Effect of Lard Quality on Chemical Interesterification Catalyzed by KOH/Glycerol

The effects of water content, acid value, and peroxide value on interesterification catalyzed by potassium glycerolate (in situ KOH/glycerol) were investigated using lard as a model fat. SEM analysis of KOH/glycerol powder showed that numerous 0.5‐ to 5‐μm porous structures were formed and may play an important role in the interesterification reaction. Water content (up to 10 %, oil weight) and peroxide value (4.29 and 7.11 mmol/kg) significantly extended the induction period of interesterification but complete randomization was still achievable. However, when the acid value reached 5.13 mg KOH/g, complete deactivation of the catalyst was observed at 1 % catalyst content (by oil weight). The sn‐2 fatty acid composition of fully randomized lard was similar to that of non‐randomized lard. Interesterification resulted in substantial rearrangement of the triacylglycerol species and alteration of thermal behaviors. The interesterified lard exhibited a predominant β′ polymorph, as opposed to the dominating β‐form crystals found in the original lard.     

Preparation of Highly Pure n-3 PUFA-Enriched Triacylglycerols by Two-Step Enzymatic Reactions Combined with Molecular Distillation

Highly pure n-3 polyunsaturated fatty acids (PUFA)-enriched triacylglycerols (TAG) have attracted considerable attention due to their nutritional benefits and pharmacological effects. In this study, an alternative approach to the conventional method for the synthesis of highly pure n-3 PUFA-enriched TAG by using a multi-step process was reported. First, glyceride mixtures were synthesized through Novozym 435 [Novozymes A/S (Bagsvaerd, Denmark)] catalyzed esterification of n-3 PUFA-enriched FA and glycerol. Second, partial glycerides in the resulting glyceride mixtures were hydrolyzed to FA by immobilized partial glycerides-selective lipase from Malassezia globosa. The purity of TAG reached 99.84% under the optimized conditions: buffer solution of pH 6.0, water content of 100% (w/w, with respect to the oil mass), enzyme loading of 120 U/g (U/w, with respect to oil mass) and reaction temperature of 30 °C. During hydrolysis, the immobilized SMG1-F278N exhibited good reusability and TAG purity of over 94% was maintained after being used for six cycles. Subsequently, purification of TAG was accomplished by molecular distillation at low temperature (150 °C) and highly pure (99.85%) TAG with 88.73% n-3 PUFA was obtained. The final glyceride mixtures with low acid, peroxide and anisidine value were promising products for medical and dietetic purposes. Compared with the conventional one-step synthesis of n-3 PUFA-enriched TAG by enzymatic esterification or glycerolysis or the two-step method by combined transesterification and ethanolysis, this improved process allows for higher purity of n-3 PUFA-enriched TAG and significant reduction in reaction time.     

Characterization and Compositional Studies of Oil from Seeds of Desi Chickpea (Cicer arietinum L.) Cultivars Grown in Pakistan

The physiochemical properties and fatty acid (FA) composition of oil from seeds of four desi chickpea cultivars, grown in Pakistan, were investigated. The oil content was relatively low (5.88–6.87%). The physiochemical parameters determined included refractive indices (RI) at 40 °C (1.48–1.49), relative density (0.95–0.96), iodine value (IV) (111.87–113.69), acid value (AV) (2.55–2.73 mg KOH/g), saponification value (SV) (183.98–185.64 mg KOH/g), unsaponifiable matter (UM) (2.99–3.71%), peroxide value (PV) (3.97–6.37 mequiv/Kg), p-anisidine value (p-AV) (5.39–8.74), and oxidation value (OV) (13.67–22.34). Linoleic acid and oleic acid were the dominant FAs. Results from most of the parameters revealed significant (P < 0.05) differences among the cultivars. The findings reveal Desi chickpea (Cicer arietinum L.), indigenous to Pakistan, to be a potentially valuable legume crop with comparable nutritional quality oil.     

Preparation of partial glycerides by direct esterification1

A previously described procedure for the direct esterification of diglycerides without interesterification occurring has been evaluated for the preparation of mono and diglycerides. The esterifications were accomplished withp-toluenesulfonic acid catalyst and with continuous removal of water of esterification by azeotropic distillation. The effect of such variables as unsaturation, chain length, mode of addition of solvent and reaction temp on the composition and yield of glycerides was observed. Chemical and chromatographic analyses were used to determine the composition of the glycerides and their component fatty acids and to detect the presence of isomeric glycerides. Simple esterification of 1-monostearin with oleic acid at 80C yielded as much as 72.3% diglycerides, and esterification of glycerol with stearic acid at 100C yielded up to 70.1% monoglycerides, each calculated on a glyceride basis. It is concluded that simple esterification predominates with some intra- and interesterification occurring. Presented at the AOCS Meeting, Toronto, 1962.     

