Transmission of Major and Minor Serum Proteins during Microfiltration of Skim Milk: Effects of Pore Diameters, Concentration Factors and Processing Stages

Zhibin Li,Wenjin Zhang,Dasong Liu,Shu Xu,Peng Zhou

doi:10.3390/foods10040888

Zhibin Li, Wenjin Zhang + Show 3 more

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https://doi.org/10.3390/foods10040888

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Abstract

Effects of pore diameters (100, 50, and 20 nm), concentration factors (1–8) and processing stages (1–5) on the transmission of major serum proteins (β-lactoglobulin and α-lactalbumin) and minor serum proteins (immunoglobulin (Ig) G, IgA, IgM, lactoferrin (LF), lactoperoxidase (LPO), xanthine oxidase (XO)) during ceramic microfiltration (MF) of skim milk were studied. Holstein skim milk was microfiltered at a temperature of 50 °C, a transmembrane pressure of 110 kPa and a crossflow velocity of 6.7 m/s, using a tubular single stainless steel module that consisted of three ceramic tubes, each with 19 channels (3.5 mm inner diameter) and a length of 0.5 m. For MF with 100 nm and 50 nm pore diameters, the recovery yield of major serum proteins in permeate was 44.3% and 44.1%, while the recovery yield of minor serum proteins was slightly less by 0%–8% than 50 nm MF. MF with 20 nm pore diameters showed a markedly lower (by 12%–45%) recovery yield for both major and minor serum proteins, corresponding with its lower membrane flux. Flux sharply decreased with an increasing concentration factor (CF) up to four, and thereafter remained almost unchanged. Compared to the decrease (88%) of flux, the transmission of major and minor serum proteins was decreased by 4%–15% from CF = one to CF = eight. With increasing processing stages, the flux gradually increased, and the recovery yield of both major and minor proteins in the permeate gradually decreased and reached a considerably low value at stage five. After four stages of MF with 100 nm pore diameter and a CF of four for each stage, the cumulative recovery yield of major serum proteins, IgG, IgA, IgM, LF, LPO, and XO reached 95.7%, 90.8%, 68.5%, 34.1%, 15.3%, 39.1% and 81.2% respectively.

Highlights

Human milk is the best natural food for infant nutrition, sometimes infants do not get enough breast milk
Microfiltration was performed at a temperature of 50 ◦ C, a transmembrane pressure of 110 kPa and a crossflow velocity of 6.7 m/s, using the GCM-C-03 unit equipped with a tubular single stainless steel module consisting of 3 ceramic tubes, each with 19 channels
BRM was pumped into the MF system described above and filtered using ceramic membranes at 50 ◦ C with pore diameters of 100, 50 and 20 nm (0.312 m2 surface area; GC-CMF19/35/100S, GC-CUF19/35/50S, GC-CUF19/35/20S; Guochu Technology Co., Ltd., Xiamen, Fujian, China), respectively, and all the microfiltration was processed with concentration factor (CF) = 3

Summary

Introduction

Human milk is the best natural food for infant nutrition, sometimes infants do not get enough breast milk. Infant formula milk (IMF) is an ideal substitution [1]. The ratios of whey protein to casein are 20:80 and 60:40 in bovine and human milk, respectively. For the manufacture of infant formula, whey proteins are usually mixed with skim milk to increase their ratios relative to caseins [2]. Besides the major constituents including β-lactoglobulin and α-lactalbumin, WP contain minor bioactive components such as immunoglobulin (Ig) G, IgA, IgM, lactoferrin (LF), lactoperoxidase (LPO) and xanthine oxidase (XO) [3]. The major serum proteins in bovine milk are β-lactoglobulin (3.2–3.3 g/L) and α-lactalbumin (1.2–1.3 g/L), while the major serum proteins in human milk are α-lactalbumin (1.9–3.4 g/L). For the typical minor serum proteins including IgG, IgA, IgM and LF, bovine milk has a concentration around 0.15–0.8, 0.05–0.14, 0.04–0.1 and

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