medicinal Plants Research Unit, Department of Biochemistry, Faculty of Science, University of Dschang, Dschang P.O. Box 6, Cameroon
Apollinaire Tsopmo
Food Science Program, Department of Chemistry, Institute of Biochemistry, Carleton University, 1125 Colonel by Drive, Ottawa, ON K1S 5B6, Canada
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.
