Effect of Gamma-Irradiated Red Pepper Powder on the Chemical and Volatile Characteristics of Kakdugi, a Korean Traditional Fermented Radish Kimchi

The chemical and volatile characteristics of kakdugi batches prepared with irradiated red pepper powders were determined during fermentation for 7 wk at 5 °C. Acidities of kakdugies with irradiated red pepper powder (3, 5, and 7 kGy) were lower than that of kakdugi with nonirradiated control at 3 wk of fermentation, which indicated that the irradiated red pepper powder might delay the initial fermentation. Pungency and red color caused by capsanoids and capsanthin, respectively, were not altered by irradiated red pepper powder, whereas the fermentation decreased the capsanoid content. The headspace volatile compounds extracted by solid‐phase microextraction, except 2‐tricanone, were not significantly different in fresh made kakdugies with red pepper powder irradiated at dosed of 0, 3, 5, and 7 kGy; however, as fermentation progressed, the composition of volatiles was changed. A FOX 3000 electronic nose separated the odor of kakdugies with red pepper powder irradiated at 0, 3, 5, and 7 kGy into 4 different groups, and the odor patterns developed differently during fermentation.     

Production of alkyl ester as biodiesel from fractionated lard and restaurant grease

Methyl or ethyl esters were produced from lard and restaurant grease by lipase- or base-catalyzed reactions. Before esterifying, some renewable substrates (lard and restaurant grease) should be manipulated through acetone fractionation or on a chromatography column packed with an adsorbent to obtain maximal reaction rate. Because lipase activity was hindered by excess amounts (more than 1 mol) of methanol, each 1 M methanol was added sequentially after 24 h of reaction. Through a three-step reaction, 74% conversion to tallow-methyl ester was obtained. However, a porous substance, such as silica gel, improved the conversion when more than 1 M methanol was used as reaction substrate. When a 1∶3 (fractionated lard/methanol, mole ratio) substrate was used, the conversion rates (i.e., extent of conversion) were 2.7 (24 h) and 2.8% (48 h). However, with 10% silica gel in the reaction mixture, the conversion rates increased to 25 and 58%, respectively. Regenerated restaurant grease (FFA removed through column chromatography) was further converted to esters by alkali-catalyzed methanolysis. After 24 h of reaction, 96% conversion was obtained, while only 25% conversion was observed from crude grease. Alkyl esters produced in this study could be used for fuels, potentially as biodiesel.     

Immobilized lipase-catalyzed production of structured lipids with eicosapentaenoic acid at specific positions

Structured lipids (SL) were synthesized by the interesterification reaction between medium-chain triacylglycerols and eicosapentaenoic acid (EPA) ethyl ester. The products were partially purified, and the fatty acid at thesn-2 position was determined after pancreatic lipase-catalyzed hydrolysis. The effect of additives (water and glycerol) on the rate of reaction was also investigated. Mol% EPA incorporated into the triacylglycerols was increased by adding water when trilaurin and tricaprylin were the substrates and IM 60 was the biocatalyst. With SP 435, EPA incorporation was always less with additional water than without water. The addition of glycerol (0.005 g or 0.01 g) improved interesterification catalyzed by IM 60 to some degree, but an excess amount (0.02 g) inhibited the reaction. The reaction with glycerol showed no significant difference with SP 435. After scale-up and fractionation by column chromatography, we could recover approximately 0.3–0.4 g of product/g of reaction products. After hydrolysis by pancreatic lipase, we can conclude that IM 60 has a high specificity forsn-1,3 positions. With SP 435 lipase, 34.8–39.3 mol% of EPA was found at thesn-2 position of the recovered SL.     

