The effect of modified atmosphere packaging on the microbiological,physical, chemical and sensory characteristics of broadtail squid (Illex coindetii)

The aim of this work was to evaluate the effect of various atmosphere compositions (20% CO₂/80% N₂ for modified atmosphere packaging (MAP) 1, 50% CO₂/50% N₂ for MAP 2, 70% CO₂/30% N₂ for MAP 3 and vacuum packaging) on the microbial (mesophiles, psychrophiles, Pseudomonas spp., Brochothrix thermosphacta and Enterobacteriaceae), physical, chemical [trimethylamine (TMA) and total volatile basic nitrogen (TVBN)] and sensorial characteristics of broadtail squid (Illex coindetii) stored for 10 days at 2 ± 1 °C. All microbial populations were severely restrained by MAP 3 with the exception of Enterobacteriaceae, which seemed to take advantage of the lack of competitive microflora and had enhanced microbial counts on MAP samples (P < 0.05). Colour attributes were better maintained on MAP‐stored samples. Drip loss was less on vacuum‐packaged squids. MAP 2 was the best atmosphere for the preservation of tissue consistency. TMA and TVBN formation was limited by high CO₂ atmospheres, even though both elevated in all studied conditions. Shelf life based on sensory characteristics was determined to be 10, 8, 6, 6 and 4 days for MAP 3, MAP 2, MAP 1, vacuum and control samples, respectively.     

Enhancement of the nutritional status and quality of fresh pork sausages following the addition of linseed oil, fish oil and natural antioxidants

Fresh pork sausages (pork shoulder, pork back fat, water, rusk and seasoning) were manufactured where 15% of the pork back fat was substituted with linseed oil (LO) or fish oil (FO). Green tea catechins (GTC) and green coffee antioxidant (GCA) were added to both LO (LGTC 200 and LGCA 200) and FO (FGTC 200 and FGCA 200) substituted sausages at a level of 200 mg/kg. Raw and cooked pork sausages were either over-wrapped with oxygen permeable film (aerobic storage) or stored in modified atmosphere packages (MAP) containing 80% O₂:20% CO₂ or 70% N₂:30% CO₂, respectively for 7 days at 4 °C. Effects on fatty acid profiles, lipid oxidation, colour and sensorial properties were investigated. α-Linolenic acid increased from 1.34% (control) to 8.91% (LO) and up to 11.2% (LGTC 200 and LGCA 200). Addition of fish oil increased levels of EPA from 0.05% (control) to 2.83% (FO), 3.02% (FGTC 200) and 2.87% (FGCA 200) and DHA levels increased from 0.04% (control) to a maximum of 1.93% (FGTC 200). Lipid oxidation was low in raw and cooked linseed oil containing sausages. GTC (200 mg/kg) significantly (P < 0.05) reduced lipid oxidation in raw fish oil containing sausages after 7 days of storage. Colour parameters in raw pork sausages were unaffected by the packaging atmosphere. L^* lightness values were lower (P < 0.05) in LGTC 200 and a^* redness values lower (P < 0.05) in LGTC 200 and FGTC 200 after 7 days of storage. Sensory scores of cooked pork sausages were unaffected by linseed oil addition. Flavour and overall acceptability scores in cooked fish oil containing sausages were improved by GTC addition. Results obtained demonstrate potential for the production of nutritionally enhanced fresh pork sausages.     

Use of carbon dioxide enriched atmospheres in the refrigerated storage (2 °C) of salmon (Salmo salar ) steaks

 Selected microbial counts (total viable microbiota, Brochothrix thermosphacta, lactic acid bacteria and Enterobacteriaceae), biochemical parameters [pH, total volatile nitrogen, nucleotide breakdown products, non-volatile amines, d(–) and l(+)-lactic acids and short-chain fatty acids] and sensory attributes (colour and odour) of refrigerated (2  °C) salmon (Salmo salar) steaks stored under CO₂-enriched [CO₂/air (20/80, v/v), CO₂/air (40/60, v/v)] and air atmospheres were determined. When compared with air, sensory results showed shelf-life extension of 6 days and 15 days for 20% and 40% CO₂-enriched atmospheres, respectively. Microbial and biochemical results also revealed that the 40% CO₂-enriched atmosphere was the most effective packaging type for refrigerated salmon. Received: 22 April 1999     

