Chemical Analysis of Value Added Dairy Products and Their Quality ...

Chemical Analysis of Value Added Dairy Products and Their Quality AssuranceProperties of phospholipidsThe molecular structure of phospholipids is bipolar and amphiphilic, means it combines a lipophilicpart (the fatty acid tails linked to the glycerol backbone) and a hydrophilic part (the polar head group, aphosphoric acid ester mostly of an amino alcohol like choline, ethanolamine, etc.).Technological applicationsTheir bipolar structure makes phospholipids excellent natural emulsifiers, widely used in foods,cosmetics and also pharmaceutical applications. The application properties of the food additive lecithinrelates to a great extent to their phospholipid content and profile. The most prominent applicationsare for margarine, chocolate, baked products, instant powders, etc. The cosmetic industry appreciatestheir emulsifying, skin friendly and moisturising properties; pharmaceuticals use them as emulsifiersfor intravenous fat emulsions, but also for complex drug delivery systems (Iiposome).Liposomes are versatile delivery systems, originally for pharmaceutical uses, but also widely usedin cosmetics. Liposomes are tiny, artificial cell-like structures, surrounded by either one (unilamellar)or many phospholipid double layers. Inside the vesicular structure, or between the differentphos¬pholipid membranes, water compartments are entrapped, carrying and protecting water-solubleactives. But also lipophilic payloads can be entrapped and protected from the environment inside thelipophilic domains of the phospholipid double layers.Nutritiona1 profile of phospholipidsBesides their widely used technological properties, phospholipids have a very Interestingnutritiona1 profile. Lots of clinical studies have shown• Cholesterol reducing properties ( soya phosphatidylcholine - PC)• Improvement of cognitive performance - stress symptom (soya phosphatidylserlne - PS)• Liver tissue detoxification and regeneration ( soya PC).• Egg phospholipids are used to supplement infant formulae because of their content of longchain polyunsaturated fatty acids (docosahexaenoic and arachidonic acid DHA and ARA).Milk polar lipidsAnother biologically interesting lipid group in milk fat is the polar lipids, which are mainlylocated in the milk fat globule membrane (MFGM). It is a highly complex biological structure thatsurrounds the fat globulestabilizing it in the continuous aqueous phase of milk and preventing it fromenzymatic degradation by lipases (Spitsberg, 2005 ). The membrane consists of about 60% proteins and40% lipids that are mainly composed of triglycerides, cholesterol, phospholipids, and sphingolipids.The polar lipid content of raw milk is reported to range between 9.4 and 35.5 mg per 100 g of milk.The major phospholipid fractions are phosphatidylethanolamine and phosphatidylcholine followedby smaller amounts of phosphatidylserine and phosphatidylinositol. The major sphingolipidfraction is sphingomyelin with smaller portions of ceramides and gangliosides. In processing milkinto different dairy products, the polar lipids are preferentially enriched in the aqueous phases likeskimmed milk, buttermilk and butter serum.The polar lipids in milk are gaining increasing interest due to their nutritional and technologicalproperties. These compounds are secondary messengers involved in transmembrane signaltransduction and regulation, growth, proliferation, differentiation, and apoptosis of cells. They alsoplay a role in neuronal signaling and are linked to age - related diseases, blood coagulation, immunity,and inflammatory responses. In particular, sphingolipids and their derivatives are considered highlybioactive components possessing anticancer, cholesterol - lowering, and antibacterial activities.Thesepromising results from cell culture and animal - model studies warrant further confirmation andhuman clinical studies but suggest that sphingolipid - rich foods or supplements could be beneficial inthe prevention of breast and colon cancers and bowel - related diseases (Korhonen, 2010).18