**3.3. Chemical stability of lutein emulsions prepared with bovine casein /lecithin and caprine casein/lecithin as emulsifiers**

Lutein degradation in the emulsions that were prepared with different emulsifiers was in the following order: bovine casein/lecithin > caprine αs1-I-casein/lecithin > caprine αs1-II-casein/


**Table 1.** Particle size of oil droplets in lutein-enriched emulsions stabilized by bovine casein/lecithin or caprine casein/ lecithin in phosphate buffer at pH 7.0 and 21 ± 1°C.


Means with different lowercase superscripts are significantly different (p < 0.05). 1 Mean value ± Standard error.

**Table 2.** Zeta potential of oil droplets in lutein-enriched emulsions stabilized by bovine casein/lecithin or caprine casein/ lecithin in phosphate buffer at pH 7 and 21 ± 1°C.

Lutein-Enriched Emulsion-Based Delivery System: Impact of Casein-Phospholipid Emulsifiers… http://dx.doi.org/10.5772/intechopen.78601 167

**Figure 1.** Lutein degradation in corn oil-in-water emulsions (pH 7.0) stabilized by bovine casein/lecithin, caprine (αs1-I) casein/lecithin or caprine (αs1-II)-casein/lecithin at 5°C (A) and 15°C (B) as a function of storage time. Values represent the mean of three trials.

lecithin (**Figure 1**). The bovine casein/lecithin means on the bars are significantly different than the two caprine casein/lecithin means (p < 0.05) until four days of storage at 5°C (**Figure 1A**); the same tendency in lutein loss was observed during storage at 15°C (**Figure 1B**). Comparing the results of the two caprine casein/lecithin emulsifiers, the caprine αs1-II/lecithin emulsifier overall showed lower means than caprine αs1-I/lecithin emulsifier in both storage temperatures. In general, lutein degradation was faster in emulsions prepared with bovine casein/lecithin emulsifier than with the other two emulsifiers within 7 days of storage at 5 and 15°C (**Figure 1A** and **B**, respectively). The fact that lutein degradation was faster in the emulsions prepared with bovine casein/lecithin emulsifier compared to the emulsions prepared with caprine αs1-I-casein /lecithin emulsifier or caprine αs1-II-casein/lecithin emulsifier suggests that the interfacial layer formed by bovine casein/lecithin emulsifier was less efficient in protecting emulsified lutein against chemical degradation during storage at 5 and 15°C. The combination of caprine αs1-I-casein or caprine αs1-II-casein with soybean lecithin as emulsifiers resulted in a more favorable thickness of the interfacial layer thereby, slowing down the lutein degradation in these emulsions. This confirms that caprine caseins, which are 'rich' in their content of β-casein, formed a denser interfacial layer surrounding oil droplets and the possible role that the thickness of the interfacial layer played in the degradation of emulsified lutein. Furthermore, soybean lecithin, which is comprised of charged phospholipids such as phosphatidylinositol and phosphatidic acid [26], is more soluble in water and therefore, more easily absorbed at the oil-in-water interface thereby, producing a thicker interfacial layer protecting lutein.

#### **4. Conclusions**

caprine αs1-I-casein/lecithin, or caprine αs1-II-casein/lecithin. The mean particle diameters of oil droplets in the lutein-enriched emulsions stabilized by bovine casein/lecithin or caprine casein/lecithin ranged from 205.6 ± 2.3 to 208.9 ± 2.5 nm at pH 7.0 (**Table 1**). We observed no significant differences (p > 0.05) in the particle sizes of oil droplets in lutein-enriched emulsions with either bovine casein or caprine caseins during 0 and 7 days of storage at 21 ± 1°C. The zeta potentials of the casein/lecithin-coated oil droplets in the lutein-enriched emulsions were negative at pH 7.0 (**Table 2**). The zeta potentials of the oil droplets in the luteinenriched emulsions prepared with the two caprine casein/lecithin emulsifiers were not different (p > 0.05), showing mean values of −36.8 ± 1.8 mV for caprine αs1-I-casein/lecithin and −35.9 ± 1.9 mV for caprine αs1-II-casein/lecithin, respectively. The lower zeta potentials of the oil droplets in the lutein-enriched emulsions stabilized by the two caprine casein/lecithin emulsifiers compared to the lutein-enriched emulsions stabilized by bovine casein/lecithin emulsifier can imply a decreased 'net' negative charge [25]. Differences in the amino acids of

β-casein quantitatively dominates, could lead to less repulsive charge-charge interactions and this phenomenon can possibly explains why caprine caseins have lower zeta potentials (**Table 2**). On the basis of these findings, we can conclude that the lutein-enriched emulsions prepared with bovine casein/lecithin emulsifier and the two caprine casein/lecithin emulsi-

Lutein degradation in the emulsions that were prepared with different emulsifiers was in the following order: bovine casein/lecithin > caprine αs1-I-casein/lecithin > caprine αs1-II-casein/

Storage (d) Bovine casein/lecithin Caprine (αs1-I)-casein/lecithin Caprine (αs1-II)-casein/lecithin

**Table 1.** Particle size of oil droplets in lutein-enriched emulsions stabilized by bovine casein/lecithin or caprine casein/

**Table 2.** Zeta potential of oil droplets in lutein-enriched emulsions stabilized by bovine casein/lecithin or caprine casein/

0 207.8 ± 2.0 208.9 ± 2.5 208.0 ± 2.1 7 205.6 ± 2.3 206.1 ± 2.4 205.7 ± 2.2

**Emulsifier Zeta potential (mV)1**

Bovine casein/lecithin −39.7 ± 1.8<sup>a</sup> Caprine (αs1-I)-casein/lecithin −36.8 ± 1.8<sup>b</sup> Caprine (αs1-II)-casein/lecithin −35.9 ± 1.9<sup>b</sup> Means with different lowercase superscripts are significantly different (p < 0.05).

