Simple extraction procedure for free amino acids determination in selected gluten-free flour samples

Sylwia Kowalska,Aneta Jastrzębska,Edward Szłyk

doi:10.1007/s00217-021-03896-7

Sylwia Kowalska, Aneta Jastrzębska + Show 1 more

Open Access

https://doi.org/10.1007/s00217-021-03896-7

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Abstract

The simple extraction of flours samples followed by free amino acids determination procedures was studied and optimised. The conditions of amino acids derivatisation reaction with ninhydrin for chromatographic determination of free amino acids sum was discussed. The developed method was processed in terms of linearity, precision, accuracy, and limits of detection and quantification. Moreover, capillary isotachophoresis and HPLC methods were applied for individual free amino acids determination. The proposed extraction procedure is simple, fast and convenient for different flours samples. Studied procedures were used for free amino acids determination in twelve gluten-free flour samples (corn, oat, soy, rice, pumpkin, millet, peanut, hemp seed, buckwheat, amaranth, pea and chickpea) and the obtained results were compared with wheat flour.

Highlights

Due to the changes in consumer’s preferences, the demand for gluten-free products is increasing [1]
Majority of amino acids exhibit high polarity, low volatilisation, and lack of chromophore group, resulting in difficult separation and detection. These compounds were initially analysed by ion-exchange chromatography followed by postcolumn derivatisation with ninhydrin and ultraviolet detection
Ninhydrin is still frequently used as a derivatisation reagent for spectrophotometric or chromatographic determination of amino acids [7, 13, 30]

Summary

Introduction

Due to the changes in consumer’s preferences, the demand for gluten-free products is increasing [1]. Many different non-wheat cereals, pseudocereals and pulses have gained the increased attention of the food industry as an alternative to wheat products [2, 3] Cereals such as corn, rice, barley, and legumes are known for their nutritional properties, they are consumed worldwide and used for gluten-free food production [1, 2]. Rice, barley, and legumes are known for their nutritional properties, they are consumed worldwide and used for gluten-free food production [1, 2] Pseudocereals, such as buckwheat or amaranth, exhibit nutritional features which make them suitable for replacing, at least partly, traditional cereal-based products.

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