Encapsulation of oil-based cheese aroma by using spray-drying and efficience of microcapsules in model foods

Abstract

Since the world has existed, food consumption has been critical for the continuation of life. Appearance, flavor, and taste play an important role in the preference of foods in nature. In modern times, these parameters have been controlled and improved. Fermentation is invented to increase the shelf-life of the food; in addition, new volatile compounds are formed during the fermentation process. Cheese is the most consuming fermented product, and different types of cheese are made by changing fermentation and process parameters. These parameters also affect the odor and taste, providing the uniqueness of cheese. Each volatile compound has a special odor and taste, therefore, containing various volatile compounds allows different cheese varieties to have their unique odor and taste. Various extraction techniques are distillation, static headspace, dynamic headspace, solid-phase microextraction (SPME), stir bar sorption extraction, and vacuum distillation applies for the extraction of the cheese volatile compounds. Depending on the volatile compounds' qualifications such as the sensitivity of heat, light, and temperature; appropriate extractions should be chosen. The encapsulation process prevents flavors from being affected by adverse environmental conditions. Various techniques are used to encapsulate the active material. Selecting the suitable encapsulation method depends on the core material release features, wall material properties, project cost, and aim. Preparation of emulsion is the first and fundamental step of encapsulation. Wall materials that cover the core material may be consists of carbohydrates, protein, or other materials. Starch, gum, and maltodextrin carbohydrate-based derivatives to use in encapsulation; however, for getting more encapsulation efficiency carbohydrate and protein-based materials are preferred together. Both animal and plant-based derivatives are used as protein wall materials. High pressure, micrtechniquesing technique, and ultrasonication are used to homogenize and provide emulsion to good dispersion. The spray drying technique is one of the most common encapsulation techniques in the food industry. The spray drying process is based on the principle of atomizing the material to be dried under high pressure and then drying it in a very short time with hot dry air. In this experiment, commercial cheese aroma is encapsulated by the spray drying technique. Using maltodextrin and protein are used as wall material at different concentrations. 30 % of the emulsion mixture consists of solid ingredients. This solid content is prepared with 16 % aroma and 84 % mixture of maltodextrin with dextrose equivalent 11-16 and whey protein concentrate, 50 %. Protein content in the solid mixtures is 8 % and 4%. These emulsions are kept in a shaking bath at 40 C° for 20 hours at 80 rpm to improve hydration. 16 % aroma of total emulsion is added to both emulsions. After the hydration and adding aroma, the emulsion is mixed first at 450 rpm, for 1 hour; then homogenized by Ultra-turrax at 17000 rpm for 5 minutes. Laboratory scale Buchi B-290 is used at an 8 mL/min feed rate, 180 ± 2 C° inlets, and 80 ± 2 C° outlet temperature. Encapsulation duration keeps 40 minutes. Encapsulated and commercial aroma is added, a total of 1 % flavor, in cracker dough samples that include 60 % flour, 15 % oil, and other ingredients. Then the crackers are cooked in the oven at 220 C°, for 10 minutes. The aroma added cracker is oiled at % 10 without aroma. Cracker dough without aroma is prepared and cooked; however, the encapsulated aroma and liquid aroma are added in the oil process at 0.2 %. GC & MS analysis results are compared with the results of commercial liquid flavoring as a reference. Encapsulated A and B aroma volatile compounds concentrations show similar results. Butyric acid is lost after the encapsulation process; however, 9,12-Octadecadienoic acid (Z, Z) concentration dramatically increases after the encapsulation in both encapsulated aromas. 2-Decenal and 2-Nonenal concentrations show a slight rise and these compounds are also derivatives of the oxidation. Heptanoic and Undecanal concentrations in the encapsulated aroma are higher than in the liquid flavor. Other compound concentrations are similar between A & B aromas and commercial products. Added the encapsulated aromas and commercial aroma in cracker doughs, volatile compounds concentrations do not show dramatically difference; however, 2- Decenal concentration in three samples slightly increases with comparing the reference liquid aroma. 9,12-Octadecadienoic acid concentration is differentiated between encapsulated aroma and liquid aroma, higher concentration in the encapsulated aroma. Heptanoic acid concentration could not be maintained in doughs when using liquid flavoring and showed a decrease. After the cooking, adding the aroma to the top oil process demonstrates the different volatile compounds concentrations. Heptanoic acid, 2-Nonenal, 2-Decenal, dihydro-5-pentyl-2(3H)-Furanone, and Tetradecanal compounds concentrations are higher than reference liquid aroma and cracker that include aromas in the dough. Other compounds' concentrations are similar to the commercial aroma. The change in the concentrations of the volatile components in the aroma may be caused by oxidation and the combination of the aroma with other components and creating different reactions. The panelists do not realize dramatically difference between using encapsulated B aroma and liquid aroma in dough with cheese odor, cheese flavor, aftertaste of cheese flavor, and general taste. Significant differences are observed between crackers that use oil including aroma and added commercial aroma in the oil process. The samples using the encapsulated B flavor in the oil are more like in terms of cheese odor and flavor, aftertaste cheese flavor, and general taste than the crackers using the reference aroma. In line with these results, industrial cheese flavor managed to preserve most of its volatile components with its wall material consisting of maltodextrin and whey protein concentration. The encapsulated aromas are used in the dough of cracker samples, which are applied at high temperatures during cooking, and in the oil applied to them after cooking. Although some volatile compounds of crackers, such as butyric acid and 2-nonenal, are lost when high temperature is applied; a high amount of volatile components are retained. Added aroma in oil shows greater volatile compound concentrations, also added encapsulated aroma in oil is more preferred than others.