Physical Properties of trans-Free Bakery Shortening Produced by Lipase-Catalyzed Interesterification

Amelioration of nutritional properties of bakery fat using omega-3 fatty acid-rich edible oils: a review

Bakery products have gained prominence in modern diets due to their convenience and accessibility, often serving as staple meals across diverse regions. However, the fats used in these products are rich in saturated fatty acids and often comprise trans fatty acids, which are considered as a major biomarker for non-communicable diseases like cardiovascular disorders, obesity and diabetes. Additionally, these fats lack the essential omega-3 fatty acids, which are widely known for their therapeutic benefits. They play a major role in lowering the risk of cardiovascular diseases, cancer and diabetes. Thus, there is need for incorporating these essential fatty acids into bakery fats. Nevertheless, fortifying food products with polyunsaturated fatty acids (PUFAs) poses several challenges due to their high susceptibility to oxidation. This oxidative deterioration leads to not only the formation of undesirable flavors, but also a loss of nutritional value in the final products. This review focuses on the development of healthier trans-fat-free bakery fat enriched with omega-3 fatty acids and its effect on the physicochemical, functional, sensory and nutritional properties of bakery fats and products. Further, the role of various technologies like physical blending, enzymatic interesterification and encapsulation to improve the stability of PUFA-rich bakery fat is discussed, where microencapsulation emerged as a novel and effective technology to enhance the stability and shelf life. By preventing deteriorative changes, microencapsulation ensures that the nutritional, physicochemical and sensory properties of food products remain intact. Novel modification methods like interesterification and microencapsulation used for developing PUFA-rich bakery fats have a potential to address the health risks occurring due to consumption of bakery fat having higher amount of saturated and trans fatty acids. © 2023 Society of Chemical Industry.

Fat replacers in baked products: their impact on rheological properties and final product quality

Many baked products, except for bread, (i.e., cakes, cookies, laminated pastries, and so on) generally contain high levels of fat in their formulas and they require different bakery fats that impart product-specific quality characteristics through their functionalities. Even though, fat is crucial for baked product quality, strategies have been developed to replace fat in their formulas as high fat intake is associated with chronic diseases such as obesity, diabetes, and cardiovascular heart diseases. Besides, the solid bakery fats contain trans- and saturated fats, and their consumption has been shown to increase total and low-density lipoprotein cholesterol levels and to constitute a risk factor for cardiovascular diseases when consumed at elevated levels. Therefore, the aim of this review was to provide a detailed summary of the functionality of lipids/fats (endogenous lipids, surfactants, shortening) in different baked products, the rheological behavior of bakery fats and their contribution to baked product quality, the impact of different types of fat replacers (carbohydrate-, protein-, lipid-based) on dough/batter rheology, and on the quality characteristics of the resulting reduced-fat baked products.

Melting, Crystallization, and In Vitro Digestion Properties of Fats Containing Stearoyl-Rich Triacylglycerols

Fats containing the stearoyl-rich triacylglycerols (TAGs) of 1,2-distearoyl-3-oleoylglycerol (SSO) and 1,3-dioleoyl-2-stearoylglycerol (OSO) were synthesized via the lipase-catalyzed acidolysis of tristearin (SSS)-rich fat and oleic acids, followed by solvent fractionation. Their physicochemical properties and in vitro digestibilities were compared. The SSS-, SSO-, and OSO-rich fats comprised 81.6%, 52.9%, and 33.1% stearic acid, respectively, whereas oleic acid comprised 2.9%, 37.5%, and 56.2%, respectively. The SSS-, SSO-, and OSO-rich fats contained the TAGs of SaSaSa (100.00%), SaSaMo (86.98%), and MoSaMo (67.12%), respectively, and the major TAGs were SSS, SSO, and OSO, respectively. Melting and crystallization temperatures were higher and fat crystals were larger and densely packed in the descending order of SSS-, SSO and OSO-rich fats. Both in vitro multi-step digestion and pH-stat digestion were more rapid for OSO- than SSO-rich fat. Oleic acid was digested faster than stearic acid during the initial digestion, then the rate decreased, whereas that of stearic acid increased over prolonged digestion. Fats that were richer in stearoyl at the sn-1,3 position of TAG melted and crystallized at higher temperatures, had a densely packed microstructure of large fat crystals and were poorly digested. Stearic acid imparts the essential physical attributes of melting and crystallization in solid fats, and the low digestible stearoyl-rich fat would be a viable substitute for trans fatty acids in food lipid industry.

