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This paper reports the effects of adding talc particles on the physical properties of palm oil (PO)-based shortening formed by working refined PO (RPO) after rapid cooling. We examined the thermal and viscoelastic behavior of RPO in bulk fat systems, and the polymorphism and hardness of the shortening in the presence and absence of talc particles. In addition, the microstructure of fat crystals formed was observed. The effects of talc addition are summarized as follows: (i) When RPO was cooled at a rate of 5°C/min, crystallization of the high-melting fraction, including tripalmitoylglycerol (PPP) and 1,3-dipalmitoyl-2-oleoyl glycerol (POP), was preferentially promoted to form small-sized microcrystals. During cooling, the increase in the viscoelasticity of RPO was suppressed at low temperatures. (ii) When the shortening was stored at 5°C, β′-crystallization of 1-palmitoyl-2,3-dioleoyl glycerol (POO) and β-crystallization, probably of a molecular compound (MC) of POP and 1,2-dipalmitoyl-3-oleoyl glycerol (PPO), were delayed compared to β′-crystallization of PPP and POP. During storage, the homogeneity of the fat crystal dispersion improved and the hardness of the shortening decreased. These results indicate that talc improved the physical properties of the PO-based shortening by changing the crystallization kinetics and the networking processes of the fat crystals. Practical applications: The present study showed that adding talc particles effectively improved the physical properties of palm oil (PO)-based shortening during storage. This is considered beneficial for resolving problems in the quality control of PO-based products, such as post-hardening and the formation of granular crystals due to low rates of crystallization. Storage modulus (G′) of refined palm oil (RPO) with and without talc particles in bulk fat systems, obtained from dynamic viscoelasticity measurements during cooling at a rate of 5°C/min. Adding talc particles drastically changed the three-stage increases in G′ of pure RPO, promoting the first-stage increase but suppressing subsequent increases at low temperatures.

We recently found that new types of additives including talc promoted the crystallization of monoacid saturated triacylglycerols (TAGs) in stable polymorphs. This study reports the effects of size and concentration of talc particles and cooling rate on the crystallization of trilauroylglycerol (LLL), tripalmitoylglycerol (PPP), and 1,3-dipalmitoyl-2-oleoyl glycerol (POP). Talc particles were mixed with molten TAGs, and the mixtures were then cooled at designated cooling rates. Polymorphic crystallization was observed by simultaneous use of X-ray diffractometry and differential scanning calorimetry and by polarized optical microscopy. The following results were obtained: (i) talc promoted the crystallization of LLL in stable polymorphs with decreasing particle size and increasing concentration; (ii) the promotional effects were influenced by the cooling rate; (iii) the same behavior was observed for PPP and POP; and (iv) hydrophobic modification of talc surfaces did not affect the promotional effects. These results indicate that talc particles having median sizes of less than 2.5 μm and concentrations exceeding 0.1 wt.% effectively promote fat crystallization, and that the promotional effects can be maximized by choosing proper cooling rates according to the target fats. Furthermore, we propose a model of the heterogeneous nucleation of TAG crystals taking account of the molecular adsorption on cleavage surfaces of talc. 1 Practical applications Talc is widely approved as a food-grade ingredient, and the additive effects on various triacylglycerols widen its applicability to fat-based food and cosmetic materials. With grinding, talc particles exhibit anisotropic surfaces: cleavage surfaces are hydrophobic, and edge (lateral) surfaces are hydrophilic. Hydrophobic modification of the edge surfaces does not affect the additive effects of talc particles on fat crystallization, indicating adsorption of fat molecules on the cleavage surfaces.

We examined the promotional effects of additives on fat crystallization, such as inorganic (talc, carbon nanotube (CNT), and graphite) and organic (theobromine, ellagic acid dihydrate (EAD), and terephthalic acid) materials. The triacylglycerols (TAGs) of trilauroylglycerol (LLL), trimyristoylglycerol (MMM), and tripalmitoylglycerol (PPP) were employed as the fats. The additives (1 wt%) were added to the molten TAGs, and then the mixtures were cooled at a rate of 1°C/min followed by heating at a rate of 5°C/min. The crystallization and melting properties were observed using differential scanning calorimetry, X-ray diffraction, and polarized optical microscope (POM). Consequently, we found that the above six additives remarkably increased the initial temperatures of crystallization (Ti) on cooling without changing the melting temperatures. For example, in the case of LLL, the increases in Ti were 2.6°C (talc), 3.9°C (CNT), 8.1°C (graphite), 1.1°C (theobromine), 2.0°C (EAD), and 6.8°C (terephthalic acid). Very similar effects were observed for the crystallization of MMM and PPP with the six additives. Furthermore, the polymorphs of the first occurring crystals were changed from metastable to more stable forms by many of these additives. The POM observation revealed that the crystallization was initiated at the surfaces of additive particles. This study has shown for the first time that the heterogeneous nucleation of fat crystals can be greatly promoted by new types of additives. Such additives have great potential to promote fat crystallization by not only hydrophobic but also hydrophilic molecular interactions between the fats and additives.

