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

Abstract

a b s t r a c tCarob 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 g GAE /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.

Nanofiltration and reverse osmosis as a platform for production of natural botanic extracts: The case study of carob by-products

“…Screening of the kibbles using selected sieves (Retsch, Germany) with different pore sizes and an appropriate sieve shaker (EVS1, Endecotts, England) showed that 27% was larger than 8 mm, 40% of the material was between 8 and 4 mm, 21% between 2 and 4 mm, and only 11% of the kibbles was smaller than 2 mm. Aqueous extracts from carob kibbles were produced as described previously [7]. The membranes used in this work are described in Table 1, with specifications obtained from the producers.…”

“…The one-step water extract from carob kibbles, optimised by Almanasrah et al [7] for the recovery of phenolic compounds (at a liquid to solid mass ratio of 4, 100°C and during 220 min), had a dark appearance. Due to the presence of a high concentration of sugars, the extract presented a high viscosity.…”

“…The characterisation of the extract after dilution is shown in Table 3. The phenolic compounds present, identified through capillary zone electrophoresis (CZE) analysis by Almanasrah et al [7], were the high value catechin (molecular mass of 290. The two-steps aqueous extractions from carob kibbles were also optimised in a previous work [7].…”

“…In our previous work [7], a one-step aqueous extraction from carob kibbles was optimised aiming the recovery of phenolic compounds. However, the extract obtained presented a high concentration in mono-and disaccharides and gallic acid.…”

Towards Include Preservation of Vitamins in Fenugreek and Carob Seeds by the Instant Controlled Pressure-Drop Process (DIC Process)

“…Scientific researchers showed that carob seed are rich in phenolic compounds [17], sugar, fatty acids [18], tannins, proteins [19] In this study we will follow the evolution of vitamins in those fenugreek and carob seed, optimize processing conditions by Instant Controlled Pressure Drop…”