Surfactant-Free Pickering Emulsification Using Chinese Quince Fruit Fiber.

Quince fruit powder can be obtained from the waste of the edible product. In this study, we modified the powder with various solvents and investigated its application in Pickering emulsification. The crushed Chinese quince fruit possessed excellent Pickering emulsifying abilities when the water-soluble components were removed. In addition to cellulose, the powder contains hydrophilic pectin and hydrophobic lignin fibers. Similarly, a powder consisting of cellulose and a small amount of lignin without pectin, which was obtained by further solvent treatment, also showed high emulsification performance. Although these two powders had different fiber compositions, their water contact angles were almost equal, and their surface hydrophilicity was lower than that of the cellulose-only powder without emulsification ability.

Dietary protein restriction increases hepatic leptin receptor mRNA and plasma soluble leptin receptor in male rodents.

Leptin is an adipokine that regulates adipose tissue mass through membrane-anchored leptin receptor (Ob-R). Extracellular domain of Ob-R in plasma is called soluble leptin receptor (sOb-R), and is the main leptin-binding protein. Based on a previous DNA microarray analysis that showed induction of hepatic Ob-R mRNA in low-protein diet-fed mice, this study aimed to clarify the effect of dietary protein restriction on hepatic Ob-R mRNA and plasma sOb-R levels. First, the effect of protein restriction on hepatic Ob-R mRNA level was examined together with fasting and food restriction using male rats as common experimental model for nutritional research. Hepatic Ob-R mRNA level was increased by feeding low-protein diet for 7 d, although not significantly influenced by 12-h fasting and sixty percent restriction in food consumption. Then, effect of protein restriction on liver Ob-R and plasma sOb-R was investigated using male mice because specific sOb-R ELISA was more available for mice. Hepatic Ob-R mRNA level was also increased in protein restricted-mice although it did not increase in hypothalamus. Hepatic Ob-R protein was decreased, whereas plasma sOb-R was increased by protein restriction. Because the concentration of sOb-R increased without changing plasma leptin concentration, free leptin in plasma was significantly reduced. The direct effect of amino acid deprivation on Ob-R mRNA level was not observed in rat hepatoma cells H4IIE cultured in amino acid deprived medium. In conclusion, dietary protein restriction increased hepatic Ob-R mRNA, resulting in increased plasma sOb-R concentration, which in turn, reduces plasma free leptin level and may modulate leptin activity.