These factors influence the macrosc

These factors influence the macroscopic functionality
that is related to physical properties like melting point,
SFC, and rheological properties. Out of these, the
rheological properties and melting properties of a fat
mixture are further dependent on polymorphism and
polytypism (the crystalline state of the fat system),
packing density, spatial distribution, and size and shape of
the microstructure of the resulting network. The rheology
of a fat system is determined by its consistency and texture. Consistency depends not only on the solid-to-liquid
ratio present at different temperatures but as well on the
various structural levels within the shortening network.
Desirable solid-liquid ratio can be achieved by blending and controlling hydrogenation. Oils are chosen for
their particular crystal habit. Crystal habit is also affected by the conditions of processing. The polymorphic
modification or crystal habit of the fat composition is a
very important property. For example, it is important,
for example, because beta-polymorphs are desirable in
chocolate products whereasbeta-primepolymorphs are
desirable in shortenings and spreads (Wiedermann,
1978). Betapolymorphs, being large crystal, give a
desirable snap in chocolate products, whereas betaprime polymorphs, being small crystals, give smooth
mouth feel in table spreads. Types of processing treatment that affect the structure of a fat at the microstructural, crystalline, and molecular levels are
hydrogenation, interesterification, fractionation, and
blending (Wiedermann, 1978). The degree of cooling
rate and shear during processing also greatly affects the
microstructure.
10.1. Hydrogenation
Vegetable oils are too soft for margarines or shortenings because of their liquid nature, while on the other
hand saturated fats are too hard. Depending on the end
use, most shortening fat systems require hardness that is
intermediate. Hydrogenation or the hardening process,
is a saturation process (Bailey, Feuge, & Smith, 1942).
Hydrogen is added to the double bonds of unsaturated
Table 12
Fatty acid composition
Fatty acid Canola
a
(%) Rapeseed
a
(%) Sunflower
a
(%) Palm oil
b
(%) Soya oil
b
(%)
Palmitic acid (P) 43 4 46 11
Stearic acid (S) 2 1 3 5 4
Oleic acid (O) 58 17 3439 23
Linoleic acid (L) 21 1459 9 54
Linolenic 11 9 – 0.5 8
Gadoleic acid 2 11 – – –
Erucic acid

Hasil (Bahasa Indonesia) 1:

These factors influence the macroscopic functionality
that is related to physical properties like melting point,
SFC, and rheological properties. Out of these, the
rheological properties and melting properties of a fat
mixture are further dependent on polymorphism and
polytypism (the crystalline state of the fat system),
packing density, spatial distribution, and size and shape of
the microstructure of the resulting network. The rheology
of a fat system is determined by its consistency and texture. Consistency depends not only on the solid-to-liquid
ratio present at different temperatures but as well on the
various structural levels within the shortening network.
Desirable solid-liquid ratio can be achieved by blending and controlling hydrogenation. Oils are chosen for
their particular crystal habit. Crystal habit is also affected by the conditions of processing. The polymorphic
modification or crystal habit of the fat composition is a
very important property. For example, it is important,
for example, because beta-polymorphs are desirable in
chocolate products whereasbeta-primepolymorphs are
desirable in shortenings and spreads (Wiedermann,
1978). Betapolymorphs, being large crystal, give a
desirable snap in chocolate products, whereas betaprime polymorphs, being small crystals, give smooth
mouth feel in table spreads. Types of processing treatment that affect the structure of a fat at the microstructural, crystalline, and molecular levels are
hydrogenation, interesterification, fractionation, and
blending (Wiedermann, 1978). The degree of cooling
rate and shear during processing also greatly affects the
microstructure.
10.1. Hydrogenation
Vegetable oils are too soft for margarines or shortenings because of their liquid nature, while on the other
hand saturated fats are too hard. Depending on the end
use, most shortening fat systems require hardness that is
intermediate. Hydrogenation or the hardening process,
is a saturation process (Bailey, Feuge, & Smith, 1942).
Hydrogen is added to the double bonds of unsaturated
Table 12
Fatty acid composition
Fatty acid Canola
a
(%) Rapeseed
a
(%) Sunflower
a
(%) Palm oil
b
(%) Soya oil
b
(%)
Palmitic acid (P) 43 4 46 11
Stearic acid (S) 2 1 3 5 4
Oleic acid (O) 58 17 3439 23
Linoleic acid (L) 21 1459 9 54
Linolenic 11 9 – 0.5 8
Gadoleic acid 2 11 – – –
Erucic acid <145 – – – Values in percentages of total fatty acid present.
a
deMan and deMan, 2001.
b
Kamel, 1992.
