油脂取代物的研究进展

以 1 996年FDA批准Dlestra可作为油脂替代物应用于部分食品为标志 ,油脂取代物的研究开发取得了重大的进展。本文着重对油脂取代物的 2大类产品———油脂替代物、油脂模拟物的种类以及它们在食品中的应用作了综述。     

新型功能性油脂问题浅析

近二十年来,人们一直关注着过度膳食脂肪对健康所带来危害,同时各种新型功能性油脂也应 运而生。该文论述这些新型功能性油脂在制备技术、理化性质与应用,及食物安全性等方面存在问题, 并对其进行讨论。     

Eating quality of low‐fat beef burgers containing fat‐replacing functional blends

Tapioca starch, carrageenan, oat fibre, pectin, whey protein and a commercial mixture of carrageenan and locust bean gum were assessed for their ability to mimic fat characteristics in cooked low‐fat (10%) beef burgers. Thirteen different blends of the ingredients were formulated in order to examine their effects on quality parameters of low‐fat beef burgers. The beef burgers were tested for cook yield, water‐holding capacity (WHC), retention of shape, sensory and mechanical texture analysis. Most blends significantly (P<0.05) increased both cook yield and WHC, in particular blends containing tapioca starch, oat fibre, whey protein and the carrageenan/locust bean gum mixture. These blends substantially reduced both Warner–Bratzler and Kramer shear values. Sensory analysis showed that beef burgers containing tapioca starch, oat fibre and whey protein were acceptable in terms of flavour and texture. The low‐fat control was found to be the toughest and driest of the beef burgers examined. This study shows that blends of these ingredients can be used to offset the poor quality associated with low‐fat beef burgers. © 1999 Society of Chemical Industry     

Development and application of soy‐protein films to reduce fat intake in deep‐fried foods

A soy protein film coating was developed and evaluated to reduce fat transfer in deep‐fried foods during frying. Soy protein isolate solutions (10% SPI) with 0.05% gellan gum as plasticizer cooled after being held at 80 °C for 20 min provided suitable films. There was a significant fat reduction (55.12 (±6.03)%db) between fried uncoated and coated discs of doughnut mix. The same films were used on potato fries. Some panellists observed a slight difference between the coated and uncoated fries but many preferred the coated fries over the uncoated ones. Penetration test on potato fries showed no significant difference between the texture of coated (SPI with gellan gum) and the uncoated fried samples. A solution of 10% SPI with 0.05% gellan gum is recommended for coating foods to reduce fat intake during deep‐fat frying. © 2000 Society of Chemical Industry     

Enrichment in unsaturated fatty acids and emulsion droplet size affect the crystallization behaviour of milk triacylglycerols upon storage at 4 °C

Increasing the unsaturated fatty acid (UFA) content in milk fat is of primary importance to improve the long-term health of consumers. However, such changes can affect the crystallization properties of milk triacylglycerols (TAG) and their functional properties. The objectives of this study were to investigate the crystallization properties of milk fat as a function of its FA composition and emulsion droplet size upon storage at refrigerated temperature. UFA-enriched TAG were obtained using cow diet supplemented with linseed oil and compared to control TAG. Homogenization was used to vary the size of emulsion droplets, from 1.7 to 0.2 ??m. The crystallization properties of TAG were studied using synchrotron X-ray diffraction coupled to differential scanning calorimetry. We characterized the coexistence of several solid fat phases with a liquid phase, the characteristics of which depended on the temperature, FA composition and droplet size. The enrichment in UFA from 29 to 51 wt.% led to a decrease in the enthalpy ratio (??H_partial/??H_total) from 64 ± 4 to 54 ± 4% at 4 °C and to the formation of 2 L (41.8 Å) structure with ??₁, ??′₁, and ??′₂ polymorphic forms while 2 L (39.5 Å) and 3 L (56.6 Å) structures with ??₁, ??₂, ??′₁ and ??′₂ polymorphic forms were formed with control TAG. The size of the emulsion droplets also affected the structural and thermal properties of milk TAG. Such experiments increased the knowledge about the crystallization properties of TAG dispersed in emulsion and will be useful for industrial applications and the development of UFA-enriched dairy products with improved nutritional properties.     

