Color and Oxidative Rancidity of Gamma and Electron Beam-Irradiated Boneless Pork Chops

Color and oxidative rancidity were determined for chilled (3 ± 2°C) and frozen (?17 ± 3°C) boneless pork chops packaged in vacuum or air and irradiated to an absorbed dose of 0, 1.5 or 2.5 kGy (chilled) or 0, 2.5 or 3.85 kGy (frozen) of electron beam or cobalt⁶⁰ irradiation. Irradiation of vacuum-packaged chops produced redder, more stable (color and rancidity) product. More pronounced oxidative rancidity and less stable display color were noted for samples irradiated in aerobic packaging. Irradiation source had varying but limited effects on color and rancidity. Optimum packaging conditions can control color and rancidity changes in boneless chops, thereby enabling irradiation to be a useful intervention technology.     

Changes in Fatty Acids and Sensory Quality of Fresh Water Prawn (Macrobrachium rosenbergii) Stored Under Frozen Conditions

The effects of frozen storage and packaging methods on the oxidation of fatty acids and rancidity development in fresh-water prawn Macrobrachium rosenbergii were studied. The lipids of these fresh prawns contained 23% saturated, 46% monounsaturated, and 31% polyunsaturated fatty acids. The fatty acids, especially the unsaturated ones decreased during frozen storage for 6 months at -18°C, regardless of the packaging procedure employed. No objectionable rancid flavor was detected in these prawns during the 6-month frozen storage study.     

Vacuum Packaging, Ascorbic Acid and Frozen Storage Effects on Heme and Nonheme Iron Content of Mackerel

Vacuum packaging and ascorbic acid were tested for their ability to prevent heme iron loss in mackerel (Scomber scombrus). Vacuum packed samples had less heme breakdown than air packed samples at frozen storage temperatures above ?20°C. Ascorbic acid protected the heme at all temperatures when compared to air or vacuum packed samples.     

Effect of previous gutting on rancidity development in horse mackerel (Trachurus trachurus) during frozen storage at −20 °C

Gutting was applied to fresh horse mackerel (Trachurus trachurus) to study its effect on rancidity development during a prolonged frozen storage (up to 12 months at −20°C). To do so, chemical (free fatty acids, FFA; peroxide value, PV; thiobarbituric acid index, TBA-i; fluorescence ratio, FR) and sensory (odour and taste) analyses were carried out. The results showed that the gutting of horse mackerel led to a higher degree of oxidation in the frozen product, according to the chemical (PV, TBA-i and FR) and sensory (odour and taste) analyses. However, a lower extent of lipid hydrolysis (FFA formation) was detected at the end of the storage (twelfth month) as a result of gutting. It is concluded that the gutting of a medium-fat fish species such as horse mackerel is not recommended as previous treatment to frozen storage.     

Effect of a flax seed (Linum usitatissimum) soaking treatment on the frozen storage stability of mackerel (Scomber scombrus) fillets

The effect of a flax seed (Linum usitatissimum) soaking on the development of rancidity in frozen mackerel (Scomber scombrus) was studied. Fresh mackerel fillets were soaked in an aqueous flax seed extract for 20 min and then kept frozen (?20 °C) for up to 7 months. A parallel experiment with non‐soaked fillets was carried out under the same conditions. The development of rancidity was measured by biochemical (free fatty acids, peroxides, conjugated dienes and trienes, secondary oxidation products, fluorescent and browning compounds and lipoxygenase activity) and sensory (general aspect, odour and colour) analyses. An inhibitory effect of the soaking treatment on rancidity development was observed according to the peroxide content and the formation of fluorescence and browning. A lower lipoxygenase activity was detected at 1 month in the soaked fillets; after this, no differences were obtained between either type of sample, whose activities at month 7 were negligible. According to the sensory analyses, non‐soaked fillets had fair quality at 1 month and were rejectable at 3 months, while the soaked ones were still of good quality at 1 month and rejectable at 5 months. According to the present results, soaking in an aqueous flax seed extract could be useful for inhibiting the development of rancidity in fatty fish fillets. Copyright © 2006 Society of Chemical Industry     

Effect of MAP and vacuum sealing on sensory qualities of dry-salted olive

The ‘Gemlik’ olive, grown in Turkey, is the main variety used in the production of commercial table olives. The aim of the present work was to determine the effect on sensory qualities of dry-salted olives of the ‘Gemlik’ cultivar packed with vacuum sealing or modified atmosphere packaging and stored at 4 or 20°C. Storage temperature did not have a significant effect on the sensory profile (p>0.05). However, with the exception of the color attribute, somewhat higher overall scores were given to samples stored at 4°C. In both vacuum sealing and modified atmosphere packaging (MAP) samples stored at 4°C, the lack of oxygen and dipping the olives in 10 ppm chlorine solution before dry-salting, prevented the growth of yeast and mold and therefore both rancidity and softness attributes scored higher points by panelists.     

Chemical Changes and Visual Appearance of Albacore Tuna as Related to Frozen Storage

Fresh albacore tuna (Thunnus alalunga) were frozen and stored at –18°C and –25°C for 1 yr. Chemical and visual analyses were carried out at 1, 3, 6, 9 and 12 mo storage. Storage time correlated (P<0.05) with the low loss of moisture at –18°C, slight reduction of TVBN at –25°C and low increases of DMA, TMA, and TBARS at both temperatures. TMAO concentration (p=0.07), drip loss on cooking (p=0.52), peroxide value (p=0.059), FFA concentration (p=0.33) and pH (p=0.20)did not change significantly with period of storage but ?25°C resulted in a lower production of DMA and FFA than ?18°C. Results from chemical analyses correlated well with basic visual appearance.     

Storage and Lipid Quality of Chunked, Formed Roasts Containing Mechanically Separated Lamb

Restructured chunked and formed roasts containing 10 or 30% mechanically separated lamb (MSL) were made with meat from ram or wether lambs. Roasts were either frozen immediately after formulation and stored at -30°C before cooking to 71°C, or precooked immediately to 63°C, chilled and reheated to 71°C before storage at 4 and -30°C. Storage periods varied depending upon treatment. Roasts with 10% MSL contained less total fat and less free fatty acids (FFA) than those with 30% MSL. There was little evidence of extensive lipid oxidation as measured by thiobarbituric acid values and peroxide oxygen values in any of the roasts. There was an indication that pre-cooking and curing prior to storage increased glycerolipid hydrolysis because of increased levels of FFA. Apparently increased hydrolysis occurred in triglycerides since levels of phospholipids did not change.     

Processing and Frozen Storage Effects on the Iron Content of Cod and Mackerel

Processing and subsequent frozen storage affected the iron content of cod (Gadus morhua) and mackerel (Scomber scombrus) muscle tissue. Frame mince was obtained from the bone rack, without the head or viscera remaining, after filleting. Frame mince had significantly higher iron levels than intact fillets with or without skin or fillets that were subsequently minced. Skin-on fillets had more iron than skin-off fillets. Cod frame mince had about 50% heme iron, while mackerel frame mince ranged from 20-64%. Nonheme iron increased during frozen storage due to heme breakdown. Storage above ?14°C was more deleterious to the heme molecule than lower temperatures (?20°C or ?40°C).     

Inhibition of Lipid Oxidation and Rancidity in Precooked Pork Patties by Radical‐Scavenging Licorice (Glycyrrhiza glabra) Extract

This study investigated the efficacy of licorice extract (LE) to curtail lipid oxidation and protect sensory attributes of ground pork during refrigerated and frozen storage. Pork patties (20% fat) were formulated with 0%, 0.02%, 0.05%, and 0.1% (meat basis) LE or rosemary extract (RE) as comparison or 0.01% (fat basis) BHA with 0 or 1.5% NaCl. Raw and precooked (75 °C) patties were packaged in polyvinylchloride overwrapped trays and stored at 2 °C up to 7 and 14 d, respectively, or at –20 °C up to 6 mo. Lipid oxidation (thiobarbituric acid‐reactive substances [TBARS]) and sensory attributes of stored patty samples were evaluated, radical scavenging activity of the LE was measured, and the active phenolic compounds were identified. Cooking yield (<85%) was similar among antioxidant treatments, and lipid oxidation was minimal in refrigerated or frozen raw samples. However, TBARS values in refrigerated precooked control patties (0.22 mg/kg) rose to 9.3 to 9.4 mg/kg after 14 d, compared to 3.4 to 4.4 and 4.4 to 6.9 mg/kg in patties treated with 0.1% LE and RE, respectively. In frozen precooked samples, TBARS (0.22 mg/kg) increased to 1.3 mg/kg (P < 0.05) in control patties after 6 mo and had no significant change in patties treated with 0.1% LE or 0.01% butylated hydroxyanisol. Sensory panel evaluation confirmed strong inhibition of rancidity production by LE, corroborating its remarkable antiradical activity due to the presence of multiple phenolics. The results indicate that licorice has great potential as a natural antioxidative additive to extend the shelf‐life of precooked pork.     

Hydrolysis and oxidation of European eel oil during frozen storage for 48 weeks

The quality assessment of the wild European eel (Anguilla anguilla) stored at −20 °C was assessed by sensory, chemical (total volatile basic nitrogen (TVB-N), peroxide value (PV), free fatty acid (FFA), thiobarbituric values (TBA) and pH) methods. The sensory analysis of showed that European eels were acceptable by panellists and can be stored for more than 48 weeks at −20 °C. No effects of frozen storage were observed on the proximate composition of eel. The level of TVB-N showed fluctuations (7.09–14.72 mg TVB-N/100 g) during frozen storage period, thus TVB-N could not be used as an indicator of frozen eel quality. FFA, PV and TBA values showed fluctuations during frozen storage period but remained low at the end of storage period, PV reached to the maximum level of 13.20±1.73 meq/kg, which did not exceed the maximum recommended value for human consumption (20 meq/kg). The release of FFA slightly increased (P>0.05) from the initial value of 0.88 to 2.14 (expressed as % of oleic acid) until 32 weeks of frozen storage while TBA increased from the initial value of 0.085 mg MA/kg to maximum level of 0.7696 mg MA/kg after week 40. After that, their values decreased to 1.82 and 0.5577 at week 48, respectively. This study showed that off-flavour and off-odour was not detected and frozen European eels were still acceptable by panellists and can be stored for more than 48 weeks at −20 °C.     

Effect of brine pre-treatment on lipid stability of frozen horse mackerel (<Emphasis Type="Italic">Trachurus trachurus</Emphasis>)

The rancidity development during the frozen storage (-20 °C) of an under-utilised medium-fat fish species (horse mackerel; Trachurus trachurus) was investigated. Special attention was given to a pre-freezing treatment consisting of an immersion in NaCl solution (5%, 10%, and 20%) and its effect on lipid damage during the fish frozen storage. Lipid hydrolysis (free fatty acid content) and oxidation (conjugated dienes formation; peroxide value, PV; thiobarbituric acid index, TBA-i; fluorescence formation, FR) were studied up to 270 days of frozen storage. Oxidative rancidity measured by the PV, TBA-i, and FR showed an increase with the frozen storage time and also as a result of an increasing salt content in fish muscle. A high peroxide formation was observed at day 210 of frozen storage, especially in the case of 20% NaCl treated samples. Lipid hydrolysis also increased with the frozen storage time; at the end of the experiment (270 days), a decreasing effect of muscle salt content on lipid hydrolysis was observed. Employment of appropriate antioxidant additions is recommended if salting pre-treatment is to be needed to avoid a large lipid oxidation development and ensure a longer shelf-life time.     

Dried Pork as Influenced by Nitrate, Packaging Method and Storage

A new technique was developed to produce high quality, uniform and attractive thin sliced, cured dried pork. The effects of nitrate, packaging method and storage time on residual nitrite, TBA values, sensory properties and microbiological counts were determined. Residual nitrite decreased with increased storage time at 3 ± 1°C. The addition of nitrate plus vacuum packaging caused a greater residual nitrite level and a lower TBA value during storage. Nitrite and/or nitrate acted as an antioxidant to retard oxidative rancidity (TBA value). Dried pork manufactured by the technique described had no major rancidity problem and had an acceptable shelf life. Total aerobic plate counts, lactic acid producing microbial counts and total anaerobic counts were not affected by nitrate or packaging methods. Coliforms, molds and yeasts were not found in this dried pork.     

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

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     

Cryoprotective additives and cryostabilisation effects on muscle fillets of the freshwater teleost fish Rohu carp (Labeo rohita) during prolonged frozen storage

The effects of various cryoprotective additives separately and in combination were studied on the myofibrillar protein integrity, biochemical enzyme activity levels and muscle ultrastructure in the freshwater teleost fish Rohu carp (Labeo rohita). Fish muscle samples were divided into eight groups and immersed in different mixtures of cryoprotective additives (S1–S8), then frozen at ? 20 or ? 30 °C for 24 months. Electrophoretic studies revealed early (within 6 months) alteration of the myofibrillar proteins myosin light chain, α‐actinin and tropomyosin. Reduction of the storage temperature from ? 20 to ? 30 °C slowed down the degradative processes. Sodium dodecyl sulfate polyacrylamide gel electrophoresis indicated that fish muscle treated with cryoprotective mixture S8 (40 g L^?1 sorbitol/3 g L^?1 sodium tripolyphosphate/4 g L^?1 sodium alginate) showed minimal post mortem changes in myofibrillar proteins. Ultrastructural results also revealed post mortem damage to the muscle, seen earliest (within 6 months) in the sample frozen‐stored without additives (S2), as compared with the normal, unfrozen muscle (S1). The influence of cryoprotectants alone and in combination on fish muscle structural proteins, myosin and actin filaments (A and I bands), during prolonged frozen storage was investigated. After 12 months, samples frozen‐stored with various cryoprotective additives (S2‐S7), except S8, showed signs of myofibrillar disintegration. Beyond that time the degradative processes started showing up in all samples, with minimal muscle ultrastructural damage in sample S8. Again, reducing the storage temperature from ? 20 to ? 30 °C slowed down the degradative processes. Ultrastructural results correlated well with levels of biochemical enzymes (Ca²⁺ myofibrillar ATPase and succinic dehydrogenase) during frozen storage. This is the first report of the cryoprotective effects of these additives on this popular edible fish species. Of the various combinations of additives tested, cryoprotective mixture S8 was found to preserve the muscle structure longest under frozen storage conditions. However, even this mixture was only effective for 18 months at ? 30 °C. Beyond that time the myofibrillar degradative processes were apparent with correlative electrophoretic, biochemical and ultrastructural studies. Copyright © 2006 Society of Chemical Industry     

Degradation kinetics of ascorbic acid in encapsulated spray-dried honey powder packaged in aluminium laminated polyethylene and high-density polyethylene

The present study evaluated the stability of nutritionally rich encapsulated spray-dried honey powders in terms of hygroscopicity, glass transition temperature, total phenolic content, antioxidant activity and ascorbic acid using maltodextrin, gum arabic, and whey protein concentrate as carriers during a storage period of 180 days using high-density polyethylene and aluminium laminated polyethylene as packaging materials at 25°C (room temperature) and 35°C (accelerated temperature). The results revealed that temperature caused a negative influence on the glass transition temperature and stability of ascorbic acid. The kinetics of ascorbic acid degradation followed a first-order reaction with a reaction rate constant dependent on temperature and packaging material. Honey powder developed with whey protein concentrate as carrier agent and stored in aluminium laminated polyethylene pouches at 35°C possessed the highest antioxidant activity and ascorbic acid due to the presence of phenolic compounds in honey, aonla (Emblica officinalis. Gaertn), and basil (Ocimum sanctum) extract. The honey powders stored in aluminium laminated polyethylene pouches showed comparatively better antioxidant properties (total phenolic content, ascorbic acid, and antioxidant activity) and minimum hygroscopicity than the powders stored in high-density polyethylene at both the storage temperatures.     

Frozen Storage Performance of Cooked Cultivated Mussels (Mytilus edulis L.)—Influence of Ascorbic Acid and Chelating Agents

The usefulness of ascorbic acid and chelating agents in retarding sensory deterioration and progression of oxidative rancidity in frozencooked mussels was investigated. Ascorbic acid with and without chelating agents proved effective in arresting progression of oxidative rancidity, in samples held at – 12°C for 20 wk. However, these agents proved ineffective in preventing sensory deterioration of mussel meats under the same conditions. Mussels held at – 30°C showed an improved sensory stability throughout the study and demonstrated less progression of lipid oxidation compared with mussels held at – 12°C. Sensory deterioration at – 12°C storage is associated in part, with lipid oxidative changes. The ineffectiveness of antioxidant agents in preventing sensory deteriorative changes may indicate the presence of other, as yet undetermined, degradative pathways.     

Antioxidant activity of ginger extract in sunflower oil

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     

Lipid Oxidation in Ground Beef Patties as Affected by Time-Temperature and Product Packaging Parameters

Oxidative rancidity in fresh and stored ground beef samples was measured using a thiobarbituric acid (TBA) assay with antioxidant protection. The independent variables were fat concentration (15 or 30%), package type (polyethylene or vacuum-packaged), freezer storage temperature (-12.2°, -23.3° or -34.4°C) and storage time (4, 8, 12, 16, or 20 weeks). At the end of each storage time samples were thawed and TBA values were determined on the samples before and after cooking. TBA values increased during the first 12 to 16 weeks after which time it decreased for both the cooked and uncooked samples. The higher fat samples, packaged in polyethylene, had higher TBA values for both cooked and uncooked patties. Uncooked patties stored at - 12.2°C had higher TBA values than those stored at -23.3°C or -34.4°C but cooked sample TBA values showed no dependence on storage temperature.     

Effect of handling and storage on alkylamides and cichoric acid in Echinacea purpurea

Changes in alkylamide and cichoric acid concentrations during the handling and storage of freshly harvested and dried Echinacea purpurea plants were investigated. Plants subjected to varying degrees of physical damage to simulate rough handling were found to show no change in the concentrations of alkylamides and cichoric acid when subsequently dried within 24 h. Storage of undamaged fresh plant material at 20 °C and 60% RH for 30 days also showed no significant loss of either group of constituents. Storage of dried crushed plant material showed that alkylamides were degraded at 20 and 30 °C, especially when held in light, but no loss occurred when stored at 5 °C in the dark. Cichoric acid was found to be stable at 5, 20 and 30 °C provided that the moisture content remained low or enzymic activity was eliminated by blanching. The findings have implications for the handling and storage of echinacea to optimise retention of alkylamides and cichoric acid. © 2000 Society of Chemical Industry