Table 13
Compositional/functional relationships (Wiedermann, 1978)
Groups Melting point (C) TAG
I 65 SSS
61.1 SSP
60 SPP
56.1 PPP
II 41.6 SSO
37.7 SPO
35 PPO
32.7 SSL
30 SPL
27.2 PPL
III 22.7 SOO
15.5 OOP
6.1 SOL
5.5 OOO
IV 1.1 SLL
1.1 OOL
2.7 PLO
4.2 PLL
6.6 OLL
13.3 LLL
S, stearic acid; P, palmitic acid; O, oleic acid; L, lauric acid.
1036 B.S. Ghotra et al. / Food Research International 35 (2002) 1015–1048
fatty acids, thus transforming them to saturated fatty
acids, which in turn converts oil into solid fat. In the
case of complete hydrogenation, arachidonic, linolenic,
linoleic, and oleic acids present in the original oil will
convert entirely into the corresponding saturated acids
(Bodman et al., 1951). Hydrogenation can therefore be
defined as a process which imparts oxidative stability to
oils. Thus, this process maintains the organoleptic
characteristics of oils for longer shelf life. Firmness in
margarines is increased by the hydrogenation of the
base stock due to the formation of saturated and trans
fatty acids (TFA;Mensink & Katan, 1993), as shown in
Fig. 10. Acids of high molecular weights appear to
hydrogenate less readily than low molecular weight
acids (Mattil, 1964b). Fully hydrogenated oil is
obtained when all the double bonds are saturated;
otherwise the oil is referred to as partially hydrogenated
oil. Depending on the conditions applied during the
process, hydrogenation can be classified into two types:
selective and non-selective hydrogenation. Factors that
affect the hydrogenation process and consequently the
resultant products, are the temperature of the oil mixture, hydrogen gas pressure, catalyst activity, catalyst
concentration, agitation of the mixture, and time duration of the process (Bodman et al., 1951; Chrysam,
1985; Coenen, 1976; Mattil, 1964b). Selectivity (Selectivity refers to the hydrogenation of acids containing
active methylene groups in preference to acids devoid of
such groups) can make a lot of difference in the final
composition of TAGs and consequently affects the
melting profile of the product obtained as a result of
hydrogenation (Bailey 1951; Bailey et al., 1942; Beal &
Lancaster, 1954; Chrysam, 1985; Mattil, 1964b). The
relationship of the catalyst, temperature, and pressure
to the selectivity of the hydrogenation reaction for oil
has been studied extensively (Bailey, 1951). It has been
reported that selectivity is directly proportional to the
temperature applied during hydrogenation (Bodman et
al., 1951; Coenen, 1976). Increases in the degree of
agitation favors non-selectivity and suppresses the formation of high meltingtrans-isomers (Bailey et al.,
1942). Beal and Lancaster (1954)studied the effect of
agitation and batch size on the rate of hydrogenation,
and on the stability of the fat. They observed that the
rate of hydrogenation increased with an increase in the
degree of agitation of an oil or mixture of oils. Furthermore, the stability of the fats increased with an
increase in the hydrogenation batch size. High temperature of the oil during hydrogenation favors greater
selectivity and thus results in more TFA generation
(Coenen, 1976; Mattil, 1964b). Mattil (1964b)reported
that high hydrogen gas pressure during hydrogenation
increased the rate of hydrogenation and caused a
decrease in the selectivity of the reaction. Such conditions favor less TFA formation. Furthermore, Mattil
also stated that high catalyst concentration favored
selectivity with large amounts of TFA formation. High
catalyst concentration increases the rate of hydrogenation (Mattil, 1964b).
Normally hydrogenation is done under less selective
conditions. In non-selective hydrogenation, lower temperatures and higher hydrogen pressures are applied in
the presence of spent nickel as a catalyst (Mattil,
1964b). SFC profiles of selectively hydrogenated oils are
much steeper than the oil processed to approximately
the same degree of hydrogenation (or same iodine
value) under non-selective conditions. An oil with a
steeper SFC profile typically has a very narrow plastic
range whereas a fat system with a flat SFC profile typically has a wide plastic range (as shown inFig. 2). The
degree of selectivity in hydrogenation also affects the
crystal stability of the resulting fat. A study carried out
by Yap (1988)showed that selectively hydrogenated
canola oil formed a mixture of beta-prime and beta
crystals; whereas non-selective hydrogenation resulted
in the betaform of crystals. Incorporation of trans fatty
acids through selective hydrogenation favorsbeta-prime
crystallization (Naguib-Mostafa & deMan, 1985).

