Valorization of buttermilk powder to produce a milk fat globule membrane (MFGM) enriched ingredient
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Date
2022-05
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The Ohio State University
Abstract
Milk fat globule membrane (MFGM) is the multicomponent structure surrounding milk lipid globules. MFGM can be recovered from butter industry byproducts, including buttermilk. Supplementing a diet with MFGM has many potential health benefits throughout life impacting cognitive function, gut health, and the immune system. The objective was to use buttermilk powder (BMP) to prepare an ingredient enriched in milk fat globule membrane (MFGM), reduced in casein and whey proteins, and suitable for beverage industry applications. A method for isolating and concentrating MFGM from rehydrated buttermilk was developed. Ammonium hydroxide (NH4OH), rennin, and acetic acid treatments with or without trisodium citrate (TSC) were tested. NH4OH and TSC were expected to solubilize casein micelles; rennin and acid treatments were expected to precipitate out caseins. The best method was chosen based on qualitative observations of the degree to which sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and thin layer chromatography (TLC) showed the presence of MFGM proteins or phospholipids in treated samples. Rennin precipitation (30°C, 1% CaCl2, pH 5.47, 5% rennin), followed by cheesecloth straining, addition of TSC (2.5%) to the liquid fraction (whey/serum), ultrafiltration (50 kDa; 4x concentration, 5x diafiltration), and centrifugation of the whey retentate was determined to be the best method to obtain a MFGM enriched semi-solid pellet ("the ingredient"). SDS-PAGE results showed this treatment had the most consistent enrichment in MFGM proteins, with a large reduction in casein proteins. Bands with molecular weights of 169, 80, 58, 38, 21, and 20 kDa were detected, corresponding to MFGM proteins xanthine oxidase/dehydrase, butyrophilin, and lactadherin/periodic acid Schiff base 6 and 7 doublet, and to the milk proteins casein, beta lactoglobulin, and alpha lactalbumin. Difficulties separating out whey proteins could be due to protein-protein aggregates induced by heat treatment of BMP. TLC results confirmed the presence of MFGM phospholipids (sphingomyelin, phosphatidylcholine, phosphatidylserine, phosphatidylinositol, phosphatidylethanolamine). Using the ingredient, several prototype MFGM enriched, probiotic fruit-flavored beverages were made. Valorization of BMP can reduce dairy industrial waste and expand MFGM nutritional benefits to the general population beyond infant formula.
Description
CFAES Undergraduate Research Forum (2nd place in division)
ADSA Annual Meeting (2nd place in Student Affiliate Division)
ADSA Annual Meeting (2nd place in Student Affiliate Division)
Keywords
milk fat globule membrane, buttermilk powder, rennin precipitation, dairy waste reduction