Limit of the solid fat content modification of butter

Three ways have been undertaken to modify solid fat content of butter oil: (i) interesterification, (ii) adjunction of high-melting glycerides and (iii) joint effect of adjunction of high-melting glycerides and interesterification. A solvent-free interesterification, carried out with 1,3-specific lipase fromMucor miehei, resulted in an increase of the solid fat content (SFC) by about 114% after 48 h of interesterification. The changes in triglyceride composition induced by this method were followed by quantitative determination of triglycerides of different equivalent carbon number (ECN) and different theoretical carbon number. The major changes in the triglyceride composition occurred mainly in the concentration of three groups of triglycerides with the same ECN (ECN=38). Adding high-melting glycerides trimyristin (MMM) and tripalmitin (PPP) led to an increase of the SFC measured at 20°C as these proportions increased in the mixture. The joint effect of the addition of MMM or PPP and interesterification was quite significant, mainly for triglycerides that included myristic and palmitic acids. As far as the increase of SFC is concerned, the effect of interesterification decreases when both substrate amounts increase.     

Interesterification of edible oils

Types of interesterification discussed are (a) interchange between a fat and free fatty acids, in which the most important reaction is the introduction of acids of low mol wt into a fat with higher fatty acids; (b) interchange between a fat and an alcohol, e.g., with glycerol, in order to produce emulsifiers like monoglycerides; (c) rearrangement of fatty acid radicals in triglycerides, the so-called transesterification which in recent years has taken on the same importance as hydrogenation or fractionation. In natural fats, the fatty acid radicals are not usually randomly distributed but become so by rearrangement; the distinctive physical properties of natural fats and oils can be changed within limits by this transesterification. Well-known examples are cocoa butter, palm oil, and lard. More important is the transesterification of a mixture of different fats and oils; e.g., the combination of hydrogenation and interesterification allows the production of a solid fat with high linoleic acid content. The composition of glycerides after random interesterification can be calculated by formulas. Distinct from random is such directed interesterification. This is done by working at low temperatures that glycerides with higher melting point crystallize from the reaction mixture. Directed interesterification can be combined with fractionation, for instance, to get a higher yield of liquid fraction from palm oil than is obtained by fractionation alone. The transesterification process can be performed in a batch or continuously. A small amount of metallic sodium or sodium ethylate is used as catalyst, which is destroyed by water or acid and removed after the reaction.     

Influence of Extraction Method on Yield,Physicochemical Properties and Tocopherol Content of Manketti (<Emphasis Type="Italic">Schinziophyton rautanenii</Emphasis>) Nut Oil

The influence of extraction method on yield, physicochemical characteristics and tocopherol content of manketti nut oil extracted by four different methods has been determined. Soxhlet (SE) and supercritical fluid (SFE) extractions yielded 45.3 and 44.8%, respectively, while screw press and mechanical shaking extractions had 39.7 and 27.3%, respectively. SPE and SE extractions gave oils that had lower values of unsaponifiable matter (0.70; 0.74%) indicating lower amounts of minor components such as tocopherols (233.13; 290.68 µg/g oil), a greater extent of lipid peroxidation parameters; peroxide values (6.25; 3.01 mequiv O₂/kg), para‐anisidine values (10.22; 9.94), totox value (22.72; 15.96), flavour score (?0.25; 2.11), and high acid values (1.23; 1.03 mg KOH/g oil), respectively, compared to SFE and MSE oils. This was attributed to the high processing temperatures of SPE and SE extractions compared to SFE and MSE oils. Refractive indices (1.485–1.487), iodine values (127.97–129.07, Wijs) and density (0.908–0.914 g/cm³) were not affected by extraction method indicating that the oils generally had the same double bond content. Saponification values (182.98–192.95 mg KOH/g oil) and ester values (181.95–192.11), were not affected by extraction method except for SE oil which had lower values that were speculated to be due to co‐extraction with colour pigments.     

