BACKGROUND: The widespread use of palm oil in food production affects high consumption of long-chain saturated fatty acids, which increases the risk of cardiovascular disease. Solid or semi-solid wax-based oleogels obtained as a result of edible oils structuring can be an alternative.RESULTS: Oleogels, obtained by structuring a mixture of refined rapeseed and linseed oils (1:1) with 30-80 g kg −1 candelilla wax (CW), were investigated using optical techniques: multi-speckle diffusing wave spectroscopy, centrifugal stability analysis, reflection method, and polarized light microscopy. Refined palm oil was a comparative sample. Increasing CW concentration resulted in an increase in values of L * parameter and opacity, a decrease in the Yellowness Index and a slight increase in the average crystal size. The microstructure of oleogels with 30 or 40 g kg −1 CW was least like the crystal network. Solidification of oleogels took place in two stages. Increase in CW concentration shortened solidification time and increased solidification temperature (greater elasticity of oleogels). Palm oil solidified the longest (497.1 min) and at the lowest temperature (29.3 °C). It showed lower resistance to centrifugal force than oleogels at 20 and 30 °C. All oleogels were stable (no oil release occurred) at 20 °C.CONCLUSION: Optical methods allow for an objective and detailed analysis of physical properties of palm oil and oleogels, as well as identification and tracking changes at the microstructural level over time. It has great potential in the edible lipid quality control at various stages of processing or storage.

IntroductionSolid and semi-solid fats are widely used by the food industry. The high utility value of these fats mainly is a consequence of the high content of saturated fatty acids SFAs . Moreover, despite the advances in fat processing/ modification technology, foods still contain trans fatty acids TFAs , mainly due to hardening by partial hydrogenation 1, 2 . In general, the SFAs contribute to increasing the risk of cardiovascular disease, and the dietary guidelines recommend limited consumption of products with high SFAs content, regardless of origin. The total intake of SFAs should be less than 10 of total energy per day 3,4 . SFAs ought should be replaced in a diet with unsaturated fatty acids 5 . Palm oil, which is widespread in the food industry, is a natural plant-based alternative to milk fat. Such replacement is not the solution to the SFAs problem, although it brings economic and technological benefits. In recent years, the cultivation of oil palm trees has caused

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The influence of the amount of inulin addition (3%, 6%, 9%, 12% or 15% w/w) on the physicochemical properties of natural yogurt was analyzed. The acidity (titration; pH), texture parameters (penetration test), viscosity curves (rotational rheometer), microrheology (macroscopic viscosity index, MVI; elasticity index, EI; solid-liquid balance—SLB; multi-speckle diffusing-wave spectroscopy, MS-DWS) and physical stability (syneresis; LUMiSizer test) of yogurts were investigated. All samples were non-Newtonian pseudoplastic liquids. The sample with 15% inulin content presented an approx. 4% higher pH value (4.34), 3-fold greater MVI and almost 5-fold higher penetration force, compared to the control sample (0% of inulin). In turn, the use of inulin addition in the range of 3–15% w/w resulted in a reduction of syneresis (p < 0.05). A linear decrease in the values of instability indexes and sedimentation velocities was noted in the function of inulin content increase (LUMiSizer test). The application of inulin (in the range of 3–15% w/w) as a functional additive to yogurts significantly contributed to enhancement of their physical stability. Summing up, the possibility of obtaining natural yogurts with a high content of this prebiotic has been demonstrated, thus such products can be classified as functional foods and a health claim can be put on the label.

