Investigation of Australian Olive Mill Waste for Recovery of Biophenols

Abstract

Olive mill waste is a potential source for the recovery of phytochemicals with a wide array of biological activities. Phytochemical screening of hexane, methanol, and water extracts revealed a diversity of compounds, perhaps overlooked in previous studies through intensive cleanup procedures. Methanol and water extracts contained large amounts of biophenols, and further testing of polar extraction solvents, including ethyl acetate, ethanol, propanol, acetone, acetonitrile, and water/methanol mixtures, highlighted the latter as the solvent of choice for extraction of the widest array of phenolic compounds. Stabilization of the resulting extract was best achieved by addition of 2% (w/w) sodium metabisulfite. Quantitative data are reported for nine biophenols extracted using 60% (v/v) methanol in water with 2% (w/w) sodium metabisulfite. Six compounds had recoveries of greater than 1 g/kg of freeze-dried waste: hydroxytyrosol glucoside, hydroxytyrosol, tyrosol, verbascoside, and a derivative of oleuropein.

Filamentous fungi from Plantago lanceolata L. leaves: Contribution to the pattern and stability of bioactive metabolites

“…Therefore, water extracts were spiked with different concentrations of sterile ascorbic acid (AA) and Na 2 EDTA (EDTA) solutions, and samples were incubated for 15 days. Acteoside decomposition was quantified from samples, the results are plotted in (Obied et al, 2005), who found that oxygen was essential for acteoside degradation in an olive mill waste model system, and phenolic compounds' recovery could be enhanced by addition of the antioxidant sodium metabisulphite. Antioxidants were also shown to inhibit decomposition of CA derivates in Echinacea (Chantal Bergeron, 2002).…”

Influence of postharvest processing and storage on the content of phenolic acids and flavonoids in foods

“…The extraction efficiency of hydroxycinnamic acids from olive mill waste was highest when 50% v/v aqueous solutions of ethanol, propanol, ACN and acetone were used [85]. The two-phase decanter method preserved more of the phenolic content than the three-phase method by which the oil, water and husk is separated from the olive paste [84].…”

“…The following aspects are mentioned in the papers: Storage under different conditions [3, 14, 16, 20, 23, 40, 41 -43, 46, 49, 53, 63, 67, 68, 70, 74, 75, 77 -80, 83, 91, 100, 102], washing treatment [78,104], blanching [59,65,101], drying [102], sun-drying [37,45], treatment with a growth regulator [23,41], alkaline and acid hydrolysis [90], juice centrifugation [65], flash release process [54], cowinemaking and wine aging [52,56,105], grape destemming [17], fermentation [44,57], germination [22,82,93], extraction [60,84,85,89], thermal stability [44], bread making [86], cooking [22], roasting [97], stir-baked processing [96], steaming [87], thermal treatment [50,58,68,81], SO 2 treatment [106], break-process [72], freezing [4,71], freeze-drying [64], maceration [47,48,51], enzymatic treatment …”

“…Grapefruits [124,126], buckwheat [131], rooibos tea [117], artichokes [132], honey [133], parsley [134], olives [85,134,135], lemons [129,130,136], lettuce [137], pepper [137], chicory [137], wine [138,139], grape juice [7], grapes [124], wheat [140], plums [124], peas [124], bamboo leaves [64,141], oranges [5,66,124,142], ponkan (mandarin-type) [143], tangerine essential oils [144], broccoli [145], hop [18], cabbage [124], and blueberries [124].…”

“…The following list gives an enumeration of all the measures or procedures investigated: Grafting [136], time of harvest [130,137], storage [146], maturity [130], wine ageing [147], geographical origin [144,147], authentication [133], juice and nectar production [129], distribution in fruit [142,143], thermal treatment [5,148], cold-pressing of essential oils [144], extraction procedures [85,142], and recovery from waste [85].…”