frying -...
TRANSCRIPT
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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