摘要:

ABSTRACTThe oxidative stability of microencapsulated seal blubber oil (SBO) was compared with that of its unencapsulated counterpart. Wall materials tested were β‐cyclodextrin, maltodextrin and corn‐syrup solids. Aqueous dispersions containing the wall material, Tween‐80 as an emulsifier, and SBO were thoroughly mixed and then spray‐dried. The storage stability of the spray‐dried products at room temperature was determined by monitoring changes in their fatty acid composition, peroxide, conjugated diene and 2‐thiobarbituric acid reactive substances (TBARS). Among the wall materials tested, β‐cyclodextrin and to a lesser extent corn‐syrup solids were found to be suitable encapsulating agents for SBO, but maltodextrin was inadequate. The encapsulated oils may be easily handled and incorporated into

ISSN:1065-7258    

DOI:10.1111/j.1745-4522.1995.tb00032.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

ABSTRACTThe technological characteristics and the fatty acid composition ofRicinodendron heudelotii(Bail.) seed oil from two different regions of Cameroon were studied. The fatty acid composition was determined by gas chromatography on a capillary column. The oil content varied according to the region (44.9–54.7%). The iodine value (160), saponification value (190) and unsaponifiable matter content (1.6%) were similar for the two types of seeds examined. The oil was composed mainly of linoleic acid (25–30%) and a polyunsaturated fatty acid (PUFA) found to be α‐elaeostearic acid (48–56%). The latter fatty acid is subject to transformation during the esterification processes due to its trienic conjugated bonds. The triacylglycerol profile obtained by reversed phase liquid chromatography showed 20 triacylglycerols with two major ones identified as linoleodi‐α‐elaeostearic (29.7–33.1%) and tri‐α‐elaeo

ISSN:1065-7258    

DOI:10.1111/j.1745-4522.1995.tb00033.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

ABSTRACTTransisomers of polyunsaturated fatty acids (PUFA) are formed during heat treatment of oils. In the present work, the effect of dietary geometrical isomers of α‐linolenic acid (18:3 n‐3) on the Δ6 desaturation of allcis18:3 n‐3 was investigated, using rat liver microsomes. The desaturation rates were higher in microsomes from animals fed acisn‐3 deficient diet, as compared to those from the control group or those from rats fed 18:3 n‐3 and itstransisomers. These data and the incorporation of long chaintransPUFA in microsomal lipids suggest that geometrical isomers of 18:3 n‐3 are probably slowly desaturated and elongated into long chaintranspolyunsaturated fatty acids compare

ISSN:1065-7258    

DOI:10.1111/j.1745-4522.1995.tb00034.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

ABSTRACTAnin vitroassay previously developed (Emenhiseret al.1994) for measuring the rate of lipase‐catalyzed hydrolysis of olive oil was used to determine the dependency of reaction rate on the concentration and ratios of various constituents. Calcium and bile salts, at various concentrations encountered in the human duodenum, had a significant effect on rate; rate changes being smaller with the former than the latter. Rates of lipolysis proceeded independent of colipase‐to‐lipase ratios>0.45:1. MES (2‐[N‐morpholino] ethanesulfonic acid) buffer was studied at molar concentrations ranging from 0.01 to 0.3, and rate changes were experimentally unimportant over this range. Alteration of pH from 6.0 to 7.0 had only a moderate effect on rate of lipolysis, and minor pH changes (± 0.1 units) from the standard pH of 6.5 had a negligible effect on rate. The effect of various dietary fibers on pH was small (± 0.04 units). Attempts to achieve conditions yielding zero‐order reaction kinetics with respect to olive oil were n

ISSN:1065-7258    

DOI:10.1111/j.1745-4522.1995.tb00035.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

ABSTRACTStudies were conducted on the release of free fatty acids (FFA) from lipids during ensilation of herring mince at room temperature. The silages were produced by the addition of 3.5% formic acid and the effects of heat treatment and also the presence or absence of an antioxidant (ethoxyquin) were examined. The lipid classes extracted from silages at different ensiling stages were determined by Chromarod/Iatroscan‐TLC/FID. Free fatty acids were rapidly released from lipids at the beginning of ensilation in all three silages examined. The maximum level of FFA released in silages without heat treatment was reached after only 6 days of ensilation and levels of about 6% of true FFA in total lipids were maintained until the end of the ensilation process. The heat treatment of 55C for 10 min effectively inhibited the release of FFA from lipids and the amounts of FFA released were significantly lower than in those lots without heat treatment. The presence of ethoxyquin in silage did not show a significant effect in controlling the production of Iatroscan‐detectable FFA from lipids when compared with the silage made without ethoxyquin. A large amount of oxidized lipid, corresponding to a decrease in triacylglycerol, was detected by TLC‐FID in the lot of silage made without the addition of ethoxyquin; however, the addition of antioxidant in two other silages effectively protected the lipids from oxidation during the ensilation period. The experimental results confirmed that lipases play an important role in lipid autolysis. By examining the changes in phospholipids, it was possible to show that the majority of the FFA released originated from phospholipids and only a small fraction came from neutral lipids. The maximum production of FFA in herring silage should depend, to a large extent, on the amount of phospholipids present in the raw mate

ISSN:1065-7258    

DOI:10.1111/j.1745-4522.1995.tb00036.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

ABSTRACTGround chicken breast and beef top round (semimembranosus) muscles were treated with CaCl2(0.05, 0.10, 0.15, and 0.20% on final sample weight basis) and cooked to an internal temperature of 80C. Cooked samples were aerobically stored at 4C for 0 or 4 days and analyzed for 2‐thiobarbituric acid (TBA)‐reactive substances. Results indicated that CaCl2can either inhibit or accelerate lipid oxidation in cooked meat depending on its concentration/meat animal species. TBA values of chicken samples were decreased by CaCl2used at ≥ 0.1% of final weight. However, only beef samples treated with the highest CaCl2level (0.20%) tended to have lower TBA values when compared to control samples (treated with deionized water only). CaCl2used at low levels (0.05% for chicken and ≤0.15% for beef) tended to elevate cooked meat TBA

ISSN:1065-7258    

DOI:10.1111/j.1745-4522.1995.tb00037.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY