Dairy Process Engineering

Module 4. Mechanization in manufacture of indigenous dairy products

Lesson 21
GHEE MAKING MACHINES

21.1 Introduction

Generally the extra fat of milk is best preserved by converting it either into butter or ghee. In this chapter different types of the ghee making equipments are described.

21.2 Ghee Making Equipments

Steps for ghee making

1. Concentration of milk fat

2. Breaking of fat in water emulsion to bring fat in continuous phase.

3. Development of typical ghee flavour.

4. Control of moisture

5. Removal of ghee residue

Concentration can be done by centrifugal separation and heating the cream. Alternatively, cream can be churned into butter and then heated. Ghee flavour is developed when the fat is heated with milk solids at high temperatures.

21.2.1 Batch method

It contains

1. steam heated butter melting vat

2. Pre-stratification tank (optional)

3. Ghee kettle for clarification

4. Ghee settling tank

5. Storage tanks

6. Filling machine

21.2.2 Ghee kettle (Boiler)

It is made up of a steam jacketed S.S. pan with agitator. Steam jacket may be of more than one compartment. At the bottom outlet valve for removal of ghee is present or a hollow S.S. tube at the centre of the bottom of vessel is present or a simple pan tilting device may be present for ghee removal. For better operational controls the steam controlling mechanism and steam pressure and temperature gauges are also provided. Raw material is either unsalted melted butter or a cream. In some cases pre-stratification method may also be present.

21.3 Continuous Ghee Making Equipments

Continuous ghee making equipment consists of receiving cum heating vat, pressurized SSHE coupled with vapour separator and a pump. The raw material is melted in the vat and then pumped to balance tank. It then enters in to SSHE and vapour separator where the flashed vapour is separated out. The product then goes to second stage where flavour development is completed. If cream is used then the third stage is necessary. Ghee residue is removed by standard filtering and clarifying devices.

Advantages

a) It handles large volume
b) Automation is possible
c) High fat recovery and
d) CIP is possible.
e) High heat transfer coefficient, hence compact design
f) No foaming problem
g) Less scale formation