Scaled-up production of zero-trans margarine fat using pine nut oil and palm stearin

An interesterified structured lipid was produced with a lipid mixture (600 g) of pine nut oil (PN) and palm stearin (PS) at two weight ratios (PN:PS 40:60 and 30:70) using lipase (Lipozyme TL IM, 30 wt.%) as a catalyst at 65 ^°C for 24 h. Major fatty acids in the interesterified products were palmitic (35.1–40.4%), oleic (29.5%), and pinolenic acid (cis-5, cis-9, cis-12 18:3; 4.2–5.9%). α-Tocopherol (1.1–1.3 mg/100 g) and γ-tocopherol (0.3–0.4 mg/100 g) were detected in the interesterified products. Total phytosterols (campesterol, stigmasterol, and β-sitosterol) in the interesterified products (PN:PS 40:60 and 30:70) were 63.2 and 49.6 mg/100 g, respectively. Solid fat contents at 25 ^°C were 23.6% (PN:PS 40:60) and 36.2% (PN:PS 30:70). Mostly β′ crystal form was found in the interesterified products. Zero-trans margarine fat stock with desirable properties could be successfully produced from pine nut oil and palm stearin.     

Antioxidant Activity of Soybean Oil Containing 4-Vinylsyringol Obtained from Decarboxylated Sinapic Acid

4-Vinylsyringol was produced by decarboxylation from sinapic acid. To evaluate the antioxidant activity of 4-vinylsyringol, 500 ppm of 4-vinylsyringol, sinapic acid, or α-tocopherol was added to soybean oil and the oxidation processes were monitored by the peroxide value (PV), the thiobarbituric acid reactive substances value (TBARS) assay, and ¹H-NMR spectroscopy. The results obtained by PV and TBARS indicated that soybean oil containing 4-vinylsyringol (SBO-VS) showed the highest oxidative stability. ¹H-NMR analysis also showed concurring results. After 19 days of oxidation, the degradation rates of linoleic acid (4.2 %) and linolenic acid (4.4 %) in SBO-VS were significantly lower than those in other oils. Secondary oxidation products (i.e. aldehydes) were undetectable in SBO-VS by ¹H NMR, whereas concentrations of such compounds in soybean oils containing α-tocopherol or sinapic acid were 38.0 ± 0.4 and 2.75 ± 0.2 mM oil, respectively. In addition, synergistic antioxidant effect between any two antioxidants was not observed.     

Emulsifying Properties of Lecithin Containing Different Fatty Acids Obtained by Immobilized Lecitase Ultra-Catalyzed Reaction

Lecitase Ultra and 6 triacylglycerol lipases (lipases PS, M, AH, AY, R, and AK) were immobilized on Amberlite XAD 7HP and used to catalyze the acidolysis reaction between lecithin and capric acid (C10:0) for comparison. The highest molar incorporation value (51.0 mol%) was observed for the immobilized Lecitase Ultra. Further, immobilized Lecitase Ultra was selected for catalyzing acidolysis between lecithin and fatty acids with different chain lengths (C6:0, C8:0, C10:0, C12:0, and C14:0). After reaction, free fatty acids were removed by SPE and the resultant was called modified lecithin fraction 1 (MLF1). The highest molar incorporation value was obtained for C10:0 (51.0 mol%) at 45 °C with a mole ratio of 10/1 (C10:0/lecithin) for 72 h. After removal of lysophosphatidylcholine by solid-phase extraction from MLF1, the resultant modified lecithin fraction 2 (MLF2) was used to prepare an oil-in-water emulsion. All emulsions prepared with MLF2 exhibited significantly higher emulsion stability (ES) values (16.2–17.7) and smaller particle sizes (d ₃₂ 0.40–0.49 μm, d ₄₃ 0.75–1.01 μm) than the emulsion prepared with unmodified lecithin (ES 14.1, d ₃₂ 0.76 μm, d ₄₃, 1.26 μm) (P < 0.05). Furthermore, less clarification and droplet aggregation were observed in emulsions prepared with MLF2 than in lecithin-based emulsions. Overall, the MLF2s showed better emulsifying properties than lecithin.     

