Food Process Engineering in a Changing World - 11th International ...

Mass Transfer of Fruit Slices in Hypertonic Solution
Farid Amidi Fazli a , Neda Amidi Fazli b
a
Food Science and Technology Department of Islamic Azad University, Soofian Branch, Iran
(amidi_f@yahoo.com)
b
B.Sc student of Food Science and Technology, Tabriz, Iran
INTRODUCTION
Emerging of fruits in concentrated solutions cause counter current flow between fruit and
syrup, the water flow from food material to surrounding syrup and solutes from syrup to food.
The result of this process is semi dehydrated food with higher dry matter content in compare
with untreated food; the other aspect of this process is self formulation of food staff or
enrichment of it by adding especial and desirable osmosis agents like antioxidants or minerals.
The healthy foods are demanded by consumers in recent years; enriched fruits by minerals are
a kind of these products. They provide minerals which are needed to human body; the minerals
are used by body cells for daily activities as well as cell maintenance, minerals have important
role in precise periods of life like growth and mature ages. By osmosis process it is possible to
obtain natural enriched food materials with any type of minerals in desirable content.
The effect of calcium lactate on osmotic dehydration kinetics and on the respiration rate,
mechanical properties and shelf-life of fresh, vacuum impregnated (VI) and pulsed vacuum
osmodehydrated (PVOD) grapefruit has studied by moraga et al. [1]. Apple cylinders were
vacuum impregnated, osmodehydrated and rehydrated using solutions of glucose, sucrose and
trehalose. The kind of solute affected mass transfer rate and the glucose solution showed the
lowest kinetics [2].
MATERIALS & METHODS
This paper indicates the result of osmotic dehydration of kiwi fruit and banana slices in 55%
sucrose syrup in presence of calcium and phosphorus ions. Osmosis agent (55% (w/w)) was
prepared by solving sucrose in deionized water and adding calcium or phosphorus in 1 and 2%
concentration. 1 centimeter in thickness sliced fruits emerged in above syrup and process
completed in 30 and 60 minutes. Dry matter was determinate for untreated and treated samples
using 100 C oven. Osmosis parameters as solid gain (SG), water loss (WL) and weight
reduction (WR) were calculated using below equations [3], where W0, W, S0 and S are initial
and final sample weight and initial and final sample dry matter respectively.
WR= (W0-W)/W0
SG= (S-S0)/W0
WL= WR+SG
RESULTS & DISCUSSION
Results (table 1) showed that highest mass transfer in kiwi fruit occurs when 1% calcium
solution applied for 60 minutes, values obtained for solid gain, water loss and weight reduction
were 42.60, 51.97 and 9.37 respectively in kiwi fruit where highest values for solid gain and
water loss were 35.25 and 41.07 respectively.
11th International Congress on Engineering and Food - Athens, Greece, 2011 1609