| The unhealthy fats(saturated fatty acids and trans fatty acids)in traditional plastic fats are not good for human health.Excessive intake will increase cholesterol levels in the body,leading to chronic diseases such as blood clots,arteriosclerosis and cardiovascular and cerebrovascular diseases.Therefore,it is urgent to find an alternative to traditional plastic fat production and processing methods.The purely physical self-assembly preparation process of the lipid gel and the absence of trans fatty acids attract attention.Due to the single nutrient composition of the lipid product and the instability of the storage period,its application in food is limited.In this study,oil gel was prepared using rice bran wax(RBX)as a gelling agent.Based on this,the application of oleogel in the oil-based foods(peanut butter)and emulsions(W/O/W)was explored to replace some products with high trans fatty acid content on the market.The specific research results were as follows:Firstly,the effects of different preparation conditions on the crystallization kinetics of RBX-based oleogel were studied.The emphasis was on the influence of the rheological properties,microstructure,hardness,and thermodynamic behavior of the oleogel system from the three aspects of RBX addition,heating temperature and crystallization temperature.The results showed that the RBX could form a threedimensional crystal network in the liquid oil,and the liquid oil was tightly bound in the network structure,thus forming the oleogel.Considering the performance and production cost of the oleogel,the optimal preparation conditions of the RBX-based oleogel were as follows: the addition amount of RBX at 4.0%,the heating temperature at 80 °C,and the crystallization temperature at 25 °C.The RBX-based oleogel prepared under these conditions has good mechanical properties.Secondly,the effect of RBX on the stability of peanut butter was studied.The essence of RBX affecting the stability of the system was that the network structure formed by the system with a large amount of RBX was denser,which restrained more oil droplets.Oil loss and viscosity were used as indicators to characterize its stability and texture quality,and its internal structure was observed with a laser confocal microscope.Centrifugal acceleration stability test and texture test showed that the best preparation conditions were as follows: the addition amount of RBX at 4.0%,the stirring temperature at 80 °C,and the cooling temperature at 20 °C.Under the best conditions,the oil loss was 4.04% and the viscosity was 165.9 g.The laser confocal scanning microscopy analysis showed the solid particles were evenly distributed in the oil phase under better conditions.Phase separation did not occur to the peanut butter prepared under this condition within six months,and the acid value and peroxide value remained unchanged during storage.Finally,the effect of RBX on the stability of multiple emulsions and the bioavailability of the delivered proanthocyanidins and ?-carotene was studied.W/O/W emulsions were easily prepared by oleogelation of the oil phase using RBX(6.0%,8.0%,10.0%,and 12.0%)and their microstructure,stability,rheology and protection of proanthocyanidins and ?-carotene were investigated.Formation of the W/O/W emulsion was confirmed by confocal laser scanning microscopy and staining of the inner aqueous phase by tartrazine.The average particle size and viscosity of the emulsion increased as the RBX concentration increased.RBX increased the stability of the emulsion and the emulsion was the most stable after addition of 8.0% or 10.0%RBX.Compared with the emulsion without RBX,RBX-containing emulsions performed better in simultaneously encapsulating proanthocyanidins and ?-carotene.Specifically,proanthocyanidins and ?-carotene in RBX-containing emulsions had higher stability and bioaccessibility,and both their chemical stability and bioaccessibility reached the maximum value with addition of 8.0% or 10.0% RBX. |
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