Study On Two Drying Technology Of Royal Jelly Powder

Royal jelly and honey are the natural nutritional supplements, which have been well received by consumers. In this paper, the optimal formula was determined by orthogonal experiment to explore royal jelly powder (a new type of health care products) made from acacia honey and royal jelly. The technologies of Vacuum freeze-desiccation and Spray-desiccation were studied. The results were summarized as follows:1. Formulation of royal jelly powder: Orthogonal experiment L₉(3⁴) of honey content (A), royal jelly content(B), the ratio of maltodexrin toβ-cyclodextrin(C) and feed concentration(D) was designed to observe the sensory score, flowability, water content and solubility of royal jelly powder. The result is that the content of honey significantly influences the water content and solubility of products, and the optimum formula of these two indexs is A₁, so we chose A₁. The content of royal jelly has notable impact on the sense of the products, so we chose B₂, and the content of malto dextrin andβ-cyclodextrin has obvious effect on product liquidity, so we chose C₃, while the concentration of feed liquid has indistinctive effect on the four indexes of royal jelly-honey power, all of above means that from the three respects of sense, water content and dissolubility, the optimum selection is D₂, so we chose D₂. The best formula was honey(25%):royal jelly(40%), the ratio of maltodexrin toβ-cyclodextrin (6﹕1) and feed concentration (30%)。2. Study on technological parameters of royal jelly powder:According to the principium of Box-Behnken central composite experimental design, the liquid thickness (mm), pre-freezing time (h) and drying time (h) were taken as the independent variables, and yield (%), water content (%) and solubility (%) as the response value of Freeze-desiccation. For the Spray-desiccation, inlet temperature(℃), feed material volume (mL/min), air flow index (L/h) were taken as the independent variables, and yield (%), water content (%) and solubility (%) as the response value. Design-Exper 8.0 was used to optimize the technological parameters of royal jelly powder through Box-Behnken three factors-levels response surface methodology. The optimum operation conditions of Vacuum freeze-desiccation were thickness(2.0 mm), pre-freezing time (14 h) and drying time(14 h). The optimum operation conditions of Spray-desiccation were inlet temperature(160℃) , eed material volume (20mL/min) and air flow index (600 L/h).3. Contrast studies of vacuum freeze drying and spray drying technologies: the indexes technologies of two products are more or less the same, the liquidity of spray drying product is better than that of vacuum freeze drying product in physicochemical indexs, and its water content, dissolubility, yield is 16%, 2.0%, 2.2% lower than that of vacuum freeze drying respectively. The content of 10-HDA, total sugar and reducing sugar of vacuum freeze drying product is 18.33, 1.6%, 2.2% higher than that of spray drying respectively, while its hydroxymethylfurfural content is 8.7% lower than that of spray drying in nutritional indexs. However, considering from the aspect of energy-saving and environmental protection, the production period of vacuum freeze drying is much longer than that of spray drying, and the former is time-consuming with high energy consumption, thus, based on an overall consideration of various factors we conclude that spray drying has more advantages than vacuum freeze drying in production.