Characterization of enzymatically interesterified palm oil-based fats and its potential application as cocoa butter substitute

Cocoa butter substitutes (CBS) used for chocolate preparation was produced using a mixture of palm kernel oil (PKO) and enzymatically interesterified fats. The interesterified fats consisted of palm olein (POL), fully hydrogenated palm oil (FHPO) and PKO that were catalyzed using Lipozyme TL IM at 65 °C in a solvent-free packed bed reactor. An interesterification degree of 97.10% was obtained using feed flow rate of 70 mL/min and the interesterified fats showed steep solid fat content (SFC) curve characteristics with low SFC at high temperature. In the binary system, PKO and the interesterified fats showed good compatibility at 5-10 °C, while eutectic effects were observed at 15-35 °C. CBS produced from PKO and the interesterified fats in a mass ratio of 4:6 (CBS-46) and 3:7 (CBS-37) had crystals formed prominently in the β' form. Without the need of a tempering process, chocolate made using CBS-46 as the base oil exhibited the desired properties in terms of hardness and fracturability.

Interesterified blend-based and physical blend-based special fats: storage stability under fluctuating temperatures

BACKGROUND

Temperatures that special fat faces in a real environment fluctuate, thus, understanding the property changes of special fats under fluctuating temperatures will be helpful in guiding how to keep its high quality in the production and application process. Therefore, a comparative study was carried out on the storage stability of physical blend-based and interesterified blend-based special fats (PBSFs and IBSFs) and their oxidative stability, crystallization and physical properties were studied under fluctuating temperatures.

RESULTS

The peroxide values of IBSFs and PBSFs were less than 10.0 mmol kg^-1 after 4 weeks of storage, and IBSFs had better oxidative stability. There was little change in the solid fat content, and the hardness decreased when IBSFs and PBSFs were stored for 4 weeks. X-ray diffraction results indicated that PBSFs had only β-crystal, but IBSFs had β- and β'-crystal after storage. Moreover, in IBSFs, the transformation from β'- to β-form in PS:RO-IBSF was more obvious than that in PS:SO-IBSF (PS, palm stearin; SO, soybean oil; RO, rapeseed oil) after 4 weeks of storage, and the good integrity of crystalline network in fast-frozen special fats during fluctuating temperature storage followed the order: IBSF > PBSF, PS:RO-PBSF > PS:SO-PBSF.

CONCLUSION

The results suggest IBSF can better maintain its quality during fluctuating temperature storage than PBSF. © 2019 Society of Chemical Industry.

Storage stability studies on interesterified blend-based fast-frozen special fats for oxidative stability, crystallization characteristics and physical properties

The storage stability of two kinds of interesterified blend-based fast-frozen special fats (PS:SO-IBSF, PS:RO-IBSF) with varied triacylglycerols (TAGs) compositions under different temperatures for 4 weeks was investigated. Rancimat and peroxide values experiments indicated that both IBSFs display good oxidation stability throughout a 4-week storage. As for the physical properties of both IBSFs, the solid fat content and hardness decreased with the increase of storage temperature, and IBSFs still exhibited a viscoelastic solid-like behavior. X-ray diffraction results showed that crystal transformation from β'- to β-form was more serious when stored at 25 °C. The more content of ECN 50-type TAGs in PS:RO-IBSF is helpful to reduce its crystal transformation from β'-to β-form compared to PS:SO-IBSF. On the other hand, storage at 4 °C was beneficial for both IBSFs to keep their crystal network integrity, and the PS:RO-IBSF maintained better quality under the same storage conditions.

An investigation on the physicochemical characterization of interesterified blends of fully hydrogenated palm olein and soybean oil

In this study, the effect of interesterification (using sodium methoxide) on physicochemical characteristics of fully hydrogenated palm olein (FHPO)/soybean oil blends (10 ratios) was investigated. Interesterification changed free fatty acid content, decreased oil stability index, solid fat content (SFC) and slip melting point (SMP), and does not affected the peroxide value. With the increase of FHPO ratio, oil stability index, SFC and SMP increased in both the interesterified and non-interesterified blends. Fats with higher FHPO ratio had narrower plastic range, as well. Compared to the initial blends, interesterified fats had wider plastic ranges at lower temperatures. Both the non-interesterified and interesterified blends showed monotectic behavior. The Gompertz function could describe SFC curve (as a function of temperature, saturated fatty acid (SFA) content or both) and SMP (as a function of SFA) of the interesterified fats with high R2 and low mean absolute error.

