Maximum Peroxide Value Research Articles

Assessment of the impact of whey protein hydrolysate on myofibrillar proteins in surimi during repeated freeze–thaw cycles: Quality enhancement and antifreeze potential

The quality of surimi, widely used in processed seafood, is compromised by freeze–thaw cycles, leading to protein denaturation and oxidative degradation. The objective of this study is to explore the effects of adding natural whey peptide hydrolysate (WPH) on the myofibrillar proteins of repeatedly freeze–thawed surimi. Results indicated surimi treated with 15% WPH exhibited only a 128% increase in surface hydrophobicity and a maximum peroxide value of 7.84 μg/kg, significantly lower than the control group. Additionally, salt-soluble protein content, emulsification activity, and stability decreased with the increase in freeze–thaw cycles. With a 15% WPH offering the most significant protective effect, evidenced by reductions of only 25.02%, 42.52% and 37.02% in salt-soluble protein content, emulsification activity, and stability, respectively. These outcomes demonstrate that WPH effectively reduces protein denaturation during repeated freeze–thaw processes. Future research should explore the molecular mechanisms underlying WPH's protective effects and evaluate their applicability in other food systems.

Mobilizing the seed storage oil in milk thistle (Silybum marianum) can supply energy for seed germination and early seedling growth and apply as TAGs breakdown marker

Milk thistle (Silybum marianum) is a crucial medicinal plant containing a large amount of oil. In the study, the changes in storage oil during seed germination and seedling transition from heterotrophic phases were investigated. The results showed that seed oil decreased from 19.53% to 0.88% on the 7th day of seedling development. Oil hydrolysis continued until the 4th day of germination with a low slope, but then increased the use of oils in seed germination end seedling growth metabolism. The results indicated that the quantitative changes in fatty acids, presented at lower amount, were relatively higher than dominant fatty acids. There were decreasing phenolic content in the developing seedlings, but overall, lowest level of total phenolic content can be attributed to the control (30.52 ​mg· 100 ​g· Oil−1). In contrast, the maximum peroxide value (2.58 meq· kg Oil−1) in the developing seedling was observed on the last day of the experiment. The results showed that there was a significant correlation between saturated fatty acid, unsaturated fatty acid, and lipase activity. However, the correlation between lipase activity and polyunsaturated fatty acids was significantly higher than between lipase activity and monounsaturated fatty acids (R2 ​= ​90% and R2 ​= ​77%, respectively). Therefore, the lipolysis process acts selectively in milk thistle oils. According to the results, C12:0 exhibits a greater impact on the early seedling growth rather than on the germination process and is one of the determining factors in the transition from heterotroph to autotroph. Also, it can be a marker for TAGs breakdown.

Properties of Oil Extracts from Local Sesame Seeds (Sesamum Indicum L.)

This study was conducted to determine the main physiochemical properties of sesame oil extracted from three sesame seeds samples, the differences between mixed (A-C) and the sieved sesame seed (A1-C3): which were taken from Sharzoor in Sulaymaniyah (S, mixed brown), Akre in Duhok (A, mixed brown) and Mala Omar in Hawler (MO, mixed brown). And to evaluate the differences between the OIL characteristics of mixed (Akre ,A, Sharzoor B, Mala Omar ,C ) and the sieved seeds with three different mesh size sieve (1.50, 1.35, 1) mm included (A1,A2,A3,.B1,B2,B3 ,C1,C2 and C3). The properties that included to study in this work were viscosity, specific gravity, fatty acid content, acid value, iodine value, and peroxide value. From the results of this study, it was found that the Mala Omar sample in all parts especially C2 48.42% is considered good source for oil, the viscosity of (hawler) samples especially C3 with 0.0490 Pas, the lowest viscosity while the A1 has a maximum viscosity 0.0525 Pas. More than 80% of sesame seeds' fatty acid composition is unsaturated, with high concentrations of oleic, linoleic, and lenolinic acids. Saturated fatty acids, primarily palmitic and stearic acids, account for the remaining 20%. Acid value in sample A1 of sharazoor sesame oil had the lowest content (2.1030 mg KoH\gm oil), whereas sample C3 had the greatest concentration. Omar Mala 15.5815. A3 sharazoor sample a higher 11.4954 gm I2\100gm oil, iodine value. While the maximum peroxide value was found in the B3 sesame oil sample of 15.9267 meq/kg, and the lowest peroxide value was found in the B sesame oil sample at 3.8850 meq/kg.

Omega-3 Fatty Acid Retention and Oxidative Stability of Spray-Dried Chia–Fish-Oil-Prepared Microcapsules

Background: Omega-3 fatty acids are essential fatty acids that the body cannot create itself; thus, they must be obtained from functional foods. Therefore, the food processing industries are becoming more interested in the production of omega-3 enriched food products, as consumers and healthcare organizations are increasingly demanding functional foods with minimal fatty acid loss and higher oxidative stability. Moreover, the stability of long-chain, polyunsaturated fatty acids in functional foods is a major challenge for the food processing industries. Therefore, the spray drying method was used to prepare spray-dried microcapsules (SDMs) with the minimum loss of, and more stable, fatty acids. Methods: In this study, emulsion blends of chia seed oil (CSO, 50%) and fish oil (FO, 50%) were spray-dried using varied operating conditions, including the inlet air temperature (IAT) (125, 140, 155, 170, and 185 °C), wall material (WM) (5, 10, 15, 20, and 25%), pump speed (PS) (3, 4, 5, 6, and 7 mL/min), and needle speed (NS) (3, 5, 7, 9, and 11 S). Results: The maximum loss of ALA in the spray-dried microcapsules (SDMs) was observed (9.90 ± 0.40%) at 170 °C, and the minimum loss was 4.18 ± 0.20% in run order 9. A similar trend was observed in the maximum retention loss of EPA and DHA (9.71 ± 0.39% and 9.77 ± 0.39%) at a high temperature of 170 °C, while the minimum losses of EPA and DHA were observed in run order 9. Furthermore, the maximum peroxide value (PV) of the SDMs was observed at a lower temperature of 140 °C (1.45 ± 0.19 meq O2/kg), and the minimum PV was 1.33 ± 0.16 meq O2/kg. Conclusions: Overall, based on the results, we concluded that the oxidative stability of the SDMs was improved and that it can be used as a fortifying agent in the processing of many food products.

Assessment of Quality of Commercially Available Some Selected Edible Oils Accessed in Ethiopia

In the present study, an effort has been performed to determine trans fatty acid, free fatty acid, and cholesterol content of some selected edible oils in Ethiopia. Five brands of locally made different edible oil samples were purchased from super markets of Ethiopia. The quality of these edible oils was analyzed by evaluating their chemical properties such as acid, saponification and peroxide values using standard methods (titrimetric technique). The results of the study revealed that maximum and minimum acid value was 5.59± 0.02 mg/g for Beksa (Niger oil) and 0.11±0.02 mg/g for Tena (sunflower) oil respectively. Similarly, the saponification value showed (223.2±0.39 mg/kg) for Tena and (173.4±0.46 mg/kg) for Beksa. The maximum peroxide value was observed in Lulu (vegetable oil; 11.67±0.11 meq O2/kg) and minimum value found in Sunny (sunflower oil; 2.84±0.05 meq O2/ kg). The highest total free fatty acid as oleic acid was observed in Beksa (2.95±0.03%) and lowest total free fatty acid in Tena oil (0.06±0.03%). On the other hands, two trans fatty acids; oleic acid (C 18:1) and linoleic acid (C 18:2) were detected in the 5 edible oils by using GC method.

Impact of Stevia rebaudiana substitution on physico-chemical characteristics, sensory profile and microstructure in selected Indian desserts.

Stevia rebaudiana has been used since hundreds of years as a natural sweetener, it is 300-450 times sweeter than sugar. The study aimed at incorporation of S. rebaudiana in traditional Indian desserts and test its sensory profile, storage properties, textural and color attributes. Carrot halwa (CH) and kesar peda (KP) were prepared with variations such as complete replacement of sugar in variation 1 (V1: CHV1 & KPV1) and 40% replacement of sugar in variation 2 (V2: CHV2 & KPV2) with stevia. Standard methods such as Quantitative Descriptive Analysis scores for sensory profile, fat oxidation for storage studies and surface morphology, texture profile and color analysis of samples were studied. Sensory profile revealed higher taste acceptability in CHV1 and KPV2. During storage, the maximum peroxide value was 5mEq/kg in all products of refrigerated KP. Microstructural studies revealed changes in surface morphology wherein stevia incorporation increased ragged edges in CH and porosity in KP. Both products exhibited increased hardness, gumminess and chewiness during storage. There was no major change in the color profile of products. Overall, incorporation of stevia in Indian desserts can significantly reduce the use of sugar and can be relished by people who are health conscious.

Reducing Peroxide Value In Used Cooking Oil Using Ampo As An Adsorbent

Cooking oil can only be used two or three times, more than that the oil is deemed unsuitable and can harm our health. The reason is, every time the cooking oil is used for frying, an oxidation reaction that is triggered by heat occured and causes the chemical chain bonds in cooking oil become unstable and forms hydroperoxides. The hydroperoxide found in used cooking oil increases the peroxide value. In which, the suitability of cooking oil is based on the peroxide value. In order to reduce the peroxide value in used cooking oil, in this study, Ampo is used as an adsorbent to adsorb the peroxide compound. The procedure used in this study includes a preliminary analysis of the used cooking oil to determine the initial peroxide value. After that, the Ampo adsorbent is activated with 1N Citric Acid to open the pores on the surface of the Ampo. Activated Ampo will then be mixed into 200 ml of used cooking oil with a magnetic stirrer with a stirring speed of 300 rpm and with a temperature of 50oC. The adsorption process was carried out by varying the mass variables of Ampo into 70, 75, 80, 85, and 90 grams, and stirring time of 30, 60, 90, 120, and 150 minutes. After the adsorption process is completed, the cooking oil that has been filtered by the Ampo adsorbent will be analyzed to get the final peroxide value. By knowing the peroxide value before and after the adsorption process, the adsorption isotherm can be calculated. The adsorption process of used cooking oil with Ampo adsorbent proved to reduce the peroxide value, in which stirring times and adsorbent masses were the influential variables in the study. The best result was obtained with 60 minutes stirring time and mass of 75 grams. This condition provided a peroxide value of 0.99 meq/kg, which means that there was a decrease in the peroxide value by 93%. This result is in accordance with the provisions of SNI 3741-2013, with a maximum peroxide value of 10 meq/kg. The maximum adsorption capacity in this study was obtained from the Freundlich equation of 14.6487 mg/gram

Eco‐Friendly Alternative to Brining for Sustainable Storage of Table‐Olives Based on the Analyses Done with the Extracted Oil

AbstractDegree of quality changes in coated and uncoated reference table olives are assed based on the analyses done with the extracted oil at different storage temperatures. The results reveal that storing the table olives after coating with chitosan reduces the product and embeds energy waste. Kinetic studies show that coating delays and slows down the lipid oxidation and decreases the maximum peroxide values attained. At all storage temperatures, the amounts of phenolics retained in the olives are significantly higher in the coated samples when compared with the uncoated references. The results show that coating may also raise the tolerable storage temperature by 14 °C. Coating 10% of the total global table oil production with chitosan may lead to up to 6720 MJ of storage energy savings and 546 t of less CO2 emissions into the atmosphere.Practical Applications: Coating olives with chitosan may improve the quality of the stored oils and reduce the energy requirement of the storage process and consequently reduce the amount of carbon dioxide emissions into the atmosphere compared to in‐brine storage method.

Kandungan Bilangan Peroksida Minyak Goreng Pedagang di Jalan Perintis Kemerdekaan Kota Padang

