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:

Faktor-faktor ini mempengaruhi fungsi makroskopikyang berhubungan dengan sifat-sifat fisik seperti titik leleh,SFC, dan rheological pada. Keluar dari ini,rheological pada dan sifat-sifat mencair lemakcampuran lebih tergantung pada polimorfisme danpolytypism (negara kristal sistem lemak),kepadatan pengemasan, distribusi spasial, dan ukuran dan bentukmikrostruktur jaringan dihasilkan. Reologisistem lemak ditentukan oleh konsistensi dan tekstur. Konsistensi tidak hanya tergantung pada padat ke cairrasio hadir pada suhu yang berbeda tetapi juga padaberbagai tingkat struktural dalam jaringan shortening.Diinginkan rasio padat-cair dapat dicapai oleh pencampuran dan mengendalikan hidrogenasi. Minyak dipilih untuksifat kristal tertentu mereka. Sifat kristal juga dipengaruhi oleh kondisi pengolahan. Polimorfikmodifikasi atau kristal kebiasaan komposisi lemakProperti sangat penting. Sebagai contoh, hal ini penting,Misalnya, karena beta-polimorf diinginkanadalah produk cokelat whereasbeta-primepolymorphsdiinginkan di shortenings dan spread (Wiedermann,1978). Betapolymorphs, menjadi kristal besar, memberikandiinginkan patah produk cokelat, sedangkan polimorf betaprime, menjadi kristal kecil, memberikan halusmulut merasa di meja spread. Jenis pengolahan pengobatan yang mempengaruhi struktur lemak pada tingkat molekuler, kristalin dan microstructuralhidrogenasi, interesterification, fraksinasi, danpencampuran (Wiedermann, 1978). Tingkat pendinginantingkat dan geser selama pemrosesan juga sangat mempengaruhimikro.10.1. hidrogenasiMinyak nabati terlalu lunak untuk margarines atau shortenings karena sifat mereka cair, sementara di sisi lainlemak jenuh tangan terlalu keras. Tergantung pada akhirkekerasan yang memerlukan penggunaan, kebanyakan sistem lemak shorteningmenengah. Hidrogenasi atau proses pengerasan,adalah proses saturasi (Bailey, Feuge, & Smith, 1942).Hidrogen ditambahkan ke ikatan ganda jenuh12 tabelKomposisi asam lemakAsam lemak Canolaa(%) Brassica napusa(%) Bunga mataharia(%) Kelapa sawitb(%) Kedelai minyakb(%)Asam palmitat (P) 43 4 46 11Asam stearat (S) 2 1 3 5 4Asam oleat (O) 58 17 3439 23Asam linoleat (L) 21 1459 9 54Linolenic 11 9 – 0.5 8Gadoleic asam 2 11- -Asam erukat < 145---nilai-nilai dalam persentase total asam lemak yang hadir.adeMan dan deMan, 2001.bKamel, 1992.13 MejaKomposisi/hubungan fungsional (Wiedermann, 1978)Kelompok titik lebur (C) TAGSAYA 65 SSS61.1 SSP60 SPP56.1 PPPII 41,6 SSO37.7 SPO35 PPO32. 7 SSL30 SPL27.2 PPLSOO III 22,715.5 OOP6.1 SOL5.5 OOOIV 1.1 SLL1.1 OOL2.7 PLO4.2 PLL6.6 OLL13.3 BMPKS, asam stearat; P, asam palmitat; O, asam oleat; L, asam laurat.1036 BS Ghotra et al. / Food Research International 35 (2002) 1015-1048asam lemak, dengan demikian mengubah mereka untuk jenuh lemakasam, yang pada gilirannya mengkonversi minyak ke dalam lemak padat. Dalamkasus lengkap hidrogenasi, arachidonic, linolenic,linoleic dan asam oleat hadir dalam minyak asli akanmengkonversi sepenuhnya ke dalam asam jenuh yang sesuai(Bodman et al., 1951). Hidrogenasi karena itu dapatdidefinisikan sebagai proses yang menanamkan stabilitas oksidatifminyak. Dengan demikian, proses ini mempertahankan organoleptikKarakteristik minyak untuk kehidupan rak lagi. Ketegasan dalammargarines meningkat oleh proses hidrogenasistok dasar karena pembentukan jenuh dan transasam lemak (TFA;Mensink & menunaikan, 1993), seperti yang ditunjukkan dalamGambar 