Synthesis of structured lipids containing behenic acid from fully hydrogenated Crambe abyssinica oil by enzymatic interesterification

Low-calorie structured lipids (SLs) rich in behenic and oleic acids were produced by enzymatic (EI) and chemical interesterification (CI) of high oleic sunflower oil and fully hydrogenated Crambe abyssinica oil in proportions of 60:40, 50:50, 40:60 and 30:70 (w/w), respectively. The immobilized lipase from Thermomyces lanuginosus (Lipozyme TL IM) was used for 3 h at 70 °C at a dosage of 7% (w/w) free of organic solvents. The original blend (BE) and the reaction products were evaluated for their fatty acid (FA) and triacylglycerols (TAG) compositions, solid fat contents, thermal analysis, regiospecific distribution of the FA, microstructure and polymorphism. The tendency was towards a reduction in the C₅₂, C₅₄, C₆₀, C₆₂ and C₆₄ TAG contents and an increase in the C₅₆, C₅₈ e C₆₆ TAG contents, therefore the solid fat content was reduced. There was lower acyl migration at the sn-2 position of the TAGs in EI as compared to CI in all the blends ratios. Needle-like crystals were predominant in the IE while large symmetrical spherulites were observed in the BE. Reduction in the mean crystal diameter was observed in all the blends, in addition to modifications of the crystal morphology. X-ray diffraction analysis showed a predominance of the β' form crystals in both the IE and CI. The SLs were produced for application in the food industry as bakery/confectionery fats in the proportions of 60:40/50:50 and as additive in the crystallization of lipids in the proportions of 40:60/30:70.

Investigations of in vitro bioaccessibility from interesterified stearic and oleic acid-rich blends

Interesterification was previously found to impact stearic acid absorption in a randomized cross-over study, when human volunteers consumed a 70 : 30 wt% high-oleic sunflower and canola stearin blend (NIE) compared to the same blend which had undergone either chemical (CIE) or enzymatic (EIE) interesterification.

Characteristics and Feasibility of Trans-Free Plastic Fats through Lipozyme TL IM-Catalyzed Interesterification of Palm Stearin and Akebia trifoliata Variety Australis Seed Oil

Akebia trifoliata var. australis seed oil (ASO) was used as an edible oil in China. However, in-depth research studies on ASO have yet to be conducted for production of plastic fats in food industry. In this work, an immobilized lipase from Thermomyces lanuginosus (TL IM) was employed to catalyze palm stearin (PS) with different ratios of ASO in a laboratory-scale operation at 60 °C. The physical properties [e.g., fatty acid profile, slip melting point (SMP), solid fat content (SFC), polymorphic form, and microstructure] of physical blends (PBs) were analyzed and compared with those of the interesterified products (IPs). Results showed that SMPs of IPs (33.20-37.60 °C) decreased compared with those of PBs (48.03-49.30 °C). Meanwhile, IPs showed a good SFC range from 16.11% to 28.29% at 25 °C with mostly β' polymorphic forms determined by X-ray diffraction analysis. It should be mentioned that no trans fatty acids (TFAs) were detected in any products, suggesting much more health-benefits of IPs. Texture tests showed that PBs (3318.19 ± 86.67 g) were markedly harder than IPs (557.02 ± 12.75 g). Conclusively, our study demonstrated that ASO can be utilized to produce trans-free plastic fats with good qualities through lipase-catalyzed interesterification.

Unsaturated emulsifier-mediated modification of the mechanical strength and oil binding capacity of a model edible fat crystallized under shear

The effects of processing using a scraped surface heat exchanger (SSHE) before and after adding unsaturated monoglyceride (UM) on blends of fully hydrogenated soybean oil (FHSO) and soybean oil (SO) were studied. Mixtures of 40:60 and 45:55 FHSO:SO were melted at 80 °C for 30 min and crystallized statically or in the SSHE (shear rate of 25 s(-1)) at a cooling rate of 9 °C/min. Upon shearing and UM addition, polymorphic transformations toward more (β) or less (β') stable forms were governed by the combination between system concentration, composition, and crystallization conditions, as determined by differential scanning calorimetry and powder X-ray diffraction. Nuclear magnetic resonance was used to measure the solid fat content (SFC) development which showed to increase with processing conditions due to the high nucleation rate induced. Processing conditions greatly affected the nano- and microcrystalline structures which were characterized by polarized light microscopy (PLM), cryogenic transmission electron microscopy (Cryo- TEM), and Scherrer analysis of the powder X-ray diffraction data. Crystallization under shear promoted the longitudinal growth of the nanoplatelets; nevertheless, meso structural elements showed a decrease in their dimensions under the same crystallization conditions. The relative oil loss determined gravimetrically was inversely related to the elastic modulus and yield stress of the sheared fat blends, and values were closer to the desirable usability ranges for bakery applications. Our results suggest that fully hydrogenated fats can be functionalized by crystallization in a SSHE and/or by judicious addition of an unsaturated emulsifier.

