急冷温度及凝胶剂添加量对植物甾醇/谷维素油凝胶 物理特性的影响

Abstract

为促进植物甾醇/谷维素油凝胶在零反式、低饱和的营养型塑性脂肪中的应用，以大豆油为基料油，植物甾醇/谷维素为凝胶剂，在不同急冷温度（5、20 ℃）及凝胶剂添加量下制备油凝胶，测定不同急冷温度及凝胶剂添加量下植物甾醇/谷维素油凝胶的晶型、晶体形态、物理稳定性、质构和热力学特性的变化。结果表明：随着凝胶剂添加量的升高，油凝胶中晶体排列逐渐致密，硬度增大，熔点升高；尽管急冷温度对油凝胶的晶型（β晶型）没有明显影响，但相对于5 ℃急冷，20 ℃急冷得到的油凝胶晶体组装更为致密，物理稳定性增强；在与传统甘三酯固脂对比SFC与硬度和熔点的关系中发现，在油凝胶体系中熔点随SFC的增加呈现非线性关系增长，但低固体脂肪含量（4.85%）即可赋予植物甾醇/谷维素油凝胶较高的硬度。综上，急冷温度及凝胶剂添加量对植物甾醇/谷维素油凝胶的物理特性具有显著的影响。 To promote the utilization of the phytosterol/oryzanol oleogels in the development of zero-trans, low saturated and nutritional plastic fats, with soybean oil as base oil, phytosterol/oryzanol as gelator, olegoels was prepared under different rapid cooling temperature(5, 20 ℃) and gelator dosages, and the changes of crystal form, crystal morphology, physical stability, texture and thermodynamic properties of phytosterol/oryzanol oleogels were investigated. The results showed that the hardness and melting point of the oleogels increased with the increase of gelator dosage, attributing to a denser arrangement of crystals. Although no obvious effect on the β crystal form of oleogels by rapid cooling temperature, the rapid cooling at 20 ℃ resulted in a denser crystals and higher physical stability compared with rapid cooling at 5 ℃. Compared with the traditional triglyceride solid fat, the relationship between SFC and hardness as well as melting point showed that the melting point increased in a non-linear with the increase of SFC in the oleogels system. Interestingly, a low SFC(4.85%) endowed a high hardness of phytosterol/oryzanol oleogels. To sum up, the rapid cooling temperature and gelator dosage have significant effect on the physical properties of phytosterol/oryzanol oleogels.

Keywords

• 急冷温度；凝胶剂添加量；植物甾醇；谷维素；油凝胶；物理特性
• rapid cooling temperature; gelator dosage; phytosterol; oryzanol; oleogel; physical property