The influence of fibre level and fat supplementation in expander‐processed diets on grower–finisher pig performance

Seventy‐two entire male pigs (40.4 ± 1.0 kg) were used to study the effects of increasing crude fibre (CF) level in the diet and maintaining the digestible energy (DE) content of the diet by increasing dietary fat inclusion on pig performance and nutrient digestibility in a 3 × 2 factorial experiment. Productive performance and nutrient digestibility were determined in individually fed pigs offered expander‐processed pelleted diets ad libitum containing three levels of CF (50, 60 and 70 g kg^?1) and two levels of fat supplementation (25 and 50 g kg^?1) until slaughter at 100 kg. All diets were expander processed at 105 °C for 5 s at 35 bar pressure having been previously conditioned at 85 °C for 5 s. All diets were formulated to have similar concentrations of digestible energy (13.5 MJ kg^?1) and lysine (10 g kg^?1) and the fat source was a 60:40 blend of tallow and palm oil. The increase in dietary CF level decreased (P < 0.05) the apparent digestibility of crude protein, organic matter (OM) and energy, while the inclusion of 50 g kg^?1 fat decreased (P < 0.01) OM and energy digestibility. The inclusion of 50 g kg^?1 fat in the diet increased (P < 0.01) ether extract digestibility at the 50 and 60 g kg^?1 CF levels; however, fat inclusion had no effect at the 70 g kg^?1 CF level. There was no CF × fat interaction in any growth criteria. The inclusion of 50 g kg^?1 fat in the diet significantly reduced (P < 0.05) feed intake (2.28 versus 2.43 kg day^?1, SEM 0.039), average daily gain (ADG; 0.877 versus 0.927 kg day^?1, SEM 0.017) and DE conversion ratio (36.1 versus 35.0 MJ kg^?1, SEM 0.40). The increase in dietary CF level decreased (linear, P < 0.05) feed intake (2.45 versus 2.32 versus 2.29 kg day^?1, SEM 0.040), ADG (0.940 versus 0.896 versus 0.872 kg day^?1, SEM 0.021) and kill‐out proportion (740 versus 741 versus 730 g kg^?1, SEM 3.6). In conclusion, increasing both the CF level and supplementary fat inclusion rate had a negative effect on pig growth performance and nutrient digestibility. © 2002 Society of Chemical Industry     

Fat digestion and absorption in spice‐pretreated rats

BACKGROUND: A few common spices are known to stimulate secretion of bile with higher amount of bile acids which play a major role in digestion and absorption of dietary lipids. It would be appropriate to verify if these spices enable efficient digestion and absorption during high‐fat intake. In this context, dietary ginger (0.05%), piperine (0.02%), capsaicin (0.015%), and curcumin (0.5%) were examined for their influence on bile secretion, digestive enzymes of pancreas and absorption of dietary fat in high‐fat (30%) fed Wistar rats for 8 weeks. RESULTS: These spices enhanced the activity of pancreatic lipase, amylase, trypsin and chymotrypsin by 22‐57%, 32‐51%, 63‐81% and 12‐38%, respectively. Dietary intake of spices along with high‐fat enhanced fat absorption. These dietary spices increased bile secretion with higher bile acid content. Stimulation of lipid mobilisation from adipose tissue was suggested by the decrease in perirenal adipose tissue weight by dietary capsaicin and piperine. This was also accompanied by prevention of the accumulation of triglyceride in liver and serum in high‐fat fed rats. Activities of key lipogenic enzymes in liver were reduced which was accompanied by an increased activity of hormone‐sensitive lipase. CONCLUSION: Thus, dietary ginger and other spice compounds enhance fat digestion and absorption in high‐fat fed situation through enhanced secretion of bile salts and a stimulation of the activity pancreatic lipase. At the same time, the energy expenditure is facilitated by these spices to prevent the accumulation of absorbed fat. Copyright © 2011 Society of Chemical Industry     

Diet‐induced obesity regulates the galanin‐mediated signaling cascade in the adipose tissue of mice

Galanin is a neuropeptide that regulates the food intake, neurogenesis, memory, and gut secretion. This study was conducted to evaluate the high‐fat diet (HFD)‐induced regulation of the galanin receptors (GalRs) and the associated signaling molecules in the adipose tissues of mice. Twenty C57BL/6J mice were given either an HFD or a normal diet for 12 wk. The results of the semiquantitative RT‐PCR analyses indicated that the HFD upregulated the expression of GalR1, GalR2, GalR3, resistance to audiogenic seizures, peroxisome proliferator‐activated receptorγ2, adipocyte protein 2, and protein kinase Cδ and downregulated the expression of peroxisome proliferative activated receptor γ coactivator 1α and uncoupling protein 1 in the adipose tissues. The immunoblot results showed that the protein levels of peroxisome proliferator‐activated receptorγ2 and adipocyte protein 2, and the phosphorylation of c‐Raf and extracellular signal‐regulated kinase 1/2 were increased, while the phosphorylation of cyclic adenosine monophosphate‐responsive element‐binding protein, which regulates peroxisome proliferative activated receptor γ coactivator 1α and uncoupling protein 1, was decreased in the epididymal adipose tissues of the HFD‐fed mice. These results suggest the possible association of the galanin‐mediated signaling pathways in the manifestation of the HFD‐induced activation of adipogenesis along with the suppression of thermogenesis in the adipose tissues of mice.     

