Polyglycerol Polyricinoleate and Lecithin Stabilized Water in Oil Nanoemulsions for Sugaring Beijing Roast Duck: Preparation, Stability Mechanisms and Color Improvement

Traditional Beijing roast duck often suffers from uneven color and high sugar content after roasting. Water-in-oil (W/O) nanoemulsion is a promising alternative to replace high concentration of sugar solution used in sugaring process according to similarity-intermiscibility theory. Herein, 3% of xylose was embedded in the aqueous phase of W/O emulsion to replace 15% maltose solution. W/O emulsions with different ratios of lecithin (LEC) and polyglycerol polyricinoleate (PGPR) were constructed by high-speed homogenization and high-pressure homogenization. Distribution and penetration extent of solutions and emulsions through the duck skin, as well as the color uniformity of Beijing roast duck were analyzed. Emulsions with LEC:PGPR ratios of 1:3 and 2:2 had better stability. Stable interfacial film and spatial structure were important factors influencing emulsion stabilization. The stable W/O emulsions could more uniformly distribute onto the surface of duck skin and longitudinally penetrate through the skin than solutions.