Synthesis,characterization, and comparison of self‐doped,doped, and undoped forms of polyaniline,poly(o‐anisidine), and poly[aniline‐co‐(o‐anisidine)]

Polyaniline (PANI), poly(o‐anisidine), and poly[aniline‐co‐(o‐anisidine)] were synthesized by chemical oxidative polymerization with ammonium persulfate as an oxidizing reagent in an HCl medium. The viscosities, electrical conductivity, and crystallinity of the resulting polymers (self‐doped forms) were compared with those of the doped and undoped forms. The self‐doped, doped, and undoped forms of these polymers were characterized with infrared spectroscopy, ultraviolet–visible spectroscopy, and a four‐point‐probe conductivity method. X‐ray diffraction characterization revealed the crystalline nature of the polymers. The observed decrease in the conductivity of the copolymer and poly(o‐anisidine) with respect to PANI was attributed to the incorporation of the methoxy moieties into the PANI chain. The homopolymers attained conductivity in the range of 3.97 × 10^?3 to 7.8 S/cm after doping with HCl. The conductivity of the undoped forms of the poly[aniline‐co‐(o‐anisidine)] and poly(o‐anisidine) was observed to be lower than 10^?5 J/S cm^?1. The conductivity of the studied polymer forms decreased by the doping process in the following order: self‐doped → doped → undoped. The conductivity of the studied polymers decreased by the monomer species in the following order: PANI → poly[aniline‐co‐(o‐anisidine)] → poly(o‐anisidine). All the polymer samples were largely amorphous, but with the attachment of the pendant groups of anisidine to the polymer system, the crystallinity region increased. The undoped form of poly[aniline‐co‐(o‐anisidine)] had good solubility in common organic solvents, whereas doped poly[aniline‐co‐(o‐anisidine)] was moderately crystalline and exhibited higher conductivity than the anisidine homopolymer. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

Preparation of glycerides by controlled esterification

A simple procedure for esterifying glycerides without interesterification occurring would be highly useful for preparing on a large scale a number of tailor-made fats, including cocoa butter-like fats. Such esterifications were carried out by employingp-toluenesulfonic acid as catalyst and continuously removing the water of esterification by azeotropic distillation with aliphatic hydrocarbons or by stripping with vaporized hydrocarbons. Even thoughp-toluenesulfonic acid rapidly disproportionated 1-monostearin, even at 120C, apparently esterification was faster and only a moeerate amoung of ester-ester interchange and acidolysis occurred. Diacid glycerides might be prepared from monoglycerides by the procedure which was employed. Saturated diglycerides were esterified with oleic acid with little ester-ester interchange or acidolysis occurring; however, intraesterification was extensive. The reaction between 1,3-distearin and oleic acid yielded approximately 75% 1-oleodistearin and 25% 2-oleodistearin. Saturated diglycerides were esterified with sebacic acid, again with little or no interesterification occurring. Presented at the AOCS meeting in New Orleans, La., 1962; and at the VIth Congress of the International Society for Fat Research, London, England, 1962. A laboratory of the So. Utiliz. Res. and Dev. Div., ARS, U.S.D.A.     

Thermal Oxidation Kinetics of Refined Hazelnut Oil

In this study, oxidation kinetics of refined hazelnut oil heated at the temperature range from 80 to 180 °C was evaluated. The changes in peroxide value, p‐anisidine value, polymer triglyceride content, α‐tocopherol content, and color values during oxidation were best fitted to zero‐order kinetic model. The rate constants for the p‐anisidine value, polymer triglyceride content, and degradation of α‐tocopherol of hazelnut oil increased at the temperatures between 80 and 160 °C, while the rate constant for peroxide value decreased at the temperatures between 80 and 140 °C. The activation energies for the formation of peroxides (at 80–140 °C), secondary oxidation products such as alkenals, the polymer triglycerides, and degradation of α‐tocopherol were found as 47.49, 29.95, 52.65, and 14.22 kJ mol^?1, respectively. The induction period of hazelnut oil was observed to reduce with increasing oxidation times. The increase in the b* value with the oxidation time and temperature was attributed to the fact that the heating process intensified the yellow color of the oil.     

