Comparative extraction approaches of cell wall polysaccharides from cranberry pomace sources: Aqueous, alkaline, sequential (acid/alkaline) and enzymatic extractions

Cranberry pomace, a major by-product of juice production, is a valuable source of carbohydrates and polyphenols. This study investigated four types pomace types: two pomaces from cultivar Stevens , and downgraded fruits, and two milled and side-stream pomaces from juice production. The comparison of composition and polyphenol content between these sources enabled the examination of the effects of cranberry variety, fruit quality, and processing scale on pomace composition. Carbohydrates, particularly dietary fiber, ranged from 55.9 to 81.9%, depending on the source and pomace type. Pectic polysaccharides predominated in pomaces (52.7-60.0%) and their corresponding cell wall materials (66.1-73.9%), with uronic acid proportions ranging from 20.4 to 25.3% and from 30.7 to 41.4%, respectively. Different extraction methods, including hot water, alkaline, sequential (acid/alkaline), and enzymatic extractions were investigated. Sequential (55.3%) and enzymatic (49.2%) extractions yielded the highest pectic polysaccharide proportions compared to water (37.1%) and alkaline (32.8%) extractions. Hemicellulosic polysaccharides were more abundant in water (62.8%) and alkaline extracts (66.5%). High molecular weight polysaccharides (100-500 kDa) and (10-100 kDa) were abundant in alkaline extract. Oligosaccharides (0.5-3 kDa) were predominantly produced by sequential, water and enzymatic extractions.