Peroxide Value (peroxide + value)

Distribution by Scientific Domains


Selected Abstracts


Effects of drying process on biochemical and microbiological quality of silverside (fish) Atherina lagunae

INTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 6 2010
Salah Selmi
Summary Changes in biochemical and microbiological quality of silverside during two drying process were investigated. Total fatty acid and amino acid contents in silverside were 5.42 and 10.9 g 100 g,1 fresh sample, respectively, in which, palmitic acid and glutamic acid were the most abundant. N-3 and n-6 polyunsaturated fatty acids (PUFA) levels were 0.59 and 0.62 g 100 g,1 fresh silverside respectively. After hot air and solar drying treatments, Peroxide value and thiobarbituric acid reactive substances of the total lipids increased significantly (P < 0.05) to reach 2.58 and 3.41 meq active O2 kg,1 oil and 0.87 and 1.27 mg MA kg,1 oil, respectively. Fatty acid profile of non-polar lipid remains unchanged during experimental drying process. However, PUFA (% of total fatty acids) of polar lipid decreased significantly (P < 0.05) during both drying process with lower levels in solar drying process. Drying conditions had a significant effect on the microbiological quality. Therefore, mesophiles and total coliforms increased within drying treatment with higher counts in solar drying process. [source]


IMPROVING THE QUALITY AND SHELF LIFE OF TURKISH ALMOND PASTE

JOURNAL OF FOOD QUALITY, Issue 4 2008
ESRA CAPANOGLU
ABSTRACT Almond paste is an economically valuable product produced from almonds, sugar and a small amount of water. Oxidative rancidity and oil separation are the major problems that are encountered in the paste products affecting the shelf life. Another problem appears to be drying on the surface of the product resulting in poor consumer acceptability. In this study, the formulation of product was altered by adding a commercial stabilizer, antioxidant mixture and maltose syrup to prevent undesirable quality changes during storage at 4C and 30C. Peroxide value, free fatty acid and Rancimat analysis showed that the addition of antioxidant mixture prevented oxidation effectively and improved sensory scores significantly (P , 0.05). Although stabilizer addition had a detrimental effect on the textural properties, samples that have maltose had high sensory scores. The results showed that incorporation of maltose syrup and antioxidant may improve the texture and shelf life of almond paste. PRACTICAL APPLICATIONS The available literature on almond paste is mainly focused on the microbiological quality of the product and the prevention of spoilage reactions by modifying packaging materials. However, there is no report on the optimization of the composition to extend the shelf life of almond paste. Turkish almond paste, a healthy and expensive dessert, is a specialty product that is manufactured by using traditional grinding equipment. However, the limited shelf life of this product decreases its export potential resulting in economical losses. Therefore, improved shelf life and quality of the product is of importance from the economical point of view. In our study, we aimed to improve the quality and shelf life of Turkish almond paste by modifying its formulation in order to minimize the undesirable changes that occur during storage. [source]


COMPARISON AMONG GLUTEN, MALTODEXTRIN, AND SOYBEAN OIL COATINGS AS FLAVOR CARRIERS ON PITA CHIPS,

JOURNAL OF FOOD QUALITY, Issue 5 2000
H.A. MANSOUBI
ABSTRACT Dietary health concerns of consumers have prompted manufacturers to produce snacks with lower fat content. Reduced fat products need additional ingredients to compensate for flavor loss. Gluten and maltodextrin coatings were compared with soybean oil as a carrier of cheese powder on pita chips. Coated pita chips were packaged with or without nitrogen and stored at 33C and 50% humidity for 60 days. Physical, chemical, microbiological, and sensory properties of the chips were evaluated. Saturation index and hue angle were significantly different at 30 and 60 days for all treatments. Instrumental texture analysis was inconclusive due to high standard deviations. Peroxide value for oil-coated chips increased significantly over time. Consumer acceptance testing indicated a stronger cheese flavor for maltodextrin and gluten treatments compared with oil. No off-flavors were detected from any chips. Microbial counts were low and did not differ significantly among treatments. Gluten and maltodextrin coatings may be alternative flavor carriers to oil for reduced fat content in snack foods. [source]


Compatibilized Ny6-based blends as innovative packaging materials: determination of some important properties relevant to food contact application

PACKAGING TECHNOLOGY AND SCIENCE, Issue 3 2001
P. Laurienzo
Abstract Chemical physical analysis, photo-oxidative stability and lipid oxidation of innovative polymeric films based on blends of nylon 6 and ethylene-co-vinyl alcohol for use in food packaging have been investigated. Thermal mechanical analysis showed that the presence of an interfacial agent in the blend stabilized the films towards the action of permeants. Synergistic effects of the interfacial agent are reported with respect to UV photostability. Peroxide value (PV) was used to follow the oxidation of the olive oil, and for this parameter also the influence of the interfacial agent was clearly detected. Copyright 2001 John Wiley & Sons, Ltd. [source]