The purpose of this study was the evaluation of the physical stability of low-fat oil-in-water model emulsions containing oleogels based on ethyl cellulose), compared to emulsions with anhydrous milk fat. The oleogels were prepared using rapeseed oil with ethyl cellulose at the level of 4.5, 5.0, 5.5 or 6.0% w/w. The O/W emulsions (30/70 w/w) were stabilized by guar gum (0.6% w/w) and soy lecithin (5.0% w/w). The physical properties of oleogels and anhydrous milk fat (centrifugal stability, spreadability/penetration test), rheology and the physical stability of the emulsions (MS-DWS method, centrifugal/thermal stability) were determined, a storage test of the emulsions (CSA method, LUMiSizer) was also conducted. It was demonstrated that ethyl cellulose is an effective edible oil structuring agent. The increase in ethyl cellulose content enhanced the centrifugal stability and hardness of the oleogels. As a result of a microrheology analysis, it was found that the emulsion with anhydrous milk fat had the most elastic strength, macroscopic viscosity and the highest solids content. All emulsions demonstrated high centrifugal/ thermal stability. A higher temperature and extended storage time caused a reduction in the stability of all emulsions and increased the velocity of particle migrations. The ethyl cellulose-oleogels are potential fat phases for stable O/W emulsions, which could be used as a vegan alternative to traditional products based on animal components. K e y w o r d s: oleogels, ethyl cellulose, oil-in-water emulsions, MS-DWS method, storage test, CSA method

The aim of this study was to evaluate the macro- and microscopic properties of oleogels with yellow beeswax using different methods, especially modern optical techniques. Microrheological properties, physical stability and morphology of oleogel crystals obtained by structuring of peanut oil with yellow beeswax was analyzed. It was observed that oleogels, even with the smallest concentration of beeswax (2%), were resistant to centrifugal force. Increase in yellow beeswax concentration (from 2, 4, 6 to 8 %) resulted in significant differences in the characteristics of oleogels: increased elasticity (EI), macroscopic viscosity (MVI) and the firmness values of oleogels. It was concluded that non-invasive optical techniques (multi-speckle diffusing wave spectroscopy—Rheolaser Master) are useful in obtaining a quick evaluation of physical properties of oleogels at the microstructural level, and the received information allows for quality assessment.

The aim of this study was the evaluation of the influence of different HHP levels (150 and 300 MPa) and time treatment (5, 10, 20 min) on the gelation and properties of hydrogels with different inulin concentration (15, 20, 25 g/100 g). High-pressure treatment, in tested ranges, induces inulin gels and allows obtaining gel structures even at a lowest tested inulin content (i.e., 15 g/100 g). Selecting the pressure parameters, it is possible to modify the characteristics of the created hydrogels. The use of higher pressure (i.e., 300 MPa) allows to increase the stability of the hydrogels and change their structure to more compressed, which results in higher yield stress, lower spreadability, harder and more adhesive structure. For example, increasing the inulin gelling induction pressure (concentration 20 g/100 g) from 150 to 300 MPa with a time treatment of 10 min resulted in an increase in yield stress from 38.1 to 711.7 Pa, spreadability force from 0.59 to 4.59 N, firmness from 0.11 to 1.46 N, and adhesiveness from −0.06 to −0.65 N. Extending the time treatment of HHP increases this effect, but mainly when higher pressure and a higher concentration of inulin are being used. For example, extension of time treatment at 300 MPa pressure from 5 to 20 min resulted in an increase in yield stress from 774.8 to 1273.8 Pa, spreadability force from 6.28 to 8.43 N, firmness from 1.87 to 2.98 N, and adhesiveness from −0.94 to −1.27 N. The obtained results indicate the possibility of using HHP to create inulin hydrogels tailored to the characteristics in a specific food product.

Microorganisms can be a promising source of bioactive food ingredients derived from unconventional agricultural farms. The quality of batter and final products in which 20%–80% of the fat has been replaced by β-glucan, obtained from microorganisms, was analyzed. The instrumental texture measurements showed that β-glucan batter and muffins were harder than the control sample. Fat substitution over 40%, while enriching muffins with yeast β-glucan (over 2%), led to a decrease in the quality of products after baking and during 14-day storage. The incorporation of 3% or more β-glucan into the composition increased the hardness of the batter and deteriorated the quality of the muffin crumb, after baking and during storage. The sensory study revealed that fat replacement up to 40% with β-glucan provided acceptable biscuits, but higher replacement decreased the overall acceptability.