Food Chemistry
Fatemeh Sadat Khanagaei; Fateme Akrami Mohajeri; Elaheh Askari; Hossein Fallahzadeh; Elham Khalili Sadrabad
Abstract
IntroductionCanola oil with high unsaturated fatty acids and nutritional value is susceptible to oxidation due to lipid oxidation. Lipid oxidation leads to a reduction of nutritional quality, sensory and safety characteristics of the vegetable oils. To retard lipid oxidation, the synthetic antioxidants ...
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IntroductionCanola oil with high unsaturated fatty acids and nutritional value is susceptible to oxidation due to lipid oxidation. Lipid oxidation leads to a reduction of nutritional quality, sensory and safety characteristics of the vegetable oils. To retard lipid oxidation, the synthetic antioxidants are usually used in the vegetable oils. By increasing the public concern about health problems of synthetic antioxidants, the use of natural antioxidants is increasing. Lavender (Lavandula officinalis) is an evergreen plant native to the Mediterranean. The presence of linalool, linalyl acetate, 1,8-cineole B-ocimene, terpinen-4-ol, and camphor in lavender essential oil, make it a good natural antioxidant which could use in food industry. Therefore, in the current research, it was aimed to investigate the antioxidant effect of lavender essential oil on the stability of canola oil. Materials and MethodsThe lavender was bought from Golestan province and dried in room temperature. The lavender essential oil was prepared by hydro distillation of flower heads. Then, the phenolic compounds were determined using GC-MASS. The Total phenolic content (TPC), flavonoid content (TFC), and antioxidant activity (FRAP and DPPH) of lavender essential oil were evaluated. Then, lavender essential oil in concentrations of 200, 400, 600, 800, and 1000 mg/kg was added to the crude canola oil compared to canola oils without antioxidants and synthetic antioxidant TBHQ (100 and 200 mg/kg). Then, the samples were kept at 60 to 70 oC for 12 days. The analysis was done in an interval of 24 h for 12 days. Lipid oxidation of samples was determined by peroxide value, p-anisidine value, TOTOX value, and thiobarbituric acid each 24 h. analyses of Data were done by one-way analysis of variance (ANOVA) using SPSS software and the means were compared by the Tukey multiple range test. Results and Discussion According to the GC-MS analysis, 1, 8-cineole (59.45 %), linalool acetate (32.48 %), linalool (6.31 %), and limonene (1.06 %) were identified as the major constituent of lavender essential oil. Also, Total phenol, flavonoid, FRAP and DPPH (IC50) contents of lavender essential oil were 71.55 mg GAE/g, 82.66 mg of rutin/100 g, 12.63 mmol H2SO4, and 55.88 mg/ml, respectively. According to the results, all lipid oxidation indexes were increased after twelve days of storage. In general, lavender essential oil was effective in retarding the oxidation of canola oil at a temperature of 70 oC. Also, the concentration of 1000 mg/kg of the essential oil had antioxidant activities similar to the TBHQ in 100 mg/kg concentration. Conclusion It was showed that lavender essential oil, as a natural antioxidant, has the ability to react with the radicals resulting from the oxidation of lipids and causes the interruption of oxidation chain reactions and increases the time and decreases the rate of oxidation. As observed, the oxidation of canola oil in all samples, especially the samples without antioxidants or antioxidants to a lesser extent, increased significantly with increasing storage time. In general, lavender essential oil at L1000 concentration and also in some oxidation indices of lavender essential oil at L800 concentration has an effective role in preventing the oxidation of canola oils like synthetic antioxidant TBHQ.
Nasser Sedaghat; Sara Khoshnoudi
Abstract
Introduction : Pistachio (Pistaciavera L.) is a tasty nut and a good source of nutrients. Ithas a high content of numerous beneficial nutritive and bioactive compounds such as proteins, carbohydrate, moisture, vitamins, minerals, fiber and other micronutrients compounds, but the most exceptional components ...
