High-resolution nuclear magnetic resonance (NMR) spectroscopy provides useful data for analyzing fatty acid compositions of edible vegetable oils. Quantitation of each fatty acid was carried out by evaluation of particular peaks. According to the 1 H NMR method, terminal methyl protons, divinyl protons, and allyl protons are useful to calculate linolenic acid, linoleic acid, and oleic acid, respectively. The ω-2 carbon, divinyl carbon, and allylic carbons were used for calculation of these acids by the 13 C NMR method. Compositional results obtained by NMR coincided well with those of the conventional gas chromatography (GC) method. Results from 13 C NMR were in better agreement with those from GC than were the results obtained by the 1 H NMR method.

High-resolution 1 H nuclear magnetic resonance ( 1 H NMR) has been found to be an effective tool for the direct, rapid, and automated determination of the iodine value (IV) of vegetable oils, including hydrogenated oils (IV = 45.9-140.2). The total time required to obtain the 1 H NMR data is about 3 min per sample. The IV is calculated from the number of double-bonded protons and the average molecular weight derived directly from the spectrum. The average of olefinic protons and allylic plus divinyl protons area was used to calculate the absolute number of double-bonded protons. The 1 H NMR results were compared with those obtained by the traditional Wijs-cyclohexane methods. The correlation coefficient between traditional IV and the novel 1 H NMR method was r 2 = 0.9994 for the regression equation Y = 0.9885X + 2.8084, where X was the result given by the traditional method. With the proposed regression equation, IV calculated by the 1 H NMR method was within an error of ±1 unit of the result obtained by the traditional method. The proposed method is practically viable if one can afford to have the NMR system. JAOCS 75, 15-19 (1998).

The use of palm oil for plastic fats has encountered serious difficulty due to its crystallization properties, one of which is the formation of granular crystals. The granular crystals cause sandy taste and inhomogeneity of fat crystal morphology of end products. In the present study, we analyzed the formation process of these granular crystals. Chemical and physical analyses for triacylglycerol (TAG) compositions, polymorphism and melting points of the granular crystals led to the conclusion that the granular crystals are of the most stable polymorph, /31, of POP (1,3-dipalmitoyl 2-oleoyl glycerol} with triple chalulength structure. This conclusion was supported by reproducing the formation process of the granular crystals in a model fat blend consisting of POP and rapeseed oil. The following characteristics of {~t polymorph of POP contribute to the formation of granular crystals in fat blends containing palm oil: (i) ~1 reveals well-defined plate-like crystal morphology, which grows easily into the bulky granular form; (ii} the triple chainlength structure of POP has a tendency to segregate and does not form a solid solution together with other TAGs.

High-resolution nuclear magnetic resonance (NMR) spectroscopy provides useful data for analyzing fatty acid compositions of edible vegetable oils. Quantitation of each fatty acid was carried out by evaluation of particular peaks. According to the 1 H NMR method, terminal methyl protons, divinyl protons, and allyl protons are useful to calculate linolenic acid, linoleic acid, and oleic acid, respectively. The ω-2 carbon, divinyl carbon, and allylic carbons were used for calculation of these acids by the 13 C NMR method. Compositional results obtained by NMR coincided well with those of the conventional gas chromatography (GC) method. Results from 13 C NMR were in better agreement with those from GC than were the results obtained by the 1 H NMR method.

The bioreactor system to interesterify edible oils and fats at an ultra-micro aqueous phase of 100 ppm and less was investigated. The adsorption of lecithin, together with lipase onto a carrier, was effective for conducting the interesterifying reaction efficiently for oils and fats in micro aqueous phase.To improve the handling properties of palm oil at rather low temperature, palm oil was blended with canola or soybean oil, and then these blended oils were modified by enzymatic selective interesterification in a solvent-free, ultra-micro aqueous bioreactor system with an immobilized lipase that had 1,3-positional specificity. The effects of enzymatic interesterification were confirmed by triglyceride determination, by solid fat content profiles and by cloud point profiles, which were also compared to products of chemical interesterification. The improvement in the fluidity of blended oils with canola oil by the enzymatic reaction was bigger than with soybean oil, and chemical interesterification had no effects on the fluidity of blended oils.