Monitoring struturants of fat blends with ultrasound based in‐line rheometry (ultrasonic velocity profiling with pressure difference)

Ultrasonic velocity profiling with pressure difference (UVP‐PD) was demonstrated to be a successful, non‐invasive, in‐line measurement system for instantaneous velocity and rheological flow profiling of complex, opaque fat blends. Model systems of 25% Akomic, 75% rapeseed oil; and 25% Akomic, 74% rapeseed oil and 1% Grindsted^® Crystalliser 110 were compared under real process conditions with UVP‐PD. Results indicated that the sample containing the crystalliser had twice the viscosity of the control. These in‐line results are in agreement with previous off‐line results, and offer the chance to probe the mechanics of fat blend physics under real, dynamic conditions.     

Carbohydrate-based fat replacers in the modification of the rheological, textural and sensory quality of yoghurt: comparative study of the utilisation of barley beta-glucan, guar gum and inulin

Barley beta‐glucan, partially hydrolysed guar gum and inulin were used in the processing of low‐fat yoghurts. The possible beneficial effects of carbohydrate fat replacers on the rheological, textural and sensory quality of low‐fat yoghurt‐based products were determined. Comparisons were made between the sample yoghurts made from a low‐fat milk base, and full‐fat and low‐fat yoghurt controls. The inclusion of the carbohydrate components reduced product syneresis and improved the texture and rheological properties of the low‐fat‐based products so that their quality characteristics were similar to yoghurt made with full‐fat milk. Both the type and also the amount of carbohydrate component altered product characteristics. Beta‐glucan addition at low level (0.5%) was effective in improving serum retention of the yoghurt and its viscoelastic nature (G′, G′ and tan δ). In contrast, higher levels (above 2%) of inulin and guar gum were needed to exert significant improvements in the textural characteristics of yoghurt. Sensory analysis conducted on the samples illustrated that the inclusion of carbohydrate‐based fat replacers could be successfully utilised to mimic full‐fat products.     

Measurement of solid fat content by ultrasonic reflectance in model systems and chocolate

A series of confectionery coating fat (CCF) and cocoa butter (CB) dispersions in corn oil were prepared and tempered to a range of temperatures (10, 12 and 15 °C and 26, 27.5 and 29 °C respectively) to produce samples with solid fat contents (SFC) between 0 and 9%. The ultrasonic velocity in the CCF samples increased with increasing SFC and decreased with temperature, however the CB samples were too attenuating to allow velocity measurements. The ultrasonic reflectance at the surface of both sets of dispersions decreased linearly with SFC but at the same level of solids was less for CB than CCF suggesting some dependence on other aspects of fat structure. The microstructures and thermal properties of the fat systems are compared in an attempt to understand these structural differences. Finally ultrasonic reflectance is shown to respond to changes in a chocolate melt during tempering.     

人造奶油的流变性质与涂抹性的关系

在5°～25℃范围内,使用Haake BV12锥板粘度计测定了8种商品餐用人造奶油的流变参数,同时对这8种人造奶油的质构——涂抹性进行感官评定,并与所测定的流变性质进行了比较。又使用核磁共振仪测定了8种人造奶油的固体脂肪含量,对人造奶油的流变性、涂抹性与人造奶油的油脂配方三者间的关系进行了研究。研究表明,在5°～25℃范围内,流变参数随温度的变化愈小,则其涂抹性愈好。在相同的工艺操作条件下,通过调节人造奶油的油脂配方,可以得到最佳的流变性质,以改善人造奶油的涂抹性。     

Comparison of pulsed NMR and ultrasonic velocity techniques for determining solid fat contents

An ultrasonic velocity technique has been compared with pulsed NMR'weight' and 'direct' methods of determining solid fat contents (SFC). Measurements were made at 18°C using samples 0–20% of rapidly cooled tristearin in paraffin oil, tristearin in sunflower oil and tripalmitin in paraffin oil. Correlations between the amount of triglyceride added and the SFC predicted by each of the techniques were always better than 0.995 ( n ± 13). The precisions of the ultrasonic technique (0.2%) and the weight method (0.3%) were significantly better than that of the direct method (0.7%). The ultrasonic technique may therefore offer a suitable alternative or adjunct to the established pulsed NMR technique for SFC determinations; it has considerably lower capital cost and a faster sampling rate.     

