Gastric aggregation of micellar casein powders induced by high hydrostatic pressure: Effect of serum Ca2+ level

Lu Peng; Jinbo Ren; Fang Chen; Xiaosong Hu; Song Miao; Lingjun Ma; Junfu Ji

doi:10.1016/j.foodres.2023.113558

Gastric aggregation of micellar casein powders induced by high hydrostatic pressure: Effect of serum Ca²⁺ level

Food Res Int. 2023 Dec;174(Pt 1):113558. doi: 10.1016/j.foodres.2023.113558. Epub 2023 Oct 4.

Authors

Lu Peng¹, Jinbo Ren², Fang Chen¹, Xiaosong Hu², Song Miao³, Lingjun Ma⁴, Junfu Ji⁵

Affiliations

¹ College of Food Science and Nutritional Engineering, National Engineering Research Center for Fruit and Vegetable Processing, China Agricultural University, Key Lab of Fruit and Vegetable Processing, Ministry of Agriculture and Rural Affairs, Beijing 100083, China.
² College of Food Science and Nutritional Engineering, National Engineering Research Center for Fruit and Vegetable Processing, China Agricultural University, Key Lab of Fruit and Vegetable Processing, Ministry of Agriculture and Rural Affairs, Beijing 100083, China; Xinghua Industrial Research Centre for Food Science and Human Health, China Agricultural University, Xinghua 225700, China.
³ Teagasc Food Research Centre, Moorepark, Fermoy, Co. Cork, Ireland.
⁴ College of Food Science and Nutritional Engineering, National Engineering Research Center for Fruit and Vegetable Processing, China Agricultural University, Key Lab of Fruit and Vegetable Processing, Ministry of Agriculture and Rural Affairs, Beijing 100083, China; Xinghua Industrial Research Centre for Food Science and Human Health, China Agricultural University, Xinghua 225700, China. Electronic address: lingjun.ma@cau.edu.cn.
⁵ College of Food Science and Nutritional Engineering, National Engineering Research Center for Fruit and Vegetable Processing, China Agricultural University, Key Lab of Fruit and Vegetable Processing, Ministry of Agriculture and Rural Affairs, Beijing 100083, China; Xinghua Industrial Research Centre for Food Science and Human Health, China Agricultural University, Xinghua 225700, China. Electronic address: junfu.ji@cau.edu.cn.

PMID: 37986436
DOI: 10.1016/j.foodres.2023.113558

Abstract

Micellar casein (MC) has a unique gastric colloidal behavior in response to Ca²⁺ cross-linking, and its aggregation properties are closely related to pepsin and gastric acid. In this study, MC with different levels of colloidal calcium phosphate (CCP) was obtained by high hydrostatic pressure (HHP) at different pressures, followed by spray drying to obtain the powders. Different amounts of calcium chloride (exogenous Ca²⁺) were added to MC powders prior to in vitro simulated digestion to investigate the effect of exogenous serum Ca²⁺ levels on the aggregation behavior and the structure change of curds generated in gastric tract. The results revealed that HHP induced the emergence of more Ca²⁺-binding sites, thus Ca²⁺ was more likely to bind to MC matrix with low CCP levels. Meanwhile, high serum Ca²⁺ level provided more opportunities to form aggregates. The Highest pressure (500 MPa) with the highest Ca²⁺ level (5 mM) caused the lowest solubility aggregates, which were only 30% at the end of gastric digestion (120 min), half of the control sample (0 MPa with 0.15 mM Ca²⁺). The results of wide-angle X-ray scattering / small-angle X-ray scattering suggested that both pepsin and gastric acid-induced aggregation via Ca²⁺ as a bridge. For pepsin, Ca²⁺ cross-linked between para-κ-casein; For gastric acid, Ca²⁺ recombined phosphorylation sites and caused cross-linking of casein subunits.

Keywords: Aggregation behavior; Calcium ion (Ca(2+)); High hydrostatic pressure (HHP); In vitro digestion; Micellar casein (MC).

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Caseins* / chemistry
Hydrogen-Ion Concentration
Hydrostatic Pressure
Micelles*
Pepsin A
Powders

Substances

Micelles
Caseins
Powders
Pepsin A