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Waste mitigation: From an effluent of apple juice concentrate industry to a valuable ingredient for food and feed applications
- Cruz, Marco G., Bastos, Rita, Pinto, Mariana, Ferreira, João M., Santos, João F., Wessel, Dulcineia Ferreira, Coelho, Elisabete, Coimbra, Manuel A.
- Journal of cleaner production 2018 v.193 pp. 652-660
- apple juice, beta-sitosterol, byproducts, ciders, feed formulation, fructose, glucose, hexane, industrial wastes, ingredients, juice industry, lipophilicity, oligosaccharides, polysaccharides, racing pigeons, sewage, total solids, ultrafiltration, wastewater
- Retentate is a by-product of the concentrate apple juice industry, resultant from clarification through an ultrafiltration process. It has a liquid to sludgy appearance, with 8% of total solids content, usually discarded as industrial waste, conveyed as wastewater directly to the sewage plant. However, its origin and expected composition may allow to define its use as a source of valuable compounds as well as its application in food and feed. The present work shows that retentate is very rich in carbohydrates, namely 40% fructose (dry weight), glucose (8%), oligosaccharides (5%), and polysaccharides (3%). It is also rich in protein (8%) and an available and inexpensive source of β-sitosterol (0.6%). This was the major sterol identified, accounting for 21% of total lipophilic compounds recovered by n-hexane. The retentate suspension was successfully used as nutritive medium for production of cider by a microbrewery and the protein-rich water insoluble material (28% of protein) was successfully used in feed formulations for racing pigeons.