Determination of the efficiency of removal of whey protein from sweet whey with ceramic microfiltration membranes

Abstract

Our research objective was to measure percent removal of whey protein from separated sweet whey using 0.1-µm uniform transmembrane pressure ceramic microfiltration (MF) membranes in a sequential batch 3-stage, 3× process at 50°C. Cheddar cheese whey was centrifugally separated to remove fat at 72°C and pasteurized (72°C for 15 s), cooled to 4°C, and held overnight. Separated whey (375 kg) was heated to 50°C with a plate heat exchanger and microfiltered using a pilot-scale ceramic 0.1-µm uniform transmembrane pressure MF system in bleed-and-feed mode at 50°C in a sequential batch 3-stage (2 diafiltration stages) process to produce a 3× MF retentate and MF permeate. Feed, retentate, and permeate samples were analyzed for total nitrogen, noncasein nitrogen, and nonprotein nitrogen using the Kjeldahl method. Sodium dodecyl sulfate-PAGE analysis was also performed on the whey feeds, retentates, and permeates from each stage. A flux of 54 kg/m 2 per hour was achieved with 0.1-µm ceramic uniform transmembrane pressure microfiltration membranes at 50°C. About 85% of the total nitrogen in the whey feed passed though the membrane into the permeate. No passage of lactoferrin from the sweet whey feed of the MF into the MF permeate was detected. There was some passage of IgG, bovine serum albumen, glycomacropeptide, and casein proteolysis products into the permeate. β-Lactoglobulin was in higher concentration in the retentate than the permeate, indicating that it was partially blocked from passage through the ceramic MF membrane.

Efficiency of removal of whey protein from sweet whey using polymeric microfiltration membranes

“…There was no detectable level of lactoferrin (LFR) passage into the permeate and no intact α S -or β-casein (Figure 1) in the separated whey, retentates, or permeates (Table 6). Carter et al (2021) reported a similar observation that there was no detectable LFR in permeate from ceramic membranes when processing sweet whey at 50°C (Figure 2). There were CNPP present in the whey; they were measurable in the MF retentate but below detection limits on our SDS-PAGE gel in the permeate.…”

“…It was assumed the sweet whey contained 0.91% protein on a TN basis, as reported in the current paper. A TN-based protein removal in permeate from sweet whey using ceramic membranes resulted in 84.8% removal in MF permeate reported by Carter et al (2021) and a 68.8% removal in MF permeate for polymeric membranes reported in the current paper. The WPI and WPPC protein yields (kg/d) were calculated assuming that 1,000,000 kg of separated sweet whey was processed in 1 d with either a ceramic or a polymeric membrane system operated under the conditions reported by Carter et al (2021).…”

“…A TN-based protein removal in permeate from sweet whey using ceramic membranes resulted in 84.8% removal in MF permeate reported by Carter et al (2021) and a 68.8% removal in MF permeate for polymeric membranes reported in the current paper. The WPI and WPPC protein yields (kg/d) were calculated assuming that 1,000,000 kg of separated sweet whey was processed in 1 d with either a ceramic or a polymeric membrane system operated under the conditions reported by Carter et al (2021). The yield of WPI was calculated assuming 90% TN-based protein on a TS basis, and the yield of WPPC was calculated based on the assumption that 50% of the solids in WPPC were TN-based protein.…”

“…The noncasein nitrogen content of retentates was determined using Kjeldahl (AOAC International, 2000;method 998.05;33.2.64). Analysis of feed, retentate, and per-meate were measured for relative protein percentages by SDS-PAGE, and protein removal was calculated as described by Carter et al (2021).…”

“…Recently, Carter et al (2021) reported results for MF of sweet whey using a 0.1-μm ceramic membrane system and compared the efficiency of removal of whey proteins from sweet whey [84.8% on a total nitrogen (TN) basis] to the efficiency of removal of milk-derived whey protein from skim milk with the same ceramic membranes (98.3%; . Carter et al (2021) also reported that the percent removal of milk-derived whey protein from skim milk was lower when using SW MF compared with when using ceramic MF under the same 3-stage, 3× MF process at 50°C [70.3% (Beckman et al, 2010) vs. 98.3% ].…”