KOMPONEN UTAMA SUSU Souvia Rahimah,STP., M.Sc. Jatinangor, 1 Maret 2011
Jurusan Teknologi Industri Pangan FTIP – Univesitas Padjadjaran
TPK
Setelah mengikuti kuliah dengan pokok bahansan KOMPONEN UTAMA SUSU, mahasiswa dapat dengan benar menjelaskan tentang komponen air, lemak,, protein, mineral, laktosa, lemak laktosa, mineral, serta enzim enzim--enzim yang terdapat pada susu
PENDAHULUAN Komponen utama susu : padatan 12 % dan air 88% Padatan Utama
Lemak susu : 3,9 % Protein : 3,25 % KH : 4,6 % Mineral : 0,65 % Lipila lain dan gas
Padatan minor : enzim, enzim, vitamin, NPN dan mineral
Komposisi
AIR
Berfungsi sebagai pelarut bagi komponen susu yang dapat larut atau membentuk suspensi
LAKTOSA Lactose, or 00-4-D-galactopyranosyl galactopyranosyl--(1,4)(1,4)glucopyranose,, is the major carbohydrate glucopyranose of milk lactose is only synthesized in the Golgi vesicles of the lactating cells. This occurs due to the presence of α-lactalbumin Cows’ milk contains traces of other carbohydrates, e.g., glucose and galactose,, but no polysaccharides. galactose
LAKTOSA
Mudah mengkristal. mengkristal. Pada T 20o C : α-lactose : 38 % β-lacrose : 62 % ( (lebih lebih mudah larut
Menyebabkan lactose intolerace Digunakan untuk :
Campuran makanan bayi Campuran obat Warna cokelat untuk produk bakery Bom asap
Pemanasan Laktosa
Lactose may isomerize into lactulose lactulose.. Sebagian glukosa berubah menjadi fruktosa Isomerisasi glukosa menjadi manosa yang menghasilkan epictose. Aktif sebagai katalis
caramelization and Maillard reactions
The latter occur in the presence of amino groups, especially the ε-amino group of lysine residues in proteins. These reactions can lead to formation of flavor compounds and brown pigments, and to a decrease in the nutritionally available lysine.
Tingkat Kemanisan Laktosa
a lactose solution is approximately 0.3 times as sweet as a sucrose solution of the same concentration. In milk, the sweetness is, moreover, to some extent masked by the protein, primarily casein. Consequently, unsoured whey has a sweeter taste than milk. If the lactose in milk is hydrolyzed into glucose and galactose, the sweetness is considerably enhanced.
These bacteria contain an enzyme called lactase which attacks lactose, splitting its molecules into glucose and galactose. galactose.
LEMAK
Terdapat dalam globula lemak Diameter 1 – 20 µ, ratarata-rata 3 µ Jumlah : 1000 x 106 per ml Luas permukaannya sangat besar, besar, shg mudah menyerap bau Butiran lemak terpisah :
Tegangan permukaan lebih kecil Ada membran protein dan proteinproteinlipida Terdapat kolesterol kolesterol,, karotenoid, karotenoid, vitamin A, dan enzim
Komponen Lemak Susu
Trigliserida (98 – 99 %)
Digliserida (0,5 %) Monogliserida (0,04 %) Asam lemak (50 jenis) Jenuh : 60 – 70 % Tidak Jenuh : 25 – 30 %
Fat Globule
Asam Lemak dalam Susu
Melting Point Fat with a high content of highmelting fatty acids is hard. Fat with a high content of lowmelting fatty acids is soft.
