EKSTRUSI

PK SJMP DIPLOMA Institut Pertanian Bogor

EKSTRUSI

•Ekstrusi adalah suatu proses yang mengkombinasikan beberapa proses meliputi pencampuran, pemasakan, pengadonan, penghancuran, pencetakan, dan pembentukan.

•Tujuan ekstrusi adalah untuk meningkatkan keragaman jenis produk pangan dalam berbagai bentuk, tekstur, warna, dan cita rasa.

Popular reasons for extrusion

Versatility. A wide variety of products are possible by changing the minor ingredients and the operating conditions of the extruder

Reduced cost, because extruder has lower cost and higher productivity than others

High productions rates and automated production

No process effluents are produced.

•Dapat dibuat dari bahan baku yg beragam, umumnya tepung terigu, tepung jagung. Sedangkan yg lain misalnya tepung beras, kentang, gandum hitam, barley, oat, sorgum, ketela pohon, tapioka, dan tepung kacang-kacangan.

•Pada proses ini kadar air bahan yg digunakan relatif lebih rendah dibandingkan dengan kadar air bahan atau adonan pada proses konvensional.

Bahan Baku

Classification of Extruders By the method of operation :

Cold Extruders : paste product, confectionery

Extruder-cookers (Hot Extruder) : snack

By the method of construction: Single-screw extruders Twin-screw extruders

Cold Extruders

The product is extruded into strips without cooking or distortion of foods caused by expansion.

It is used to produce pasta, hot dogs, pastry doughs and certain confectionery.

Extruder-cookers (Hot Extruder)Food is heated in an extrusion cooker by a

steam-jacketed barrel and/or by a steam heated screw.

In some designs, electric induction heating elements are used to heat the barrel directly.

Single-screw extrudersClassification according to the extend of shearing on food :

High shear (breakfast cereals and snackfoods)

Medium shear (breadings and semi-moist petfoods)

Low shear (pasta and meat products)

Flow through a single-screw extruder

Twin-screw extruders

The throughput is independent of feedrateCan handle oily, sticky or very wet materials

or other products that slips in a single screw.Forward or reverse conveying is used to

control the pressure in the barrelA short discharge section develops the

pressure required for extrusion and thus subjects a small part of the machine to wear than a single screw extruder

A mixture of particles sizes, from fine powders to grains, may be used, whereas a single screw is limited to a specific range of granular particle sizes.

Single screw Double screw

Effect on foods

Sensory characteristics Minor effects on the natural color and

flavor of foodsNutritional value

Vitamin losses in extruded foods vary according to type of food, the moisture content, the temperature processing and the holding time. However, in general losses are minimal in cold extrusion

What happened during Extrusion Phase

• Gelatinization of the starch• Denaturizing of the protein• Heating above 100 deg C• Homogenizing• Development of pressure

Physico-chemical Phase

Contoh tipe Die

Die System

EXTRUDER