Hasil (Bahasa Indonesia) 2:

Faktor-faktor ini mempengaruhi fungsi makroskopik
yang berkaitan dengan sifat fisik seperti titik leleh,
SFC, dan sifat reologi. Dari ini,
sifat reologi dan sifat leleh lemak
campuran yang lebih bergantung pada polimorfisme dan
polytypism (keadaan kristal dari sistem lemak),
kemasan kepadatan, distribusi spasial, dan ukuran dan bentuk
struktur mikro jaringan yang dihasilkan. Reologi
sistem lemak ditentukan oleh konsistensi dan tekstur. Konsistensi tidak hanya bergantung pada solid-to-liquid
ratio hadir pada temperatur yang berbeda tetapi juga pada
berbagai tingkat struktural dalam jaringan shortening.
rasio padat-cair diinginkan dapat dicapai dengan pencampuran dan mengendalikan hidrogenasi. Minyak yang dipilih untuk
kebiasaan kristal khusus mereka. Kebiasaan kristal juga dipengaruhi oleh kondisi pengolahan. The polimorfik
modifikasi atau kristal kebiasaan komposisi lemak adalah
properti yang sangat penting. Sebagai contoh, adalah penting,
misalnya, karena beta-polimorf yang diinginkan dalam
produk cokelat whereasbeta-primepolymorphs yang
diinginkan dalam shortening dan menyebar (Wiedermann,
1978). Betapolymorphs, menjadi kristal besar, memberikan
sekejap diinginkan dalam produk cokelat, sedangkan betaprime polimorf, menjadi kristal kecil, memberikan mulus
mulut merasa spread tabel. Jenis pengobatan pengolahan yang mempengaruhi struktur lemak di bagian mikro, kristal, dan tingkat molekuler
hidrogenasi, interesterifikasi, fraksinasi, dan
pencampuran (Wiedermann, 1978). Tingkat pendinginan
tingkat dan geser selama pemrosesan juga sangat mempengaruhi
struktur mikro.
10.1. Hidrogenasi
minyak nabati yang terlalu lunak untuk margarin atau shortening karena sifat cair mereka, sementara di sisi lain
sisi lemak jenuh terlalu keras. Tergantung pada akhir
penggunaan, sebagian besar sistem lemak pemendekan membutuhkan kekerasan yang
menengah. Proses pengerasan hidrogenasi atau,
adalah proses saturasi (Bailey, Feuge, & Smith, 1942).
Hidrogen ditambahkan ke ikatan rangkap tak jenuh
Tabel 12
Fatty acid komposisi
lemak asam Canola
a
(%) Rapeseed
sebuah
(%) Sunflower
a
( %) Minyak sawit
b
(%) minyak kedelai
b
(%)
Asam palmitat (P) 43 4 46 11
Asam stearat (S) 2 1 3 5 4
Asam oleat (O) 58 17 3439 23
Asam linoleat (L) 21 1459 9 54
Linolenic 11 9-0,5 8
Gadoleic asam 2 11 - - -
asam erusat <145 - - -. Nilai persentase dari total asam lemak hadir
sebuah
. Deman dan Deman, 2001
b
. Kamel, 1992
Tabel 13
komposisi: / hubungan fungsional (Wiedermann , 1978)
Grup Titik lebur (? C) TAG
I 65 SSS
61,1 SSP
60 SPP
56.1 PPP
II 41,6 SSO
37,7 SPO
35 PPO
32.7 SSL
30 SPL
27.2 PPL
III 22,7 SOO
15,5 OOP
6.1 SOL
5.5 OOO
IV 1.1 SLL
? 1.1 OOL
? 2.7 PLO
4.2 PLL?
6.6 OLL?
13,3 BMPK?
S, asam stearat; P, asam palmitat; O, asam oleat; L, asam laurat.
