Transmission Electron Microscopy Study of Casein Micelle in Raw Milk with Different Somatic Cell Count Levels

Preparation and Properties Nano-encapsulated Wheat Germ Oil and its Use in the Manufacture of Functional Labneh Cheese

BACKGROUND AND OBJECTIVE

There is a growing interest to develop novel versions of traditional dairy products by upgrading their health properties. The use of wheat germ oil (WGO) known by its health-promoting effects, in the fortification of dairy products such as Labneh represents a challenge. This study was aimed to prepare nano-encapsulated WGO and to develop Labneh enriched with nano-encapsulated WGO.

MATERIALS AND METHODS

The WGO was encapsulated in casein micelles by pH changes and ultra-sonication. Transmission electron microscopy and laser light scattering characterized the size and shape of the prepared WGO capsules and their zeta potential was determined. The antioxidant activity and oxidative stability of encapsulated WGO were measured. Labneh was made from standardized (3% fat) milk and by replacement 50% of milk fat with free and encapsulated WGO, respectively. Labneh was analyzed for gross composition, textural parameters, colour and sensory properties during cold storage for 20 days.

RESULTS

High encapsulation efficiency (>95%) of different levels of WGO (0.3 to 1.2%) in casein micelles was obtained. The encapsulated WGO had a spherical shape and nano sizes. The particle sizes increased with the increase of the encapsulated level of WGO. The encapsulated WGO retained high DPPH scavenging activity and exhibited high oxidative stability. Labneh made with encapsulated WGO had composition and quality comparable to the control.

CONCLUSION

Functional Labneh of acceptable quality and high antioxidant activity could be prepared by replacement of 50% of milk fat with encapsulated WGO.

Preparation and Characterization of Sustained Released Zinc Citrate Encapsulated in Whey Protein Nanoparticles

BACKGROUND AND OBJECTIVES

The use of milk proteins for drug delivery is a new trend in functional foods and pharmaceutical. Recently, researchers have focused on the utilization of whey proteins in the preparation of nanoparticle and carrier for drugs and micronutrients. The objectives of this paper were to use whey proteins isolate (WPI) nanoparticles for the encapsulation of zinc citrate micronutrients and characterization of the prepared nanoparticles.

MATERIALS AND METHODS

Nanoparticles were prepared from WPI with pH cycling and used for the encapsulation and sustained release of zinc citrate with three ratios (7, 14 and 28 mM) of zinc citrate per gram WPI. The particle size of the prepared nanoparticles was characterization and examined by transmission electron microscopy. The release of Zinc from the prepared nanoparticles was carried out using simulated gastric fluid at pH 1.2 using dialysis membranes, the amount of zinc citrate loaded whey protein (14.36 mg Zinc in 1 g WPI) within range of daily dose of zinc for healthy adults.

RESULTS

The WPI nanoparticles were able to encapsulate efficiently zinc, with encapsulation efficiency that ranged between 99.79 and 96.31%. Zinc was highly released from the prepared nanoparticles in acidic media (pH 1.2).

CONCLUSION

It can be concluded that WPI can be used as an effective vehicle for the protection and sustained release of zinc in food and pharmaceutical preparations.

Influence of race and crossbreeding on casein micelles size

Casein (CN) micelles are colloidal aggregates of protein dispersed in milk, the importance of which in the dairy industry is related to functionality and yield in dairy products. The objective of this work was to investigate the correlation of milk CN micelles diameter from Holstein and Zebu crossbreds with milk composition (protein, fat, lactose, total and nonfat solids and milk urea nitrogen), somatic cell count (SCC), age, lactation stage and production. Average casein micelles diameters of milk samples obtained from 200 cows were measured using photon correlation spectroscopy and multiple regression analysis was used to find relationship between variables. CN micelle diameter, SCC and nonfat solids were different between animals with different Holstein crossbreed ratios, which suggests influence of genetic factors, mammary gland health and milk composition. Overall, results indicate the potential use of CN micelle diameter as a tool to select animals to produce milk more suitable to cheese production.