10. Asam tinggi berat molekul tampaknyahydrogenate lebih mudah daripada berat molekul rendahasam (Mattil, 1964b). Sepenuhnya hidrogenasi minyakDiperoleh ketika semua ikatan rangkap jenuh;Sebaliknya minyak dirujuk sebagian terhidrogenasiminyak. Tergantung pada kondisi diterapkan selamaproses hidrogenasi bisa digolongkan menjadi dua jenis:hidrogenasi selektif dan non selektif. Faktor yangmempengaruhi proses hidrogenasi dan akibatnyaproduk yang dihasilkan, adalah suhu campuran minyak, tekanan gas hidrogen, aktivitas katalis, kataliskonsentrasi, agitasi campuran, dan durasi waktu dari proses (Bodman et al., 1951; Chrysam,1985; Coenen, 1976; Mattil, 1964b). Selektivitas (selektivitas merujuk kepada proses hidrogenasi yang mengandung asamkelompok-kelompok aktif metilena dalam preferensi asam telahkelompok-kelompok seperti itu) dapat membuat banyak perbedaan di finalKomposisi tag dan akibatnya mempengaruhiprofil produk yang diperoleh sebagai hasil dari pencairanhidrogenasi (Bailey 1951; Bailey et al., 1942; Beal &Lancaster, 1954; Chrysam, 1985; Mattil, 1964b). Thehubungan katalis, suhu dan tekananuntuk selektivitas reaksi hidrogenasi untuk minyaktelah dipelajari secara ekstensif (Bailey, 1951). Sudahmelaporkan bahwa selektivitas berbandingsuhu yang diterapkan selama hidrogenasi (Bodman etAl., 1951; Coenen, 1976). Peningkatan tingkatagitasi nikmat bebas-selektivitas dan menekan pembentukan meltingtrans-isomer tinggi (Bailey et al.,1942). Beal dan Lancaster (1954) mempelajari efek dariagitasi dan batch ukuran pada tingkat hidrogenasi,dan pada stabilitas lemak. Mereka mengamati bahwatingkat hidrogenasi meningkat dengan peningkatantingkat agitasi minyak atau campuran minyak. Selain itu, stabilitas lemak meningkat denganpeningkatan hidrogenasi batch ukuran. Suhu tinggi minyak selama hidrogenasi nikmat lebih besarSelektivitas dan dengan demikian menghasilkan lebih banyak generasi TFA(Coenen, 1976; Mattil, 1964b). Mattil (1964b) melaporkantekanan gas hidrogen tinggi selama hidrogenasimeningkatkan laju hidrogenasi dan menyebabkanpenurunan selektivitas reaksi. Kondisi seperti mendukung pembentukan TFA kurang. Selain itu, Mattiljuga menyatakan bahwa konsentrasi tinggi katalis yang disukaiSelektivitas dengan jumlah besar TFA pembentukan. Tinggikatalis konsentrasi meningkatkan tingkat hidrogenasi (Mattil, 1964b).Biasanya hidrogenasi dilakukan di bawah kurang selektifkondisi. Dalam non selektif hidrogenasi, suhu yang lebih rendah dan lebih tinggi hidrogen tekanan diterapkan dalamkehadiran menghabiskan nikel sebagai katalis (Mattil,1964b). SFC profil selektif hidrogenasi minyak yangbanyak lebih curam daripada minyak diproses untuk sekitargelar yang sama hidrogenasi (atau sama yodiumnilai) kondisi non selektif. Minyak dengancuram SFC profil biasanya memiliki plastik sangat sempitberbagai sedangkan sistem lemak dengan SFC datar profil biasanya memiliki berbagai lebar plastik (seperti ditunjukkan inFig. 2). Thetingkat selektivitas di hidrogenasi juga mempengaruhikristal stabilitas lemak dihasilkan. Sebuah studi yang dilakukanoleh Yap (1988) menunjukkan bahwa selektif terhidrogenasiminyak canola membentuk campuran beta-Perdana dan betakristal; sedangkan non selektif hidrogenasi menghasilkandalam betaform kristal. Penggabungan dari lemak transasam melalui hidrogenasi selektif favorsbeta-Perdanakristalisasi (Naguib-Mostafa & deMan, 1985).

Hasil (Bahasa Indonesia) 2:

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).