ABSTRACT: This study investigates t

ABSTRACT: This study investigates the crystallization kinetics
of palm stearin (PS), a palm oil fraction, in blends with sesame
seed oil. The results indicate that the crystallization behavior of
PS in sesame oil is mainly associated with the crystallization of
tripalmitin. Therefore, crystallization of blends of 26, 42, 60,
and 80% (wt/vol) PS in sesame oil was described by equations
developed for simpler systems (e.g., Fisher and Turnbull equation). The isothermal crystallization, melting profile, and fitting
of the kinetics of nucleation to the Fisher and Turnbull equation
showed that the 26, 42, and 60% PS/sesame oil blends crystallized mainly in the β
1
′ polymorph state. In contrast, the 80%
blend crystallized in two different polymorph states (i.e., β
1
′ at
T ≤307.6 K and β
1
at T ≥308.2 K). The data indicated that, in
spite of the higher concentration of PS in the 80% PS/sesame
oil system, crystallization in the β
1
state required more free energy for nucleation (∆Gc
) than β
1
′ crystallization in the 26, 42,
and 60% PS/sesame oil. At the low cooling rate used (1 K/min)
it was observed that, for a particular PS blend, the higher the effective supercooling the higher the viscosity of the oil phase and
the smaller the induction time of crystallization (T
i
). Additionally, the β
1
′ crystals from PS, developed at the highest effective
supercooling investigated, were smaller than the β
1
crystals obtained at lower effective supercooling.
Paper no. J9235 in JAOCS 77, 297–310 (March 2000).
KEY WORDS: Avrami, crystallization, Fisher-Turnball, oil viscosity, palm oil, palm stearin.
Sesame (Sesamum indicum L.) is an important annual oilseed
crop in developing countries. India, China, Sudan, Mexico, and
Burma produced approximately 60% of its global production
for the period 1987–1991 (1,2). Sesame oil, conventionally extracted by pressing roasting seeds without further refining, has
a mild, pleasant, and unique taste with remarkable oxidative
stability. The fatty acid composition, triacylglyceride distribution, concentrations of sterols, tocopherols and lignins in the
oil, and the effect of several processing conditions on its oxidative stability have been studied (1,3–7).
Nowadays consumers are demanding edible oils devoid of
any chemical treatment and with natural characteristics and
natural flavor. As a consequence, the market for novel oils that
are cold-press extracted and that possess natural oxidative stability has been developing worldwide during the last few years.
Sesame seed oil fulfills most of these characteristics and is now
marketed in industrialized countries, mainly as a gourmet salad
oil with unique flavor. However, additional value-added products like margarine, spreads, and squeezable spreads based on
sesame oil have not been developed. These products require a
solid-to-liquid ratio with the appropriate melting profile to obtain the texture and functionality (i.e., spreadability) desired by
consumers. However, the natural triglyceride composition of
sesame oil is highly unsaturated, consisting of 7–12% palmitic,
3.5–6% stearic, 0.09–0.29% palmitoleic, 39–43% oleic,
40–44% linoleic, and 0.40–0.85% linolenic acids (1,8). Using
differential scanning calorimetry (DSC), Dibildox-Alvarado
and Toro-Vazquez (8) determined the crystallization exotherm
for triglycerides in sesame oil with an onset at around −2.5°C
and a maximum at around −7°C. Thus, the development of a
functional solid phase in sesame oil without the use of chemical processes, such as hydrogenation and interesterification, is
not an easy task.
Several processes are used to modify the phase change properties of vegetable oils and improve their plasticity, and therefore, the versatility for use by the food industry. The most utilized processes are hydrogenation and interesterification (9).
However, hydrogenation of the naturally occurring cisunsaturated fatty acids (i.e., oleic, linoleic, and linolenic fatty acids)
produces trans fatty acids. Consumer concern associated with
the atherogenic effects of trans fatty acids limits the future of
this process as a way to modify the solid-to-liquid ratio in vegetable oils. In fact, more trans-free spreads (e.g., obtained without hydrogenation) are being introduced successfully into the
market. This trend is expected to continue as the proposal of
the U.S. Food and Drug Administration to specify transfatty
acid content in food product labels proceeds (10). On the other
hand, chemical or enzymatic interestification processes, technologies utilized mainly in European countries, have particular
drawbacks that are mainly associated with the yield efficiency
and cost of the processes (11). In these processes, a high-melt

Hasil (Bahasa Indonesia) 1:

