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36 Valorization of By-Products of Milk Fat Processing

36.3.3

Buttermilk as a Source of Phospholipids

Phospholipids are the polar lipids that are essential for emulsification of fat in milk

matrix. MFGM contains phospholipids along with glycol protein, cholesterol, free

fatty acids, glycolipids, total and partial glycerides. During churning of cream for

butter manufacture, the mass is separated into aqueous phase called buttermilk and

oily phase called butterfat. The process involves mechanical destabilization, causing

globule coalescence leading to formation of solid phase. Different washing proce-

dures are used during butter manufacture and bring out various degrees of damage

to MFGM affecting the lipid profile of the buttermilk. The glycerophospholipids

present in buttermilk could be classified as phosphatidylethanolamine (PE – 39%),

phosphatidylcholine (PC – 24%), phosphatidylserine (PS – 8%), and phosphatidyli-

nositol (PI – 9%) [26]. Another important component of the phospholipids profile of

buttermilk is SM. It exerts a significant biological role due to its effect on regulating

the cell growth and development and its role in controlling aging and aging-related

disease and cell apoptosis [27]. Additionally, buttermilk is a good source of

9-O-acetyl-GD3, a ganglioside having vital bioactive role [28]. This molecule has the

potential to modulate the production of specific antibodies and is being explored as

indicative molecule for detection of melanoma. Thus, buttermilk has a unique lipid

profile making it a store house of many valuable molecules, which when extracted

and purified can be exploited for its economic and functional importance.

36.4

Valorization of Ghee Residue

Ghee residue is the by-product obtained as the solid retentate during the production

of the ghee. It is primarily composed of the light brown or darker brown sediment

of charred or burnt particles during the heat clarification of butter. Irrespective of

the method of ghee preparation (country/desi, creamery butter, direct cream, and

continuous butter making method), the heating process induces physicochemical

variations in the SnF fraction. The solid matrix thus produced settles down as a

residue, trapping within it the caramelized lactose, denatured milk protein, phos-

pholipids, minerals, moisture, and some of the flavoring compounds such as lac-

tones, carbonyls, and free fatty acids, etc.

The yield and composition of ghee residue depends on the type of milk as well

as the method of ghee preparation. Moisture content of ghee residue prepared from

various methods and bovine milk may range from 5% to 14%, while the fat content

may usually range from 60% to 80%. Protein content in the ghee residue is observed

to be between 20% and 35%, while the by-product may have <5% of mineral con-

tent [29]. Among its various constituents, the fat and protein profiles are the most

valuable components in terms of scope for economic valorization.

The easily absorbable short and medium-chain fatty acids present in ghee residue

make it beneficial for disease treatment [30]. The amino acid profile of ghee residue

is known to influence immune function, antioxidant activity, inhibit apoptosis,

anti-inflammation property, prevent autoimmune neuro-inflammation. Thus, ghee