| Citrus,a subplant of the Rutaceae family,is the largest fruit species in the world.Citrus’s nutritional value mainly attributed to the vitamins,polysaccharides,minerals,essential oils and flavonoids and other functional active components.At present,citrus products mainly consists of fresh fruit,juice and canned products.A large amount of citrus peels were often discarded as wastes,causing serious resource waste and environmental pollution.Therefore,in order to utilize the citrus endogenous functional components efficiently and fully,and realize the high-value processing of citrus by-products,this paper constructed the food assembly system according to the physical and chemical properties and functional properties of citrus components,and studied the system performance and application value.First of all,the use of citrus water-soluble(Ca2+,citric acid,ascorbic acid and pectin)and fat soluble（essential oil）composition of orange emulsion system to build success,stability mechanism of each component in the system,then the system as a food materials added to the orange juice in order to improve the flavor,nutritional value and storage stability;Then,the citrus flavone,citrus essential oil and citrus pectin were assembled into solid citrus microcapsule powder by using the microencapsulation technology.The influence of preparation conditions on the properties of the microcapsules was systematically expounded,and the change mechanism in the preparation and application of the citrus microcapsules was revealed.The study in this paper realized the high-value utilization of citrus peel residues,effectively solved the problem of waste of citrus by-products resources,and had important significance to improve the competitiveness of citrus market in China.The main results are as follows:（1）)Citrus endogenous active ingredient to assemble the build and stability of the emulsion system research:Firstly,citrus pectin as the emulsifier,orange essential oil as oil phase,a solution containing the citrus water-soluble ingredients for water to build,and the high added value,high stability of orange emulsion system,and found that the addition of water-soluble ingredients on the citrus pectin-the nature of the oil emulsion has significantly increased.The addition of water-soluble Ca2+can improve the viscosity of the system and avoid the emulsion instability caused by the decrease of emulsifying ability.The addition of organic acids（citric acid and ascorbic acid）can change the acidic environment of the emulsion,make the pectin structure more compact,improve its migration and diffusion ability,and thus obtain the emulsion with small particle droplets,thus enhancing the stability of the emulsion.In addition,The results of HPLC and GC-MS showed that adding 1 wt%ascorbic acid to citrus oil emulsion could effectively alleviate the degradation of D-limonene in citrus essential oil.In order to verify the orange emulsion system application in food,innovation in the citrus pectin and the orange oil emulsion stability in the form of food additive added to the commercialization of orange juice,natural health,uniform stability is obtained by high pressure homogeneous emulsion and high added value-orange juice system,illuminates the orange emulsion of orange juice,physical and chemical properties and sensory properties,nutrition characteristics and the influence of the shelf life.The results show that the citrus endogenous active ingredients have the potential to construct the food-grade assembly system,realize the high-value utilization of citrus peel residues,and provide a scientific method for the improvement of the comprehensive utilization rate of citrus.（2）Study on the construction and performance of citrus endogenous active ingredient microcapsule system:For the first time,the citrus flavone,citrus essential oil,citrus pectin and maltodextrin were encapsulated layer by layer by secondary embedding.Then,the effects of preparation conditions on the physicochemical properties and PMF embedding rate of citrus microcapsule powder were investigated by adjusting different drying temperature systems.In addition,the effects of resolution treatment on the embedding rate of citrus flavone were also investigated.The results showed that when the spray drying temperature was 150oC,the moisture content of microcapsule powder was low（1.7%）,the powder yield was high（51.4%）,the particle integrity was good,and the emulsion obtained after the resolution treatment had a smaller droplet diameter and higher stability.With the increase of spray drying temperature（from110 oC to 150 oC）,especially at 190 oC,the encapsulation rate of PMF decreased significantly.Electronic nose and gas chromatography-mass spectrometry showed that the microencapsulation process resulted in partial loss of volatile components in citrus oils,but the overall aroma was still very similar to that of the original citrus oils.In addition,the structure distribution of citrus capsules was determined by Fourier transform attenuated total reflection infrared spectroscopy（ATR-FTIR）,and the potential of microcapsule powder as an assembly system of lipophile components such as flavones was proved.The results of this study are expected to provide scientific guidance for the development of functional foods of solid citrus. |
