sorption isotherms

1. PROPOSAL FOR:
THE STUDY OF SORPTION ISOTHERMS FOR VARIED TEMPERATURES
OF AVERRHOA CARAMBOLAAND CHRYSOPHYLLUM ALBIDUM

2. CONTENT
Introduction
Types of sorption isotherms
Averrhoa carambola
Chrysophyllum albidum
Statement of research problem
Objectives of study
Significance of study
Scope of study
Materials and methods

3. INTRODUCTION
 Moisture sorption characteristics of agricultural and food products play important roles in technological
processes such as drying, handling, packaging, storage, mixing, freeze-drying and other processes that
require the prediction of food stability, shelf life, glass transition and estimation of drying time and
texture and prevention of deteriorative reactions.
 Biological materials at constant moisture content and temperature display characteristic vapor pressure
and would tend to approach equilibrium with the temperature and vapor pressure of the surrounding
gaseous atmosphere.

4. INTRODUCTION CONT.
TYPES OF SORPTION ISOTHERMS
Brunauer et al., 1940 classified sorption isotherms according to their shape and processes, establishing five
different types;
 Type 1: Langmuir and/or similar isotherms
 Type 2: Sigmoidal sorption isotherms,
 Type 3: known as the Flory-Huggins isotherm,
 Type 4: It describes the adsorption of a swellable hydrophilic solid until a maximum of site hydration is
reached.
 Type 5: the Brunauer-Emmett-Teller (BET) multilayer adsorption isotherm.
The two isotherms most frequently found in food products are the types 2 and 4.

5. INTRODUCTION CONT.
Some of the common mathematical models that are used for modelling sorption phenomena in food
products are:
 The Langmuir equation
 The BET (Brunauer-Emmett-Teller) equation
 The Oswin model
 The Smith model
 The Halsey model
 The Henderson model
 The Iglesias-Chirife equation
 The GAB (Guggenheim-Anderson-De Boer) model
 The Peleg model
(Sahina and Gulum, 2006).

6. INTRODUCTION CONT.
AVERRHOA CARAMBOLA (STAR FRUIT)
 Star-fruits are fleshly, crunchy, juicy and slightly tart, acidic and sweet in the taste.
 Star-fruit is a good source of various minerals and vitamins such as sodium, potassium, calcium,
phosphorus, magnesium etc. Star-fruits are also a rich source of natural antioxidants such as L-ascorbic
acid (Vitamin C) and Gallic acid, which aid in scavenging reactive oxidative species (ROS) (Moresco
et al, 2012).
 In addition, the presence of high amounts of fibres in fruits aids in absorbing glucose and retarding the
glucose diffusion into the blood stream; as a result, it helps in controlling blood glucose concentration
(Wu et al, 2019).

7. INTRODUCTION CONT.
CHRYSOPHYLLUM ALBIDUM (AFRICAN STAR APPLE)
 Chrysophyllum albidum fruit pulp is very high in potassium, calcium, and phosphorus, zinc,
manganese and copper which are needed for electrolyte balance, neurotransmission, development of
strong bones and teeth (Roth and Townsend, 2003).
 The flesh can taste either very sweet or sour. The covering of the sweet fruits are seen to be yellow
while that of the sour ones are usually a mix of yellow and green colours when mature (Houessou et al,
2012).
 The fruits are not only consumed fresh but also used to produce jam, jellies, stewed fruit, marmalade,
syrup and several types of soft drinks.

8. STATEMENT OF RESEARCH PROBLEM
Fruits are most times perishable crops and often times needs to be transported from one region to the other,
mainly from the tropical regions which grow them to other parts of the world which either cannot grow or
have them in limited supply. In the transportation of this fruits, it might take days to arrive the desired
destination added with the means of packaging. In respect to this, the life span is reduced by means of
packaging and so tends to soften, loses nutritional value or even get rotten before the destination is
reached. Therefore, causing the traders or transporter to run at a loss.

9. OBJECTIVES OF STUDY
The main objective of this research is to determine the sorption isotherms for star fruit and African star
apple at varied temperatures.
The specific objectives are:
 To determine the physicochemical properties of star fruit and African star apple
 To determine the sorption isotherms of star fruit and African star apple at temperature range of 30oC -
60oC.
 To evaluate the ability of several commonly used sorption models to describe the experimental data.
 To develop empirical model for the sorption isotherms of star fruit and African star apple.
SIGNIFICANCE OF STUDY
 This project will aid in the reduction of loss and wastage as best fit models will be determined to
condone deficiencies such as short shelf life.
 It will also help in sustaining this crop for future use without altering it properties such as nutritional
contents

10. SCOPE OF STUDY
The scope of this study shall be as follows:
 The experimental temperatures would be varied. These temperatures would be 30oC, 40oC, 50oC and
60oC.
 Determination of physicochemical properties such as moisture content, crude protein, fiber, fat, ash and
carbohydrate content.
 Creation of water activities using saturated saline solutions.
 The determination of the sorption isotherms.
 Use of sorption isotherm models to analyze the experimental data.
 The goodness of fit for these models would be determined
 Empirical models would be developed and validated for the adsorption process and for design purpose.

11. MATERIALS
Samples: Chrysophyllum albidum (African star apple) and Averrhoa carambola (star fruit).
Sample source:
Fresh star fruit and African star apple samples will be obtained from the botany garden in the
Department of Botany, Faculty of Science, University of Uyo, Uyo, Akwa Ibom State, Nigeria
Sample preparation:
These samples will be washed in water, sliced with a knife and dried using a hot air oven until constant
weight.
Apparatus: Knife, Water (for washing), Moisture cans , Weighing balance, Desiccator, Electric Hot air
oven, fume cupboard, Buckner funnel equipped with muslin clothe, Kjeldahl apparatus , Kjeldahl
Digestion flask and Kjeldahl distillation apparatus, Muffle furnace, Crucibles.
Reagents: Copper sulphate (CuSO4) , sodium sulphate (NaSO4), tetra oxo-sulphate (vi)(H2SO4), sodium
hydroxide (NaOH), hydrochloric acid (HCl).

12. EXPERIMENTAL METHODS
The following experimental methods would be employed to determine the physicochemical propertied of
the samples:
 Moisture content determination
 Crude protein determination
 Fat determination
 Ash determination
 Carbohydrate determination

13. REFERENCES
Brunauer S, Emmett PH, Teller E. adsorption of gases in multimolecular layers. J Am Chem Soc.1938 Feb;
60 (2):309-319
HH Moresco et al., Rev. Bras. Farmacogn. 22: 319-24 (2012)
Houessou L.G., T. O. Lougbegnon, F. G. Gbesso, L.E. Anagonou, and B. Sinsin, , "Ethno-botanical study
of the African star apple (Chrysophyllumalbidum G. Don) in the Southern Benin (West Africa),“Journal of
Ethnobiology and Ethnomedicine, vol. 8, pp. 1-10, 2012. Available at: https://doi.org/10.1186/1746-
4269-8-40.
Roth AR, Townsend CE (2003). Nutrition and diet therapy 8th ed. Delmar Learning, Thomson Learning
Inc. Canada. p. 132.
Sahin S, Gulum S. Physical Properties of Foods. New York, United States: Springer; 2006. 205,218 p.
Wu SC et al., J Agric Food Chem. 57: 5610–14 (2009) [PMID: 19453170]

14. THANK YOU