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Fourier transform Raman spectroscopy was employed for structural analysis of triacylglycerols and edible oils. Raman spectra sensitively reflected structural changes in oils. Even slight structural fluctuation between triacylglycerols and free fatty acids led to obvious differences in Raman bands as shown by C-O-C stretching from 800 to 1000 cm(-1) and the band at 1742 cm(-1). Structural difference in geometric isomers was easily distinguished as proved by C = C stretching at 1655 cm(-1) (cis) shifting to 1668 cm(-1) (trans) and by =C-H in-plane bending at 1266 cm(-1) in cis disappearing in the trans isomer. Raman intensity at 1266, 1302, and 1655 cm(-1) changed concomitantly with the change of double-bond content in oils. It showed that FT-Raman was capable of precisly reflecting the content of double bonds in oils. A linear correlation with high consistency between the Raman intensity ratio (v1655/v1444) and the iodine value was obtained for commercial oils. Based on the results, FT-Raman spectroscopy proved itself a simple and rapid technique for oil analysis since each measurement could be directly completed in 3 min without any sample modifications.

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Squalene was identified by gas chromatography-mass spectrometry and high-performance liquid chromatography (HPLC) spiking analyses in the supercritical CO(2) extracts of freeze-dried abscisic leaves of Terminalia catappa L. When the freeze-dried abscisic, senescent, mature, and immature leaves and seeds were subjected to supercritical CO(2) extraction at 40 degrees C and 3000 psi and HPLC quantitation, squalene contents were 12.29, 2.42, 1.75, 0.9, and 0% in the extracts and corresponding to 1499, 451, 210, 65, and 0 microg/g in the freeze-dried sample, respectively. When the extracts were applied for antioxidative characterization by supplementation in an iron/ascorbate system with linoleic acid and in a pork fat storage system for inhibition of conjugated diene hydroperoxide (CDHP) formation or in a free radical scavenging system with 1,1-diphenyl-2-picryl-hydrazyl (DPPH), the extracts of leaves exhibited potent antioxidative and DPPH scavenging activities and increased with an increase of leaf maturity. However, the seed extracts only exhibited potent inhibition of CDHP formation and very low DPPH scavenging activity.

Incorporation of free acids or salts of antimycotic food additives, including propionic acid, benzoic acid or sorbic acid, into low-density polyethylene (LDPE) films failed t o inhibit mould growth when the films contacted inoculated media. However, LDPE films into which benzoic anhydride was incorporated exhibited antimycotic activity when in contact with media and cheese. Benzoic anhydride, which had been added t o LDPE film, was hydrolysed within 5 h and detected as benzoic acid in potato dextrose agar (PDA) and cheese after contact with the film. LDPE films, into which 1 % benzoic anhydride was incorporated, completely inhibited Rhizopus stolonifer, Penicilliurn spp., and Aspergillus toxicsrius growth on PDA. Lower amounts of anhydride partially inhibited growth by increasing the lag phase and reducing the rate of growth in most cases. LDPE films incorporated with 0.5-2% benzoic anhydride delayed mould growth on cheese. These data suggest that addition of antimycotic agents t o LDPE during film manufacture may be a feasible way of controlling surface mould growth in foods such as cheese.

Near-infrared Fourier transform Raman (FT-Raman) spectroscopy was employed to study the molecular structure of edible zein films/coatings, which were fabricated directly from zein protein. The secondary structure of zein protein was mainly in alpha-helix and remained unaltered during film formation as evidenced by the vibrational modes of amide I at 1656 cm(-1) and amide III at 1274 cm(-1). Raman results indicated that hydrophobic interaction played an important role in the formation of zein film and disulfide bonding might be responsible for the structural stability of zein protein during film formation. To enhance its antimicrobial property, an antimicrobial zein film was manufactured by incorporating zein protein with benzoic acid whose structure was then characterized by FT-Raman. It showed that physical entrapment or hydrophobic interaction was crucial to the incorporation of benzoic acid with zein protein, and the secondary structure of the antimicrobial film was still maintained in alpha-helical form. In addition, FT-Raman exhibits its preference in directly determining the thickness of zein films/coatings. By correlating the Raman intensity ratio of nu(1003) to nu(84) (I(1003/84)) versus the thickness of zein film, a linear relationship with high coefficient (R(2) = 0.9927) was obtained, which was then used pragmatically to determine the thickness of zein coatings on apple. It showed that the FT-Raman result (thickness = 0.27 +/- 0.01 mm) was consistent with that of classical micrometric measurement (thickness = 0.28 +/- 0.02 mm). Consequently, FT-Raman provides a direct, simple, and reagent-free method to characterize the structure and the thickness of zein films/coatings.

Summary Yams (the tubers of Dioscorea spp.) are widely consumed but are also regarded as a medicinal food in China. Traditional Chinese herbal medicines using yams are only available on a seasonal basis, as yams quickly deteriorate during winter storage. Yam (Dioscorea purpurea, a major variety of yams in Taiwan) was freeze‐dried and ground to obtain yam flour. Bread was made by replacing up to 25% of wheat flour with yam flour. Although the loaf volume decreased with the addition of yam flour, the results showed that up to 20% of yam flour could be included in bread formulation without altering the sensory acceptance of the blended bread. The incorporation of yam flour in bread markedly increased the antioxidant capacity of the bread as tested by both DPPH free radical scavenging and total antioxidation tests. Breads containing yam flour can broaden the utilization of yams and may be regarded as possible health‐promoting foods.

Imazalil, an antimycotic agent, was incorporated into low density polyethylene (LDPE) film and the resulting films tested for ability to inhibit Penicillium sp., and Aspergillus toxicarius growth by measuring the rate of carbon dioxide (CO2) production in sealed jars containing either inoculated potato dextrose agar (PDA) or Cheddar cheese. Inhibition of surface mold growth on cheese was also determined in open systems. An imazalil concentration of 2000 mg/kg LDPE film delayed A. toxicarius growth on PDA while LDPE film containing 1000 mg/kg imazalil markedly delayed Penicillium sp. growth. Furthermore, LDPE film containing 1000 mg/kg imazalil inhibited both molds growing on Cheddar cheese. These data suggest that incorporation of an antimycotic agent such as imazalil into food contact packaging films would inhibit surface mold growth.