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Introduction : Pistachio (Pistaciavera L.) is a tasty nut and a good source of nutrients. Ithas a high content of numerous beneficial nutritive and bioactive compounds such as proteins, carbohydrate, moisture, vitamins, minerals, fiber and other micronutrients compounds, but the most exceptional components are the amount of fats and especially unsaturated fatty acids. Therefore, this nut is highly susceptible to rancidity, especially after roasting. Despite the high quality, raw pistachio and pistachio processing industry at Iran, export of roasted and packaged pistachio, due to low shelf life and drastic changes intaste, is not very successfull. An effort was made to investigate the efficacy of gelatin in comparison with carboxymethyl cellulose (CMC) as edible coating to retard fat oxidation in roasted pistachio.Materials and methods:Five coating formulations were investigated in this study as follow: A) Gelatin (4% w/v) + ascorbic acid (1% w/v): TGA, B) CMC (1% w/v)+ ascorbic acid (1% w/v): “TCA”, C) ascorbic acid (1% w/v): “TA”, D) Gelatin (4% w/v) + CMC (1% w/v) + ascorbic acid (1% w/v): “TCGA” and 5) control sample (uncoated sample): “TCO”.Roasted pistachio nuts were coated by dipping the nuts in the coating solutions. For each treatment, 100 gram of pistachio nuts were packaged (BOPP/Al/CPP, 80 micron plastic bags) in triplicate. The physicochemical analysis included measurement of free fatty acid (FFA), peroxide value (meq.O2 kg-1),hardness (N), moisture (%) and the sensory evaluation (texture, rancidity, taste and overall acceptability) were performed on coated and uncoated pistachio nuts stored at 35 and 50 °C. The nuts were sampled on the 0th, 1st, 2nd and 3rd month of storage. Data was analyzed using Minitab 16. Analysis of variance (ANOVA) and general linear models (GLM) procedure wereused to compare the mean values of each treatment and Significant differences between the means of parameters were determined based on the results of the Tukey’s multiple range test (p0.05).FFA content of TCGA sample was significantly lower than other samples.The highest protection, according to these criterions, was provided by gelatin-CMC coating containing ascorbic acid.The control samples exhibited more bitterness and off flavor than the coated samples, seemingly on account of chemical reaction and second products of oxidation content. Instrumental and sensory hardness of pistachio nuts which were coated with gelatin and/ or CMC (TCA, TGA and TCGA) were significantly (p
Leila Khajehvandi; Majid Javanmard; Mohammad Reza Eshaghi
Abstract
Introduction: Studies in recent years have led to the emergence of a new concept in the packaging industry namely “Active packaging”. Contrary to popular packaging that needs to be completely neutral and ineffective, in different kinds of active packaging, there is an interaction with food ...
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Introduction: Studies in recent years have led to the emergence of a new concept in the packaging industry namely “Active packaging”. Contrary to popular packaging that needs to be completely neutral and ineffective, in different kinds of active packaging, there is an interaction with food or environment, and has an active role in food materials maintenance (Brody et al, 2008). Nowadays, various kinds of polymeric materials and their different characteristics and forms has resulted in easy design and production of packaging based on special requirements of a food product (Lopez-rubio et al, 2004). Polyethylene and polypropylene along with cardboard boxes are used for packing butter (Milts, 1988). It has been proved that Alpha-Tocopherol maintains its stability in the processing conditions and low aw also maintain its stability, alpha – Tocopherol has desirable migration characteristics and excellent solubility in polyolephines. use of alpha- Tocopherol is more affordable compared to other antioxidants (Lee, 2005; Wessling et al, 1998).The aim of this study was to investigate the effect of alpha-tocopherol coating on the surface of polymer films in preventing the oxidation of lipid in butter.Materials and Methods:MaterialsDL-alpha-tocopherol acetate, low density polyethylene film(LDPE) , biaxial oriented polypropylene film (BOPP), traditional-lactic butter with salt made from cow's milk .MethodsPreparation of films: In this stage, first alpha-tocopherol was prepared with three concentrations of %0.1, %0.15and %0.2, and %70 ethanol was used as solvent. In the next step, low density polyethylene and polypropylene films were prepared in enough dimensions and numbers, and were washed and sterilized by %70 ethanol. Then, different concentrations of alpha-tocopherol (%0.1, %0.15,%0.2) were separately covered on a sufficient number of films via spraying (under identical conditions).to complete coverage of the films surface, spraying alpha-tocopherol was performed 3 times. after drying, films were kept in dark place (Pereira et al, 2011).Packaging and storage of butter: At this stage, butter pieces weighing 45 grams covered with LDPE and BOPP films with three different concentrations of alpha-tocopherol (%0.1,%0.15,%0.2) were packed. To prepare the control sample, butter was packed with alpha-tocopherol lacked films. The experiments of determining the amount of peroxide and acidity, and Sensory evaluation test was conducted on a sample of butter before packaging, and were repeated in tenth, twentieth ,and thirtieth days.Determining the amount of alpha-tocopherol remained on the films : At this stage, in order to determine the amount of alpha-tocopherol remaining on the films, weight difference of films before and after spraying alpha-tocopherol, and drying them on the films was measured. The amount was calculated by mg/cm2 stated (Contini et al, 2012).Measurement of alpha-tocopherol migration to ethanol: The total amount of alpha-tocopherol migrate from the films into the similar lipid matter(%95 ethanol)were calculated by the colorimetric method using a standard alpha-control solution and drawing the calibration curve(Corrales et al, 2009).The Sensory evaluation test: To evaluate the sensory properties including taste, color, smell and public acceptance, five-point hedonic test was used(Tafreshi et al, 2013).Methods and tools for data analysis: All tests were repeated three times. For data analysis, a factorial experiment in a completely randomized design was used. Alpha-tocopherol concentration, time and type of film were the main factors. Duncan multiple range test was used to assess the differences between means in the confidence level of %5.For all statistical analysis, MSTAT-C software version 14 was used.Results and Discussion: Findings from surveying the migration process into 95% ethanol solution, indicates that alpha-tocopherol were remained on the surface of polymeric films (LDPE &BOPP) after drying, and migrated from the surface of films into ethanol %95. With the increase of time and concentration of alpha-tocopherol, migration from the surface of films into ethanol increased (p
