DRYING KINETICS OF DISCOREA SPP for preservation of yam.pptx

Preservation of food materials is a sure way of ensuring that man and animals alike have enough food to eat and avoid shortages

1. DRYING KINETICS OF OSMOTICALLY PRETREATED YAM SLICES

2. OUTLINE Background of study Statement of problem Aim and objectives of the study. Significance of the study Scope of the study Summary of previous studies on osmotic dehydration Proposed research methodology

3. BACKGROUND OF STUDY Yam is an important source of carbohydrate in the world. Fresh yam has high moisture content which makes it susceptible to deterioration, hence there is need t o dry. Drying is a universal method for preserving food materials by reducing their moisture contents to low levels that prevent microbial spoilage. The removal of water in yam can be done either by directly drying the yam by pretreating it in an osmotic medium before it is being subjected to drying. The application of osmosis in food processing and as a dehydration process have been primarily motivated by economical factors and the quality improvement of the final product. Drying kinetics is the ratio of the mass of absorbed water during rehydration to the mass of water removed during drying.  

4. STATEMENT OF PROBLEM The convectional drying method which does not involve osmotic treatment involve long drying duration which reduces the nutritional value of the food item. It also causes damage to sensory characteristics and damage the color and flavor of the food. Long drying causes shrinkage, which affect their structure and texture. Hence pretreatment with an osmotic solution, which reduces the moisture content of the food material before drying in the oven, preserves the quality of the food and conserves the energy required for drying.

5. AIMS AND OBJECTIVES

6. SIGNIIFICANCE OF STUDY In the food processing industry, the drying sector was faced with challenges in long drying process of food materials for preservation without loosing its nutritional properties. The need to dry food materials in order to increase its shell life keeps increasing rapidly so as increase in the need to use osmotic treatment in drying of food materials. Osmosis dehydration is preferred over other methods due to retention of color, aroma, nutritional constituents and flavor of food materials.  

7. SCOPE AND LIMITATION This study is focused on yam slices (2cm diameter, 1cm thickness) that will be soaked in salt solution of varying concentrations for 30 minutes before drying in an oven at different temperatures. The effect of pretreatment on the drying kinetics of the slices would then be investigated .

8. LITERATURE REVIEW AUTHORS WORKS RESULTS Piotrowski et al.2004 He studied the influence of osmotic dehydration on the microwave convective drying of frozen strawberries. It was reported that osmotically dehydrated strawberries took less time to dry than the ones not osmotically dehydrated. Chavan et al. (2010) He developed a process for preparation of ripe banana using osmotic dehydration. It was reported that there was marginal decrease in moisture content and that products were found microbiologically safe and sensorily acceptable up to 6 months storage at ambient condition.   Sunjka and Raghavan (2004) They accessed different pretreatment methods for osmotic dehydration of cranberry at different concentration. They reported that time and concentration of osmotic agents significantly affected dehydration and that different chemical treatment showed no chemical change in product quality.  

9. MATERIALS AND METHODS

10. MATERIALS AND METHOD CONTD.

11. THANK YOU.