Influence of lipase-catalyzed interesterification on the oxidative stability of melon seed oil triacylglycerols

Melon seeds are rich in oil. However, the stability of melon seed oil (MSO) is low because of its high content of the essential fatty acid, linoleic acid (18:2n-6). MSO was physically blended or enzymatically interesterified with higholeic sunflower oil (HOSO). The fatty acid composition of MSO was remarkably changed after interesterification. Palmitic (16:0), stearic (18:0), and oleic (18:1n-9) acid contents increased at the sn-2 position of triacylglycerols, whereas 18:2n-6 decreased due to interesterification. The oxidative stability of the physical and Pseudomonas sp. (PS30) lipase-interesterified blends was assessed with the Oxidative Stability Instrument, peroxide value, and conjugated diene methods. The stability of MSO increased with increased proportions of HOSO, which was the source of 18:1n-9 in the blends. The ratio of 18:1n-9/18:2n-6 improved from 0.18 in MSO to 1.47 in the enzymatically interesterified blend. Calculated oxidizability and the results of oxidation tests of the blends confirmed the improvement in MSO stability by both physical blending and enzymatic interesterification.     

Enzymatic interesterification of tallow-sunflower oil mixtures

In an effort to improve the physical and/or thermal characteristics of solid fats, the enzymatic interesterification of tallow and butterfat with high-oleic sunflower oil and soybean oil was investigated. The two simultaneously occurring reactions, interesterification and hydrolysis, were followed by high-performance liquid chromatography of altered glycerides and by gas-liquid chromatography of liberated free fatty acids. The enzymes used in these studies were immobilized lipases that included either a 1,3-acyl-selective lipase or acis-9-C₁₈-selective lipase. The degree of hydrolysis of the fat/oil mixtures was dependent upon the initial water content of the reaction medium. The extent of the interesterification reaction was dependent on the amount of enzyme employed but not on the reaction temperature over the range of 50–70°C. Changes in melting characteristics of the interesterified glyceride mixtures were followed by differential scanning calorimetry of the residual mixed glycerides after removal of free fatty acids. Interesterification of the glyceride mixes with the two types of enzymes allowed for either a decrease or increase in the solid fat content of the initial glyceride mix.     

Influence of lipase-catalyzed interesterification on the oxidative stability of melon seed oil triacylglycerols

Melon seeds are rich in oil. However, the stability of melon seed oil (MSO) is low because of its high content of the essential fatty acid, linoleic acid (18:2n-6). MSO was physically blended or enzymatically interesterified with higholeic sunflower oil (HOSO). The fatty acid composition of MSO was remarkably changed after interesterification. Palmitic (16:0), stearic (18:0), and oleic (18:1n-9) acid contents increased at the sn-2 position of triacylglycerols, whereas 18:2n-6 decreased due to interesterification. The oxidative stability of the physical and Pseudomonas sp. (PS30) lipase-interesterified blends was assessed with the Oxidative Stability Instrument, peroxide value, and conjugated diene methods. The stability of MSO increased with increased proportions of HOSO, which was the source of 18:1n-9 in the blends. The ratio of 18:1n-9/18:2n-6 improved from 0.18 in MSO to 1.47 in the enzymatically interesterified blend. Calculated oxidizability and the results of oxidation tests of the blends confirmed the improvement in MSO stability by both physical blending and enzymatic interesterification.     

Physicochemical and thermal characterization of seed oil from Mexican mamey sapote <Emphasis Type="Italic">(Pouteria sapota)</Emphasis>

The aim of this research was to perform a physicochemical characterization of native mamey sapote seed oil [Pouteria sapota (Jacq.) H.E. Moore and Stearn]. Mamey sapote seed oil showed good oxidative stability as it had low peroxide, free fatty acid, and p‐anisidine values. The main fatty acids present in the oil were palmitic, stearic and oleic acid, constituting five major triacylglycerides families: PLP, POP, StOO, POSt and StOSt. Crystallization and melting points of the oil were ?37.7 and 23.84 °C, respectively. The oil had higher SFC when the temperature was lower than 10 °C. X‐ray diffraction patterns showed that prolonged storage times lead to the formation of β crystals. Micrographs showed granular crystals (91–105 μm), with needle edges similar to cocoa butter. In addition, mamey sapote seed oil can be used in confectionery products or as a possible substitute for cocoa butter to improve and obtain good‐quality products.     