1036 BS Ghotra et al. / Food Research International 35 (2002) 1015-1048
asam lemak, sehingga mengubah mereka untuk lemak jenuh
asam, yang pada gilirannya mengubah minyak menjadi lemak padat. Dalam
kasus hidrogenasi lengkap, arakidonat, linoleat,
linoleat, dan asam oleat hadir dalam minyak asli akan
mengkonversi sepenuhnya menjadi asam jenuh yang sesuai
(Bodman et al., 1951). Hidrogenasi sehingga dapat
diartikan sebagai suatu proses yang menanamkan stabilitas oksidatif
minyak. Dengan demikian, proses ini mempertahankan organoleptik
karakteristik minyak untuk kehidupan rak lagi. Ketegasan dalam
margarin meningkat dengan hidrogenasi dari
saham dasar karena pembentukan jenuh dan trans
fatty acids (TFA; Nishikawa & Katan, 1993), seperti yang ditunjukkan pada
Gambar. 10. Asam bobot molekul tinggi tampaknya
hydrogenate kurang mudah daripada berat molekul rendah
asam (Mattil, 1964b). Minyak terhidrogenasi sepenuhnya adalah
diperoleh ketika semua ikatan ganda jenuh,
sebaliknya minyak ini disebut sebagai terhidrogenasi parsial
minyak. Tergantung pada kondisi yang diterapkan selama
proses, hidrogenasi dapat diklasifikasikan menjadi dua jenis:
selektif dan non-selektif hidrogenasi. Faktor-faktor yang
mempengaruhi proses hidrogenasi dan akibatnya
produk yang dihasilkan, adalah suhu campuran minyak, tekanan gas hidrogen, aktivitas katalis, katalis
konsentrasi, agitasi campuran, dan durasi waktu proses (Bodman et al, 1951;. Chrysam ,
1985; Coenen, 1976; Mattil, 1964b). Selektivitas (Selektivitas mengacu pada hidrogenasi asam yang mengandung
kelompok metilen aktif dalam preferensi untuk asam tanpa
kelompok tersebut) dapat membuat banyak perbedaan di final
komposisi TAG dan akibatnya mempengaruhi
profil leleh produk yang diperoleh sebagai hasil dari
hidrogenasi ( Bailey 1951;. Bailey et al, 1942; Beal &
Lancaster, 1954; Chrysam, 1985; Mattil, 1964b). The
hubungan katalis, suhu, dan tekanan
terhadap selektivitas reaksi hidrogenasi minyak
telah dipelajari secara ekstensif (Bailey, 1951). Telah
dilaporkan bahwa selektivitas berbanding lurus dengan
suhu diterapkan selama hidrogenasi (Bodman et
al, 1951;. Coenen, 1976). Peningkatan derajat
agitasi nikmat non-selektivitas dan menekan pembentukan tinggi meltingtrans-isomer (Bailey et al.,
1942). Beal dan Lancaster (1954) mempelajari pengaruh
agitasi dan bets ukuran pada tingkat hidrogenasi,
dan pada stabilitas lemak. Mereka mengamati bahwa
tingkat hidrogenasi meningkat dengan peningkatan
derajat agitasi dari minyak atau campuran minyak. Selanjutnya, stabilitas lemak meningkat dengan
peningkatan ukuran bets hidrogenasi. Suhu tinggi minyak selama hidrogenasi nikmat besar
selektivitas dan dengan demikian menghasilkan lebih TFA generasi
(Coenen, 1976; Mattil, 1964b). Mattil (1964b) melaporkan
bahwa tekanan gas hidrogen tinggi selama hidrogenasi
meningkatkan tingkat hidrogenasi dan menyebabkan
penurunan selektivitas reaksi. Kondisi seperti mendukung kurang formasi TFA. Selain itu, Mattil
juga menyatakan bahwa konsentrasi katalis tinggi disukai
selektivitas dengan jumlah besar formasi TFA. Tinggi
konsentrasi katalis meningkatkan tingkat hidrogenasi (Mattil, 1964b).
Biasanya hidrogenasi dilakukan di bawah kurang selektif
kondisi. Dalam hidrogenasi non-selektif, suhu yang lebih rendah dan tekanan hidrogen tinggi diterapkan dalam
kehadiran menghabiskan nikel sebagai katalis (Mattil,
1964b). Profil SFC minyak terhidrogenasi selektif yang
jauh lebih curam daripada minyak yang diproses sekitar
tingkat yang sama dari hidrogenasi (atau yodium yang sama
nilai) dalam kondisi non-selektif. Minyak dengan
profil SFC curam biasanya memiliki plastik yang sangat sempit
rentang sedangkan sistem lemak dengan profil SFC datar biasanya memiliki berbagai macam plastik (seperti yang ditunjukkan inFig. 2). The
tingkat selektivitas dalam hidrogenasi juga mempengaruhi
stabilitas kristal lemak yang dihasilkan. Sebuah penelitian yang dilakukan
oleh Yap (1988) menunjukkan bahwa selektif terhidrogenasi
minyak canola membentuk campuran beta-prime dan beta
kristal; sedangkan hidrogenasi non-selektif menghasilkan
dalam betaform kristal. Pendirian lemak trans
asam melalui hidrogenasi selektif favorsbeta-prime
kristalisasi (Naguib-Mostafa & Deman, 1985).