Characterization of graininess formed in all beef tallow-based shortening

A batch of all beef tallow (BT)-based model shortening (divided into six rectangular block samples) was stored under temperature fluctuation cycles of 5-20 °C until granular crystals were observed. The lipid composition, thermal properties, and polymorphism of the granular crystals and their surrounding materials were evaluated. Furthermore, the isothermal crystallization behavior of two parts noted above was also examined by pulsed nuclear magnetic resonance (pNMR), rheology, and polarized light microscopy (PLM). The changes of nanostructure including the aggregation of high-melting triacylglycerols (TAGs) and transformation into the most stable β polymorph occurred in granular crystals compared with surrounding materials. Concomitantly, a slower crystallization rate with a simultaneous increase in crystal growth led to the formation of large crystals and further aggregated to larger granular crystals when the size ultimately exceeded the sensory threshold.

Optimisation of tripalmitin-rich fractionation from palm stearin by response surface methodology

BACKGROUND

Solvent fractionation is effective in improving separation at low temperature, resulting in higher yield and purity of the final product. Tripalmitin (PPP) is an important substrate for the synthesis of human milk fat substitute (HMFS). In this study a fraction rich in PPP was separated from palm stearin by solvent fractionation.

RESULTS

The PPP-rich fraction was concentrated from palm stearin by acetone fractionation. Response surface methodology (RSM) was employed to optimise PPP purity (Y(1), %) and PPP content (Y(2), g kg(-1) palm stearin) with the independent variables fractionation temperature (X(1), 25, 30 and 35 degrees C) and weight ratio of palm stearin to acetone (X(2), 1:3, 1:6 and 1:9). The predictive models for PPP purity and PPP content of the solid fraction were adequate and reproducible, with no significant lack of fit and satisfactory levels of R(2). PPP purity showed a positive correlation with temperature and acetone ratio, whereas PPP content exhibited a negative correlation. The optimised fractionation condition for a targeted PPP-rich fraction with > 92% PPP purity and > 225 g kg(-1) PPP content from palm stearin was predicted.

CONCLUSION

The RSM model for optimising PPP purity and PPP content in the PPP-rich fraction from palm stearin by acetone fractionation was valid. The scaled-up PPP-rich fraction obtained can be used as a substrate for the synthesis of 1,3-dioleoyl-2-palmitoylglycerol, which is a main component of HMFS in infant formulas.

Optimized synthesis of 1,3-dioleoyl-2-palmitoylglycerol-rich triacylglycerol via interesterification catalyzed by a lipase from Thermomyces lanuginosus

1,3-Dioleoyl-2-palmitoylglycerol (OPO)-rich human milk fat substitute (HMFS) was synthesized from tripalmitin-rich fraction and ethyl oleate by a lipase-catalyzed interesterification. Response surface methodology was employed to optimize its OPO content and acyl migration with reaction factors - substrate mole ratio of PPP-rich fraction to ethyl oleate (1:4, 1:5 and 1:6), reaction temperature (50, 55 and 60 degrees C) and time (3, 7.5 and 12 hours). The predictive models for OPO content and acyl migration were adequate and reproducible. The OPO content increased with substrate ratio, and decreased with reaction time and temperature, whereas acyl migration increased with temperature and time. The optimal conditions for HMFS synthesis while maximizing OPO content (31.43% OPO) and minimizing acyl migration (6.07%) were predicted at the reaction combination of 50 degrees C, three hours and 5.5 substrate ratio. HMFS was resynthesized under the same condition, and no significant difference between the observed and predicted values was found. Further, the major fatty acid of HMFS was palmitic acid (80.6%) at sn-2 position, and oleic acid (64.9%) at sn-1,3 position.