Enzymatically synthesized γ-[Glu](n≥1)-Gln as novel calcium-binding peptides to deliver calcium with enhanced bioavailability

Huan Xiang; Hui Huang; Dongxiao Sun-Waterhouse; Xiao Hu; Laihao Li; Geoffrey I N Waterhouse; Runmei Tang; Jian Xiong; Chun Cui

doi:10.1016/j.foodchem.2022.132918

Enzymatically synthesized γ-[Glu]_(n≥1)-Gln as novel calcium-binding peptides to deliver calcium with enhanced bioavailability

Food Chem. 2022 Sep 1:387:132918. doi: 10.1016/j.foodchem.2022.132918. Epub 2022 Apr 9.

Authors

Huan Xiang¹, Hui Huang², Dongxiao Sun-Waterhouse³, Xiao Hu⁴, Laihao Li⁵, Geoffrey I N Waterhouse⁶, Runmei Tang⁷, Jian Xiong⁸, Chun Cui⁹

Affiliations

¹ South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences/Key Laboratory of Aquatic Product Processing, Ministry of Agriculture and Rural Affairs/National Research and Development Center for Aquatic Product Processing, Guangzhou 510300, Guangdong, China. Electronic address: [email protected].
² South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences/Key Laboratory of Aquatic Product Processing, Ministry of Agriculture and Rural Affairs/National Research and Development Center for Aquatic Product Processing, Guangzhou 510300, Guangdong, China. Electronic address: [email protected].
³ School of Food Science and Engineering, South China University of Technology, Guangzhou 510640, Guangdong, China; School of Chemical Sciences, The University of Auckland, Private Bag 92019, Auckland, New Zealand. Electronic address: [email protected].
⁴ South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences/Key Laboratory of Aquatic Product Processing, Ministry of Agriculture and Rural Affairs/National Research and Development Center for Aquatic Product Processing, Guangzhou 510300, Guangdong, China. Electronic address: [email protected].
⁵ South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences/Key Laboratory of Aquatic Product Processing, Ministry of Agriculture and Rural Affairs/National Research and Development Center for Aquatic Product Processing, Guangzhou 510300, Guangdong, China. Electronic address: [email protected].
⁶ School of Chemical Sciences, The University of Auckland, Private Bag 92019, Auckland, New Zealand. Electronic address: [email protected].
⁷ School of Food Science and Engineering, South China University of Technology, Guangzhou 510640, Guangdong, China. Electronic address: [email protected].
⁸ School of Food Science and Engineering, South China University of Technology, Guangzhou 510640, Guangdong, China. Electronic address: [email protected].
⁹ School of Food Science and Engineering, South China University of Technology, Guangzhou 510640, Guangdong, China; Research Institute for Food Nutrition and Human Health, Guangzhou 510640, China. Electronic address: [email protected].

PMID: 35417842
DOI: 10.1016/j.foodchem.2022.132918

Abstract

Novel γ-[Glu]_(n≥1)-Gln-Ca chelates were prepared by using γ-[Glu]_(n≥1)-Gln (mixture peptides containg γ-Glu-Gln, γ-Glu-Glu-Gln, γ-Glu-Glu-Glu-Gln, γ-Glu-Glu-Glu-Glu-Gln, γ-Glu-Glu-Glu-Glu-Glu-Gln) which were synthesized by glutaminase. Based on single factor and orthogonal array experiments, the optimal calcium-chelation conditions were as follows: 30 min chelation at 70 °C; peptide concentration, 0.15 g/mL; mixture peptides-to-calcium mass ratio, 25:1. The particle size of chelates was 743.6 ± 64.2 nm and the chelates appeared stable neutral molecular entities with 91.33% of chelation rate and 35.2 mg/g of calcium, also with higher thermostability. Chelated calcium ions might be surrounded by coordination bonds linking to two or more connecting points: oxygen atoms (carboxyl oxygen, hydroxyl oxygen and oxygen of peptide bonds) and nitrogen atoms (amino nitrogen). The chelates could be used for food/nutraceutical applications, as no toxicity at 0.125-10 mg/mL and enhanced efficiency in calcium release (releasing percentage over 85% at pH 8.0), transport and uptake compared with CaCl₂ were detected in Caco-2 cells.

Keywords: Caco-2 cells; Calcium bioavailability; Coordination mechanism; γ-[Glu]((n≥1))-Gln; γ-[Glu]((n≥1))-Gln-Ca chelate.

MeSH terms

Biological Availability
Caco-2 Cells
Calcium*
Calcium, Dietary
Humans
Oxygen
Peptides* / metabolism

Substances

Calcium, Dietary
Peptides
Oxygen
Calcium