Oxidative stability and acceptability of camelina oil blended with selected fish oils

EUROPEAN JOURNAL OF LIPID SCIENCE AND TECHNOLOGY, Issue 8 2010
Deirdre N Eidhin
Abstract The effects of blending camelina oil with a number of fish oils on oxidative stability and fishy odour were evaluated. Camelina oil was found to be more stable than tuna oil, ,omega-3' fish oil and salmon oil as indicated by predominantly lower ,-anisidine (AV), thiobarbituric acid reactive substances (TBARS) and conjugated triene levels (CT) during storage at 60,C for 20,days (p,<,0.05). Peroxide values (PV) were similar for all oils until Day 13 when values for camelina oil were higher. Values for blends of the fish oils (50, 25, 15, 5%) with camelina oil were generally between those of their respective bulk oils indicating a dilution effect. Camelina oil had a similar odour score (p,<,0.05) to sunflower oil (9.2 and 9.6, respectively) indicating, as expected, an absence of fishy odours. In comparison, the fish oils had lower scores of 6.1 to 6.6 (p,<,0.05) indicating mild to moderate fishy odours. Odour scores were improved at the 25% fish oil levels (p,<,0.05) and were not different to camelina oil at the 15 or 5% levels (p,<,0.05). Practical applications: Camelina oil is a potentially important functional food ingredient providing beneficial n-3 PUFA. Oil extracted from Camelina sativa seeds contains greater than 50% polyunsaturated fatty acids of which 35-40% is ,-linolenic acid (C18:3,3, ALA), an essential omega-3 fatty acid 1. While EPA and DHA from fish oils are more potent nutritionally, they are less stable than ALA. This work evaluated innovative blends of fish oil with camelina oil for stability and acceptability. The results demonstrate that there is potential for use of blends of camelina oil with fish oils in food products, as the results show some benefits in terms of reduction of fishy odours. Such information could be valuable in relation to formulation of food products containing high levels of n-3 PUFA from both plant and fish sources. [source]


Inhibition of butter oxidation by some phenolics

EUROPEAN JOURNAL OF LIPID SCIENCE AND TECHNOLOGY, Issue 7 2007
Kalliopi Soulti
Abstract The ability of some phenolic compounds to inhibit butter oxidation was evaluated. Peroxide values and thiobarbituric acid reactive substances were monitored during storage of butter at 50,C and at 110,C. Gallic acid, caffeic acid and catechin, each at 80,mg/L, inhibited butter oxidation at 50,C to a degree equal to that of butylated hydroxyanisole (BHA) at 200,mg/L. Gallic acid, at 80,mg/L, was more effective than BHA, at 200,mg/L, in inhibiting butter oxidation at 110,C. Present results indicate that some phenolics, and especially gallic acid, may be taken into account as antioxidants in butter. [source]


Evaluation of Lipid Oxidation and Oxidative Products as Affected by Pork Meat Cut, Packaging Method, and Storage Time during Frozen Storage (,10 C)

JOURNAL OF FOOD SCIENCE, Issue 2 2007
S.Y. Park
ABSTRACT:, Lipid oxidation and oxidative volatiles as affected by pork meat cut and packaging method during frozen storage at ,10 C were evaluated. Pork belly cut had higher thiobarbituric acid reactive substance (TBARS) and pH values than did the loin, whereas the loin had higher free fatty acid (FFA) values than that of the belly cut. Peroxide values increased with increased storage time, but were not affected by pork meat cut and packaging method. Volatiles with carbon numbers less than 10 in the belly cut were higher than those in the loin cut, whereas those with carbon numbers greater than 10 in the loin cut were higher than those in belly cut. Most volatiles were decreased with increased storage time, except for propane. Both 4-pentenal and 4-methyl-2-hexanone in the belly cut showed a positive correlation with FFA, whereas 2,4-dimethyl-1-heptene and 9-octadecenal in the loin cut were positively correlated with TBARS and FFA, respectively, even though the values were not high enough to predict the degree of lipid oxidation. [source]


Storage Water Activity Effect on Oxidation and Sensory Properties of High-Oleic Peanuts

JOURNAL OF FOOD SCIENCE, Issue 5 2002
G.L. Baker
Peanuts were stored under different water activities and maintained using saturated salt solutions, for 14 wks. Peroxide values, percent moisture, and sensory attributes were determined at 2 wk intervals. Peroxide values increased over time for all treatments. The highest oxidation values were observed in the peanuts held under 0.67 water activity, followed by 0.12, 0.52, 0.44 and 0.33, respectively. Moisture increased over time for all samples and correlated with the water activity of storage. Roast peanut flavor decreased with time and the decrease was greater at higher aw of storage. [source]


Near-infrared spectroscopy for the determination of lipid oxidation in cereal food products

EUROPEAN JOURNAL OF LIPID SCIENCE AND TECHNOLOGY, Issue 12 2006
Abderrahmane At Kaddour
Abstract The present study was aimed at determining the ability of near-infrared (NIR) spectroscopy to in situ describe fat oxidation kinetics in three different cereal-based products: salted crackers (20% saturated palm oil and lauric oil, sprayed on surface); healthy crackers (10% unsaturated rapeseed oil, homogeneously distributed inside the product matrix); and moist pasteurised Asian noodles (1.5% unsaturated rapeseed oil, sprayed on surface). Products were stored under accelerated oxidation conditions at 40,C. Lipid oxidation rates were determined from peroxide value (PV) measurements. We observed no significant changes in PV for the dry crackers (3,meq/kg after 60,days), a slight linear increase in PV for the healthy crackers (40,meq/kg after 60,days), and a rapid increase for the Asian noodles (80,meq/kg after 20,days). The NIR spectra were recorded between 1000 and 2500,nm by using a Fourier Transform NIR spectrometer, using an external probe. Measurements were done directly in situ on the product, on the ground samples, and on the extracted fat phase. The analysis of NIR spectral data by PLS statistical methods demonstrated some correlation trends (R2,=,0.575,0.897; RMSEC,=,17,55%) for the products having a significant increase in PV. It was not possible to propose predictive models to calculate the oxidation rate. [source]


Correlation between physicochemical analysis and radical-scavenging activity of vegetable oil blends as affected by frying of French fries

EUROPEAN JOURNAL OF LIPID SCIENCE AND TECHNOLOGY, Issue 8 2006
Mohamed Fawzy Ramadan
Abstract The main goal of the present work was to compare and correlate the results of physicochemical parameters and antiradical performance of some oil blends during deep-frying, which will be an initial indicator for applying antiradical tests for monitoring deep-frying oils. Two oil blends were prepared. The first blend was a mixture (1,:,1, wt/wt) of sunflower seed oil and palm olein (SO/PO) and the second was a mixture (1,:,1, wt/wt) of cottonseed oil and palm olein (CO/PO). The oil blends were evaluated during intermittent frying of French fries on two consecutive days for 16,h, with oil replenishing after 8,h. Changes in the fatty acid profile and some physicochemical parameters (peroxide value, color index, viscosity, total polar compounds and UV absorbance at 232 and 270,nm) were used to evaluate the alterations during frying. A quick spectrophotometric method was developed to assess deep-frying oil quality. With the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method, the neutralization of the stable radical DPPH by antioxidants present in the oil during frying was measured. Radical-scavenging activity (RSA) of both oil blends was recorded during frying, wherein the results showed that the SO/PO blend had the highest RSA. It was evident from the results that a proportional correlation and positive relationship existed between the levels of fatty acids and the physicochemical characteristics of the vegetable oil blends and their RSA. The initial results obtained allow us to suggest that antiradical measurements could be used to quantify the oxidative and hydrolytic deterioration of vegetable oils upon frying. [source]


Effect of deep-fat frying of potato chips and chicken on the quality of soybean oil

INTERNATIONAL JOURNAL OF CONSUMER STUDIES, Issue 4 2000
Daya Goburdhun
Abstract The type of products may affect the quality of oil during deep-fat frying. The quality changes in pure soybean oil during frying of potato chips and chicken drumsticks were evaluated and compared. The oil was subjected to continuous frying at 180C for a period of 315 min. The parameters used to assess the oil quality were peroxide value (PV), iodine value (IV), free fatty acids (FFA), refractive index (RI) and colour. The percentage of oil absorbed by the two products was determined. The oil was also assessed visually for any change in colour, viscosity, turbidity, flavour and deposit. Results showed that, for both products, PV, IV, FFA, RI and colour changed significantly with time (P < 0.05). Potato absorbed oil during frying (6.9%), whereas chicken released fat into the frying medium (2.4%). When the rates of change of the various parameters in the oils were compared for the two products, significant differences (P < 0.05) were noted for PV and colour only. The oil used during the frying of chicken appeared visually to be at a more advanced stage of deterioration. [source]


Antioxidative ability of native and thermized sour whey in oxidation-catalysed model systems,

INTERNATIONAL JOURNAL OF DAIRY TECHNOLOGY, Issue 2 2007
JINHAN SHON
Antioxidative properties of sour (cottage) were evaluated with (thermized) and without (native) heat treatment (80C for 30 min). A model system comprising a Tween 20 stabilized peanut oil in phosphate buffer (pH 7.0) emulsion containing lipid oxidation catalysts, FeCl3, H2O2 and ascorbate was used. Native sour whey powder (SWP) was significantly better than thermized whey in terms of limiting the formation of thiobarbituric acid-reactive substances and peroxide value. Antioxidative ability was best at pH 3.0 and decreased with increasing pH. SWP (20%, w/v) was significantly better than all commonly used antioxidants tested after 96 h of incubation at 40C. [source]


Quality changes of farmed blackspot seabream (Pagellus bogaraveo) subjected to slaughtering and storage under flow ice and ozonised flow ice

INTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 8 2009
Victoria lvarez
Summary Flow ice (FI) combined with ozone (OFI condition) was evaluated for slaughter and storage of farmed blackspot seabream (Pagellus bogaraveo) when compared with FI alone (FI condition). When processed in either OFI or FI conditions, this species exhibited slow biochemical and microbiological spoilage mechanisms when compared with other commercial fish species. The presence of ozone slowed down microbial development (1.00,3.53 and 1.60,4.04 log CFU g,1 for fish mesophile counts from OFI and FI conditions, respectively) and trimethylamine formation, so that fish kept under OFI condition was still acceptable at the end of the experiment (day 16), while its counterpart fish treated with FI was rejectable. In contrast, a small pro-oxidant effect could be assessed by means of the ozone presence; however, oxidation values (peroxide value and thiobarbituric acid index) reached at day 16 by individuals treated under OFI conditions (8.34 and 0.19, respectively) cannot be considered specially high. [source]


Use of sunflower oil mixed with jojoba and paraffin oils in deep-fat frying process

INTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 7 2008
Radwan S. Farag
Summary The aim of the present study was to increase the stability of sunflower oil during frying process and to obtain low-calorie fried foods. Therefore, sunflower oil was mixed separately with jojoba oil and paraffin oil at ratios of 9:1 and 8:2 (v/v). The frying process was conducted at 180 5 C for 12 h continuous heating time. Some physico-chemical properties (refractive index, viscosity, colour, acid value, peroxide value, thiobarbituric acid test, iodine value and polymer content) of non-fried and binary fried oil systems were measured at various heating periods. The results demonstrated that mixing sunflower oil with jojoba oil or paraffin oil increased the stability and hence improved the quality of sunflower oil during frying process. [source]


The effect of soya flour and flaxseed as a partial replacement for bread flour in yeast bread

INTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 2006
Frank D. Conforti
Summary The aim of the study was to incorporate and determine the effect of combining flaxseed meal (15%) and soya flour (5% and 10%) and monitoring the effect of the two ingredients on product quality in yeast bread while at the same time to evaluate the effect of soya flour in preventing the development of lipid rancidity in the stored soya/flax bread. Bread volume decreased (P < 0.05) with increased addition of grains (flax and soya flour). Firming (P < 0.05) of the crumb was observed with increased percentage of soya flour. There were no significant differences (P > 0.05) in moisture in the flax and soya/flax breads. Darker crusts (P < 0.05) were developed in the control and soya/flax breads, while a darker (P < 0.05) crumb was found in flax and soya/flax breads. A 10% substitution level of soya flour did not have a significant effect on inhibiting lipid rancidity, but a lower peroxide value was produced in the bread. A 10% level of soya flour substitution also produced bread with lower quality sensory scores. [source]


MICROBIAL ANALYSIS AND TEXTURAL PROPERTIES OF CANTONESE SAUSAGE

JOURNAL OF FOOD PROCESS ENGINEERING, Issue 1 2010
YANTAO WU
ABSTRACT Cantonese sausage is one of the traditional meat products in China. In the present study, eight Cantonese sausage samples from different manufacturers were collected. Their microbial and textural properties were characterized. The chemical compositions were determined as follows: moisture, 15.18 3.40%; protein, 33.75 7.26% (expressed in dry matter); fat, 42.12 6.64% (expressed in dry matter); total carbohydrates, 9.11 3.73%; sodium chloride, 6.13 0.41%; and sodium nitrite, 35.55 6.69 mg/kg. The pH was determined to be 6.22 0.14, while the acid value was 2.02 0.71 mg potassium hydroxide/g lipid, and the peroxide value was 0.03 0.04 g potassium iodide/100 g lipid. The total viable counts were 5.55 1.48 log10 cfu/g, lactic acid bacteria were 3.59 0.68 log10 cfu/g, staphylococci/micrococci were 3.96 0.54 log10 cfu/g and yeasts/molds were 3.55 0.47 log10 cfu/g. Staphylococci/micrococci were the dominant microbial group in Cantonese sausage. This was different from other sausages. The textural profiles of Cantonese sausage were determined as follows: average values of hardness, springiness, cohesiveness, gumminess and chewiness were 3,066.56 g, 0.96 mm, 0.57, 1,736.76 g and 1,658.26 g mm, respectively. Analysis of between-variable relationships indicated that the pH value of Cantonese sausage was significantly correlated to its microbial and textural properties. PRACTICAL APPLICATIONS Cantonese sausage has gained much popularity and acceptance in China and many other countries. Commercial products from different manufacturers were collected in this work. The microbiological and textural characteristics of Cantonese sausage as well as the chemical compositions were evaluated. It is helpful to understand this type of sausage in order to improve its quality. [source]


PRESERVATION OF COMMERCIAL FISH BALL QUALITY WITH EDIBLE ANTIOXIDANT-INCORPORATED ZEIN COATINGS

JOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 5 2009
LIAN-SYUN LIN
ABSTRACT Fish ball, a surimi product rich in lipid and protein, is a popular food in Taiwan. Because lipid oxidation is one of the major deterioration reactions for fish ball, the feasibility of preservation of fish ball quality by the application of antioxidant-incorporated zein coating was investigated. Three antioxidants including butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and n-propyl gallate (PG) were used to formulate the antioxidant zein coatings. Infrared spectroscopy was used to confirm the successful incorporation of antioxidant with zein protein; peroxide value (POV), thiobarbituric acid reactive substance (TBARS) and weight loss were used as the quality indicators of fish ball stored at 4C. While all three types of antioxidant-incorporated zein coatings significantly retarded the quality deterioration, PG-incorporated zein coating exerted better quality preservation effectiveness than BHA- and BHT-incorporated zein coatings. PRACTICAL APPLICATIONS Edible coatings have been under research for several decades. However, most of the studies are conducted for the investigations of physiochemical or mechanical properties and usually using simulated food systems. The lack of applications on the commercial food products manufactured from food plants makes the edible coatings somewhat unrealistic. Not prepared in a laboratory for academic purpose only, the fish ball used in the present study was a real commercial product. The promising results of antioxidant-incorporated zein coatings on commercial products presented in this report will enhance the confidence of food manufacturers on the edible coatings. [source]


ESSENTIAL OIL AND OLEORESINS OF CINNAMOMUM TAMALA (TEJPAT) AS NATURAL FOOD PRESERVATIVES FOR PINEAPPLE FRUIT JUICE

JOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 5 2008
I.P.S. KAPOOR
ABSTRACT The essential oil and oleoresins (methanol, ethanol, isooctane and CCl4) from tejpat have been used as a natural food preservative for pineapple juice. The stored samples were studied for pH, total and reducing sugars, ascorbic acid, peroxide value, titrable acidity and microbiological count at fixed time intervals of 7 days. Significant changes were observed during the storage period. The essential oil showed better preservative effect than the oleoresins did. PRACTICAL APPLICATIONS Essential oils and oleoresins derived from spices are considered luxurious items because of their uses in aromatherapy, confectionary, beverages and pharmaceutical industries. Moreover, they also possess antioxidant and antimicrobial efficiency. Essential oil and oleoresins extracted from tejpat are used in the preservation of pineapple juice, which is better and safer than synthetic conservers. This characteristic is of great interest for the food industries. [source]


EFFECT OF PACKAGING MATERIALS ON THE QUALITY OF IRON-FORTIFIED WHOLEMEAL FLOUR DURING STORAGE

JOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 6 2007
N. HUMA
ABSTRACT The effect of packaging materials on the physicochemical and rheological characteristics of iron-fortified wholemeal flour (WMF) during storage was determined. WMF was fortified with three fortificants, namely ferrous sulfate (30 ppm), ferrous sulfate + ethylenediamine tetraacetic acid (EDTA) (20 + 20 ppm) and elemental iron (60 ppm). Each flour was also fortified with 1.5 ppm folic acid. Moisture, flour acidity and peroxide value increased during storage, while protein and fat contents decreased. Highest conversion of Fe2+ into Fe3+was observed in flour fortified with ferrous sulfate (2.72%), followed by that fortified with ferrous sulfate + EDTA (1.49%) and elemental iron (1.06%). Water absorption and dough viscosity of iron-fortified flours increased during storage. The flour containing ferrous sulfate was most acceptable regarding sensory characteristics, followed by samples containing ferrous sulfate + EDTA. Fortified flours were more stable during storage than unfortified. Addition of EDTA increased the stability of flours and fortificants. The fortified flours stored in polypropylene bags proved more stable than those stored in the tin boxes. PRACTICAL APPLICATIONS The main role of packaging is to protect the product during handling, distribution and storage against environmental and mechanical hazards. The success of a fortification program depends on the stability of micronutrients and food to which these are added. Chemical changes during storage badly affect chapatti making and sensory properties. Exposure of the fortificant to any factor including heat, moisture, air or light, and acid or alkaline environments during processing, packaging, distribution, or storage affects its stability. Flour containing elemental iron and ferrous sulfate with EDTA remained stable up to 42 days. The unfortified flour and flour containing ferrous sulfate remained stable for 21 days in tin boxes and 28 days in the polypropylene bags. Wheat flour milling industry would be benefited from this research if government is keen to launch iron fortification program in the country to curb iron deficiency anemia among population. [source]


LIPID OXIDATION OF FISH LIVER OIL AS AFFECTED BY LIGHT, ANTIOXIDANTS AND TEMPERATURE

JOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 1 2004
WEIGUO SANG
Crude and refined Mackerel liver oil with or without antioxidants were stored in artificial light or in darkness to assess the effects of photo-oxidative stress on the stability of oils and the antioxidant activity of butylated hydroxy-anisole (BHA) and tert-butylhydroquinone (TBHQ) on those oils. Changes in peroxide value (PV) and thiobarbituric acid value (TBA) were monitored over 18 days at 5C and 40C. The results showed that visible light exposure played the most critical role in the acceleration of fish liver oil oxidation. The addition of antioxidants showed a significant effect in retarding oxidation with TBHQ more effective than BHA. The oxidation rate of the oils decreased in the following order: control with light > control + BHA with light > control without light > control + TBHQ with light > control + BHA without light > control + TBHQ without light. Higher PV and TBA values were observed in refined oils versus crude oils. Increasing storage temperature accelerated the oxidation of only refined oils in light. [source]


EFFECT OF DIRECT APPLICATIONS OF SAGE (SALVIA OFFICINALIS L.) LEAVES ON OXIDATIVE STABILITY OF SUNFLOWER OIL DURING ACCELERATED STORAGE

JOURNAL OF FOOD QUALITY, Issue 5 2009
EDA ALIKO
ABSTRACT In this study, various sage applications were examined on oxidative stability of sunflower oil during accelerated storage. There are three applications: (1) direct sage leaves (S); (2) deodorized sage leaves (DeS); and (3) essential oil of sage leaves. The main compounds of essential oil were identified as, -thujone (35.87%),, -thujone (14.41%), 1,8-cineol (10.59%) and camphor (10.09%). Oxidative stability of these three applications was tested by Schall Oven test at 60C applying peroxide value and conjugated dienes, and Rancimat at 110C. Whereas the highest antioxidants activity was found for 2% S followed by 0.5% S and 2% DeS, all sage treatments statistically retarded the oxidation compared with the control sample. The most appealing result was that the residue can be used as a natural antioxidants. That means the reuse of residue may decrease economic losses and health risk in comparison with synthetic antioxidants and extracts because it is completely natural and contains no residual solvent. PRACTICAL APPLICATIONS While almost all of previous studies were concentrated on the use of herb extracts, our study investigates the results of direct application of sage on oxidation. Especially with this study, we have evaluated a possible application area for sage residue leftover after the deodorization process. [source]


PRELIMINARY EVALUATION OF THE APPLICATION OF THE FTIR SPECTROSCOPY TO CONTROL THE GEOGRAPHIC ORIGIN AND QUALITY OF VIRGIN OLIVE OILS

JOURNAL OF FOOD QUALITY, Issue 4 2007
ALESSANDRA BENDINI
ABSTRACT A rapid Fourier transform infrared (FTIR) attenuated total reflectance spectroscopic method was applied to determine qualitative parameters such as free fatty acid (FFA) content and the peroxide value (POV) in virgin olive oils. Calibration models were constructed using partial least squares regression on a large number of virgin olive oil samples. The best results (R2 = 0.955, root mean square error in cross validation [RMSECV] = 0.15) to evaluate FFA content expressed in oleic acid % (w/w) were obtained considering a calibration range from 0.2 to 9.2% of FFA relative to 190 samples. For POV determination, the result obtained, built on 80 olive oil samples with a calibration range from 11.1 to 49.7 meq O2/kg of oil, was not satisfactory (R2 = 0.855, RMSECV = 3.96). We also investigated the capability of FTIR spectroscopy, in combination with multivariate analysis, to distinguish virgin olive oils based on geographic origin. The spectra of 84 monovarietal virgin olive oil samples from eight Italian regions were collected and elaborated by principal component analysis (PCA), considering the fingerprint region. The results were satisfactory and could successfully discriminate the majority of samples coming from the Emilia Romagna, Sardinian and Sicilian regions. Moreover, the explained variance from this PCA was higher than 96%. PRACTICAL APPLICATIONS The verification of the declared origin or the determination of the origin of an unidentified virgin olive oil is a challenging problem. In this work, we have studied the applicability of Fourier transform infrared coupled with multivariate statistical analysis to discriminate the geographic origin of virgin olive oil samples from different Italian regions. [source]


Flavor Fade in Peanuts During Short-term Storage

JOURNAL OF FOOD SCIENCE, Issue 3 2006
Jodi E Williams
ABSTRACT: Flavor characteristics of roasted peanuts over short-term storage were explored through sensory and chemical analyses. The volatiles from freshly roasted peanuts were evaluated over short-time (21 d) storage using gas chromatography, chemosensory techniques, and a sensory panel to quantify and identify pyrazines and hexanal over a 21-d storage period. A significant decrease (P < 0.05) was noted in 2,3-diethylpyrazine, 2-methoxypyrazine, 2,3-dimethylpyrazine, 2-ethyl-3-methylpyrazine, and 2,3,5-trimethylpyrazine concentrations over a 21-d period. No significant difference (P > 0.05) was noted in the 2-methylpyrazine and 2-ethylpyrazine concentrations. The hexanal concentration significantly increased (P < 0.05) over the 21-d period. The peroxide values and sensory analysis agreed with these results. A significant increase (P < 0.05) in peroxide value was seen at days 14 and 21, and a significant decrease (P < 0.05) in fresh roasted peanuty flavor from day 0 to 21 and significant increases (P < 0.05) in painty, cardboardy, and bitter flavors from day 7 to 21 with the sensory analysis. The electronic nose successfully separated day 0 and 21 samples from day 7 and 14 samples, which were also separated but with some overlap. [source]


Stability of Crude Herring Oil Produced from Fresh Byproducts: Influence of Temperature during Storage

JOURNAL OF FOOD SCIENCE, Issue 9 2002
I. Aidos
ABSTRACT: Crude herring oil, extracted from fresh byproducts, was stored at 0, 20, and 50C in order to study the effect of temperature on lipid oxidation. The oil had an initial peroxide value (PV), anisidine value (AV), and free fatty acids of 0.7 meq peroxides/kg of lipid, 0.4, and 0.6%, respectively. During storage, the oil reached the secondary oxidation stage for all 3 temperatures. The formation of fluorescent compounds was inhibited at 0C. Significant decrease of the ,-tocopherol content was found after storage at 0 and 20C, but no consumption occurred at 50C. The development of oxidation products over time exhibited a temperature-dependency with a very good correlation. [source]


COMPARISON OF THE VIRGIN OLIVE OILS PRODUCED IN DIFFERENT REGIONS OF TURKEY

JOURNAL OF SENSORY STUDIES, Issue 3 2009
MUSTAFA
ABSTRACT Virgin olive oils from different regions of Turkey were collected and analyzed. The total phenolics and antioxidant capacity of the samples ranged from 30.26 to 208.61 mg gallic acid/kg and 0.60 to 5.61 Trolox equivalents/kg, respectively. Free acidity (0.44,7.31% oleic acid), peroxide value (6.83,39.60 meq O2/kg), total volatiles (0.11,0.37%), viscosity (65.50,85.40 cP), K232 value (1.30,2.54), K270 value (0.08,0.30), refractive index (1.470) and descriptive sensory properties of the samples were also measured. The multidimensional scaling (MDS) analysis indicated that positive and negative attributes classification of the olive oil sensory defining terms were mostly the case, and total phenolics content by itself may be a useful classification index. Also, MDS maps showed that the samples from Southeastern and Aegean regions are closer, while others are separate from each other. PRACTICAL APPLICATIONS Data for the physicochemical and sensory descriptive properties of virgin olive oils from Turkey are provided for the scientific community, olive oil consumers and traders. Also, utilization of sensory data by multidimensional scaling technique for geographical origin groupings provides a unique insight for researchers for similar objectives. In addition, some findings (i.e., the eligibility of phenolics content by itself for olive oil classification) of this article produce new results for fast and practical application purposes yet confirmed by other researchers. [source]


Acceptability, storage stability and costing of ,-amylase-treated maize,beans,groundnuts,bambaranuts complementary blend

JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 6 2007
Victor O Owino
Abstract The effects of ,-amylase treatment on physical properties, acceptability to mothers, and cost of roasted and extruded maize,beans,groundnuts,bambaranuts complementary porridge recipes were assessed prior to their industrial production. Storage stability of the extruded ,-amylase-treated fortified blend was assessed at 2 weeks and 6 months by sensory evaluation, peroxide value, water activity and microbiological load. The use of ,-amylase at 0.04% w/w enhanced porridge acceptability and resulted in 88% and 122% increase in flour concentration for roasted and extrusion-cooked porridge flour, respectively, while maintaining porridge viscosity at 1000-fold lower than that of traditionally used porridges. The extrusion cooked blend was stable for 6 months. ,-Amylase application increased the unit cost of the developed blend by only 1.4%. The total cost was less than US $ 2 kg,1, half the minimum price of commercially available complementary foods. Further work on marketing and the efficacy of this inexpensive food on growth of infants is warranted. Copyright 2007 Society of Chemical Industry [source]


Reduction of lipid peroxidation and H2O2 -mediated DNA damage by a red alga (Grateloupia filicina) methanolic extract

JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 14 2005
Yasantha Athukorala
Abstract The antioxidant activity of an extract of Grateloupia filicina was evaluated using linoleic acid and fish oil as substrates in an induct period at 65 C. Furthermore, the algal extract was subjected to comet assay to evaluate its protecting ability for H2O2 -induced DNA damage in rat lymphocytes. Progression of oxidation was examined using weight gain, peroxide value (PV), 2-thiobarbituric acid reactive substances and conjugated diene data. Effectiveness of the extract at 0.03 and 0.05% levels was superior to that of ,-tocopherol at 0.01% and the activity of 0.05% extract was higher than that of butylated hydroxyanisole and butylated hydroxytoluene at 0.01%. Also, the algal extract significantly inhibited H2O2 induced DNA damage in comet assay. The maximum DNA damage inhibition (68.9%) was recorded from the 50 g ml,1 alga extract when the rat lymphocyte cells were treated with 50 M H2O2. Copyright 2005 Society of Chemical Industry [source]


Antioxidant activity of ginger extract in sunflower oil

JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 7 2003
Zia-ur-Rehman
Abstract The antioxidant activity of dichloromethane extract from ginger was evaluated during 6 months of storage of refined sunflower oil at 25 and 45,C. Free fatty acid (FFA) content, peroxide value (POV) and iodine value (IV) were used as criteria to assess ginger extract as an antioxidant. After 6 months of storage at 45,C, sunflower oil containing 1600 and 2400,ppm ginger extract showed lower FFA contents (0.083 and 0.080%) and POVs (24.5 and 24.0,meq,kg,1) than the control sample (FFA contents 0.380%, POV 198.0,meq,kg,1). Sunflower oil containing 200,ppm butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) showed FFA contents of 0.089 and 0.072% and POVs of 26.5 and 24.7,meq,kg,1 respectively after 6 months of storage at 45,C. Similarly, after 6 months of storage at 45,C, IVs of sunflower oil containing 1600 and 2400,ppm ginger extract were 80 and 92 respectively, higher than that of the control sample (53). However, IVs of sunflower oil treated with 200,ppm BHA and BHT were 94 and 96 respectively after 6 months of storage at 45,C. These results illustrate that ginger extract at various concentrations exhibited very strong antioxidant activity, almost equal to that of synthetic antioxidants (BHA and BHT). Ginger extract also showed good thermal stability and exhibited 85.2% inhibition of peroxidation of linoleic acid when heated at 185,C for 120,min. Therefore the use of ginger extract in foods is recommended as a natural antioxidant to suppress lipid oxidation. 2003 Society of Chemical Industry [source]


Effect of previous chilled storage on rancidity development in frozen horse mackerel (Trachurus trachurus)

JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 15 2002
Santiago P Aubourg
Abstract Rancidity development during frozen storage (,20,C) of an underutilised medium-fat-content fish species, horse mackerel (Trachurus trachurus), was studied. Special attention was given to the effect of previous chilled storage (0, 1, 3 and 5 days) on the quality of the frozen fish. For this, chemical (free fatty acid and conjugated diene contents; peroxide value, PV; thiobarbituric acid index, TBA-i; fluorescent compound formation) and sensory (rancid odour and taste) analyses were carried out. Hydrolytic rancidity showed an increase with frozen storage time; however, no effect of previous chilling time was observed on the frozen product. Oxidative rancidity measured by chemical (PV, TBA-i and fluorescence) and sensory (odour and taste) indices increased with frozen storage time and also with previous chilling time. Satisfactory quality was maintained up to 7 months of frozen storage of horse mackerel provided that a short chilling time (not longer than 3 days) was employed. 2002 Society of Chemical Industry [source]


Effect of lipid oxidation and frozen storage on muscle proteins of Atlantic mackerel (Scomber scombrus)

JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 5 2002
Suhur Saeed
Abstract The effect of storage on the lipids and proteins in Atlantic mackerel stored for up to 24 months at ,20 and ,30,C was studied. Traditional methods including the peroxide value, thiobarbituric acid-reactive substances (TBARS) and a reverse phase HPLC method were used to determine the primary and secondary lipid oxidation products. All tests showed an increase in lipid oxidation products with storage time and at a higher storage temperature of ,20,C compared with samples stored at ,30,C. Antioxidants had a significant effect (P,<,0.01) on the inhibition of lipid oxidation, as shown by the reduction in peroxide value and hydroxides, and malondialdehyde formation. Similarly, deterioration of protein structure and functionality in mackerel stored for 3, 6, 12 and 24 months was greater at ,20 than ,30,C. ATPase activity in the myosin extract of Atlantic mackerel showed a significant decrease (P,<,0.01) with progressive frozen storage. Protein solubility in high salt concentration (0.6,M NaCl) decreased (P,<,0.01) during storage at both ,20 and ,30,C but was greater at ,20,C. Interestingly, antioxidants BHT, vitamin C and vitamin E protected the proteins against complete loss of ATPase activity and protein solubility to a significant level (P,<,0.01) for up to 1 year at ,20,C compared with samples stored without antioxidants. This study confirms the deleterious effect of lipid oxidation products on protein structure and function in frozen fatty fish. 2002 Society of Chemical Industry [source]