Kerusakan pada Lemak Ketengkan hidrolitik Reversi flavor Ketengikan oksidatif Bau karton atau minyak
PROTEIN Kasein (α, β, κ) : 80 % Whey protein : 0,5 – 0,7 %
ß –Lactoglobulins α-Lactalbumins Serum albumin Imuno globulin M, A, G
KASEIN Casein Total casein αS1- (% of total casein) αS2- (% of total casein) β- (% of total casein) κ- ( of total casein)
Goat 2.11 5.6 19.2 54.8 20.4
Cow 2.70 38.0 12.0 36.0 14.0
Protein terpenting dalam susu Bentuk kalsium kaseinat Membentuk misel kasein bersama Ca dan P Misel adalah struktur yang terbentuk dalam air dari molekul--molekul yang mempunyai gugus hidrofil dan molekul hidrofob.. hidrofob
Kasein
Casein Submicelle
Faktor yang memengaruhi kestabilan kasein
pH Konsentrasi garam Enzim renin Pemanasan Decrease in pH (Lewis, 1994) Precipitation of calcium phosphate. Denaturation of protein and interaction between whey protein and κκ-casein Modification of casein: dephosphoylation, dephosphoylation, hydrolysis of κ-casein and general hydrolysis Changes in micellar structure
Aplikasi Kasein Whipped Topping : minyak nabati + Ca Ca--kasein Pengentalan yogurt : sour cream Kembuatan Kem : Kasein + basa Pelapis kertas Plastik Tekstil mirip wool
WHEY PROTEIN
Whey : susu yang dihilangkan bagian kaseinnya.. kaseinnya Terdiri dari : –Lactoglobulins α-Lactalbumins Serum albumin Imuno globulin M, A, G Pemisahan : pH diturunkan sampai IEP atau penambahan garam
a-lactalbumin
This protein may be considered to be the typical whey protein. It is present in milk from all mammals and plays a significant part in the synthesis of lactose in the udder.
b-lactoglobulin
This protein is found only in ungulates and is the major whey protein component of milk from cows.
If milk is heated to over 60°C, denaturation is initiated where the reactivity of the sulphur-amino acid of b-lactoglobulin plays a prominent part. Sulphur bridges start to form between the blactoglobulin molecules, between one blactoglobulin molecule and a k-casein molecule and between b-lactoglobulin and a-lactalbumin. At high temperatures sulphurous compounds such as hydrogen sulphide are gradually released. These sulphurous compounds are responsible for the “cooked” flavour of heat treated milk.
MINERAL Mineral Utama : Na, K, Ca, Mg, P Peran :
Zat gizi Stabilitas protein Cu dan Fe : penyebab flavor menyimpang
Protein menyebabkan susu memiliki kapasitas buffer : pH naik, naik, Ca dan MgP mengendap sebagai koloid, koloid, pH turun, turun, P menjadi koloid
Enzim
Lipase Memengaruhi kerusakan flavor pada susu dan mentega Terdiri Plasma dan membran lipase Faktor yang menghambar inaktivasi lipase : Garam Garam--garam besi Bahan Pengemulsi Fosfatase Esterase yang menghidrolisis ester asam fosfat
Fosfatase asam asam,, pH opt 4,0 Fosfatase basa basa,, pH opt 9,6 dipakai sebagai indikatror pasteurisasi sempurna sempurna..
Katalase Enzim yang menguraikan peroksida menjadi H2O dan O2 Indikator susu yang tercampur kolostrum kolostrum,, atau terserang mastitis Menghilangkan kelebihan H2O2 pada pengolahan keju
Komponen Lain
Milk always contains somatic cells (white blood corpuscles
or leucocytes).
The content is low in milk from a healthy udder, but increases if the udder is diseased, usually in proportion to the severity of the disease. The somatic cell content of milk from healthy animals is as a rule lower than 200 000 cells/ml, but counts of up to 400 000 cells/ml can be accepted.
Komponen Lain
Milk also contains gases
some 5 – 6 % by volume in milk fresh from the udder,
but on arrival at the dairy the gas content may be as high as 10 % by volume. The gases consist mostly of carbon dioxide, nitrogen and oxygen. They exist in the milk in three states: 1. 2. 3.
dissolved in the milk bound and non-separable from the milk dispersed in the milk
Dispersed and dissolved gases are a serious problem in the processing of milk, which is liable to burn on to heating surfaces if it contains too much gas.