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     

Improvement of palm oil and sunflower oil blends by enzymatic interestrification

Palm oil (PO) and sunflower oil (SFO) blends with varying proportions were subjected to enzymatic interesterification (EIE) using a 1,3‐specific immobilised lipase. The interesterified blends were evaluated for their slip melting point (SMP), solid fat content (SFC) at 10–40 °C, p‐anisidine value, peroxide value, free fatty acids (FFA), induction period of oxidation at 110 °C (IP110) and composition of fatty acids by gas chromatography. Under EIE treatment, the blends of PO and SFO in different proportions (20:80, 40:60, 50:50, 60:40 and 80:20) had saturated and unsaturated fatty acid content in the range of 37.6–52.0% and 48.0–62.4%, respectively. The blends showed a considerable reduction in their SFC, SMP, peroxide value and oxidative stability at 110 °C, but presented increase in FFA and p‐anisidine value. The optimum condition for minimising the fatty acid in oil was obtained, at 64 °C, using 8.9% enzyme and 3 h reaction time.     

Effects of chemical interesterification on solid fat content and slip melting point of fat/oil blends

Fat/oil blends, formulated by mixing fully hydrogenated palm oil stearin or palm oil stearin with vegetable oils (canola oil and cottonseed oil) in different ratios from 30:70 to 70:30 (w/w %), were subjected to chemical interesterification reactions on a laboratory scale. Fatty acid (FA) composition, iodine value, slip melting point (SMP) and solid fat content (SFC) of the starting blends were analysed and compared with those of the interesterified blends. SMPs of interesterified blends were decreased compared to starting blends because of extensive rearrangement of FAs among triacylglycerols. These changes in SMP were reflected in the SFCs of the blends after the interesterification. SFCs of the interesterified blends also decreased with respect to the starting blends, and the interesterified products were softer than starting blends. These interesterified blends can be used as an alternative to partial hydrogenation to produce a plastic fat phase that is suitable for the manufacture of margarines, shortenings and confectionary fats.     

Impact of fat types on the rheological and textural properties of gluten-free oat dough and cookie

This study investigated the effect of six fats (margarine, butter, lard-LAR, refined palm oil-RPO, refined palm oil with stearin-RPOS, hydrogenated palm oil-HPO) with different solid fat content (SFC) on gluten-free oat dough and cookie properties. RPOS and HPO had the highest SFC. RPO dough was the softest, whereas HPO was the hardest one. Dough hardness was correlated with SFC (r = 0.87). Dough stickiness was positively correlated with dough hardness (r = 0.92). Dough hardness influenced the breaking force of the cookies (r = 0.79). HPO were the hardest cookies. Oscillatory test revealed that HPO dough was the stiffest as well as presented a higher rigidity compared to the other samples as showed by the creep tests. LAR cookies were the darkest, while HPO were the lightest. SFC of fats is the most important composition parameter which influences thermal, textural and rheological properties of the oat dough.     

Effects of fat reduction and fat replacer addition on some quality characteristics of frankfurter-type sausages

Some quality characteristics of frankfurters manufactured in three different fat levels (20%, 10% and 5%) and added citrus fibre (CF) and soy protein concentrate (SPC) were investigated. While moisture content of frankfurters increased with decreasing fat levels, protein contents increased. Lower fat levels resulted in lower water‐holding capacity (WHC), cooking losses and penetrometer values. Lower L* values and higher a* values were obtained in low fat frankfurters. SPC significantly increased the cooking losses in the sausages with 5% and 20% fat, but decreased in the sausages with 10% fat. The lower cooking loss values were obtained in sausages added CF for all fat levels. Addition of fat replacers decreased the L values but did not affect the a and b values. Addition of fat replacers increased hardness in case of low fat levels. The softer product was obtained with high‐fat formulation than low‐fat formulation. Lower taste scores were observed with addition of fat replacers.     

Influence of SFC, microstructure and polymorphism on texture (hardness) of binary blends of fats involved in the preparation of industrial shortenings

Several binary blends of vegetable oils commonly used in industrial shortenings (i.e., palm oil (PO), hydrogenated palm oil (HPO), soybean oil (SO), hydrogenated soybean oil (HSO), low-erucic acid rapeseed oil (LERO), hydrogenated low-erucic acid rapeseed oil (HLERO)) were studied for their physical properties such as solid fat content (SFC) by nuclear magnetic resonance (NMR) and textural properties (hardness). Microstructure was also observed by microscopy in order to explain the variability in hardness for samples having the same SFC values. The blends studied by microscopy were the following: HSO, HPO and HLERO diluted in LERO. For these three blends which had the same SFC, the level of network structure was different. HSO diluted in LERO had more crystals, closer to each other and overlapped. This can explain that HSO has a higher hardness than HPO or HLERO, for a same SFC value, when diluted in LERO. Polymorphism was also observed by powder X-ray diffraction. The variability in hardness for samples having the same SFC is due to various crystal types and/or network structures that are formed upon crystallization of hard fats. This work demonstrates that for binary blends of studied oils, changes in the hardness are controlled mostly by the SFC, polymorphism and also by the material’s microstructure.     

