In the present study, structured oils were prepared by introducing about 30% conjugated linolenic (CLN) or α-linolenic (LN) acid into olive oil in the form of CLN-triacylglycerol (CLN-TAG) or LN-TAG, respectively, by enzymatic transacylation. The anti-oxidative activities of natural polyphenolic compounds, such as tocopherol (Toc), sesamol (Se), epigallocatechin gallate (EGCG) and quercetin (Qu), in the prepared structured oils were then evaluated. It was found that these four kinds of hydrogen radical-donating anti-oxidants effectively prevented oxidation of the prepared structured oils, and the anti-oxidative effects of these polyphenols were shown to depend on DPPH radical scavenging ability. EGCG, which showed the highest anti-oxidative effect among these antioxidants by the conductometric determination method (CDM) improved the oxidative stability of the prepared CLN-TAG and LN-TAG by about six-fold when it was added at 3,600 ppm (equivalent to 20,000 ppm Toc in terms of radical scavenging ability). In addition, the oxidative stability of CLN-TAG was increased about eight-fold when EGCG was added at 5,500 ppm (30,000 ppm Toc in terms of radical scavenging ability). On the other hand, addition of EGCG at 3,600 ppm to LN-TAG did not improve the anti-oxidant activity. Thus, it was considered that the use of polyphenols with lipid solubility, thermal stability and high DPPH radical scavenging ability, such as EGCG at 5,500 ppm, is very effective for preventing the oxidation of CLN-TAG.

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We investigated the effects of lard and fish-oil diets during pregnancy and lactation on the composition of the stomach content and fatty acid in the brain of rat pups. Two groups of dams were fed either a lard diet (LD) or a fish-oil diet (FD) during the experimental period. On days 9, 17, 23, 29 and 35 after birth, two pups each from the litters of all dams were killed and their blood, stomach and brain were collected. On day 9 after birth, although the protein and fat energy ratios (P and F ratios) in the stomach content were higher and the carbohydrate energy ratio (C ratio) was lower, the P and F ratios decreased and the C ratio increased on the 23th day. However, there was no significant difference in the PFC ratio after birth between the two groups. On day 9 after birth, the n-3 fatty acid composition of the stomach content of pups nursed by dams fed the FD was 20 times higher than that of the LD group. Although the plasma n-3 fatty acid composition in pups nursed by dams fed the FD was 6 times higher than that of the LD group, there was no significant inter-group difference in the n-3 fatty acid composition of the brain. On days 23 and 35 after birth, the brain n-3 fatty acid composition in pups nursed by dams fed the FD was higher than that in pups of the LD group. The brain n-6 fatty acid content in pups nursed by dams fed the LD was higher than that in the FD group. The level of docosapentaenoic acid in the brain of pups nursed by dams fed the LD was higher than that in the brain of pups in the FD group. Our study suggests that FD intake during pregnancy and lactation provides more n-3 PUFA to pups and alters their brain fatty acid composition.

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This study examined whether various sugars in the diet affected the selection of foods by Zn-adequate and Zn-deficient rats. Maltose, sucrose, glucose, and fructose were used as carbohydrate sources in the diet, and the selection pattern and weight change of the growing rats were analyzed for 28 days by the two-dish preference test. On the first and second days after initiation of the experimental diets, Zn-adequate control rats showed a preference for sucrose=fructose>maltose=glucose, while through 28 days it was sucrose>maltose>glucose>fructose, whereas for Zn-deficient rats, the order of preference was sucrose and fructose before glucose, and through to 28 days it was sucrose>glucose>fructose. Both control and Zn-deficient rats preferred fructose at the beginning of the experiments, but their preference changed to avoid fructose over the long term. When offered a choice between maltose and sucrose, control rats preferred sucrose, while Zn-deficient rats preferred more maltose than sucrose. When offered a choice between sucrose and glucose, control rats continued to prefer sucrose, but in Zn-deficient rats the preference for sucrose became reduced in the latter half of the experimental period. The sum of daily food intake in rats fed the Zn-deficient diet resulting from selection of the two diets changed with cyclically with a periodicity of 3.5-3.9 days. These results suggest that a Zn-deficient status changes the sugar preference of rats.

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To investigate the influence of dietary fat type consumed by dams on the food choice of their pups after weaning, two groups of dams were fed a fish-oil diet (FD) or a lard diet (LD), respectively. Immediately after weaning, all pups were placed on a two-choice diet program comprising the FD or the LD for 27 days. At the beginning of the self-selection period, in both groups of pups, no significant difference in the amount of the FD and the LD intake was observed. However, the ratio of FD intake [FD intake (g) /total intake (g) ] in both groups of pups decreased from day 3 to 6. After day 7, the FD intake ratio for male and female pups nursed by dams that had been fed the FD was 38% and 32%, respectively, and that of male and female pups nursed by dams that had been fed the LD was 16% and 17%, respectively. Therefore, the FD intake ratio in the FD group was higher than that in the LD group. These findings suggested that the type of dietary fat consumed by pups during lactation together with that consumed by the dam contributes to their dietary fat selectivity after weaning. Perirenal fat tissue weight, and plasma lipid and hormone concentrations of dams and their pups were also examined and discussed in relation to the observed dietary preference.

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