The objective of the present study was to develop sequential extraction procedures for the major carotenoids -beta-carotene and lycopene from agro-industrial waste materials -tomato skin, tangerine and orange peels using the ultrasound-assisted extraction and the supercritical fluid extraction techniques. A rapid, effective and selective high performance liquid chromatographic method for quantitative determination of beta-carotene and lycopene in organic extracts solutions was developed and validated with respect to robustness, specificity, linearity-range, accuracy, precision, limit of detection (LOD) and quantitation (LOQ) as well. The effect of the operating pressure, the temperature, the extraction time, the flow rate of supercritical fluid, the sample size, the ultrasound power and the solvent nature used was investigated. The optimal conditions for extraction were found. The LOD and the LOQ are 0.0081µg/mL and 0.00405 µg/mL for beta-carotene, 0.034 µg/mL and 0.0085 µg/mL for lycopene, respectively. No interference was observed. The content of betacarotene per 1 g of dried agro-industrial waste material varies 8.39 -12.75 µg (tomato skin), 25.65 -32.18 µg (tangerine peel), 41.66 -59.16 µg (orange peel) and the content of lycopene -165.11 -179.56 µg (tomato skin), 11.12 -17.91 µg (tangerine peel), 8.37 -10.65 µg (orange peel).

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The aim of the present study was to develop a is simple, effective, eco-friendly, reproducible and high-yield two-stage ultrasound-assisted extraction (UAE) procedure combined with quantitative determination high performance liquid chromatographic (HPLC) method for obtaining isomeric triterpene acids - oleanolic acid (OA) and ursolic acid (UA) in the crystalline dried powdered form from apple processing agro-industrial waste material. A rapid, sensitive and specific HPLC method was developed and validated with respect to robustness, specificity, linearity-range, accuracy, precision and sensitivity. The effect of the nature and the volume of the extraction solvent, the extraction time and the sample size on the extraction efficiency were investigated. The optimal conditions for high-yield extraction were found.

Background: Apple pomace represents a low-cost and rich source of bioactive compounds with valuable properties - ursolic acid (UA) and oleanolic acid (OA). Due to the wide range of applications in pharmaceutical and nutraceutical industries, these compounds have a high commercial value, and possessing a suitable analytical method with measurement uncertainty is of great significance and practicability. Aim: The purpose of the present work was to estimate detailed measurement uncertainty for the validated HPLC method combined with the extraction procedure for the determination of UA and OA in apple pomace. Methods: The chromatographic analysis using LC-20AD Prominence Shimadzu System and ultrasound-assisted extraction using the ultrasonic bath DW-5200DTS were performed to obtain and determine UA and OA in apple pomace. The process of measurement uncertainty evaluation was performed by the Ishikawa diagram and a combination of bottom-up and top-down approaches. Results: The content of UA and OA (mg/g) in apple pomace with the value of the expanded uncertainty was calculated, which is 7.06 ± 0.647 mg/g (k=1.96; P=95%) and 4.70 ± 0.422 mg/g (k=1.96; P=95%), respectively. Six sources of all the contributors of uncertainties were observed that affected the measurement. Discussion: The A-type standard uncertainty value was 3 times less than the B-type standard uncertainty for both analytes. The results show that B-type standard uncertainty is a major contributor, and the value of the expanded uncertainty of the validated method will not change from test to test in the same laboratory conditions. Conclusions: The methodology described in this work explains well the details and practical aspects of the hybrid approach using the method validation data and proposes step-by-step instructions to evaluate the measurement uncertainty of the quantitative method.