Abstrak: Penelitian ini menyelidiki kinetika kristalisasidari sawit stearin (PS), minyak kelapa sawit sebagian kecil, dengan wijenminyak biji. Hasilnya menunjukkan bahwa perilaku kristalisasiPS dalam minyak wijen terutama terkait dengan kristalisasitripalmitin. Oleh karena itu, kristalisasi dari campuran 26, 42, 60,dan 80% (wt/vol) PS dalam minyak wijen digambarkan oleh persamaandikembangkan untuk sistem sederhana (misalnya, Fisher dan Turnbull persamaan). Kristalisasi isotermal, mencair profil, dan cocokdari Kinetika Pembentukan inti untuk Fisher dan Turnbull persamaanmenunjukkan bahwa 26, 42 dan 60% PS wijen minyak campuran mengkristal terutama di β1′ polimorf negara. Sebaliknya, 80%campuran mengkristal di dua negara berbeda polimorf (yaitu, β1′ diT ≤307.6 K dan β1di T ≥308.2 K). Data menunjukkan bahwa, dalamMeskipun konsentrasi yang lebih tinggi dari PS 80% PS wijensistem minyak, kristalisasi dalam β1negara lain energi bebas diperlukan untuk pembentukan inti (∆Gc) daripada β1′ kristalisasi dalam 26, 42,dan 60% PS wijen minyak. Pada tingkat rendah pendinginan digunakan (1 K/min)itu adalah mengamati bahwa, untuk campuran PS tertentu, semakin tinggi efektif pendinginan Super semakin tinggi viskositas fasa minyak dankecil saat induksi kristalisasi (Tsaya). Selain itu, β1′ kristal dari PS, dikembangkan di efektif tertinggipendinginan Super diselidiki, yang lebih kecil daripada β1kristal-kristal yang diperoleh pada pendinginan Super efektif lebih rendah.Kertas tidak. J9235 di JAOCS 77, 297-310 (Maret 2000).KATA kunci: Avrami, kristalisasi, Fisher-Turnball, viskositas minyak, minyak sawit, sawit stearin.Wijen (indicum wijen L.) adalah minyak tahunan pentingtanaman di negara berkembang. India, Cina, Sudan, Meksiko, danBurma memproduksi sekitar 60% dari produksi globaluntuk periode 1987-1991 (1,2). Minyak wijen, konvensional diekstraksi dengan menekan memanggang biji tanpa lebih lanjut penyulingan, telahRingan, menyenangkan dan unik rasa dengan luar biasa oksidatifstabilitas. Komposisi asam lemak, triacylglyceride distribusi, konsentrasi sterol, tokoferol dan lignins diminyak, dan pengaruh dari beberapa kondisi pengolahan pada stabilitas oksidatif telah diteliti (1,3-7). Saat ini konsumen menuntut dimakan minyak telahsetiap pengobatan kimia dengan karakteristik alam danrasa alami. Sebagai akibatnya, pasar untuk novel minyak yangyang dingin-tekan diekstrak dan yang memiliki stabilitas oksidatif alami telah berkembang di seluruh dunia selama beberapa tahun terakhir.Minyak biji wijen memenuhi sebagian karakteristik dan sekarangdipasarkan di negara-negara industri, terutama sebagai gourmet saladminyak dengan rasa yang unik. Namun, tambahan nilai tambah produk seperti margarin, menyebar, dan menyebar hal yg mudah dipengaruhi berdasarkanminyak wijen tidak telah dikembangkan. Produk ini memerlukansolid-to-liquid ratio with the appropriate melting profile to obtain the texture and functionality (i.e., spreadability) desired byconsumers. However, the natural triglyceride composition ofsesame oil is highly unsaturated, consisting of 7–12% palmitic,3.5–6% stearic, 0.09–0.29% palmitoleic, 39–43% oleic,40–44% linoleic, and 0.40–0.85% linolenic acids (1,8). Usingdifferential scanning calorimetry (DSC), Dibildox-Alvaradoand Toro-Vazquez (8) determined the crystallization exothermfor triglycerides in sesame oil with an onset at around −2.5°Cand a maximum at around −7°C. Thus, the development of afunctional solid phase in sesame oil without the use of chemical processes, such as hydrogenation and interesterification, isnot an easy task.Several processes are used to modify the phase change properties of vegetable oils and improve their plasticity, and therefore, the versatility for use by the food industry. The most utilized processes are hydrogenation and interesterification (9).However, hydrogenation of the naturally occurring cisunsaturated fatty acids (i.e., oleic, linoleic, and linolenic fatty acids)produces trans fatty acids. Consumer concern associated withthe atherogenic effects of trans fatty acids limits the future ofthis process as a way to modify the solid-to-liquid ratio in vegetable oils. In fact, more trans-free spreads (e.g., obtained without hydrogenation) are being introduced successfully into thepasar. Kecenderungan ini diperkirakan akan terus berlanjut sebagai usulanUS Food and Drug Administration untuk menentukan transfattykandungan asam dalam produk makanan label hasil (10). Di sisi laintangan, kimia atau proses enzimatik interestification, teknologi yang digunakan terutama di negara-negara Eropa, memiliki tertentukelemahan yang terutama berkaitan dengan efisiensi hasildan biaya proses (11). Dalam proses ini, tinggi-meleleh