Zero trans fats from soybean oil and fully hydrogenated soybean oil: Physico-chemical properties and food applications

Blends of soybean oil (SO) and fully hydrogenated soybean oil (FHSBO), with 10%, 20%, 30%, 40% and 50% FHSBO (w/w) content were interesterified under the following conditions: 0.4% sodium methoxide, 500 rpm stirring, 100 °C, 20 min. The original and interesterified blends were examined for triacylglycerol composition, melting point, solid fat content (SFC) and consistency. Interesterification caused considerable rearrangement of triacylglycerol species, reduction of trisaturated triacylglycerol content and increase in monounsaturated and diunsaturated triacylglycerols, resulting in lowering of respective melting points. The interesterified blends displayed reduced SFC at all temperatures and more linear melting profiles as compared with the original blends. Yield values showed increased plasticity in the blends after the reaction. Isosolid diagrams before and after the reaction showed no eutectic interactions. The 90:10, 80:20, 70:30 and 60:40 interesterified SO:FHSBO blends displayed characteristics suited to application, respectively, as liquid shortening, table margarine, baking/confectionery fat and all-purpose shortenings/biscuit-filling base.     

Development of low‐fat mayonnaise containing polysaccharide gums as functional ingredients

BACKGROUND: The objective of this study was to develop a low‐fat (LF) mayonnaise containing polysaccharide gums as functional ingredients. Xanthan gum (XG, 15 g kg^?1), citrus fiber (CF, 100 g kg^?1) and variable concentration of guar gum (GG) were used to formulate the optimum ratios of polysaccharide gums as fat replacers. The fat content in LF mayonnaise was reduced to 50% if compared with full‐fat (FF) mayonnaise, and the products still maintained ideal rheological properties. RESULTS: The rheological parameters showed that there were no (P > 0.05) differences in yield stress, viscosity and flow behavior index between XG + 10 g kg^?1 GG, CF + 5 g kg^?1 GG and FF control. LF mayonnaises had lower caloric values and higher dietary fiber content than the FF counterpart. Scanning electron microscopy (SEM) micrographs illustrated that the network of aggregated droplets in LF treatments contained a large number of interspaced voids of varying dimensions. Furthermore, in a comparison of sensory evaluation of LF treatments with commercial and our FF mayonnaises, there were no (P > 0.05) differences in any sensory scores among XG + 10 g kg^?1 GG control. CONCLUSION: This study shows that XG + 10 g kg^?1 GG and CF + 5 g kg^?1 GG could be used in LF mayonnaise formulations based on its multiple functions on processing properties. Copyright © 2010 Society of Chemical Industry     

<Emphasis Type="Italic">Trans</Emphasis>-free margarine fat produced using enzymatic interesterification of rice bran oil and hard palm stearin

Trans-free interesterified fats were prepared from blends of hard palm stearin (hPS) and rice bran oil (RBO) at 20:80, 30:70, 40:60, 50:50, 60:40, 70:30, and 80:20 weight % using immobilized Mucor miehei lipase at 60°C for 6 h with a mixing speed of 300 rpm. Physical properties and crystallization and melting behaviors of interesterified blends were investigated and compared with commercial margarine fats. Lipase-catalyzed interesterification modified triacylglycerol compositions and physical and thermal properties of hPS:RBO blends. Slip melting point and solid fat contents (SFC) of all blends decreased after interesterification. Small, mostly β′ form, needle-shaped crystals, desirable for margarines were observed in interesterified fats. Interesterified blend 40:60 exhibited an SFC profile and crystallization and melting characteristics most similar to commercial margarine fats and also had small needle-like β′ crystals. Interesterified blend 40:60 was suitable for use as a transfree margarine fat.     

Rapid Determination of Total and Solid Fat Contents in Chocolate Products by Pulsed Nuclear Magnetic Resonance

A rapid pulsed NMR method of fat analysis in chocolate without prior solvent extraction was developed. Total fat content of 43 chocolate products was determined at 60°C using sucrose-oil mixtures as standards. Solid fat content (SFC) was calculated from the liquid oil content at different temperatures. Total fat content agreed to 0.90% standard error of prediction as compared with the Soxhlet method. SFC as determined by NMR correlated well with the dilatometry (r = 0.98) and the DSC (r = 0.96) results. This technique is suitable for quality control of chocolate and other lowmoisture, high-fat products.     

