Determination of stearoyl lactylate in starchy products using liquid chromatography method after hydrazine derivation

Abstract

Sodium stearoyl lactylate (SSL) is an emulsifying agent that significantly enhances dough volume, surface area, and structural integrity while also increasing air retention even with a small amount of yeast added. Its remarkable properties extend to improving preservation quality, facilitating finer slicing, and inhibiting microbial proliferation, thereby reducing shortening. Owing to these benefits, SSL finds extensive application in the production of starch-containing industrial products. In this study, SSL was quantified following the hydrazine derivatization stage using the HPLC-PDA method. The lactate derivative was analyzed on a C18 column with a gradient program comprising 0.1% formic acid and acetonitrile. The method was validated and met the AOAC requirements for good linearity (R2 = 1). The limits of detection (LOD) and limits of quantification (LOQ) were 2.00 mg/kg and 6.66 mg/kg SSL for bread samples; 1.45 mg/kg and 4.82 mg/kg for biscuit samples. Precision was performed on spiked bread and biscuit matrices with relative standard deviations of repeatability RSDr = 1.91% and 3.07%, respectively; the relative standard deviation of reproducibility (RSDR) was 4.22% and 3.47%. Recovery values ranged between 95.1% and 105% for bread and 95.4% to 104.7% for biscuits. The validated method was subsequently applied to analyze SSL content in 20 different starchy products purchased in the Hanoi market.