schcn M e t h o d e ; Triigergas H?, 2 ml/min: D e t e k t o r : Flomrnenionisationsdetektor (FID) 270°C; Splitverhaltnis: 1: 10; I n j e k t o r t e m p . 270°C: Temperaturprogramm: 3 min isotherm bei 80"C, 80T-280"C mit 3"C/min, 10 min isotherm bei 280°C. L i t e r a t u r

h a m e d , M. H . I s k a n d a r , B. S i v i k a n d K. L a r s s o n *-0 new types of margarines were prepared in this study. The first was processed without the traditional milk flavour. The fat phase consists of 40% partially hydrogenated cottonseed oil (m. p. 42.2"C), 40 % cottonseed oil and 20 % olive oil as a source of flavouring and antioxidant materials. The second margarine was based mainly on the interesterified fat formed from lipase interesterification of a mixture of 86.5 % cottonseed oil and 13.5 % fully hydrogenated soybean oil (m. p. 672°C). Characterization and evaluation of these new types of margarines in relation to two conventional margarines are reported. The presence of diglycerides in the interesterified fat (free from mans isomers) reduced the amount of crystallized solids and the properties of the product were very close to conventional soft margarines. Margarine with olive oil taste was well accepted.

The crystallization behaviour and rheological properties of various preparations of cottonseed oil interesterified with fully hydrogenated Modifizierung von Fetten mittels Lipase-Umesterung 11: Auswirkungeo auf das Kristallisationsverhalten und funktionelle EigenschaftenEs wurden das Kristallisationsverhalten und die rheologischen Eisoybean oil by lipases were studied. Variations related to the specificity of the lipase reaction were observed. The most striking effect was genschaften verschiedener Praparate von Baumwollsaatoi und vollstandig hydriertem Sojaol nach Umesterung mit Lipasen untersucht. Dabei wurden Variationen bezuelich der Soezifitat der Lioasereaktion -an increase in the relative stability of the P'-crystal form by interesterbeobachtet. Der auffallendste Effekt war eine Zunahme der relativen ification, indicating possibilities for margarine production without Stabilitat der P'-Kristallrnodifikation nach Umesterung. Daraus ergeben sich Moglichkeiten fur die Margarineherstellung ohne trans-Fetttrans fatty acids. sauren I n t r o d u c t i o nThe availability of commercial lipases for industrial scale applications will certainly have a strong influence on fat processing in the future, providing the possibility to tailor fat molecules according to desired nutritional and other functional properties. As a model system for exploring the enzymatic reaction, and resulting effects on functional properties, we have chosen the interesterification of cottonseed oil and fully hardened soybean oil (FHSO). This model system allows the possibility of eliminating trans-fatty acids in products based on plastic fats, e. g. in margarine.A first paper in this work describes the results of the interesterification based on identification of triglyceride molecular species formed from various proportions of substrate oils and fats'. Two commercial immobilized lipase preparations were used, one preparation was 1,3-positionally specific, and the other was less positionally specific. This paper concerns the functional properties of the interesterified triglyceride mixtures produced. E x p e r i m e n t a l P r o c e d u r e sThe reaction details are given in the first part of this work', and samples were prepared as described in Table 1.Melting points were determined by the close capillary tube method' and were calculated by averaging the readings from three samples. Solidification points were determined by melting the samples completely at 80°C and then cooling under agitation (1 "C/minute) until the samples started to solidify. These determinations were also carried out in triplicate. Solid fat indices were measured by low resolution pulsed nuclear magnetic resonance. Samples were melted at 80°C and then tempered at 60°C for 15 min and at -18°C for 15 min. Measurements were then made at 10,20,30,35 and 40°C.The polymorphic forms in the original and interesterified samples were identified by X-ray analysis. Samples were sealed in mica window sample holders. A diffraction-versus-temperature (DPT) camera described earlier was ...

The effects of diglycerides, sorbitan-monoesters and sorbitantriesters on triglyceride polymorphic transitions have been examined.Earlier reported effects of retardation of + p transitions due to the presence of asymmetric diglycerides were found to be the same from the racemic and antipode forms. The a * p and p' + p transitions of tripalmitin (PPP) were followed when sorbitan-monopalmitate (SMP), sorbitan-tripalmitate (STP), or dipalmitate (DP) were present. The STP gave a slightly stronger reduction in transition kinetics than DP, whereas SMP was found to promote the transition. In order to understand the mechanisms involved the binary systems SMP-PPP and STP-PPP were examined. In the case of SMP-PPP a 1 : 1 molecular compound is formed, whereas STP-PPP shows a simple eutectic behaviour. I n t r o d u c t i o n A major problem in many fat-based food products is polymorphic transition of fat crystals during storage. Margarine and chocolate are well-known examples where transitions to the most stable crystal form lead to unacceptable product quality. The present work was undertaken in order to compare the effect of different lipids known to influence the kinetics of the polymorphic transitions, and furthermore in order to understand their function.Sorbitan esters have been utilized in various applications to inhibit the 6' + /? phase transition (cf. Ref.').The possibility to use diglycerides in order to prepare margarine from low-erucic acid rapeseed oil was studied in our laboratory'. In order to obtain comparative data on these two routes of crystallization modification, we report below a systematic study on effects of different isomers of distearin (DS) on trimyristin (MMM) polymorphism and of sorbitan-tripalmitate (STP), sorbitanmonopalmitate (SMP) and 1,2-D-dipalmitate (DP) on tripalmitin (PPP) polymorphism. Binary systems of these components were examined, and in one set of experiments we used the same fatty acid chain length in order to obtain optimal conditions for co-crystallization. E x p e r i m e n t a l Samples of trimyristin, tripalmitin, DM and DP were obtained from Sigma (> 99% in purity). STP and SMP were kindly provided by Dr. N . Krog, Grindsted Products, Brabrand, Denmark. They were purified from corresponding technical products with a purity of about Samples were mixed and equilibrated about 30°C above the melting point of the high-melting component. They were then chock-cooled to -20°C and then kept at the constant temperature where phase transition kinetics were studied (20°C, 30°C and 40"C, respectively). Melting and solidification points of binary systems were obtained from observations in the polarizing microscope 95 Y o . Phasenumwandlungen io lkipalmitin in Gegenwart von Dipalmitin, Sorbitan-Monopalmitst oder Sorbitan-lkipalmitat Die Wirkungen von Digiyceriden, Sorbitan-Monoestern und Sorbitan-Triestern auf die Kristallisation der Triglyceride wurden untersucht. Die Verzogerung von 0' + Ubergangen in asymmetrischen Diglyceriden war gleichartig in racemischen und antipodischen Formen. ...

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