Synthesis of confectionery fat from illipé butter stearin and palm mid-fraction blend via enzymatic interesterification

Cocoa butter equivalent (CBE) was synthesised from blends of illipé butter stearin (IBS) and palm mid-fraction (PMF) via enzymatic interesterification (EIE). IBS was blended with PMF in three wt ratios (70:30, 60:40 and 50:50) and the EIE reactions were performed at 50°C for 30 min using an sn-1,3-specific lipase from Rhizopus oryzae as a catalyst. The triacylglycerol (TAG) compositions, slip melting points (SMP), crystallisation and melting thermograms, solid fat content (SFC) curves, and crystal microstructure of the blends before and after EIE were studied and compared with cocoa butter (CB). After EIE, the contents of POP and StOSt decreased, whereas the POSt content increased in all blends. Blend EIE 60:40 exhibited the POP and StOSt contents that situated within the ranges of POP and StOSt contents of CB. It also showed SMP, melting peak and melting completion temperatures, melting enthalpy and crystal microstructure most similar to CB. Most importantly, its SFC curve completely matched that of CB. Consequently, EIE 60:40 was chosen for further investigation and it was found to be fully compatible with CB and crystallised into the same polymorphic form (β) as CB. Therefore, EIE 60:40 has a high potential for use as a commercial CBE.     

Dynamic rheological properties of rice flour‐starch blends

The dynamic rheological properties of blends of rice flour (RF) with six different commercial starches (sweet potato starch, potato starch, tapioca starch, waxy corn starch, hydroxypropylated potato starch, and hydroxypropylated tapioca starch) were evaluated. The magnitudes of storage modulus (G′) of all blend samples were higher than those of loss modulus (G′′) over most of the frequency range (0.63–62.8 rad · s⁻¹). In general, the dynamic moduli results of all blend samples showed that changes in G′ values were relatively greater than changes in G″ values after adding the starches when compared to RF. tan δ (ratio of G′′/G′) values (0.21–0.22) of the RF‐potato starch and RF‐hydroxypropylated potato starch blends were much lower than those (0.25–0.33) of other blends and RF, indicating that there is a more pronounced synergistic effect on the elastic properties of RF‐starch blend systems in the presence of potato starches.     

Thermal gelation of meat batters as a function of type and level of fat and protein content

The rheological behaviour of meat batters during heating was analysed as a function of protein level (10–16%), type (pork back or perirenal/peritoneal fat) and amount (10–22%) of fat used. Fat thermal behaviour was studied by differential scanning calorimetry and rheological properties of batters were assessed using non-destructive measurements (thermal scanning rigidity monitor). The higher the protein content, the higher were the rigidity values displayed by the batters, irrespective of fat type, although the magnitude of these values appeared to be dependent on the amount and characteristics of the fat. The lower the fat content, the lower were the rigidity values of the batters. This behaviour pattern was influenced by the amount of protein present. In general, samples containing perirenal/peritoneal fat exhibited lower rigidity values at high temperatures, whereas at less than 35–40 °C, the opposite appeared to be the case.     

Physico-chemical and rheological properties of full fat and low fat edam cheeses

Low fat (17% fat) and full fat (27% fat) Edam cheese manufactured and aged up to 6 months at 5 °C were studies. The objective was to investigate the impact of fat on the physico-chemical and rheological properties of Edam cheese. Total soluble nitrogen in aqueous extract (TNAE), protein nitrogen in aqueous extract (Pro-NAE) and peptide nitrogen in aqueous extract (Pep-NAE) were determined by the Kjeldahl method. Low fat Edam (LFE) had markedly higher Pep-NAE than full fat Edam (FFE). The rheological properties were determined using an Instron Universal Testing Machine. LFE had significantly higher stress values than FFE, indicating hard and rubbery texture. Furthermore, LFE had lower strain values indicating crumbliness.     

Production of zero trans Iranian vanaspati using chemical transesterification and blending techniques from palm olein, rapeseed and sunflower oils

Chemical transesterification and blending techniques were used for producing zero trans fats suitable for use as Iranian vanaspati. Triple blends of palm olein (POo), rapeseed (RSO) and sunflower oil (SFO) were subjected to two different treatments: (i) blending and then transesterification (BT) and (ii) transesterification of pure POo before blending with RSO and SFO (TB). The changes in slip melting point (SMP), solid fat content (SFC), carbon number (CN) triacylglycerol (TAG) composition, induction period (IP) of oxidation at 120 °C and IP of crystallisation at 20 °C of blends before and after treatments were investigated. Both BT and TB methods resulted in an increase in the CN48 TAG molecules, SMP and SFC, and a decrease in the IP of oxidation and crystallisation of initial blends. Samples made by TB method had higher CN48 TAG content, SMP, SFC and IP of oxidation, and lower IP of crystallisation than those made by BT method. Correlation between SFC at 20 °C and saturated fatty acid (SFA) content of the treated blends indicated that the SFA must be higher than 33.1% and 26.8% for BT and TB methods, respectively, to obtain fats suitable for use as vanaspati.