Background. Indonesian usually using repeatedly cooking oil for deep frying process. The repeated use of cooking oil can be found among street vendors. Consumption of repeatedly cooking oil could lead to hepatic disorder, cardiovasular disorder and even cancer. Objective. The research aims to describe and analyze peroxide value in cooking oil used by street vendors in Perintis Kemerdekaan street in Padang City. Methods. This is a descriptive research. The reseacrh objects were taken by purposive sample method and 23 samples cooking oil used by traders. This research was conducted at Clinical Laboratory of West Sumatera from October 2019 to May 2020. Results. This research found out 14 from 23 of cooking oil used by street vendors have peroxide value above the Indonesian National Standard (abbreviated SNI) 01-3741-2013. Cooking oil used by fritter street vendors have average peroxide value is 15.10 mEq O2/kg while pecel catfish and chicken street vendors is 10.29 mEq O2/kg. The avarage peroxide value in each type of cooking oil are bulk 10,81 mEq O2/kg, branded 14,64 mEq O2/kg and mixture 16,28 mEq O2/kg. Conclusion. More than half of the samples tested had exceed the maximum peroxide values (> 10 mEq O2/kg) and the highest average are found in fritter street vendor and mixture of bulk and branded cooking oil.

Impact of thermal extrusion and microwave vacuum drying on fatty acids profile during fish powder preparation.

The current study aimed to optimize the process for ready‐to‐eat extruded fish powder preparation and to ascertain the impact of two methods on fatty acid profiles. For the investigation, Labeo rohita (Rohu) fish was first minced, extruded, and microwave vacuum‐dried. The results show that the yield for extruded fish powder (EFP) fluctuated from 22.32% to 29.07%. The maximum retention for docosahexaenoic acid (DHA), arachidonic acid (AA), and eicosapentaenoic acid (EPA) was 3.24 ± 0.08 g/100 g lipids, 2.74 ± 0.05 g/100 g lipids, and 1.24 ± 0.09 g/100 g lipids, by using different extrusion parameters. Moreover, nonsignificant changes were observed during 0 days, and 1 and 3 months of storage (at 4°C and 25°C) for DHA, AA, and EPA, whereas significant results were recorded for the samples stored for 6 months at 25°C. Also, the maximum peroxide value (PV) and thiobarbituric acid reactive substance values (TBARS) were 1.72 ± 0.04 meq/kg fat and 0.135 ± 0.008 mg malondialdehyde/kg fat. It is anticipated from the outcomes that the study will be helpful to prepare value‐added food products in future studies.

Multi‐objective optimization of mechanical oil extraction fromCamellia oleiferaseeds using Kriging regression andNSGA‐II

AbstractThe objective of this study is to optimize the mechanical extraction process of crude camellia oil regarding yield and quality. The effects of process parameters namely applied pressure (10–45 MPa), heating temperature (40–100°C), heating time (10–40 min), and moisture content (0–9%) on oil yield, free fatty acid (FFA), and peroxide value (PV) were investigated by modeling the oil extraction process using Kriging regression (KR) models; optimum process parameters were then determined via non‐dominated sorting genetic algorithm II (NSGA‐II). The results showed that KR model is effective to predict the yield (R2= 0.9595 and A‐RMSE = 1.94), FFA (R2= 0.9983 and A‐RMSE = 0.0517), and PV (R2= 0.8733 and A‐RMSE = 0.0358). The relationship between process parameters and each objective is non‐linear. In addition, the maximum yield (42.20%) and best quality parameters (minimum FFA = 0.2917 KOH mg/g and minimum PV = 0.1316 g/100 g) are contradictory, which suggested applying Pareto‐optimal front to balance the three objectives to a satisfied degree.Practical ApplicationsHeating temperature, applied pressure, heating time and moisture content are primary operating conditions affecting the yield and quality of mechanically extracted fats and oil. Selecting the suitable values of these parameters can therefore improve the oil yield and oil quality. This could be realized by process optimization based on experimental and mathematical modeling method. The KR model and NSGA‐II were, therefore, adopted to optimize the process parameters to obtain maximum yield, minimum FFA and PV. In addition, parametric analysis was conducted to give insight into the effects of process parameters on the yield and quality, which is beneficial to understand the mechanism behind the mechanical extraction of camellia oil. The Pareto‐optimal front obtained from NSGA‐II provides engineers with several decision parameters to design the equipment and to obtain better end products more efficiently.

