FRYING

TITIS SARI KUSUMA

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FRYING

• Frying is a unit operation which is mainly

used to alter the eating quality of a food.

• A secondary consideration :

– preservative effect that results from thermal

destruction of micro-organisms and enzymes,

– reduction in water activity at the surface of the

food

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FRYING

• The shelf life of fried foods is mostly determined by the moisture content after frying:

• foods that retain a moist interior

– have a relatively short shelf life

– owing to moisture and oil migration during storage

– for example doughnuts, fish and poultry products.

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FRYING

• Foods that are more thoroughly dried by

frying,

– have a shelf life of up to 12 months at ambient

temperature

– The quality is maintained by adequate barrier

properties of packaging materials

– correct storage conditions.

– for example potato crisps,

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THEORY

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THEORY

Food placed in hot oil

Surface

T rise rapidly

Intermal T rise more

slowly towards 100C

Water is vaporarised as steam

Surface dry out

Evaporation

Crust is formed

Crust : porous structure

Different sized capillaries During frying

Water removed from the

large capillaries

Removed by hot oil

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The time taken for food to be

completely fried depends on

the type of food

the temperature of the oil

the method of frying (shallow or deep-fat frying)

the thickness of the food

the required change in eating quality.

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main methods of frying

•shallow frying

•deep-fat frying.

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SHALLOW FRYING

Definition

Shallow frying is the cooking of food in a

small quantity of pre-heated fat or oil in a

shallow pan or on a flat surface (griddle

plate).

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suited to

• foods which have a large surface-area-to-

volume ratio

• Heat is transferred to the food mostly by

conduction

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Hasil

• Pencoklatan tidak merata

• Koefisien pindah panas

dengan wajan tidak merata

• Permukaan bahan pangan

tidak merata

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DEEP FRYING

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DEEP FRYING

Ciri utama : Makanan terendam

minyak dalam penggorengan

Panas : konduksi-konveksi

Sangat cepat

Perlakuan panas seragam

Warna lebih seragam

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Cocok untuk segala jenis bahan

pangan dengan berbagai ukuran

Luas permukaan tinggi cenderung

menyerap minyak lebih banyak

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Perubahan pada bahan pangan

Pembentukan crust

Perubahan citarasa, aroma, tekstur, warna

Pengurangan air

Penyerapan minyak

Kekurangan vitamin

Gelatinisasi pati

Denaturasi/koagulasi protein

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PEMILIHAN JENIS MINYAK

Stabilitas minyak

Kualitas minyak

Biaya

Kemudahan penanganan

Effisiensi minyak dalam proses

penggorengan

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PROSES PENYERAPAN MINYAK

PADA BAHAN PANGAN

SURFACE WETTING

CAPILLARY ACTION

VACUUM ABSORPTION

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FAKTOR MEMPENGARUHI JUMLAH

MINYAK DALAM BAHAN

KUALITAS MINYAK

SUHU DAN LAMA PROSES

BENTUK DAN POROSITAS PRODUK

KOMPOSISI PRODUK

PRE-PERLAKUAN BAHAN

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Pengaruh Panas dan

Transfer Panas

• Tergantung

–Bentuk makanan

–Temperatur

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Process Change In Oils

Heating and frying

• Physical change

• Chemical change

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Physical Change

Panas dari minyak ke makanan

Air menguap

Minyak terserap

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Physical

• How Food Fries

• How heat oil

• Degradation product interact with

fried

• Optimize the frying process

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Chemical Change

• Asam lemak

• Carbonil

• Polymeric compound

• Penurunan fatty acid unsaturation

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Kerusakan secara

kimia

• Hydrolisis

• Oxidation

• Polymeration

• Form volatile +

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Perubahan Kimia

Tergantung

• Food types

• Frying condition

• Oxygen availability

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Keawetan Tergantung

• Kadar air produk akhir

–Poultry kadar air tinggi

–Keripik kentang kadar air rendah

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Produk Akhir

• Kadar air 3 – 30%

• Waktu

• Luas permukaan

• Teknik menggoreng

• Jenis bahan pangan

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Lama/waktu menggoreng

tergantung

• Jenis bahan pangan

• Suhu minyak

• Kriteria mutu produk akhir

• Metode penggorengan

• Ketebalan bahan pangan

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• Suhu laju penurunan mutu

minyak

• Boiling yg dahsyat ≈ banyak minyak yg

muncrat

• Suhu minyak produk mempunyai

kerak di permukaan dan basah di bag.

dalam

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Continuous Frying

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Vacuum Frying

a deep-frying device housed inside a

vacuum chamber.

It was originally developed for potato chip

production

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