Influence of Soy Lecithin and Sodium Caseinate on The Stability and In Vitro Bioaccessibility of Lycopene Nanodispersion
Nor Shariffa Yussof1*, Tan Chin Ping2, Tan Tai Boon2, Uthumporn Utra1 and Muhammad Ezzudin Ramli1
1Department of Food Technology, School of Industrial Technology, Building G07, Persiaran Sains, Universiti Sains Malaysia, Jalan Sungai 2, 11800, USM, Penang, Malaysia
2Department of Food Technology, Faculty of Food Science and Technology, Universiti Putra Malaysia, Jalan Universiti 1, 43400 UPM Serdang, Selangor, Malaysia
Received: 28 October 2021
Accepted: 15 December 2022
lycopene; nanodispersion; bioaccessibility; sodium caseinate; lecithin; emulsifier
Research background. Various approaches have been used to present functional lipids including lycopene in a palatable food form to consumers. However, being highly hydrophobic, lycopene is insoluble in aqueous systems and has a restricted absorption level in the body. Producing lycopene nanodispersion is expected to improve the properties of lycopene, but its stability and bioaccessibility are also affected by emulsifier type and environmental conditions such as pH, ionic strength and temperature.
Experimental approach. The influence of soy lecithin (LC), sodium caseinate (SC), and soy lecithin: sodium caseinate (LC:SC) at one to one ratio on the physicochemical properties and stability of lycopene nanodispersion prepared using the emulsification-evaporation methods before and after being subjected to different pH, ionic strength and temperature treatment were investigated. The in vitro bioaccessibility of the nanodispersions was also studied.
Results and conclusions. Under neutral pH conditions, LC-stabilized nanodispersion showed the highest physical stability by exhibiting the smallest particle size (78 nm), lowest PDI value (0.180), and highest zeta potential (-64 mV) but lowest lycopene concentration (1.826 mg/100mL). SC-stabilized nanodispersion conversely had the lowest physical stability. Combining the LC with SC at 1:1 ratio resulted in a physically stable lycopene nanodispersion with the highest lycopene concentration (2.656 mg/100mL). The lycopene nanodispersion produced by LC also exhibited high physical stability under different pH range (pH=2-8) where the particle size, PDI, and zeta potential remained fairly consistent. The SC-containing nanodispersion was unstable with respect to droplet aggregation when the pH was reduced close to the isoelectric point of SC (pH=4-5). The particle size and PDI value of LC:SC stabilized nanodispersion increased sharply when the NaCl concentration increased above 100 mM while the LC and SC counterparts were more stable. All of the nanodispersions showed good stability with respect to temperature changes (30-100 °C) except for the one stabilized by SC, which exhibited an increased particle size when heated to a temperature above 60 °C. The combination of LC and SC was found to increase the bioaccessibility of the lycopene nanodispersion. The physicochemical properties, stability, and extent of the lycopene nanodispersion digestion were highly dependent on the emulsifier types.
Novelty and scientific contribution. Producing a nanodispersion is considered one of the best ways to overcome the poor water solubility stability, and bioavailability issues of lycopene. Currently, studies related to lycopene-fortified delivery systems, particularly in the form of nanodispersion are still limited. The information obtained on the physicochemical properties, stability, and bioaccessibility of lycopene nanodispersion is useful for the development of an effective delivery system for various functional lipids.