Effects of selected substrate forms on the synthesis of structured lipids by two immobilized lipases

Two immobilized lipases, IM 60 from Rhizomucor miehei and SP 435 from Candida antarctica, were used to synthesize structured lipids (SL). Tricaprin and trilinolein were interesterified to produce SL that contained one linoleic acid per triacylglycerol molecule (SL1) and SL with two linoleic acids (SL2). SL1 and SL2 were separated by silver nitrate thin-layer chromatography according to their unsaturation, and the fatty acid at the sn-2 position was determined after pancreatic lipasecatalyzed hydrolysis of SL1 and SL2. With IM 60, 57.7 mol% capric acid and 42.3 mol% linoleic acid were found at the sn-2 position of SL1, while 43.3 mol% capric acid and 56.7 mol% linoleic acid were at the sn-2 position of SL2. The fatty acid at the sn-2 position of SL1 with SP 435 as biocatalyst was 43.6 mol% capric acid and 56.4 mol% linoleic acid, while SL2 contained 56.6 mol% capric acid and 43.4 mol% linoleic acid. Different structural forms of the capric acid-containing substrate (triacylglycerol vs. ethyl ester) and different chainlengths of triacylglycerol were selected to study the substrate selectivity of lipases. Results indicated that SP 435 had some degree of preference for the triacylglycerol form (tricaprin), and IM 60 produced SL more rapidly and reached steady state faster with tricaprin as substrate than with capric acid ethyl ester. For chainlength selectivity, mol% of synthesized SL from tricaprin + trilinolein and tristearin + trilinolein were compared. SP 435 exhibited no apparent preference for either tricaprin or tristearin. However, IM 60 showed a more rapid reaction with tricaprin than with tristearin.     

Study of Structured Lipid-Based Oil-in-Water Emulsion Prepared with Sophorolipid and its Oxidative Stability

In this study, the stability of oil-in-water (O/W) emulsions prepared with structured lipid (SL) were evaluated in which the SL was produced through lipase-catalyzed interesterification between soybean oil and rice bran oil. After interesterification, the major TAG species in the SL were PLP (22.5 %), PLL/OOLn (21.8 %), LPL (16.1 %), and LLS/PLO (16.1 %), and the total amount of tocopherol and tocotrienol was 20.9 mg/100 g of SL. Sophorolipid was used as an emulsifier for preparing SL-based O/W emulsions, and the effect of pH (pH 5.8, 7 and 7.2) on stability was studied by analyzing the fat globule size. From the results, SL-based O/W emulsions showed similar stabilities to those prepared with Tween 20 at the neutral environment. In the oxidation study, any antioxidant addition of propyl gallate (PG), ascorbic acid 6-palmitate (AP) or quercetin hydrate (Que) distinctively prevented peroxide formation on the SL-based O/W emulsion throughout the 23 days of storage while AP was less effective to lower TBARS values than PG and Que.     

Comparison of antioxidant capacity of 4-vinylguaiacol with catechin and ferulic acid in oil-in-water emulsion

Food Science and Biotechnology - The product of ferulic acid decarboxylation, 4-vinylguaiacol (4-VG), is an important antioxidant and is reported to have an antioxidant capacity comparable to...     

Comparative study of trans fatty acid content in 2005 and 2008 processed foods from Korean market

Trans fatty acids (t-FA) contents were analyzed in 26 food items that were collected from Korean grocery stores in 2005 and 2008. Lipid was extracted through Soxhlet and Mojonnier methods. Fatty acid profile, including t-FA and positional fatty acid composition was analyzed by gas chromatography. The comparative study of fatty acids composition including t-FA was employed in 2005 and 2008. Among the analyzed food items, most of the food items showed higher lipid content in 2005 than in 2008. Some food items such as biscuits (0.4–7.2 g/100 g of food), fried snacks (0.1–3.6 g/100 g of food), and cookies (0.4–2.4 g/100 g of food) contained relatively higher level of t-FA than other food groups (cracker, processed chocolate, and ice cream) in 2005. Comparing t-FA content in 2005, it was considerably decreased up to 91.5% in 2008 whereas saturated fatty acids (SFA) were increased up to 43.3% in the analyzed food items.