Oxidative Stability and Changes in Chemical Composition of Extra Virgin Olive Oils After Short‐Term Deep‐Frying of French Fries

We aimed at investigating oxidative stability and changes in fatty acid and tocopherol composition of extra virgin olive oil (EVOO) in comparison with refined seed oils during short‐term deep‐frying of French fries, and changes in the composition of the French fries deep‐fried in EVOO. EVOO samples from Spain, Brazil, and Portugal, and refined seed oils of soybean and sunflower were studied. Oil samples were used for deep‐frying of French fries at 180 °C, for up to 75 min of successive frying. Tocopherol and fatty acid composition were determined in fresh and spent vegetable oils. Tocopherol, fatty acid, and volatile composition (by SPME–GC–MS) were also determined in French fries deep‐fried in EVOO. Oil oxidation was monitored by peroxide, acid, and p‐anisidine values, and by Rancimat after deep‐frying. Differential scanning calorimetry (DSC) analysis was used as a proxy of the quality of the spent oils. EVOOs presented the lowest degree of oleic and linoleic acids losses, low formation of free fatty acids and carbonyl compounds, and were highly stable after deep‐frying. In addition, oleic acid, tocopherols, and flavor compounds were transferred from EVOO into the French fries. In conclusion, EVOOs were more stable than refined seed oils during short‐term deep‐frying of French fries and also contributed to enhance the nutritional value, and possibly improve the flavor, of the fries prepared in EVOO.     

Fatty acid composition and physicochemical properties of ostrich fat extracted by supercritical fluid extraction

The objective of this study was to determine the fatty acid composition and physicochemical properties of ostrich fat obtained by supercritical fluid extraction. The fatty acid composition was analysed by GC‐MS and the result revealed that ostrich fat contained 9‐octadecenoic acid (40.7 ± 0.3%), hexadecanoic acid (32.5 ± 0.3%), octadecanoic acid (7.43 ± 0.05%), 9, 12‐octadecadience acid (7.38 ± 0.02%) and 9‐hexadecenoic acid (7.13 ± 0.15%) as the major components. Furthermore, seven physicochemical indexes were assessed according to Chinese Pharmacopeia (2005) and relevant regulations as follows: relative density (0.92 ± 0.02%), melting point (34.7 ± 0.4°C), acid value (0.84 ± 0.02 mg KOH/g), peroxide value (0.10 ± 0.01 g/100 g), saponification value (226 ± 3 mg KOH/g), ester value (225 ± 3 mg KOH/g) and iodine value (74.6 ± 0.8 g I/100 g). It can be inferred from the basic information that ostrich fat is a promising raw material for the pharmaceutical and cosmetics industries. Practical applications : With the increasing attention being paid to ostrich fat, it is necessary to elucidate the fatty acid composition and physicochemical properties of this natural product. This basic information not only reveals the essential characteristics of ostrich fat, but also provides the data support for the quality evaluation and efficacy research.     

Stability of Cold-Pressed Oil from Commercial Indian Niger (Guizotia abyssinica (L.f.) Cass.) Seed as affected by Blending and Interesterification

Blending and interesterification of cold‐pressed oil from commercially available niger (Guizotia abyssinica (L.f.) Cass.) seeds was performed to improve its stability. The fatty acid composition of cold‐pressed niger seed oil (NSO) revealed that it contained a huge amount of polyunsaturated linoleic acid (69.2 %). NSO being rich in polyunsaturated fatty acids (PUFA) was susceptible to oxidation and hence was blended with saturated fatty acid (SFA) rich coconut oil (CNO) and monounsaturated fatty acid (MUFA) rich olive–pomace oil (OO) to enhance its stability. CNO contained a total of 91.3 % of SFA, while OO had oleic acid, C18:1 (74.3 %) as MUFA. Two blends of NSO with CNO and OO, i.e. NSO + CNO(B) and NSO + OO(B), were prepared in the ratio of 1:1. The blends were further interesterified using the lipase enzyme from Rhizomucor meihei and interesterified oils, i.e. NSO + CNO(I) and NSO + OO(I), were obtained. The oxidative stability of the oils was evaluated by incubating them at 37 °C and 55 % relative humidity (RH) for a period of 45 days. The peroxide values of NSO + CNO(B), NSO + OO(B), NSO + CNO(I) and NSO + OO(I) showed a reduction by 53.3, 42.6, 65.3 and 55.4 %, respectively, while the conjugated diene values showed a reduction by 75.0, 66.9, 76.7 and 75.3 %, respectively, as compared to NSO during the incubation period. This is probably the first report on the stability improvement of niger seed oil through blending and interesterification.     

