Acid Liquefaction of Potato (Solanum tuberosum) and Sweet Potato (Ipomoea batatas) Cultivars Peels – Pre-Screening of Antioxidant Activity/Total Phenolic and Sugar Contents
Maria Margarida Mateus,
Patricia Ventura,
Andreia Rego,
Carla Mota,
Isabel Castanheira,
João Bordado,
Rui Galhano dos Santos
Affiliations
Maria Margarida Mateus
CERENA-Centre for Natural Resources and the Environment, Instituto Superior Técnico, Av. Rovisco Pais, 1049-001 Lisboa, Portugal; Engineering Department, Universidade Atlântica, Fábrica da Pólvora de Barcarena, 2730-036 Barcarena, Oeiras, Portugal; Portugal
Patricia Ventura
CERENA-Centre for Natural Resources and the Environment, Instituto Superior Técnico, Av. Rovisco Pais, 1049-001 Lisboa, Portugal; Portugal
Andreia Rego
Food and Nutrition Department, National Health Institute Doutor Ricardo Jorge, I. P., Av. Padre Cruz 1649-016 Lisbon, Portugal; Portugal
Carla Mota
Food and Nutrition Department, National Health Institute Doutor Ricardo Jorge, I. P., Av. Padre Cruz 1649-016 Lisbon, Portugal; Portugal
Isabel Castanheira
Food and Nutrition Department, National Health Institute Doutor Ricardo Jorge, I. P., Av. Padre Cruz 1649-016 Lisbon, Portugal; Portugal
João Bordado
CERENA-Centre for Natural Resources and the Environment, Instituto Superior Técnico, Av. Rovisco Pais, 1049-001 Lisboa, Portugal; Portugal
Rui Galhano dos Santos
CERENA-Centre for Natural Resources and the Environment, Instituto Superior Técnico, Av. Rovisco Pais, 1049-001 Lisboa, Portugal; Portugal
In the present study, the liquefaction of both regular and sweet potato peels was conducted to investigate the bio-oil produced, the sugar and total phenolic content, and antioxidant activity. Initially, the bio-oil obtained after liquefaction was partitioned into two different fractions, a hydrophilic fraction and the other consisted of the portion that contained the apolar compounds. Afterward, the samples of the whole bio-oil, aqueous extract, and organic phase of both cultivars were analyzed by attenuated total reflection- Fourier Transform infrared (ATR-FTIR) spectroscopy, hydroxyl number, and acid value. This was done in combination with assessment of the sugar and total phenolic contents and antioxidant activity. The samples demonstrated a considerable content of phenolic moieties in their composition. The antioxidant activity, which was assessed by the 2,2-diphenyl-1-picrylhydrazyl radical method, revealed that the antioxidants of the liquefied products and its extracts were generally better than that of butylated hydroxytoluene. Glucose, sucrose, and maltose were identified and quantified within all of the samples.
