Beneficial effects of green tea (Camellia sinensis, Theaceae) extracts against obesity have been reported; however, the anti-obesity ability of the major components of green tea, polysaccharides, polyphenols and caffeine is not clear. Therefore, experiments with total green tea extracts, polyphenols, polysaccharides, caffeine, and a complex of polysaccharide and polyphenol at a dose of 400 or 800 mg kg⁻¹ were conducted on high-fat diet fed rats for 6 weeks to investigate their anti-obesity effects. The results indicated that polyphenols and polysaccharides were responsible for the suppressive effect of green tea extracts on body weight increase and fat accumulation. Moreover, polyphenols, polysaccharides, or caffeine can improve blood lipid and antioxidant levels, and effectively reduce rat serum leptin levels, inhibit the absorption of fatty acids, and markedly reduce the expression levels of the IL-6 and TNF-α gene. Furthermore, it was shown that polysaccharides and polyphenols were synergistic in reduction of serum leptin levels and in anti-inflammatory activity. These results suggest that the polysaccharide combination with polyphenols might be a potential therapy against obesity.

Water‐in‐oil (W/O) emulsions can be used to encapsulate and control the release of bioactive compounds for nutrition fortification in fat‐based food products. However, long‐term stabilization of W/O emulsions remains a challenging task in food science and thereby limits their potential application in the food industry. To develop high‐quality emulsion‐based food products, it is essential to better understand the factors that affect the emulsions’ stability. In real food system, the stability situation of W/O emulsions is more complicated by the fact that various additives are contained in the products, such as NaCl, sugar, and other large molecular additives. The potential stability issues of W/O emulsions caused by these encapsulated additives are a current concern, and special attention should be given to the relevant theoretical knowledge. This article presents several commonly used methods for the preparation of W/O emulsions, and the roles of different additives (water‐ and oil‐soluble types) in stabilizing W/O emulsions are mainly discussed and illustrated to gain new insights into the stability mechanism of emulsion systems. In addition, the review provides a comprehensive and state‐of‐art overview of the potential applications of W/O emulsions in food systems, for example, as fat replacers, controlled‐release platforms of nutrients, and delivery carrier systems of water‐soluble bioactive compounds. The information may be useful for optimizing the formulation of W/O emulsions for utilization in commercial functional food products.