PL EN
Distilled Spirit Extraction of Phenolic Antioxidants from Fruit and Vegetable Residues
Cesar Ortinero 1  
,   Rosalie Rafael 2  
,   Charmaine Eljie Rayos 3  
,   Katherine Bautista 4  
,   Mark Aldren Feliciano 2  
,   Lexter Natividad 3  
,   Gaudencio Natividad 2, 4  
 
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1
Department of Environmental Science, College of Science, Central Luzon State University, Science City of Muñoz 3120, Nueva Ecija, Philippines
2
Department of Chemistry, College of Science, Central Luzon State University, Science City of Muñoz 3120, Nueva Ecija, Philippines
3
University Science High School, College of Education, Central Luzon State University, Science City of Muñoz 3120, Nueva Ecija, Philippines
4
Philippine Science High School – Cagayan Valley Campus, Bayombong 3700, Nueva Vizcaya, Philippines
CORRESPONDING AUTHOR
Cesar Ortinero   

Central Luzon State University
Publication date: 2021-01-01
 
J. Ecol. Eng. 2021; 22(1):125–131
 
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ABSTRACT
There is a growing interest in natural antioxidants due to their potential in improving the quality of food and cosmetic products and their health-promoting properties. Distilled spirits contain high amount of ethanol and may be an alternative to the food-grade solvents, while agricultural by-products contain phenolic substances that may have antioxidant properties. This study was therefore conducted to find out if gin, vodka, and tequila flavored spirit, alcoholic beverages with about 40% ethanol, can extract the phenolic compounds from agricultural by-products, and to determine if the extracts possess the antioxidant activity. Peels of ripe banana (Musa acuminata), ripe mango (Mangifera indica), calamansi (Citrofortunella microcarpa), squash (Cucurbita maxima), ripe pineapple (Ananas comosus), purple yam (Dioscorea alata), and sweet potato (Ipomea batatas) were collected, dried, and ground. The phenolic substances in the plant materials were extracted with alcoholic beverages or 40% ethanol. The total phenolic content (TPC) of the extracts was determined by means of UV-Vis spectroscopy using Folin-Ciocalteau reagent and gallic acid as reference compound. The antioxidant activity of the extracts was evaluated through the 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assay. Butylated hydroxyanisole (BHA) served as positive control in the DPPH assay. Non-linear regression was applied to the DPPH assay data to estimate the values of median effective concentration (EC50). All three alcoholic beverages were able to extract the phenolic materials from the plant samples. However, the ability of vodka and gin to extract the phenolic substances was either statistically comparable or better than 40% ethanol. The results of the DPPH scavenging assay showed that the M. indica peel had the strongest activity, while C. microcarpa had the weakest scavenging activity. At 1000-ppm level, the antioxidant activity of the M. indica peel was comparable with that of BHA, regardless of the solvent used for extraction. Therefore, the M. indica peel can be a source of natural antioxidants and potential substitute to synthetic antioxidants. Both gin and vodka can be used as a substitute for food-compatible solvents.