the seeds of Camellia sinensis L. which is the fruit of tea trees and currently a by-product of tea production. According to relevant data, the fatty acid composition ratio of green tea seed oil is most similar to that of olive oil and oleifera oil, but green tea seed oil is rich in natural tea polyphenols with characteristic indexes which is different from oleifera oil. Coconut oil is a mixture of various triglycerides, the content of lauric acid is more than 50 , and the content of C6, C8 and C10 fatty acids is above 15. Therefore, it is considered to be the richest source of medium-chain fatty acids. In addition, virgin coconut oil VCO retains a large amount of natural active substances such as vitamins, polyphenols and phytosterols because it Abstract: Functional oils have broad application prospects in functional foods and beverages because of their rich beneficial ingredients and healthier intake. The small droplets of the nanoemulsion enhance the effective delivery, solubility and bioavailability of the various hydrophobic food components. This study used a mixed oil phase of green tea seed oil and fractionated coconut oil, compared the emulsifying properties of natural surfactants: Whey protein isolate, soy lecithin, tea saponin and synthetic surfactant: Tween 80 in the preparation of nanoemulsions by ultrasonic method. In particular, the impact of emulsifier type and concentration, pH, ionic strength, and heat treatment on the mean particle size and ξ-potential were investigated. The long-term storage stability of the fabricated nanoemulsions was also monitored during storage at different temperatures. In addition, the effects of emulsifier type on the bioavailability of nanoemulsions were evaluated. For all nanoemulsions studied, the mean particle size decreasing with increasing emulsifier concentration. Tea saponin and soy lecithin can produce smaller droplets of nanoemulsion than Whey protein isolate. Tea saponin has the same emulsifying ability as Tween 80. Presumably tea saponin-stabilized droplets may be maintained by electrostatic repulsion and steric repulsion. All of the nanoemulsions significantly improved the bioavailability of the mixed oil phase compared to the unemulsified oil phase. This study highlights the potential of natural surfactants in the ultrasonic preparation of nanoemulsions containing functional oils, and provides a basis for the application of natural surfactants and new functional oils in food industry.

Response surface methodology was employed to optimise the process parameters for subcritical water extraction of soluble dietary fibre (SDF) from defatted coconut flour. The obtained model was applied to predict the optimum response values and verified by validation experiment. The composition, structure, properties and bioactivities of the extracted SDF were studied. Effects of extraction temperature, extraction time, solid-liquid ratio and mesh number on the yield of SDF were investigated. The extraction at 140°C for 30 min, a solid-liquid ratio of 1:30, and a mesh number of 80 resulted in the extraction rate of SDF of 14%. Moreover, monosaccharide analysis indicated that SDF primarily contains mannose and galactose respectively. As indicated by X-ray diffraction and thermal analysis, SDF has low degree of crystallinity and high thermal stability. Additionally, SDF has high water holding, oil holding and swelling capacities, while exhibits high antioxidant activity against DPPH, ABTS + and˙OH radicals, as well as high in vitro hypoglycaemic activity. The SDF also exhibits good biofunctions, such as good toxic ions and bile acid salts adsorption. This study demonstrates that defatted coconut flour, which is an inexpensive source of natural dietary fibre, can be suitably used as a functional food ingredient in the food industry.

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