Microencapsulation of fish oil by casein-pectin complexes and gum arabic microparticles: oxidative stabilisation

This study was aimed to microencapsulate fish oil (FO) in two biocompatible polymeric blends: gum arabic (GA)-maltodextrin (MD) and casein-pectin (CP)-MD. GA-MD microparticles and CP-MD microparticles were produced by spray-drying and complex coacervation and spray-drying, respectively. Encapsulation efficiency, particle size, moisture content, oxidative stability, and morphological properties were analysed. Encapsulation efficiencies of 51.2–56.8% (w/v) for GA and 64.7–67.9% (w/v) for CP preparations were found. GA particle sizes varied from 2 to 100 μm and from 2 to 120 μm for CP microparticles. Spherical forms with depressions in the topography of both systems were evidenced by scanning electron microscopy. Confocal microscopy evidenced surface oil on GA microparticles, corroborating encapsulation efficiency. CP was more efficient than GA to reduce oxidation, with maximum peroxide values (PVs) of 17.40 mmol/kg oil after 28 d at 40 °C/75% relative humidity (RH). Thus, CP is a promising biopolymeric blend for encapsulation of FO that provides protection against lipid oxidation.

Evaluation of kinetic parameters in prevention of quality loss in stored almond pastes with added natural antioxidant

Oxidative stability and loss of nutritional values during storage are the major problems that are encountered in the nut spreads and nut pastes affecting the commercial value. In this study, kinetic behavior of lipid oxidation and depletion of the phenolic antioxidants in the black carrot juice supplemented almond pastes stored at the temperature range of 4-60°C were studied. Kinetic models were employed to quantify the observations. Lipid oxidation was modeled with the logistic equation. Addition of black carrot juice delayed lipid oxidation, and decreased the maximum peroxide value attained. Being different than the results of the previous studies performed with the similar pastes, the rate constants of peroxide formation reactions in the black carrot juice supplemented pastes decreased with increasing temperature (from 0.60 to 0.27 d-1); possibly due to capturing of the lipid oxidation intermediaries by the antioxidants at higher rates at higher temperatures. Depletion of phenolics agreed with a unimolecular first order apparent kinetic model. At the end of the storage period, phenolic losses in the pastes were 5.4, 31.8, 36.9 and 38.2% at 4, 20, 30 and 60°C, respectively. The results showed that incorporation of the black carrot juice might have an effect on the mechanism of the lipid oxidation and its temperature dependency, and improve the shelf life of the almond pastes.

Effect of chia mucilage addition on oxidation and release kinetics of lemon essential oil microencapsulated using mesquite gum – Chia mucilage mixtures

Lemon essential oil (LEO) emulsions were prepared using mesquite gum (MG) - chia mucilage (CM) mixtures (90-10 and 80-20 MG-CM weight ratios) and MG as control sample, LEO emulsions were thenspray dried for obtaining the respective microcapsules.LEO emulsions were analyzed by mean droplet size and apparent viscosity, while microcapsules were characterized through mean particle size, morphology, volatile oil retention (≤51.5%), encapsulation efficiency (≥96.9%), as well asoxidation and release kinetics of LEO. TheLEO oxidation kinetics showed that 90–10 and 80–20MG-CM microcapsules displayed maximum peroxide values of 91.6 and 90.5 meq hydroperoxides kg−1 of oil, respectively, without significant differences between them (p > .05).MG-CM microcapsules provided better protection to LEO against oxidation than those formed with MG; where the oxidation kinetics were well adjusted to zero-order (r2 ≥ 0.94).The LEO release kinetics from microcapsules were carried out at differentpH (2.5 and 6.5) and temperature (37 °C and 65 °C) and four mathematical models (zero-order, first-order, Higuchi and Peppas) were used to evaluate the experimental data; the release kinetics indicated that the 80-20 MG-CM microcapsules had a longer delay in LEO release rate, followed by 90-10 MG-CM and MG microcapsules, hence, CM addition in MG-CM microcapsules contributed to delay the LEO release rate. This work clearly demonstrates that use of a relatively small amount of CM mixed with MGimproves oxidative stability and delays the release rate of encapsulated LEO regarding MG microcapsules, therefore, MG-CM mixtures are interesting additives systems suitable for being applied in food industry.

