Distribution of aldehydes compared to other oxidation parameters in oil matrices during autoxidation.

Distribution of aldehydes between headspace (HS) and inner matrix (IM) of bulk oil or oil-in-water (O/W) emulsion was determined and contents of aldehydes were compared with other oxidation parameters in soybean oil or O/W emulsion during 50 °C autoxidation. Bulk oil matrix had higher portion of IM aldehydes than O/W emulsion. HS aldehydes in O/W emulsion reflected aldehyde content better than in bulk oil. Moisture content in soybean oil increased distinctively before the generation of oxidation products including hydroperoxides and volatiles. HS aldehydes and other oxidation parameters were simultaneously increased in soybean oil. In case of O/W emulsion, HS aldehydes had a sudden increase point while lipid hydroperoxides and conjugated did not show such increase during autoxidation. HS aldehydes reflected oxidation stage better in O/W emulsion than in bulk oil based on partition distribution and linear changes during autoxidation.

Evaluation of the effects of aldehydes on association colloid properties and oxidative stability in bulk oils.

The effects of amphiphilic aldehydes, including propanal, hexanal, and nonanal, on the critical micelle concentration (CMC) of phospholipids, moisture content, and oxidative stability in soybean oil were evaluated. The selected aldehydes are typical secondary oxidation products from unsaturated fatty acids. Moisture content increased as aldehydes were added to soybean oil during thermal oxidation at a storage temperature of 50 or 100 °C. The CMC of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) increased as propanal and hexanal were added, whereas nonanal decreased the CMC of DOPC, which implies that aldehydes participate in forming association colloids in bulk oils. The addition of aldehydes increased the rates of lipid oxidation significantly in both 50 and 100 °C treatments (p < 0.05), with the effect being more evident in oils treated at 50 °C than at 100 °C. Therefore, aldehydes formed from lipid oxidation affected the association colloidal structures and oxidative stability in a bulk oil matrix.

Effects of 1,2-dioleoyl-sn-glycero-3-phosphocholine on moisture content and oxidative stability in soybean oil-water system at different interfaces.

Effects of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) on the oxidative stability were determined in soybean oil-water system at different locations including at the interface of air-oil, in the middle of oil, and at the interface of oil-water. Also, profile changes of tocopherols were determined during UV irradiation for 18 days. Although no significant changes in tocopherol profiles were observed at three different locations irrespective of DOPC from 0 to 1250 µmol/kg oil, addition of DOPC increased total tocopherols, α-tocopherol, and δ-tocopherol whereas content of ß + γ tocopherols did not increase at any locations. Moisture content in water-oil interface was higher than other locations while those were not consistent at different DOPC concentration. Added DOPC significantly decreased oxidative stability from 250 to 830 µmol/kg oil compared to controls (p < 0.05) whereas 1250 µmol/kg oil DOPC increased oxidative stability. Stabilities of tocopherols especially α-tocopherol were lower in oil-water system than those in bulk oil at UV irradiation.

Development of a 3D scanning method to discriminate blocks of Octopus minor with surplus water gain.

A 3D scanning method was developed to differentiate Octopus minor blocks which had surplus water to increase weight of O. minor. Effects of soaking time (0.5, 1 and 3 h) and apparent density of O. minor were determined using the number of O. minor in a block (4, 5, 6, and 7). A 0.5, 1, and 3 h soaking time increased O. minor weight by 11.85, 16.02, and 24.53%, respectively. Apparent density of non-weight gained O. minor blocks was significantly higher than those of 3 h soaked samples (p < 0.05). A 3D scanning method had limited ability to differentiate 1 h soaked and non-soaked samples, whereas it had high potential to discriminate 3 h soaked samples. Blind test using 25 blocks of O. minor showed that 3D scanning method evaluated 88% of prediction percentage. The total time of 3D scanning took <30 min for one block with a relatively high precision.

Addition of Sesamol Increases the Oxidative Stability of Beeswax Organogels and Beef Tallow Matrix Under UV Light Irradiation and Thermal Oxidation.

To enhance the oxidative stability of organogels made from canola oil, 40 ppm sesamol was added to beeswax-based organogels stored under ultraviolet (UV) light irradiation and 60 or 100 °C thermal oxidation conditions. To study the practical application of organogels as animal fat substitutes, beef tallow was mixed with organogels and their oxidative stability was determined under oxidative stress conditions. Without sesamol addition, the organogels and beef tallow with organogel oxidized rapidly under UV irradiation and thermal oxidation. The addition of 40-ppm sesamol decreased the consumption of headspace oxygen and the formation of primary and secondary oxidation products significantly (P < 0.05) compared with those in samples without the addition of sesamol, irrespective of oxidative stress. Sesamol improved the oxidative stability of organogels and beef tallow with organogel, which could be used in the meat industry. PRACTICAL APPLICATION: Organogels may replace trans-fat or highly saturated lipids in food products. The high degree of unsaturation and processing temperature mean that antioxidants are needed to extend the shelf life of organogels or organogel-containing products. The addition of sesamol significantly enhanced the oxidative stability of organogels and of beef tallow-containing organogels under UV irradiation and thermal oxidation conditions. Therefore, sesamol-supplemented organogels could replace saturated fats in beef tallow and prolong the shelf-life of meat products.