METHODS: Kenaf seed oil (KSO), microencapsulated kenaf seed oil (MKSO), kenaf seed extract (KSE) and defatted kenaf seed meal (DKSM) were prepared and phytochemicals screening on these samples were done prior in vivo study. Phenolic compounds in KSE were quantified using high performance liquid chromatography. There were 40 (divided in eight diet groups of 5) male Sprague dawley rats adapted to normal standard diet or hypercholesterolemic diet (HD) with or without the treatment of these kenaf samples for 32 days.

RESULTS: All the kenaf samples exhibited to contain most of the major phytochemicals. KSE possessed gallic acid, tannic acid, catechin, benzaldehyde, benzoic acid, syringic acid, sinapic acid, ferulic acid, naringin acid, and protocatechuic acid. The significant higher (P<0.05) serum total cholesterol, low density lipoprotein cholesterol and MDA levels in HD group without treatment than the normal control group suggested the hypercholesterolemia was induced by the incorporation of cholesterol into diet. KSE exhibited higher cholesterol-lowering properties due to the significant lower (P<0.05) in serum triglycerides, total cholesterol and MDA levels. KSE showed the highest efficiency of cholesterol-lowering activity, followed by KSO, MKSO and DKSM.

EXPERIMENTAL APPROACH: The influence of soy lecithin, sodium caseinate and soy lecithin/sodium caseinate at 1:1 ratio on the physicochemical properties and stability of lycopene nanodispersion prepared using the emulsification-evaporation methods before and after treatment at different pH, ionic strength and temperature were investigated. The in vitro bioaccessibility of the nanodispersions was also studied.

RESULTS AND CONCLUSION: Under neutral pH conditions, nanodispersion stabilized with soy lecithin had the highest physical stability and the smallest particle size (78 nm), the lowest polydispersity index (PDI) value (0.180) and highest zeta potential (-64 mV) but the lowest lycopene concentration (1.826 mg/100 mL). Conversely, nanodispersion stabilized with sodium caseinate had the lowest physical stability. Combining the soy lecithin with sodium caseinate at 1:1 ratio resulted in a physically stable lycopene nanodispersion with the highest lycopene concentration (2.656 mg/100 mL). The lycopene nanodispersion produced by soy lecithin also had high physical stability under different pH range (pH=2-8) where the particle size, PDI and zeta potential remained fairly consistent. The nanodispersion containing sodium caseinate was unstable and droplet aggregation occurred when the pH was reduced close to the isoelectric point of sodium caseinate (pH=4-5). The particle size and PDI value of nanodispersion stabilized with soy lecithin and sodium caseinate mixture increased sharply when the NaCl concentration increased above 100 mM, while the soy lecithin and sodium caseinate 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 sodium caseinate, which exhibited an increased particle size when heated to above 60 °C. The combination of soy lecithin and sodium caseinate was found to increase the bioaccessibility of the lycopene nanodispersion. The physicochemical properties, stability and extent of the lycopene nanodispersion digestion highly depend on the emulsifier type.