Sacha inchi seeds from sub-tropical cultivation: effects of roasting on antinutrients, antioxidant capacity and oxidative stability

Due to the strong bitter taste, sacha inchi seeds are usually consumed after roasting, which also contributes to the elimination of antinutrients. Sacha inchi plants fully adapted to cultivation under sub-tropical climate conditions were produced in southeastern Brazil. Our main goal was to evaluate the effect of dry heating (roasting) on the antinutrient content of these seeds. We also investigated the effects of the applied roasting treatments on the antioxidant activity, proximate composition and oxidative stability of the seeds. To the best of our knowledge, this is the first report on antinutrients of sacha inchi seeds cultivated under sub-tropical conditions, outside their native tropical environment. Except for saponins, which are not heat-labile compounds, the contents of all assessed antinutrients continually reduced with the increase in roasting temperature. Roasting improved antioxidant activity and phenolic content in the seeds at the highest temperature. Oxidation changes occurred in the seed oil, and they increased with temperature. However, maximum peroxide value was within the acceptable consumption limits. As a conclusion, roasting treatments can be applied to minimize the antinutrient potential in sacha inchi seeds. Knowledge on the composition and proper processing of sacha inchi cultivated under sub-tropical conditions may support future efforts focused on the development of new production areas.

Omega–3 encapsulation by PGSS-drying and conventional drying methods. Particle characterization and oxidative stability

Particles from Gas-Saturated Solutions (PGSS)-drying has been used as a green alternative to encapsulate omega–3 polyunsaturated fatty acids (n–3 PUFAs) at mild, non-oxidative conditions. PGSS-dried particles have been compared to those obtained by conventional drying methods such as spray-drying and freeze-drying, finding encapsulation efficiencies (EE) up to 98% and spherical morphology for PGSS- and spray-dried particles. Freeze-dried powders showed irregular morphology and EE from 95.8 to 98.6%, depending on the freezing method. Differential scanning calorimetry (DSC) analysis revealed glass-transition and melting peaks of OSA-starch and a cold-crystallization peak corresponding to the encapsulated n–3 PUFA concentrate. Compared to conventionally dried powders, PGSS-dried microparticles showed lower primary and secondary oxidation after 28 days of storage at 4 °C. Ascorbic acid addition combined with the mild processing conditions of PGSS-drying yielded particles with a maximum peroxide value of 2.5 meq O2/kg oil after 28 days of storage at 4 °C.

Frying oils quality control: necessity for new approach of supervision

PurposeThe purpose of this paper is to investigate the quality of the frying oil used in restaurants, fast food establishments, and confectionary stores. The compliance of used frying oils with the quality standards as determined by the peroxide value (PV) and the total polar materials (TPMs) is investigated by analyzing 375 samples of oil.Design/methodology/approachThe PV was measured according to the national standard procedure number 4179, while the TPM was determined using a Testo 270 cooking oil tester. Frying oils with a PV>5 mEq/kg and a TPM>25 percent were considered to be non-edible. For a comparison of groups, the Mann-Whitney and Spearman correlation tests were used, and p<0.05 was considered significant.FindingsThe maximum TPM and PV recorded for frying oils in fast food restaurants were 97.5 percent and 77.9 mEq/kg, respectively. The results also revealed that 60 percent of samples were non-edible according to the TPM, while 58.9 percent of the oil samples were non-edible because of the PV. TPM and PV correlated well with each other (r=0.99, p<0.001) and with oil replacement intervals (r=0.90, p<0.001). The relationship between the TPM and PV was stronger in the polynomial model than the linear model. The following equation was obtained: peroxide (mEq/kg oil)=0.0043 TPM2 (%)+0.1587 TPM (%)–0.6152.Originality/valueConsidering the current limitations in official supervision by health authority, on-site self-monitoring of the TPM using the Testo 270 cooking oil tester by sellers as a solution seems a new approach. Food stores, restaurants, and confectionary stores should be equipped with TPM analyzers to determine the quality of the frying oil and the timely replacement of non-edible oils.

