Method for beta-carotene extraction from processed baby foods as a model for plant-based fatty food products

Reliable quantitative determination of carotenoids in complex food matrices such as processed baby food products is challenging because of their incorporation in rigid cellular structures, their sensitivity to oxidation and their lipophilic character. A one-pot liquid-liquid β-carotene extraction procedure is described for solid baby foods, in the presence of enzymes (Clara-Diastase and Rapidase) facilitating matrix disintegration. The combined extraction and enzymatic dissolution not only protected β-carotene from oxidation compared to the sequential approach, but also reduced the use of solvents and amount of filtrations steps, favouring a higher recovery. The addition of phenolic antioxidants (BHT, TBHQ and BHA) to calibration solutions and during the procedure at 25 mg/mL resulted in an up to 2.5-fold higher absorbance of β-carotene solutions which was not observed for trans-β-apo-8'-carotenal (used as internal standard) solutions. When applying the full procedure on β-carotene spiked sunflower oil, an apparent recovery of 80% for β-carotene was obtained. Finally, this protocol was applied to 50 vegetable-based and 22 fruit-based processed baby foods (range 0 to 1179 and 504 µg/100 g, respectively), and it was concluded that this extraction procedure may be used for similar processed foods products. The procedure proved to be sensitive (LOD = 0.12 µg/mL) and reproducible (CV for baby foods: 4-10%).