Abstract Commercial shortenings and margarines are mainly produced via rapid cooling with scraped surface heat exchangers (SSHE) and therefore, controlling fat crystallization in the cooling process of these systems plays an important role. In this study, four batches of puff pastry shortening were produced from palm oil blends containing 25% and 50% anhydrous milk fat (AMF) using a bench-top SSHE. The outlet temperature of SSHE was investigated at 20 °C and 12 °C relating to the difference of crystallization temperature between palm oil and milk fat. Physico-chemical properties, crystal morphology and fat stability of these shortenings during storage at 5 °C were determined by various classical technologies including differential scanning calorimetry (DSC), polarized light microscopy (PLM), rheological and texture analyzer. Our results showed that fat blends crystallized at 12 °C had a stronger crystal network after production but the discrepancy of hardness diminished after the first storage week at 5 °C. Besides, the change of crystallization temperature did not affect significantly melting behavior as well as fat polymorphism of products. Upon storage, some big aggregates were detected in shortenings as a combined result of the recrystallization of palm fat crystals and the post-crystallization of milk fat triacylglycerols (TAGs).

中文翻译：

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冷却对棕榈油和无水乳脂混合物制成的酥皮起酥油结晶和理化性质的影响

摘要 商业起酥油和人造黄油主要通过刮板式换热器 (SSHE) 快速冷却生产，因此在这些系统的冷却过程中控制脂肪结晶起着重要作用。在这项研究中，使用台式 SSHE 从含有 25% 和 50% 无水乳脂 (AMF) 的棕榈油混合物中生产了四批酥皮起酥油。SSHE 的出口温度在 20 °C 和 12 °C 下进行了研究，这与棕榈油和乳脂之间的结晶温度差异有关。这些起酥油在 5 °C 下储存期间的物理化学性质、晶体形态和脂肪稳定性通过各种经典技术进行测定，包括差示扫描量热法 (DSC)、偏振光显微镜 (PLM)、流变学和质地分析仪。我们的结果表明，在 12 °C 下结晶的脂肪混合物在生产后具有更强的晶体网络，但在 5 °C 下第一个储存周后硬度差异减小。此外，结晶温度的变化对产品的熔融行为和脂肪多晶型没有显着影响。在储存时，由于棕榈脂肪晶体的重结晶和乳脂三酰甘油 (TAGs) 的后结晶，在起酥油中检测到一些大的聚集体。