Effects of gamma irradiation on chemical and sensory characteristics of natural hazelnut kernels

In present study, natural hazelnut kernels were treated with, 0.5, 1 and 1.5kGy of gamma irradiation. The irradiated and untreated hazelnuts were stored at 20±0.5°C and 55–60% relative humidity for 18m. After irradiation, 0.5, 1 and 1.5kGy doses of gamma irradiation significantly increased the total fat values (p<0.05) and this value decreased during the storage. After treatment, free fatty acid values were similar in untreated and treated hazelnuts. After 6m of storage, irradiated and untreated hazelnuts had less than 1% free fatty acid values. However, control and 1.5kGy yielded higher than 1% free fatty acid after 9m of storage. After irradiation, peroxide values increased proportionally to the dose but the increase was not significant. Peroxide values increased during the storage period (p<0.05). Control and 0.5kGy-treated hazelnuts had maximum peroxide values after 9m of storage, while 1kGy and 1.5kGy-treated hazelnuts had maximum levels after 12m of storage. Applied doses did not cause any significant changes in crude protein, water activity (aw), crude cellulose and moisture content of hazelnuts (p>0.05). Storage period significantly affected the water activity and crude cellulose (p<0.05). Irradiation doses didn’t affect the L*, a* and b* values (p>0.05), but storage period significantly affected the color values (p<0.05). At the end of storage period, L* and vitamin E values decreased proportionally to the dose.The 0.5kGy-treated hazelnuts had the lowest free fatty acid and peroxide values and such a case also reflected in sensory analyses. Furthermore, these hazelnuts had the highest vitamin E value after the control group. Application of 0.5kGy gamma irradiation seems to be acceptable for natural hazelnut kernels, but food safety issues have to be evaluated in order to recommend its application as a useful conservation alternative.

Characterisation of a highly saturated Irvingia gabonensis seed kernel oil with unusual linolenic acid content

The search for new sources of oil with improved characteristics has focused our attention on the characterisation of Irvingia gabonensis seed kernel oil. Physicochemical analysis have revealed the following assets: refractive index (1.42 ± 0.00), free fatty acids (2.3 ± 0.8%), peroxide value (3.33 ± 0.57 meq O(2)/kg), iodine value (32.43 ± 1.22 g I(2)/100 g), saponification value (233.75 ± 2.60 mg KOH/g), unsaponifiable matter (1.5 ± 0.02%), carotenoids (63 ± 0.01 mg β-carotene/100 g) and phospholipids (2.1 ± 0.01%). Absorbance of this oil decreased abruptly in the range of UV-B and UV-A wavelengths. Gas chromatography analysis showed that the major fatty acids were saturated, being mainly composed of lauric (C12:0, 39.35 ± 0.01%) and myristic acids (C14:0, 20.54 ± 0.01%). Nevertheless, an unusually high amount (6.44 ± 0.02%) of linolenic acid was also noted. Mass spectrometer analysis of volatile compounds highlighted the presence of various aromatic and aliphatic organic compounds. I. gabonensis seed kernel oil also showed oxidative stability at 60 °C after 12 days of storage with maximum peroxide value of 34.66 meq O(2)/kg. In view of these interesting characteristics, I. gabonensis seed kernel could be used as an alternative source of oil for lipid industries.

Lipid Quality of Anchovy (Engraulis Encrasicholus) Fillets Affected by Different Cooking Methods

The influence of cooking methods (baking, grilling, or frying) on lipid oxidation and fatty acid composition of anchovy (Engraulis encrasicholus) fillets was evaluated. All of the treatments reduced the free fatty acid content of the fillets (P < 0.05) and minimal values were determined in grilled (3.30 g/100 g lipid) and fried (2.84 g/100 g lipid) fillets. The peroxide value and thiobarbituric acid value of the fillets were also increased by the cooking process (P < 0.05). While the maximum peroxide value content of anchovy fillets was determined in grilled fillets as 16.23 meq O2/kg lipid (P < 0.05), the highest thiobarbituric acid values were determined as 3.63 mg MDA/kg fillet and 2.96 mg MDA/kg fillet for grilled and baked fillets, respectively. In the grilled fillets, the increase of thiobarbituric acid value exceeded the permitted limiting value. All of the cooking methods used caused modifications in the fatty acid compositions and only frying caused modification in the n-3/n-6 ratio of the fillets. The modifications in the fatty acid compositions were more prominent in the fried fillets. These results indicated that grilling may be hazardous because of the formation of lipid oxidation products as a result of thermal degradation of lipids during cooking.