Improvement of Physicochemical Properties of Lard Through Modification Catalyzed by a KOH‐Glycerin Low Transition Temperature Mixture

ABSTRACT The properties of fats can be modified by interesterification. Current researches focus on the interesterification catalyzed by lipases and CH3ONa. This work provides a newly modification method of fats catalyzed by potassium hydroxide‐glycerol (KOH‐G) mixture. KOH‐G mixtures (KOH:G, 1:2, 1:3, 1:4, and 1:5 (mol/mol), named by KOH‐G2, KOH‐G3, KOH‐G4, and KOH‐G5, respectively) were prepared and used to catalyze lard modification. The differential scanning calorimetry (DSC) results indicated that KOH‐G mixtures were low transition temperature mixtures (LTTM). The ratios of KOH to G significantly affected the catalytic efficiency of these LTTMs, KOH‐G2 showed higher catalytic efficiency than other KOH‐Gs, moreover the modification could be performed at relatively low temperature (100°C). In the modification process, the interesterification and glycerolysis occurred simultaneously, leading to the variation of triacylglycerols and acylglycerols composition and slip melting point (SMP) of lard. The completely interesterified lard (CIL) was prepared at 100°C for 90 min with 1% KOH‐G2 addition (on lard weight), triacylglycerols and diacylglycerols in CIL were about 88% and 11%, respectively; CIL had lower content of monounsaturated disaturated triacylglycerol (USS), and higher content of tirunsaturated triacylglycerol (UUU), monosaturated‐diunsaturated triacylglycerol (UUS), and trisaturated triacylglyerol (SSS) than lard. Though lard and CIL had similar solid fat content (SFC) profile, they presented obviously different thermal property. The main crystalline form was changed from β of lard to β′ of CIL, and the crystal aggregates of CIL was more delicate than that of lard, implying the sandiness of lard might be alleviated after modification. Practical Application : The results could provide a new method for oil modification, such as improving its physiochemical properties.