It has been reported that oil thermally processed with wheat gluten (gluten oil) exhibited safe weight-loss promoting effects in animal experiments. However, as the oil has a high color index, and its chemical properties and smell differ from those of fresh oil, it is uncertain if the oil will find market acceptance. In order to resolve the issue, frying oil was heated with soybean protein under reduced pressure (soybean protein oil), resulting in a product with an appearance, chemical properties and smell comparable to those of fresh oil. This improved oil was mixed (7 wt%) with powdered AIN93G no fat, defined standard diet and fed to 10-week-old Wistar rats ad libitum. The experimental rats grew normally, ingesting the same amount as that of the control rats; however, there was a negative correlation between body weight increases and fecal weight increases. After the 12-week feeding period, all the rats were sacrificed to obtain blood and organs. In the experimental group, liver weight, retroperitoneal fat tissue weight and serum triacylglycerol (TG) levels decreased significantly. Aspartate aminotransferase (AST), alanine aminotransferase (ALT), and histological analysis supported the safety of the improved oil. In conclusion, it was found that soybean protein oil inhibited body weight increases without any adverse effects in animal experiments. The oil holds promise as a novel dieting oil that steadily decreases body weight at an appropriate rate.

Publisher Summary After the development of the hydrogenation process as a processing method to enhance the use of liquid oils, the hydrogenated fats containing Trans Fatty Acid (TFA) became a part of a variety of different foods. The hydrogenated fats are solidified as a fine crystalline material, stable in the beta-prime form, and show better oxidative stability. The hydrogenation technique was an excellent process for the efficient use of natural liquid oils and its use spread rapidly among food manufacturers. However, nutritional studies reported that continuous TFA intake of more than 2% of total energy increases the risk of cardiovascular disease. Most of the studies showing a harmful influence on human health were based on the analytical results from Western countries, where the consumption of TFA was higher. Although the effect of TFA on Japanese people (who have a smaller intake of TFA) was not clear, a movement to reduce TFA intake also started in Japan around 2003. This chapter addressed the recent developments on TFA in Japan, especially the intake amount, the TFA content in various foods, the TFA labeling, analytical methods, and various ways to reduce TFA.

We examined the fecal fat excretion of mildly hypertriacylglycerolemic subjects who ingested soft cookies containing 1(3)-behenoyl-2,3(1)-dioleoyl-rac-glycerol (BOO) for 7 days. The subjects included 14 healthy men (average age; 44.9 ± 1.7) whose fasting plasma triacylglycerol level ranged from 150 to 250 mg/dL. Every day for 7 days, the subjects ate 5 soft cookies containing margarine with the BOO-rich experimental oil (BOO intake, 2.46 g/day). The placebo group ate soft cookies containing margarine without BOO. This study was a randomized double-blind, placebo-controlled, crossover study. Feces were collected for 3 days prior to the end of the treatment period, and fecal fat and fatty acid composition were determined. The fecal wet weight was significantly increased in BOO group compared with that in the placebo group. Moreover, fecal fat and fatty acid level were significantly higher in the BOO group than in the placebo group. There were no significant differences in the fecal fatty acid composition of the BOO and placebo groups. These results suggest that dietary BOO increases fecal excretion of dietary fat in humans. However, BOO does not increase the excretion of specific fatty acids; it increases the excretion of all fatty acids of dietary origin, which may lead to lower and delay intestinal absorption of dietary fat.

We have previously reported that a soy oil-containing experimental diet (fat-free AIN93G containing oil thermally processed with soybean protein followed by filtration), inhibited body weight increases without any adverse effects when given ad libitum to male Wistar rats for 12 weeks. In the present paper, the mechanism of weight-loss promoting effects was investigated. Fasted 10-week-old rats were fed a slurry composed of AIN93G (fat-free), Cr(2)O(3) (marker), water, and 7 wt% soy oil or fresh oil (control) and sacrificed at 20, 60, 90, 120, 150, 210, 270 or 360 min. The stomach, small intestine, cecum, colon and feces were then collected to determine the distribution of the slurry in the digestive tract. The results indicated that the content was transferred faster from stomach to small intestine in the soy oil group than in the control group. Fecal excretion (derived from a commercial standard diet ingested before slurry administration) in the soy oil group was significantly higher than in the control group. Digestive enzyme activities, lipase, sucrose, and maltose, were not inhibited by soy oil. In addition, feces collected in the 12-week feeding experiment were more in the dry weight and contained higher levels of nitrogen and water in the soy oil group than in the control group, revealing that an increased amount of nutrition was continuously excreted in the former group. The above-described findings suggest that soy oil stimulated peristalsis of the gastrointestinal tract and that colon contents are actively excreted, resulting in safe and steady body weight decreases.