Ultrasound-Assisted Extraction in Food Analysis
Food products are complexmixtures of vitamins, sugars, proteins and lipids, ﬁbers, aromas, pigments, antioxidants, and other organic and mineral compounds. Before such substances can be analyzed, they have to be extracted from the food matrix. Direct analyses are generally not possible to achieve due to the complexity of food samples and necessitate the introduction of samples under a liquid form to the analysis detector. Different methods can be used for this purpose, e.g., Soxhlet extraction, maceration, elution, steam distillation, cold pressing, and simultaneous distillation-extraction. Nevertheless, many food ingredients are well known to be thermally sensitive and vulnerable to chemical changes. Losses of some compounds, low extraction efﬁciency, time-and energy-consuming procedures (prolonged heating and stirring in boiling solvent, use of large volumes of solvents, etc.) may be encountered using these extraction methods. These shortcomings have led to the use of new sustainable ‘‘green’’ techniques in extraction, which typically involve less solvent and energy, such as ultrasound-assisted extraction (UAE) , supercritical ﬂuid extraction , headspace method , microwave extraction , controlled pressure drop process , accelerated solvent extraction ,
and subcritical water extraction . Extraction under extreme or nonclassical conditions is currently a dynamically developing area in applied research and industry. Alternatives to conventional extraction procedures may increase production efﬁciency and contribute to environmental preservation by reducing the use of solvents, fossil energy, and generation of hazardous substances.