Thumbnail Image

Theses

Browse

20153
Reset filters
Subject: Agricultural Processing and Food Engineering × Author: KAU × End date: 2015 × Start date: 2015 ×
Reset filters

Search Results

Now showing 1 - 3 of 3
  • Thumbnail Image
    ThesisItemOpen Access
    Development and evaluation of an ultra violet radiation assisted with ohmic heating system for preservation of pineapple juice
    (Department of Food and Agricultural Process Engineering, Kelappaji College of Agricultural Engineering and Technology, Tavanur, 2015) Dileep, Sean Y; KAU; Prince, M V
    Ultraviolet (UV) radiation is one such non-thermal processing alternative that has been shown to be effective against many types of foodborne pathogens. But there is a limitation of practical application of UV to disinfect liquid food products due to low penetration depth. Ohmic heating (OH), another promising technology, has been widely applied in food processes. This generates heat immediately in the food product, creating a rapid and uniform heating that reduces thermal abuse, as opposed to conventional thermal processing methods. Often times, ohmic heating cause heat-sensitive nutrients within food to be deteriorated by excessive current flow. These advanced technologies could contribute to shorten processing times, energy savings, and highly balanced safe food; however, they alone still cannot guarantee food safety without damaging the food’s quality. Therefore, a new concept to combine ultraviolet and ohmic heating has been extensively evaluated. This combination technology would optimize each of the individual technology’s strengths and reduce each of their individual weaknesses. The present study envisages development of a UV radiation assisted with ohmic heating system for pineapple juice and evaluation of the developed system in retaining the quality characteristics and microbial safety. In this study, a dual cylindrical ohmic and ultraviolet treatment combination continuous flow chambers was designed and fabricated to pasteurize the pineapple juice. UV treatment 800, 1200 and 1600 mJ/cm2. Ohmic treatment until the sample temperature reached 50°C, 55°C and 60°C; and ohmic heating combined with UV treatment as the temperature rose to 50 °C, 55 °C, and 60 °C along with 800, 1200 and 1600 mJ/cm2 dosages. Combined ohmic heating at 50 °C and UV treatment of 1200 mJ/cm2 were found to be superior based on biochemical, microbiological and organoleptical characteristics. Storage study of best sample revealed that could give a shelf life of 25 days under a refrigeration temperature at 4 °C retaining its biochemical characteristics while keeping the microbial level safe.
  • Thumbnail Image
    ThesisItemOpen Access
    Design and development of a solar refrigeration system
    (Department of Food and Agricultural Process Engineering, Kelappaji College of Agricultural Engineering and Technology, Tavanur, 2015) Rakhi, J F; KAU; George, Mathew
    When solar power, either thermal or photovoltaic, is used to provide energy to any refrigeration system, it is called as solar refrigeration system. The main objective of the study was to design and develop a solar absorption refrigeration system and performance evaluation of the developed system. In this study 40 L capacity three fluid vapour absorption refrigeration system (VARS) was designed and a commercially available three fluid absorption refrigerator working on electricity was procured and modified for using heat energy. The solar radiation at KCAET Tavanur was measured and it was observed that a maximum solar radiation intensity of 783.81 W/m2obtained at 1.00 PM at Tavanur. The performance of the modified VARS was tested using hot water obtained from solar water heater. It was found that the hot water from the solar water heater was not sufficient to produce any cooling effect. Hence a hybrid system using hot water from solar water heater and subsequent heating of the hot water using other heating sources such as electricity and LPG were utilized and the hot water was converted to steam at high temperature. Under this new set up the system worked perfectly and produced refrigeration. The performance of the modified VARS was then tested in the laboratory under simulated conditions using water at 100°C, steam at 103°C, 106°C, 116°C and 121°C and using electric heater. The experiments with low temperatures could not produce any cooling whereas steam at116°C and 121°C and electric heater at 150°C produced refrigeration effect. The corresponding generator temperature obtained were 105°C and 110°C and the ice tray temperatures were 6.8°C and 1.9°C. The temperature obtained in the cabin of the refrigerator was 10.9°C and 8.1°C which was ideal for keeping fruits vegetables and other perishable items. For effective working of this system using only on solar energy, instead of flat plate collector, a solar steam generator that could produce steam can be used.
  • Thumbnail Image
    ThesisItemOpen Access
    Studies on microencapsulation of vanilla extract
    (Department of Food and Agricultural Process Engineering, Kelappaji College of Agricultural Engineering and Technology, Tavanur, 2015) Sariga, S; KAU; Prince, M V
    Vanilla is one of the minor spices, most popular flavoring agent and second most expensive spice in the world. Vanillin flavour is highly volatile, heat sensitive and application in food incorporation is limited; this can be minimized by encapsulation technique with suitable wall material. The microencapsulation technique protects the vanilla extract from undesirable changes and coverts into a free flowing powder. Spray drying is the most common and commercial method for carry out the microencapsulation process. Therefore, to increase the storage stability of the microencapsulated vanilla extract powder, an investigation has been taken up to develop optimum process parameters to produce best quality microencapsulated vanilla extract powder. The microencapsulation of vanilla extract was carried out in tall type spray drier with twin fluid atomizer. Maltodextrin and maize starch were used as wall material. Different proportion of wall materials were used for the emulsification such as 100% maltodextrin, 100% maize starch, combination of 75% maltodextrin and 25% maize starch and 75% maize starch and 25% maltodextrin. The wall materials were emulsified with 10, 20 and 30% of vanilla extract for spray drying. The physico-chemical characteristics of vanilla extract and wall materials, and emulsion characteristics were carried out and the emulsions were spray dried at different inlet temperatures of 170, 180 and 1900C. The encapsulated vanilla extract powder were collected and packed in aluminum foil and stored in room temperature for five months. The powder characteristics of encapsulated vanilla extract powders were carried out and analyzed. Based on the emulsion and powder characteristics, optimum conditions for the production of best quality encapsulated vanilla extract powder were found out. The study concluded that the encapsulated vanilla extract powder produced from 100% maize starch, vanilla extract concentration of 10% and inlet air temperature of 1800C was found to be superior. The cost of one kilogram of optimised microencapsulated vanilla extract powder using spray drying technique was estimated to be Rs.850.