During frying operations, vegetable oils break down and compounds with undesirable flavors are produced. Various procedures have been developed to extend the useful life of frying oils, including treatment with bleaching clays. In this article, we describe the activation of kaolin minerals by a combination of grinding and chemical treatments, and report their performance in removing breakdown products generated in palm oil that had been used for 20 hours continuous frying. There was little influence of the original kaolin mineral form on the ability to reduce the free fatty acid (FFA) contents, and grinding only changed FFA reduction from ∼32% to ∼36%. However, much greater FFA reductions were obtained after chemical treatment of the ground clays, and the best performing kaolin product gave similar FFA reduction to a commercial bleaching clay (∼76% and ∼77%, respectively). This activated kaolin also produced a reduction in viscosity at 40 °C from ∼73 to 48.4 cSt (compared to 45.5 cSt in the unused oil), and in the peroxide value from 30.0 to 22.0 meq/kg (compared to 10.0 meq/kg in the initial oil). Thus, activated kaolin samples represent a cheap and convenient alternative to conventional bleaching clay for improving common quality parameters in used palm oil, although we also found that the optimum kaolin preparation conditions were different from those that have been reported for raw rice bran oil refining.

中文翻译：

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活化高岭土矿物作为漂白土，可延长工业油炸操作中棕榈油的使用寿命

在油炸过程中，植物油会分解，产生带有不良风味的化合物。已经开发出各种程序来延长煎炸油的使用寿命，包括用漂白粘土进行处理。在本文中，我们描述了通过研磨和化学处理相结合的高岭土矿物的活化作用，并报告了它们在去除棕榈油中产生的分解产物中的性能，该分解产物已被连续油炸20小时。原始高岭土矿物形式对降低游离脂肪酸（FFA）含量的能力影响不大，而研磨仅使FFA的降低从约32％变为约36％。但是，对地面黏土进行化学处理后，FFA的减少量大大增加，以及性能最好的高岭土产品，其FFA减少量与市售漂白土相似（分别为〜76％和〜77％）。这种活化的高岭土在40°C时的粘度也从约73降低到48.4 cSt（未使用的油中为45.5 cSt），过氧化物值从30.0降低到22.0 meq / kg（相比之下，过氧化氢为10.0 meq / kg）。初始油）。因此，尽管我们还发现最佳的高岭土制备条件与已报道的用于粗制米糠油精制的最佳条件不同，但活化的高岭土样品代表了常规漂白粘土的廉价，方便的替代品，用于改善用过的棕榈油中的常见质量参数。过氧化物值为30.0至22.0 meq / kg（相比之下，初始油中为10.0 meq / kg）。因此，尽管我们还发现最佳的高岭土制备条件与已报道的用于粗制米糠油精制的最佳条件不同，但活化的高岭土样品代表了常规漂白粘土的廉价，方便的替代品，用于改善用过的棕榈油中的常见质量参数。过氧化物值为30.0至22.0 meq / kg（相比之下，初始油中为10.0 meq / kg）。因此，尽管我们还发现最佳的高岭土制备条件与已报道的用于粗制米糠油精制的最佳条件不同，但活化的高岭土样品代表了常规漂白粘土的廉价，方便的替代品，用于改善用过的棕榈油中的常见质量参数。