Antioxidants limonene

Many EOs also exhibit antioxidant activity and therefore several studies have been carried out in order to elucidate the activity of the components [139,153]. For instance, y-terpinene retarded the peroxidation of linoleic acid [139, 154-156], sabinene showed strong radical-scavenging capacity [139, 157], a-pinene [158] and limonene [146] showed low antioxidant activity in the 2,2-diphenyl-1-picrylhydrazyl (DPPH) test, while terpinene and terpinolene showed high hydrogen-donating capacity against the DPPH radical [146, 150, 155, 158],... 

Main components Linalyl acetate, linalool, limonene, fi-pinene, y-terpinene. Additives (e.g. carriers, preservatives, antioxidants) NIL Bergaptene less than 20 ppm. 

A low purity (40-80%) divinylbenzene and chloromethylstyrene were used in the presence of a Friedel-Crafts catalyst (AICI3) for the synthesis of a polymeric phenolic antioxidant from p-cresol and l,3-bis(l-hydroxy-l-methylethyl)benzene in the presence of p-toluene sulfonic acid [115]. The obtained product was either used directly as AO for thermosetting resins or was treated consecutively with a-methylstyrene [116] or /ert-butylalcohol [117]. Other polymeric phenolic AO were obtained by reaction of phenol with p-men thane-1,8-diol, l-p-menthen-8-ol or limonene [118] or of p-cresol with 3- or 4-chloromethylstyrene in the presence of BF3-etherate or anhydrous AICI3 [119] the product thus obtained was finally aralkylated by a-methylstyrene. Thermostabilizer and/or LS for PUR was obtained, e.g. 98. 

Limonene has recently been used in rice bran oil extraction as an alternative to hexane, which is commonly used in such processes.The yield and quality of crude rice bran oil obtained from the limonene extraction were almost equivalent to those obtained using hexane. Interestingly, although antioxidants were not present in the limonene, only a very small amount (<1 wt%) of oxidation product was found in the recovered limonene, and therefore the solvent is potentially recyclable in such a process. This also suggests that... 

Tocopherol was effective and ascorbic acid ineffective in the protection of citrus oils evaluated by aroma (13). In a typical study, 5 g of orange oil was oxidized in 75-mL open brown bottles at 45°C and was evaluated by a panel after 6 d, at which time it was ranked as off-odor, "terpeney. The peroxide value of the initial oil was zero the oxidized material had a PV of 100. As a result, days to reach 100 PV was used as an endpoint. Comparative antioxidant effects on a number of citrus oils and on D-limonene [cyclohexene, l-methyl-4-(l-methylethenyl)-(R)-5989-27-5] are presented in Table X. BHA is the most active while AP has no activity alone but does synergize with tocopherol. 

See the discussion above about International Eragrance Association (IFRA) guidelines that D-limonene is a recommended quencher in that it can decrease the sensitizing effect of cinnamic aldehyde when used at a 1 1 ratio with cinnamic aldehyde. IFRA guidelines also state that limonene and natural products containing substantial amounts of it should only be used when the level of peroxides is kept to the lowest practical level, for instance by adding antioxidants at the time of production. Such... 

Karlberg, A.T., Magnusson, K. and Nilsson, U. 1994. Influence of an antioxidant on the formation of allergenic compounds during auto-oxidation of 4-limonene. Ann. Occup. Hyg. 38(2) 199-207. 

Methyl oleate N,N,N, N -Tetramethylethylenediamine Triethylamine intermediate, rubber accelerators Allyl mercaptan t-Butylamine Diethylamine Isopropylamine 2-Methylpropanal p-Phenylenediamine Piperidine intermediate, rubber additives Benzoyl chloride intermediate, rubber antioxidants 2-Methylpropanal intermediate, rubber chemicals Benzonitrile Bisphenol A n-Butylamine Cyclopentanone Diethanolamine Ethylene carbonate Ethylenediamine Hexamethyleneimine dl-Limonene 2-Mercaptoethanol... 

Pino et al. (2010) investigated the chemical composition and antioxidant features of leaf and fruit essential oil of Melaleuca lucandendra L. GC-MS revealed 41 volatile compounds for the leaf oil, where the main compounds were 1,8-cineole (43.0%), a-pinene (5.3%), a-terpineol (7.0%), limonene (4.8%), and viridi orol (24.2%), while for fruit oil, 64 compounds were identi ed with viridi orol (47.6%) as the most present compound, followed by globulol (5.8%), guaiol (5.3%), and a-pinene (4.5%) also as major compounds. 

Singh, P., R. Shukla, B. Prakash et al., 2010b. Chemical pro le, antifungal, antia atoxigenic and antioxidant activity of Citrus maxima Burm. and Citrus sinensis (L.) Osbeck essential oils and their cyclic mono-terpene, -limonene. FoodCjwmCTQ j., 48(6) 1734 1740. 

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