Impact of Trans‐Fats on Heat‐Shock Protein Expression and the Gut Microbiota Profile of Mice

Partially hydrogenated oils are known to cause metabolic stress and dyslipidemia. This paper explores a new dimension about the interaction between dietary trans‐fats and the defense heat‐shock protein (HSP) system, inflammation, and the gut microbiota of mice consuming a hyperlipidic diet containing partially hydrogenated vegetable oil free of animal fat. Five diet groups were installed: control diet, 2 hyperlipidic‐partially hydrogenated‐oil diets, each containing either casein or whey‐protein hydrolysate (WPH) as protein source, and 2 consuming hyperlipidic‐unhydrogenated‐oil diets containing either WPH or casein as a protein source. The partially hydrogenated oil inhibited c‐Jun NH₂‐terminal kinase phosphorylation in the casein diets, but without altering κ‐B kinase. Neither the lipid nor the protein had an influence on the proinflammatory toll‐like receptor 4 (TLR4) pathway, but the combination of the high‐lipid content and WPH impaired glucose tolerance without altering insulin or glucose transporter‐4 translocation. It was remarkable to observe that, contrary to the case of a common high‐fat diet, the lard‐free hyperlipidic diets were hardly able to invert the Bacteroidetes:Firmicutes phylum ratio. Our results suggest that, in the absence of lard, the intake of trans‐fatty acids is less harmful than expected because it does not trigger TLR4‐inflammation or pose great threat to the normal gut microbiota. WPH had the effect of promoting the expression of HSP90, HSP60, and HSP25, but did not prevent dysbiosis, when the diet contained the unhydrogenated oil. The partially hydrogenated oil also seemed to antagonize the ability of WPH to induce the expression of protective HSPs.     

Investigation of the retronasal flavour release during the consumption of coffee with additions of milk constituents by ‘Oral Breath Sampling’

The aim of this study was the investigation of the influence of milk proteins (casein and whey proteins) and milk fat on the release of flavour compounds from white coffee beverages in the oral cavity. For this reason a retronasal headspace technique for measurement of the after-flavour was adapted. A ‘Gas Sampler’ equipped with a mouthpiece was used as an ‘Oral Breath Sampler (OBS)’. Analyses were performed by gas chromatography with mass spectrometric detection. It was noticed that the sampling at different hours resulted in different standard deviations. The flavour release is more constant in the morning (Variation coefficient from 3% to 28%; median: 10%) than in the afternoon (7–52%; median: 23%). The relationships between flavour release and some salivary parameters like salivation rate, buffer capability and protein content were also studied. The ‘Oral Breath Sampling’ was considered to be a valuable sampling method for the analysis of the retronasal aroma release from coffee beverages.     

脂肪替代物及其在食品中的应用

本文介绍脂肪替代物的必要性、替代机理、替代物分类、应用、及存在问题等。     

脂肪代用品的特点及应用

脂肪代用品可以代替天然脂肪应用于食品、化妆品、医药工业。阐述了多种脂肪代用品的物理、化学性质和生理特性 ,并分别介绍了它们在实际生产中的应用。     

Rheological and physical evaluation of jet‐cooked oat bran in low calorie cookies†

Different levels of shortening in cookies (10%, 20% and 30% by weight) were replaced with 20% jet‐cooked oat bran, also called Nutrim oat bran (OB), to prepare cookies with fewer calories. The cookies containing Nutrim OB were investigated in terms of rheological and physical properties and compared with a control. As more shortening was replaced with Nutrim OB, a decrease in the diameter and an increase in the height of cookies were observed. The increased moisture content from Nutrim OB caused a decrease in the dynamic viscoelastic properties of cookie dough. Squeezing flow method showed shear thinning behaviours in all cookie doughs. Also, the elongational viscosity of cookie dough decreased significantly with more replacement of shortening with Nutrim OB. The rheological properties of cookie dough during baking indicated that all of the samples had similar types of viscoelastic characteristics during baking. However, the cookies containing more Nutrim OB exhibited more elastic properties which resulted in a decreased cookie diameter. There was no significant difference in cookie hardness among samples with up to 20% shortening replacement but the cookies became lighter in colour as the Nutrim OB content was increased.