title: Optimization of extraction parameters on the antioxidant properties of banana waste.
abstract: BACKGROUND
  Banana is grown worldwide and consumed as ripe fruit or used for culinary purposes. Peels form about 18-33% of the whole fruit and are discarded as a waste product. With a view to exploiting banana peel as a source of valuable compounds, this study was undertaken to evaluate the effect of different extraction parameters on the antioxidant activities of the industrial by-product of banana waste (peel).
  
  
  METHODS
  Influence of different extraction parameters such as types of solvent, percentages of solvent, and extraction times on total phenolic content (TPC) and antioxidant activity of mature and green peels of Pisang Abu (PA), Pisang Berangan (PB), and Pisang Mas (PM) were investigated. The best extraction parameters were initially selected based on different percentages of ethanol (0-100% v/v), extraction time (1-5 hr), and extraction temperature (25-60°C) for extraction of antioxidants in the banana peels. Total phenolic content (TPC) was evaluated using Folin-Ciocalteu reagent assay while antioxidant activities (AA) of banana peel were accessed by DPPH, ABTS, and β-carotene bleaching (BCB) assays at optimum extraction conditions.
  
  
  RESULTS
  Based on different extraction solvents and percentages of solvents used, 70% and 90% of acetone had yielded the highest TPC for the mature and green PA peels, respectively; 90% of ethanol and methanol has yielded the highest TPC for the mature and green PB peels, respectively; while 90% ethanol for the mature and green PM peels. Similar extraction conditions were found for the antioxidant activities for the banana peel assessed using DPPH assay except for green PB peel, which 70% methanol had contributed to the highest AA. Highest TPC and AA were obtained by applying 4, 1, and 2 hrs extraction for the peels of PA, PB and PM, respectively. The best extraction conditions were also used for determination of AAs using ABTS and β-carotene bleaching assays. Therefore, the best extraction conditions used have given the highest TPC and AAs.
  
  
  CONCLUSIONS
  By-products of banana (peel) can be considered as a potential source of antioxidants in food and pharmaceutical industry.
authors.affiliation: Department of Food Science and Nutrition, Faculty of Applied Sciences, UCSI University, Kuala Lumpur, Malaysia.
authors.forename: Pui Yee
authors.initials: PY
authors.lastname: Toh
authors.affiliation: Department of Food Science and Nutrition, Faculty of Applied Sciences, UCSI University, Kuala Lumpur, Malaysia.
authors.forename: Fei Shan
authors.initials: FS
authors.lastname: Leong
authors.affiliation: TÜB&#;TAK Marmara Research Center, Food Institute, Gebze-Kocaeli, Turkey.
authors.forename: Sui Kiat
authors.initials: SK
authors.lastname: Chang
authors.affiliation: Department of Nutrition and Dietetics, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia.
authors.forename: Hock Eng
authors.initials: HE
authors.lastname: Khoo
authors.affiliation: Department of Food Science and Nutrition, Faculty of Applied Sciences, UCSI University, Kuala Lumpur, Malaysia.
authors.forename: Hip Seng
authors.initials: HS
authors.lastname: Yim
mesh_terms: D000096:Acetone / Q000737:chemistry; D000975:Antioxidants / Q000737:chemistry / Q000302:isolation & purification*; D018556:Crops, Agricultural / Q000737:chemistry* / Q000191:economics / Q000254:growth & development; D000431:Ethanol / Q000737:chemistry; D005503:Food Additives / Q000737:chemistry / Q000191:economics / Q000302:isolation & purification; D005525:Food-Processing Industry / Q000191:economics; D005638:Fruit / Q000737:chemistry* / Q000191:economics / Q000254:growth & development; D006358:Hot Temperature; D007220:Industrial Waste / Q000032:analysis* / Q000191:economics; D008296:Malaysia; D000432:Methanol / Q000737:chemistry; D028521:Musa / Q000737:chemistry* / Q000254:growth & development; D010636:Phenols / Q000032:analysis / Q000737:chemistry / Q000191:economics / Q000302:isolation & purification; D010936:Plant Extracts / Q000737:chemistry / Q000302:isolation & purification*; D012997:Solvents / Q000737:chemistry*; D013997:Time Factors
chemical_list: D000975:Antioxidants; D005503:Food Additives; D007220:Industrial Waste; D010636:Phenols; D010936:Plant Extracts; D012997:Solvents; D000096:Acetone; D000431:Ethanol; D000432:Methanol
keywords: antioxidant activity; banana peel; extraction parameters; total phenolic content