Styrenation of castor oil and linseed oil by macromer method

In this study a novel macromer technique has been described for the styrenation of triglyceride oils. Macromers were prepared through the interesterification of castor oil with linseed oil followed by esterification with acrylic acid. In this preparation various castor oil/linseed oil ratios were applied to obtain a macromer which gave a copolymer with good film properties after copolymerization with styrene. Macromers were styrenated at 100°C using benzoyl peroxide as an initiator. The styrenation leads to improved film properties with the related interesterification product although castor oil is a non‐drying oil.     

Chemical Characterization of Six Microalgae with Potential Utility for Food Application

Microalgae contain high levels of proteins, carbohydrates, and lipids, and have found a useful application in enhancing the nutritional value of foods. These organisms can also synthesize long‐chain fatty acids in the form of triacylglycerols, such as α‐linolenic acid (ALA), eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), linolenic acid (LA), γ‐linolenic acid (GLA) and arachidonic acid (AA). The aim of this study was to determine the chemical composition and measure protein, carbohydrates, fibers, lipids as well as the fatty acids composition of six microalgae species with potential application in the food industry. Two freshwater species, Chlorella vulgaris and Spirulina platensis, and four marine species, Nannochloropsis oculata, Nannochloropsis gaditana, Porphyridium cruentum, and Phaeodactylum tricornutum, were used in the experiments. Intracellular protein was the most prominent algal component (42.8–35.4 %), followed by carbohydrate + fiber (32.3–28.6 %), and lipids (15.6–5.3 %). N. gaditana is rich in saturated fatty acids, mainly palmitic acid (5.1 g/100 g), while the cells of S. platensis and C. vulgaris algae are abundant in GLA (1.9 g/100 g) and ALA (2.8 g/100 g) acids, respectively. P. cruentum differs from other algae, because it contains a large amount of AA (3.7 g/100 g). The marine microorganisms N. oculata and P. tricornutum are also a source of essential long‐chain polyunsaturated fatty acids (LC‐PUFA‐?3), mainly composed of EPA and DHA. Our results suggest that the freshwater species C. vulgaris and S. platensis are attractive nutritional supplements because of their low fiber and high protein/carbohydrate contents, while the marine species P. tricornutum and N. oculata can enrich foods with LC‐PUFA‐ω3, because of their favorable ω3/ω6 ratio.     

Bleaching augments lipid peroxidation products in pistachio oil and its cytotoxicity

Pistachio consumption is associated with reductions in serum cholesterol and oxidative stress due to their constituents of unsaturated fats, phytosterols, fiber, and antioxidants. Bleaching has been applied to whiten nut shells for antifungal and cosmetic purposes. However, the impact of bleaching on nutritional quality and safety of pistachios remains to be examined. In this study, we investigated whether bleaching would increase malondialdehyde (MDA) or 7‐keto‐sitosterol and decrease phytosterols in pistachio oil, as well as cause cytotoxicity of modeled Hepa1c1c7 cells. Bleaching increased MDA by more than 32% from 0.23 µg/g in raw oil, with the largest increase noted with the bleach containing H₂O₂ and Fe²⁺ (P ≤ 0.05). Bleached pistachio oil had larger than 12.6% decrease in β‐sitosterol and total phytosterols as compared to the raw oil (P ≤ 0.05). Bleaching with Fe²⁺ significantly increase 7‐keto‐sitosterol compared to bleaching alone. Hepatic cell viability was decreased the most by the oil of the pistachios treated with bleach containing Fe²⁺ (P ≤ 0.05), and lactate dehydrogenase activity in medium was elevated by >18‐folds (P ≤ 0.05). Compared to natural pistachios, the bleaching treatment had detrimental effects on nutritional quality and expected health benefits of pistachios by increasing lipid peroxidation, decreasing phytosterol content, and causing cytotoxicity. Practical applications: Bleaching has been applied to whiten the nut shell for antifungal and cosmetic purposes. However, the results of this study indicate that bleaching treatment has a detrimental impact on nutritional quality and expected health benefits of pistachios. Particularly, treatment with a bleach formula with hydrogen peroxide and transit metals increases formation of lipid peroxidation products and decreases phytosterol content. The resulting pistachio oil causes cell toxicity. Thus, bleaching practice for whitening pistachios is strongly discouraged.