Lipids Waxes and Edible Coatings

Lipids: Waxes

• Waxes are derivatives of higher alcohols (C12-C28) esterified to long-chain fatty acids.
• Traditionally used as coatings on fruits and vegetables to extend their shelf life post-harvest.
• Common use as lipid coatings for encapsulating food ingredients, especially water-soluble ones.
• Edible waxes resist moisture transport more effectively than other lipids or non-lipids.
• Beeswax's primary ester is myricyl palmitate.

Fatty Esters of Waxes

• Various fatty acid esters of myricyl and cetyl alcohol are components of waxes.
• Examples include palmitic acid ester of myricyl alcohol and hexaeicosan acid ester of myricyl alcohol and palmitic acid ester of cetyl alcohol.

Beeswax Composition

• Major components include alkanes, free fatty acids, monoesters, diesters, and hydroxy-monoesters.
• Fatty alcohols and hydroxy-diesters are minor constituents.

Edible Coatings

• Edible coatings can significantly extend the shelf life of fruits and vegetables by reducing water loss.
• This impact can be observed after 7 days using an emulsion coating on strawberries and apples.

Lipid Coatings: Lecithins

• Lecithin is a general term for a group of yellow-brownish fatty substances found in both animals and plants.
• Lecithin's composition includes phosphoric acid, choline, fatty acids, glycerol, glycolipids, triglycerides, and phospholipids. Examples include:
• phosphatidylcholine
• phosphatidylethanolamine
• phosphatidylinositol

Lecithin Vesicles

• Lecithin vesicles are recently used in encapsulating food enzymes.
• Lecithin capsule formation can occur effectively at low temperatures.
• Lecithin can be blended with existing coating materials.

Liposomes

• Liposomes consist of natural phospholipids.
• They also may include mixed lipid chains, with surfactant characteristics such as phosphatidylethanolamine.
• Liposomes serve as vehicles for pharmaceutical drugs and nutrients
• They can be produced by disrupting biological membranes (e.g., sonication or microfluidization).

Liposome Applications

• Significant applications in food, especially in delivering functional foods, nutraceuticals, and bioactive compounds.
• Liposomes can deliver various compounds like peptides, bioactive phytochemicals/plant extracts, essential oils, marine oils (EPA/DHA), vitamins, and minerals.
• This can lead to improved bioavailability, controlled release, and enhanced physicochemical properties of food components.

Liposome Production Methods

• Different techniques exist for liposome production, including thin-film hydration, detergent removal, solvent injection, extrusion, heating, supercritical anti-solvent methods, supercritical reverse-phase evaporation, microfluidization, and ultrasonication.
• These methods vary in the encapsulated materials, lipid vehicles used to generate the liposomes, and the advantages they provide in terms of stability, bioavailability, and improved properties.

Thin Film Preparation (Liposome)

• Liposomes can be prepared using the thin film hydration method.
• The method involves dissolving the lipid in an organic solvent, evaporating the solvent, and hydrating the lipid film with an aqueous solution. This results in a liposome formulation and helps prevent degradation during storage.