Non-digestible oligosaccharides of green coffee spent and their prebiotic efficiency.

The processing of green coffee for the extraction of polyphenols resulted in green coffee spent (GCS) accounting
90% dietary polysaccharides. The GCS rich in Non-digestible carbohydrates (oligosaccharides) represent promising
prebiotic nutrients. These Non-digestible oligosaccharides were extracted and characterized for valorization
of the GCS. The enzymatic (Viscozyme), thermal (roasting) and aqueous (hot water infusion) extraction
yielded 19.92 ± 2.1% of Mono-oligosaccharides with mannose (6.90 ± 0.9 μg/Mg) and galactose
(8.35 ± 1.0 μg/Mg) as major components. Further, the GCS oligosaccharides were evaluated for prebiotic efficiency
using Lactobacillus species (L. plantarum, L. casei and L. fermentum). The GCS oligosaccharides also
stimulated the growth of Lactobacillus casei (MTCC 1423) and Lactobacillus fermentum (MTCC 903) by increasing
their number from 8.96 Log CFU/ml to 9.82 Log CFU/ml and from 8.97 Log CFU/ml to 9.66 Log CFU/ml
respectively. The maximum utilisation of Mannose (70%) and galactose (66%) was observed in L. plantarum.
Additionally GCS oligosaccharides tested for acid resistance and found resistant towards artificial human gastric
juice. The non-digestibility of GCS oligosaccharides noted 90% at pH 1. This study provides insights about biosustainable
approach of use of GCS in designing synbiotic functional food.