**3.3. Chemical stability of lutein emulsions prepared with bovine casein /lecithin** 


side chains of κ-, αs

166 Progress in Carotenoid Research

**Particle size (nm)1**

Mean value ± Standard error.

Mean value ± Standard error.

1

1

fiers exhibited relatively good physical stability [13].

**and caprine casein/lecithin as emulsifiers**

lecithin in phosphate buffer at pH 7.0 and 21 ± 1°C.

lecithin in phosphate buffer at pH 7 and 21 ± 1°C.

The stabilizing role of phospholipids in emulsions is important in the absorption of lutein by the host. From the nutritional point of view consumption of a lutein-enriched beverage emulsion stabilized by bovine casein/lecithin emulsifier or caprine casein/lecithin emulsifier will be a valuable means to counterbalance the deficiency in consumption of fruits and vegetables; this approach will reduce the negative effects of lower ingestion of health-promoting carotenoids. Overall, these results indicate that a high chemical stability of lutein in corn oil-inwater emulsions can be achieved by altering the physical properties of the emulsion droplet interface by the addition of emulsifiers such as caprine αs1-I-casein/lecithin and caprine αs1- II-casein/lecithin. The different effects of the bovine casein/lecithin and the caprine casein/ lecithin emulsifiers on the stability of lutein is expected to be derived from the difference in the composition of bovine and caprine caseins, in particular the β-casein and its role at the interface of emulsion for the protection of emulsified carotenoids, specifically the lutein of the xanthophyll group. The charged phospholipids, phosphatidyl inositol and phosphatidic acid, in soybean lecithin may also decrease the degradation of lutein in oil-in-water emulsions by producing a thicker interfacial layer.

[4] Berman J, Zorilla-López U, Farré G, Zhu C, Sandmann G, Twyman RM, Capell T, Christou P. Nutritionally important carotenoids as consumer products. Phytochemistry

Lutein-Enriched Emulsion-Based Delivery System: Impact of Casein-Phospholipid Emulsifiers…

http://dx.doi.org/10.5772/intechopen.78601

169

[5] Eisenhauer B, Natoli S, Liew G, Flood VM. Lutein and zeaxanthin-food sources, bioavailability and dietary variety in age-related macular degeneration protection. Nutrients.

[6] Chung HY, Rasmussen HM, Johnson EJ. Lutein bioavailability is higher from luteinenriched eggs than from supplements and spinach in men. The Journal of Nutrition.

[7] Ranard KM, Jeon S, Mohn ES, Griffiths JC, Johnson EJ, Erdman JW Jr. Dietary guidance for lutein: Consideration for intake recommendations is scientifically supported.

[8] McClements DJ, Decker EA, Park Y, Weiss J. Structural design principles for delivery of bioactive components in nutraceuticals and functional foods. Critical Reviews in Food

[9] Roohinejad S, Oey I, Wen J, Lee SJ, Everett DW, Burritt DJ. Formulation of oil-inwater β-carotene microemulsions: Effect of oil type and fatty acid chain length. Food

[10] Frede K, Henze A, Khalil M, Baldermann S, Schweigert FJ, Rawel H. Stability and cellular uptake of lutein-loaded emulsions. Journal of Functional Foods. 2014;**8**:118-127.

[11] Boon CS, McClements DJ, Weiss J, Decker EA. Factors influencing the chemical stability of carotenoids in foods. Critical Reviews in Food Science and Nutrition. 2010;**50**:515-532.

[12] Nagao A. Bioavailability of dietary carotenoids: Intestinal absorption and metabolism. Japan Agricultural Research Quarterly. 2014;**48**:385-392. DOI: 10.6090/jarq.48.379 [13] McClements DJ. Emulsion stability. In: Clydesdale FM, editor. Food Emulsions: Principles, Practice, and Techniques. 2nd ed. Boca Raton: CRC Press; 2005. pp. 269-339. ISBN:

[14] García-Moreno PJ, Horn FA, Jacobsen C. Influence of casein-phospholipid combinations as emulsifiers on the physical and oxidative stability of fish oil-in-water emulsions. Journal of Agricultural and Food Chemistry. 2014;**62**:1142-1152. DOI: 10.1021/jf405073x

[15] Ginger MR, Grigor MR. Comparative aspects of milk caseins. Comparative Biochemistry and Physiology Part B: Biochemistry & Molecular Biology. 1999;**124**:133-145. DOI:

[16] Mora-Gutierrez A, Kumosinski TF, Farrell Jr HM. Quantification of αs1-casein in goat milk from French-Alpine and Anglo-Nubian breeds using reversed-phase high performance liquid chromatography. Journal of Dairy Science. 1991;**74**:3303-3307. DOI:

European Journal of Nutrition. 2017;**56**:537-542. DOI: 10.1007/s00394-017-1580-2

Science and Nutrition. 2009;**49**:577-606. DOI: 10.1080/10408390902841529

Chemistry. 2015;**174**:270-278. DOI: 10.1016/j.foodchem.2014.11.056

Reviews. 2015;**14**:727-743. DOI: 10.1007/s11101-014-9373-1

2017;**9**:1-14. DOI: 10.3390/nu9020120

DOI: 10.1016/j.jff.2014.03.011

10:0849-32023-2

DOI: 10.1080/10408390802565889

10.1016/S0305-0491(99)00110-8

10.3168/jds.S0022-0302(91)78516-0

2004;**134**:1887-1893. DOI: 10.1093/jn/134.8.1887
