Selective recovery of phenolic compounds and carbohydrates from carob kibbles using water-based extraction

• The selective recovery of carob kibbles’ sugars and phenolics was accomplished by a two-step aqueous extraction.
• It yield a nearly complete recover of sugars and a high recover of phenolics (70%).
• The developed strategy was easily scaled-up.

Carob kibbles are an important renewable source of valuable compounds, such as fermentable sugars and phenolic compounds. However, the selective recovery of these compounds is not a trivial task. In this work, a strategy was developed to enable the recovery of both classes of compounds by means of a water-based extraction.One-step extraction recovered only approximately 20% of the phenolic compounds, corresponding to an extraction yield of 0.6 g Gallic acid equivalents (GAE)/100 g dry mass of carob kibbles. The obtained extract contained a significant amount of carbohydrates (110 g/L). The alternative two-step extraction developed enabled higher compound selectivity together with an increase in the yield of the phenolic compounds to about 70%, corresponding to 1.9 gGAE/100 g carob dry matter.The two-step extraction was easily scaled-up and is an effective method to obtain significantly separated carbohydrates and polyphenol-rich streams that can be further processed, e.g., in biorefineries or food industries, respectively.