1 OSMOTIC DRYING OF POTATO FOR CONSUMPTION .pptx

This work is based on osmotic drying of potato and yam for commercial and consumption purposes

1. OPTIMIZATION OF THE OSMOTIC DEHYDRATION OF POTATO AND YAM SLICES

2. OUTLINE

3. BACKGROUND OF STUDY Potato is a starchy tuber of the plant Solanum Tuberesome which are edible and available worldwide. They are relatively cheap to grow, rich in nutrient and can make can a delicious treat. Yams are multispecies and vegetative propagated tuber crops cultivated widely in the tropics (FAO 2002). Over 90% of the world yam production occurs in the yam belt of West and Central Africa, with Nigeria alone accounting for about 68% of the World’s total production ( Sobukola 2007). Osmotic dehydration is the removal of water from the lower concentration of solute to higher concentration through semi permeable membrane which results in the equilibrium condition in both sides of the membrane (Tiwari 2005).

4. STATEMENT OF PROBLEM About 20-40% of potato and yam production goes to waste due to lack of adequate storage capacity and moisture retention. This brings the question of ‘how can potato and yam be preserved to avoid waste?’.

5. AIM AND OBJECTIVES

6. SIGNIFICANCE OF STUDY This study will help to discover the best way to which potato and yam slices will be dehydrated using osmotic agents such as salt. It is also important because weight measurement will be taken before and after soaking the food material in the osmotic agent and the difference in weight taken. This study will draw attention to amount of moisture gained while soaking and also the amount of moisture lost after dehydration.

7. SCOPE OF STUDY The scope of this study will be a laboratory scale dehydration of potato and yam slices using salt solution as the osmotic agent under controlled conditions of time and the size of food material.

8. LITERATURE REVIEW Mehdia Mihoubi and Ali Ferradji (2015) did a study on the optimization of osmotic dehydration of potato slices in sugar solution using Response surface methodology (RSM) to determine the optimum processing conditions that yield maximum water loss (WL), weight reduction (WR) and minimum solid gain (SG). Mokhtar et al.( 2019) did a study on the dehydration of potato slices following brief dipping in osmotic solutions in order to allow the osmotic medium to occlude to the surface of the slices, holding the slice under ambient conditions.

9. MATERIALS AND METHOD Materials The potato (sweet) and yam that will be used for this study will be obtained from Use Offot market, Uyo in Akwa Ibom state. Also, salt(NaCl) will be gotten from the market for the preparation of the osmotic agent. Methodology The potato and yam slices will be immersed into the osmotic solution which ranges from 10 – 30% in concentration to determine the water loss and salt content gained. Optimization of this process will be carried out using RSM (Response Surface Methodology).

10. Osmotic Dehydration Treatment The potato and yam slices would be divided into the pretreated sample and the untreated sample. The slices to be treated will be soaked in the osmotic solution of different concentration of 10%, 15%, 20%, 25%,and 30%.The slices will be removed from the solution at 20, 40, 60, 80 and 100 minutes after immersion, drained, and the excess of solution on the surface will be removed with absorbent paper. Oven Drying The treated and untreated sample will be subjected to moisture analysis as the sample will be weighed and placed in single layers on pre-weighed drying trays, and there after loaded into the oven. The sampled will be taken out for weighing after every 30 mins to determine the moisture loss until a constant weight is obtained. Then the treated and untreated samples will be compared.

11. Mathematical models For Drying Different authors have come up with various mathematical models used for drying. Some of those models can be seen in the table below. Model Name Model References Lewis MR=exp(- kt ) Westerman et al.(1973) Henderson and Pabis MR=a exp(- kt ) Yagcioglu et al. (1999) Logarithmic MR=a exp(- kt )+c Yaldiz and Ertekein (2001) Page MR=exp (- kt^n ) Page (1949) Simplified Fick’s Diffusion MR=a exp(- kt )+c Celma et al. (2007)

12. Drying Kinetics Drying kinetics is the representation of the drying rates versus the drying time or the moisture content. It is a graphical representation of the evolution of the moisture content. The above chosen models will be tested on each data to determine their fitness. The model with the best fit will be selected as that describing the drying process, drying rate and other parameters will then be determined from the selected models. The effect of treatments in the osmotic solution on the drying behavior will then be examined.