摘要:

ABSTRACT‘Alto’canola seed and sesame seed were toasted at 180, 200, 220, 240, and 260C, for 8 min or 10 min. As temperature increased, minor changes in fatty acid composition were observed. Darkness and blueness in canola oil increased with toasting temperatures up to 240C, and then decreased. The darkness, greenness and yellowness of sesame seed oil increased with increasing toasting temperature. The overall color of canola oil was significantly darker than that of sesame seed oil (α 0.05). 2‐Thiobarbituric acid (TBA) numbers for both oils increased as toasting temperature increased. TBA numbers of the canola oil increased with extended storage time up to 4 weeks and then decreased. For sesame seed oil, TBA numbers also were influenced by storage time, but less change was observed than for canola oil. 2‐Thiobarbituric acid reactive substances (TBARS) content of canola oil was significantly higher than that for sesame seed oil when TBA numbers were compared to the same t

ISSN:1065-7258    

DOI:10.1111/j.1745-4522.1996.tb00050.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

ABSTRACTOxidative stability of light and dark comminuted muscle of raw and thermally processed mackerel stored at 4C was studied over a 21 day period by monitoring changes in conjugated dienes (CD) and 2‐thiobarbituric acid (TBA) values. The quantity of headspace (HS) volatiles, propanal, and hexanal as well as the ratio of aliphatic to olefinic (Rao) or diallylmethylene (Rad) protons in the proton nuclear magnetic resonance (1NMR) spectra of oils were determined. The content of CD of light and dark ground mackerel muscle samples exhibited a consistent increase over the entire storage period. Furthermore, secondary oxidation products as reflected in the TBA values and content of propanal, hexanal and HS gases, generally, showed a gradual increase in their level. The concentration of propanal, the dominant volatile of the HS gases, increased markedly up to day 6 of storage, but afterwards began to decline continuously. A similar trend was noted for hexanal, but at a lesser extent. The Raoand Radvalues in the1H NMR spectra of lipids from all stored samples increased constantly during storage. In all samples, the dark ground muscle exhibited a higher degree of oxidation than its light counterpart. Furthermore, heat‐processed dark comminuted muscle oxidized faster than its raw counterpart while generally an opposite trend was observed for the light ground mus

ISSN:1065-7258    

DOI:10.1111/j.1745-4522.1996.tb00051.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

ABSTRACTThe influence of dietary oils [fish (FO), flax (LO), palm (PO) and sunflower (SO) oil] and tocohperol supplementation on the oxidation of cholesterol and lipids of chicken meat was investigated. Lipid oxidation in chicken meat powders was determined by thiobarbituric acid reactive substances (TBARS) and cholesterol oxidation products were estimated by capillary gas chromatography (GC) after trimethylsilylation. Peak identities from GC were confirmed by mass spectrometry. Freeze‐dried chicken meat powder, stored in contact with air at room temperature for four months showed the presence of 7α‐ and 7β‐hydroxycholesterol, 7‐ketocholesterol, α and β‐epoxide, and cholestane‐triol. Total cholesterol oxides contents significantly (P<0.05) increased with storage. The amount of cholesterol oxides in the meat powder was the highest in FO and SO group, and lowest in PO group. Lipid and cholesterol oxidation were accelerated by the presence of long‐chain PUFA. Lipid and cholesterol stability of chicken meat were improved by the dietary supplementat

ISSN:1065-7258    

DOI:10.1111/j.1745-4522.1996.tb00052.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

ABSTRACTViscous syrups with between 20 and 34% moisture were made from homogenized slurries of sugars, nonfat dry milk, anhydrous butteroil and emulsifiers. Homogenized mixtures were condensed under vacuum at 45C for 35 min, to form ordered structures with a syrup‐like consistency. Complex viscosity determined through dynamic spectrometry increased with increasing fat content. At low frequency, high fructose corn syrup and maltose‐based syrups showed more solid‐like behavior (G″>G″) while the sucrose‐based syrup was more liquid (G″>G′). Thermal analyses showed all composites to have a uniform melting range (95–140C), whereas the original components melted in the range 20–200C. The rheological and thermal properties suggest that these syrups could be useful confec

ISSN:1065-7258    

DOI:10.1111/j.1745-4522.1996.tb00053.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

ABSTRACTSesame oil was prepared from raw and processed seeds. Processing conditions were roasting at 200C for 20 min, steaming at 100C for 20 min, roasting at 200C for 15 min + steaming for 7 min and microwaving at 2450 MHz for 15 min. Oxidative stability of the resultant hexane‐extracted oils was determined during storage under Schaal oven test conditions at 65C for up to 35 days. Methods employed included determination of fatty acid composition, iodine value (IV), peroxide value (PV), conjugated dienes (CD), para‐ansidine value (p‐AV) and 2‐thiobarbituric acid (TBA) value. The oils from raw and roasted‐steamed seeds had better oxidative stability than other processed oils. In addition, nuclear magnetic resonance (NMR) spectroscopy was used to evaluate the extent of oxidation of sesame oils by measuring the relative changes of aliphatic to olefinic (Rao) and aliphatic to diallylmethylene (Rad) protons of the oils. A gradual increase in the (Rao) and (Rad) values was observed during the entire stora

ISSN:1065-7258    

DOI:10.1111/j.1745-4522.1996.tb00054.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

ABSTRACTRats were fed for 8 weeks a diet containing either Baobab seed oil (FBO) rich in cyclopropenoid fatty acids (CPFA) or heated oil (HBO) devoid of CPFA. In FBO rats, compared to controls (CO), the monounsaturated fatty acid content of adipose tissue lipids, liver triacylglycerols, liver and adrenal cholesteryl esters and liver, kidney, adrenal phospholipids were highly decreased to the benefit of saturated fatty acid content. In cholesteryl esters and phospholipids, the arachidonic acid (20:4 n‐6) content was markedly decreased, especially in adrenals. In adrenal cholesteryl esters, adrenic acid (22:4 n‐6) content was decreased more than its precursor. The effects of HBO on the tissue lipid fatty acid profile were practically absent. It is concluded that inhibition of fatty acid desaturation by CPFA previously demonstratedin vitro, was reflectedin vivoin tissue lipid fatty acid composit

ISSN:1065-7258    

DOI:10.1111/j.1745-4522.1996.tb00055.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY