Effect of light on colour and reaction of nitrite in sliced pork bologna under different chilled storage temperatures

The effect of different lighting conditions (darkness and exposure to 1900 ± 100 lux) on colour stability, conversion of added nitrite (residual nitrite, nitrite converted to nitrate, nitroso heme pigments, and protein-bound nitrite) and oxidative rancidity (2-thiobarbituric acid index) in sliced, vacuum-packaged pork bologna as a function of storage temperature (0 ± 1°C and 7 ± 1°C) was studied. Colour (redness) losses over the storage period were more dependent upon photochemical processes than on thermal processes, and the action of temperature on colour was attributable to its effect on microbial growth, which in turn also affects oxygen availability. Conversion of nitrite into the different fractions studied was chiefly temperature-dependent, but exposure to light lowered the residual nitrite content. Nevertheless, the effect of illumination on the constant rate of residual nitrite depletion was dependent on the storage temperature. Recovery of the added nitrite, i.e. the total of the nitrite in all the fractions combined, was highly dependent upon fluctuations in the residual nitrite levels and varied over the storage period. Under the conditions of the experiment, photo-oxidation did not appear to be a determining factor in lipid oxidation.     

Modification of physico-chemical and colour parameters during the marketing of 'paté'

The evolution of different physico-chemical parameters (iodine number, TBA test, residual nitrite level, pH and moisture) and CIE L^*a^*b^* colour evolution, in pork liver ‘pate’, with and without sodium ascorbate addition, were studied.

The samples were stored in an illuminated display cabinet at different lux intensities and in the dark. The regression equations were obtained for each one of the parameters under study, from the first day of exposure to light.

The sodium ascorbate showed a protective effect on the photo-oxidation mechanism (measured by TBA test), but it did not have an influence on the samples in darkness.

In both types of paté exposed to light, fading takes place and the most important variations in colour parameters are produced during the first 24 h of exposure to light.     

Effect of modified atmosphere packaging on oxidative changes in frozen stored cold water shrimp (Pandalus borealis)

Shrimps caught at sea were boiled in seawater, air blast or nitrogen frozen, glazed and then packed in plastic bags with a low oxygen transmission rate. The bags were either flushed with nitrogen (modified atmosphere packaging) or with atmospheric air before sealing. The shrimps were then stored for up to 12 months in a freezer cabinet at −17°C with fluctuating temperatures. During storage they were either exposed to fluorescent light or kept in darkness. To investigate the effect of fluctuating temperatures some of the modified atmosphere-packed shrimps were stored in darkness in a cold store at a constant temperature of −18°C. Quality changes were determined by sensory evaluation combined with chemical/physical analyses, including determination of the pigment astaxanthin and measurement of the oxidative stability by determination of thiobarbituric acid-reactive substances (TBARS). Packaging in modified atmosphere resulted in overall better quality in relation to colour fading, development of rancid flavour and toughening of the meat. Light exposure influenced both colour fading and lipid oxidation negatively. Temperature fluctuations resulted in very pronounced formation of frost in the packages. After 6 to 9 months of frozen storage, the amount of frost corresponded to the weight of the glazing layer applied before storage.     

Effect of Storage Conditions on Quality Characteristics of Bologna Sausages Made with Citrus Fiber

ABSTRACT: Bologna sausage with added citrus fiber was improved nutritionally in fiber content and had decreased residual nitrite levels and a delay in the oxidation process as determined by TBA values and red color. Only TBA values and redness were influenced by storage conditions (light and darkness) mainly due to the oxidant effect attributable to light. In both cases these effects were minimized by the citrus fiber. Citrus fiber at all concentrations made the products harder and less springy and chewy. All samples had similar satisfactory quality scores except bologna with 2% citrus fiber, which had the lowest scores. Microbial growth was not modified by citrus fiber during storage.     

Effect of rosemary extract dose on lipid oxidation, colour stability and antioxidant concentrations, in reduced nitrite liver pâtés

The oxidative stability of liver pâté was investigated in relation to different doses of rosemary extract (RE) and sodium nitrite. Colour stability, lipid oxidation (TBARS) and concentrations of ascorbic acid, α-tocopherol, carnosic acid and nitrite were measured on the batters before cooking and on the cooked liver pâté before and after exposure to light and air for 48 h at 4 °C. Results showed that the use of RE significantly reduced lipid oxidation, whereas it had no effect on colour stability. Ascorbic acid and nitrite concentrations were significantly higher and lower respectively when RE was added. RE dose-dependently increased the concentration of carnosic acid. Lower sodium nitrite doses resulted in significantly lower nitrite concentrations and slightly lower TBARS values. It was concluded that in liver pâté sodium nitrite levels may be lowered to 80 mg/kg without negatively affecting colour and lipid stability and that the use of RE may help in maintaining lipid stability.     

Factors controlling the growth of Clostridium botulinum types A and B in pasteurized cured meats VI. Nitrite monitoring during storage of pasteurized pork slurries

Residual nitrite levels were monitored during storage for up to 6 months, in a model pork slurry system used to study the relative effects of curing ingredients and additives used in pasteurized cured meats to control the growth of Clostridium botulinum.
In 'low' pH slurries the rate of loss of nitrite fell with reducing storage temperature. Less residual nitrite remained after HIGH heat treatment but the rate of loss of that residual nitrite was slower during storage than nitrite remainly after LOW heat treatment. Inclusion of nitrate resulted in higher residual nitrite levels, particularly after HIGH heat and if stored below 20°C. If isoascorbate was added nitrite became undetectable within circa 30 days, even when nitrate had been added. The rate of loss of nitrite was slower in 'high' pH slurries (pH 6.3–6.8).
Monitoring levels of nitrite in the product soon after production would detect its accidental overuse but monitoring nitrite in the product during distribution or at retail, without knowledge of the composition and prior history of the product, gives little indication of the amount used at manufacture. The level of residual nitrite was not directly related to the ability of the curing mixture to control the growth of CI. botulinum types A and B. Some slurries in which C1. botulinum grew least during 6 months' storage contained no residual nitrite because isoascorbate was also present.     

Influence of an Extract of Heart on Stability of Color and Development of Rancidity During Storage of Sliced Bologna

To investigate whether the presence of substances extracted from the heart could improve the stability of the color and retard rancidity during storage, three batches of beef bologna containing 0, 5.43 and 10.86% of a heart extract were prepared. The product containing a greater amount of extract had a more intense, pink color than product with less or no extract. The rate of change of the color and lipid oxidation pattern were found to be the same for the three batches during a 60-day storage period. The positive influence of the extract on color was attributed to the extra amount of pigment provided in the extract rather than to a protective reducing mechanism.     

Monitoring beer during storage by fluorescence spectroscopy

The present study demonstrates the use of fluorescence spectroscopy and multivariate data analysis for monitoring changes in beer during storage. Total luminescence spectra and synchronous scanning fluorescence spectra were recorded for fresh beer and beer samples stored in clear glass vials for three weeks in darkness at 4 °C and at 22 °C, and exposed to light at 22 °C, respectively. A pronounced decrease of fluorescence features ascribed to riboflavin was observed in samples exposed to light as compared to those kept in the dark. Principal component analysis of synchronous scanning fluorescence spectra revealed clear clustering of samples according to storage conditions. Successful classification of differently stored samples was accomplished using both the nearest neighbour method (kNN) and linear discriminant analysis (LDA).     

Effect of light on colour stability of sliced smoked rainbow trout Oncorhynchus mykiss fed astaxanthin

Colour stability of sliced smoked fillets of trout fed astaxanthin exposed to light during chilled storage was monitored by instrumental colour measurements and analyses of flesh astaxanthin content. When exposed to light changes in colour parameters at the surface of sliced smoked rainbow trout fillets occurred. The slices became paler. The level of astaxanthin was not affected by either light or storage conditions. Slices exposed to light had higher TBARS values than those stored in the dark. In our experimental conditions the use of a high initial vacuum level and packaging film with a low oxygen transmission rate maintained the astaxanthin content. However these optimal packaging conditions were not able to prevent significant oxidation of lipids after the initial 2–3 days of display.     

Studies on Pasteurized and Commercially Sterilized Poultry Meat Bologna. Effects of Nitrite Addition and Vacuum Cutting

Turkey bologna was prepared from mixed light and dark turkey meat and heat processed in cans under simulated commercial pasteurizing and sterilizing conditions. The bologna was prepared with and without added sodium nitrite and chopped in air or under vacuum. Nitrite and vacuum chopping had no effect on shear value, texture evaluation, pH, fat layer, soluble protein, residue or salt soluble protein. Nitrite addition increased cooking loss and protein sol. Vacuum chopping increased cooking loss and decreased the amount of protein sol. The pasteurized bologna had firmer texture and lower cooking losses than bologna processed to commercial sterility.     

Stability of bixin in annatto oleoresin and dye powder during storage

Annatto dye is a natural colour extracted from the pericarp of seed of Bixa orellana L. Bixin is the principle colouring agent, and can be extracted from the annatto seeds into oil, alkali and organic solvents. Considerable losses were reported during storage in bixin content of annatto dye depending upon the conditions. In the present study, the loss of bixin in annatto dye stored in the form of dye powder or annatto oleoresin at three different conditions, viz; cold conditions in darkness, in darkness at room temperature (RT) and at RT in diffused daylight were evaluated spectrophotometrically at 470 nm in choloroform. Accordingly, annatto oleoresin and dye powder of approximately equivalent bixin strengths were exposed to different storage conditions in glass bottles for a period of 360 days. The losses were very high in the case of dye powder when compared to the oleoresin under all the storage conditions. Mass fraction of bixin lost in oleoresin stored at cold dark conditions was negligible (0.011) throughout the study, whereas considerable losses were observed in dye powder (0.229). The mass fraction of bixin lost in oleoresin and dye powder samples stored at RT (dark) were 0.082 and 0.542 respectively. Similarly in case of RT (diffused day light) conditions, the losses of bixin in oleoresin and dye powder were 0.136 and 0.600, respectively. Loss of 0.154 was observed in bixin content in the seed stored in jute bags during the period. The second-order rate constants for degradation of bixin were calculated, and were found to be much lower for oleoresin when compared to dye powder. It is recommended that the dye can be conveniently stored in the oleoresin form until it is formulated for application in foods.     

Impact of polylactate and poly(hydroxybutyrate) on food quality

Cups based on polylactate (PLA) and poly(hydroxybutyrate) (PHB) were found to be as effective as high-density polyethylene (HDPE) cups in protecting an orange juice simulant and a dressing from quality changes during storage. The orange juice simulant and the dressing were stored in PLA, PHB and HDPE for 10 weeks at 4 °C under fluorescent light or in darkness. The suitability of PLA and PHB compared to HDPE was investigated by determination of colour changes and loss of ascorbic acid of the juice simulant and by determination of colour changes, primary (peroxide value) and secondary lipid oxidation (volatiles determined by static headspace) products and reduction of f-tocopherols of the dressing. The study also revealed that the quality changes were primarily induced by light, since the quality of samples stored in light changed considerably compared to the quality of samples stored in darkness.     

Effect of acid adaptation on growth during storage at 10 degrees C and resistance to simulated gastric fluid of Listeria monocytogenes inoculated onto bologna formulated with or without antimicrobials

The fate of acid-adapted and nonadapted Listeria monocytogenes inoculated onto bologna slices (formulated with or without antimicrobials) was examined during storage and after exposure to in vitro gastric challenge. Bologna slices formulated with no antimicrobials (control), 3% sodium lactate (SL), or 1.8% SL plus 0.25% sodium diacetate (SD) were inoculated (2 log CFU/cm2) with a 10-strain composite of acid-adapted or nonadapted L. monocytogenes strains. Growth or survival of the two inocula on bologna was evaluated during vacuum-packaged storage (10 degrees C) for up to 36 days. Survival of previously acid-adapted or nonadapted L. monocytogenes on stored bologna exposed to simulated gastric fluid (adjusted to pH 1.0 with HCl) for 20, 40, and 60 min also was determined. As expected, inclusion of antimicrobials in the product formulation inhibited growth of L. monocytogenes during storage of vacuum-packaged bologna compared with growth on control samples. Acid adaptation of L. monocytogenes prior to product inoculation did not affect subsequent survival or growth on bologna or resistance to simulated gastric fluid (P > 0.05). Survival of L. monocytogenes exposed to simulated gastric fluid during storage increased with product age, growth phase of the cells, and possibly age of the cells, particularly for control samples (no antimicrobials), in which the pathogen grew uninhibited to approximately 6 log CFU/cm2 by day 8 of storage. Inhibition of L. monocytogenes growth on product formulated with antimicrobials was associated with only sporadic and small numbers of survivors following exposure of these samples to simulated gastric fluid, especially in samples stored longer. However, cell numbers in these treatment groups before the gastric challenge did not exceed 3.8 log CFU/cm2. Inhibition of growth on product with antimicrobials precluded detection of survivors resistant to the effects of simulated gastric fluid.     

The relationship of added nitrate to pigment formation in native pork-sausage (longaniza)

The nitrosomyoglobin, residual nitrate and nitrite concentrations of the native pork-sausage (longaniza) were analysed within a ten-day storage period. Several levels of nitrate (50, 100, 300, 500 and 2000, 3500 and 5000 ppm) were employed. These were examined to determine the minimum amount of nitrate that could be added to the curing mixture for the making of longaniza whilst still obtaining acceptable organoleptic properties, especially colour.Pigment formation in longaniza due to the added nitrate occurs from the onset and reaches its maximum on the third or fourth day. The desirable pink to red colour in the cured meat was obtained even with amounts of nitrate as low as 50 ppm. All treated longaniza showed high and similar colour scores compared with the control. However, higher colour stability was obtained with the use of greater than 500 ppm nitrate. The amount of residual nitrate and nitrite is directly proportional to the initial quantity of nitrate added. The use of 50 to 500 ppm nitrate poses no danger to public health while the use of 2000 to 5000 ppm nitrate enhances the possibility of carcinogenic nitrosamine formation and incidence of methemoglobinemia.     

Effects of light exposure on chlorophyll,sugars and vitamin C content of fresh‐cut celery (Apium graveolens var. dulce) petioles

Effects of light exposure (24 μmol m^?2 s^?1) on fresh‐cut celery nutritional quality were evaluated during 8‐day storage at 7 °C using darkness as control. Light exposure preserved 47% chlorophyll a and 48% chlorophyll b contents more than darkness at the end of storage. Sucrose, reducing sugar and glucose contents in light‐stored petioles were 17%, 25% and 67% higher than those in dark‐stored petioles after 8‐day storage, respectively, thus resulting in higher total soluble solids content in light condition. Moreover, l ‐ascorbic acid content increased at 2‐day storage in light condition and was 46% more than in darkness at the end of storage. The fresh weight loss significantly increased in all petioles, and this increase was markedly accelerated by light exposure with a maximum of 1.43% at the end of storage. Dry matter content was induced more by light exposure than by darkness at 2‐day storage.     

Inhibition of Listeria monocytogenes on bologna sausages by an antimicrobial film containing mustard extract or sinigrin

The ability of Listeria (L.) monocytogenes to convert glucosinolates into antimicrobial isothiocyanates was investigated. Mustard glucosinolates in pure (sinigrin) or extract forms (sinigrin, oriental; sinalbin, yellow mustard) were used in broth media and in a polyvinyl polyethylene glycol graft copolymer (PPG) packaging film with bologna to examine their value as antimicrobial precursors for the control of L. monocytogenes viability and extension of bologna shelf-life at 4 °C. During broth tests with deodorized (myrosinase-inactivated) mustard extracts (10 d at 20 °C) or with purified sinigrin (21 d at 20 °C) L. monocytogenes was only inhibited when exogenous myrosinase was added. None the less, the organism was able to hydrolyze almost half the pure sinigrin by 21 d in tests without added enzyme. Reductions in sinigrin levels were measured by reversed-phase liquid chromatography, and in the absence of L. monocytogenes or added myrosinase the glucosinolate was stable. When pure sinigrin, oriental or yellow mustard extracts were incorporated in PPG films containing 3, 5 and 6% (w/w) of the corresponding glucosinolate and used to package bologna inoculated with 4 log CFU/g L. monocytogenes, the pathogen became undetectable in bologna packed with the oriental mustard extract at 52 d storage and remained undetectable at 70 d. The yellow mustard extract was less inhibitory and the pure sinigrin was not antimicrobial. L. monocytogenes numbers reached >7 log CFU/g in the film and untreated controls at 17 d storage. At 35 d storage, samples packed with control film contained sufficient numbers of lactic acid bacteria (LAB) (>7 log CFU/g) to be considered spoiled, whereas treatments containing mustard or sinigrin remained <7 log CFU/g LAB for ≤ 70 d. L. monocytogenes played a key role in exerting control over its own viability in bologna by hydrolysis of the glucosinolate in the oriental mustard film, but other antimicrobials in treatments may have contributed.     

Determination of Critical Oxygen Level in Packages for Cooked Sliced Ham to Prevent Color Fading During Illuminated Retail Display

ABSTRACT:  The effect of packages with different oxygen transmission rates (OTR), different gas-to-product-volume (GP) ratios, and various levels of residual oxygen after packaging on the color stability of cooked ham exposed to commercial retail light conditions was studied. Sliced cooked ham was packaged in thermoformed packages with OTR of 0.04 and  0.06 mL O₂/pkg × 24 h  and GP ratios of 2.6 and 4.1. After packaging, the packages were additionally divided into groups with 4 levels of residual oxygen ranging from 0.09% to 0.46%. The packaged ham was stored in darkness at 4 °C up to 33 d, and during the storage period samples were withdrawn and exposed to light for 2 d before instrumental and visual color evaluation. In order to maintain an acceptable color of this particular ham product when exposed to typical retail light conditions, the highest acceptable level of oxygen in the headspace of the packages was 0.15% oxygen at the time of illumination. This threshold level was independent of the storage time before light exposure. A residual oxygen level of below 0.15% just after packaging combined with the package with the lowest OTR  (0.04 mL O₂/pkg × 24 h)  and the lowest GP ratio (2.6) was the optimal condition for maintaining the color of the tested ham product throughout the entire storage period.     

Lemon albedo as a new source of dietary fiber: Application to bologna sausages

The aim of this work was to study the effect of the addition of lemon albedo in bologna sausages. Two types of albedo (raw and cooked) and five concentrations (0%, 2.5%, 5%, 7.5% and 10%) were added to sausages. Chemical, physicochemical and sensory analyses were made. The addition of albedo to bologna sausages represents an improvement in their nutritional properties and may have beneficial effects, possibly due to the presence of active biocompounds which induce a decrease in residual nitrite levels. The formulations which gave products with sensory properties similar to conventional sausages were sausages with 2.5% and 5% raw albedo and 2.5%, 5% and 7.5% cooked albedo.     

Investigation of colour changes of some tomato products during frozen storage

The colour changes of frozen tomato pulp were investigated under different conditions of frozen storage (?25°C; in open bags with presence of O₂ and in artificial light or darkness; in closed bags also in artificial light or darkness). In addition the antioxidative effect of tomato seeds and spices (sage, thyme, rosemary, oregano, majoram) was studied. The colour change of tomato pulp was determined with instrumental colour measurement, the carotenoid pigments loss was measured with UV/VIS spectrophotometry. It was found that exposure to light and oxygen accelerated the colour loss and oppositely packaging and storage in darkness had a colour saving effect. The ground tomato seeds (5%) could stabilize the carotenoid pigments after longer time frozen storage (min. 10 weeks). The commercial spices (0.2%), mainly rosemary and marjoram significantly reduced the pigment degradation. The tomato seeds and the spices did not change significantly the taste of tomato pulp.     

Influence of polyphenols isolated from <Emphasis Type="Italic">Scutellaria baicalensis</Emphasis> Georgi and <Emphasis Type="Italic">Crataegus oxyacantha</Emphasis> on the oxidative stability of cholesterol in butter stored in various conditions

The aim of the present study was to determine whether the exposure of two types of butter (A1, A2) to different conditions (4 °C and 30 °C in darkness and exposed to light 3600–3900 lx at 50 °C) could be stabilized with natural polyphenols. The polyphenols (500 ppm) added to butter included flavones of skullcap in the form of root powder, 95% pure baicalin and procyanidins from the bark of hawthorn. The rate of cholesterol oxide products (COPs) as well as the storage periods were closely connected with sample storage conditions and the type of butter. Among the polyphenols used, the flavones of skullcap proved to be stronger inhibitors of oxidation process than procyanidins of hawthorn. The storage of samples with the addition of flavones at 50 °C and exposed to light resulted in preserving 50% of cholesterol in both types of butter. The lowest amounts of COPs were formed in samples stored at 4 °C with no light exposure and, under the other conditions, in samples with flavones of skullcap added.