Shelf‐life extension of refrigerated seabass slices under modified atmosphere packaging

The effect of CO₂‐enriched atmosphere in combination with either oxygen or nitrogen on the keeping quality of seabass slices stored at 4 °C was investigated. The inhibitory effect on bacterial growth increased proportionally to the CO₂ concentration in the packaging, maximum inhibition being achieved with 100% CO₂ (P < 0.05). Seabass slices stored in CO₂‐enriched atmosphere had lower total volatile base, trimethylamine, ammonia and formaldehyde contents than those stored in air (P < 0.05). However, increases in lightness and exudate loss were observed for samples packaged in high‐CO₂ atmosphere, suggesting the denaturation of both muscle and pigment proteins by carbonic acid formed. Thiobarbituric acid‐reactive substances (TBARS) increased as the CO₂ concentration increased (P < 0.05). However, odour, flavour and overall acceptability of CO₂‐enriched packaged samples, particularly with 80 and 100% CO₂, were acceptable throughout storage for 21 days. Chemical and microbial changes in all samples were generally in agreement with sensory panel evaluations. The shelf‐life of seabass slices packaged in 80–100% CO₂ atmosphere could be extended to more than 20 days at 4 °C, compared with 9 days for those packaged in air. © 2002 Society of Chemical Industry     

Effects of fibre orientation, myoglobin redox form, and postmortem storage on NIR tissue oximeter measurements of beef longissimus muscle

To determine near-infrared tissue oximeter responses to muscle fibre orientation, display time, and surface colour differences of beef longissimus lumborum steaks, beef loins were cut into steaks either perpendicular or parallel to the muscle fibre orientation. Surface colour differences were created by packaging steaks in vacuum (VAC), 80% O₂ and 20% CO₂ modified atmosphere packaging (HiOx MAP), polyvinyl chloride film overwrap (PVC), and HiOx MAP converted to PVC (HiOx-PVC) after 2 days. Changes in surface colour and subsurface pigments during display (0, 2, 4, 10, and 15 days at 2 °C) were characterized by using a reflectance-spectrophotometer and a near-infrared tissue oximeter, respectively. Fibre orientation, storage, and packaging affected (P < 0.05) colour, total pigment, deoxymyoglobin, and oxymyoglobin content. Tissue oximetry measurements appear to have potential for real-time monitoring of myoglobin redox forms and oxygen status of packaged meat, but fibre orientation needs to be controlled.     

Combined effects of thymol, carvacrol and temperature on the quality of non conventional poultry patties

The combined effect of thymol (0–300 ppm), carvacrol (0–300 ppm), and temperature (0–18 °C) on the quality of non conventional poultry patties packaged in air and modified atmosphere (MAP: 40% CO_2; 30%O₂; 30% N₂) was investigated using a simplex centroid mixture design. The patties were monitored for microbiological (total viable count, Enterobacteriaceae, lactic acid bacteria, Pseudomonas spp.) physico-chemical (pH, colour) and sensory attributes. For the patties mixed with the antimicrobials and stored at low temperature (0–3 °C) a reduction of the cell load of about 1–1.5 log cfu/g was observed. The log reduction was lower at the end of storage time and decreased with the increase of the temperature. For the poultry patties packaged in MAP the higher log reduction for Pseudomonas spp. during all the storage time was observed. In both packaging atmospheres the combination of the essential oils and low temperature determined no modification for off-odour during the first 4 days of storage.     

A dissolving CO2 headspace combined with organic acids prolongs the shelf-life of fresh pork

The aim of this paper was to evaluate the effect of a novel CO₂ packaging method in combination with organic acids on the microbial growth in fresh pork meat. Fresh pork fillet was packed with a small amount of 100% CO₂ (initial gas/product ratio 0.2/1.0) and a brine solution containing citric acid (3% w/w, pH 5), acetic acid (1% w/w, pH 5) or a combination of both. Microbial counts and composition in the product were determined. CO₂, citric acid and acetic acid each reduced total growth after four weeks of storage and delayed the onset of microbial growth. Combinations of treatments increased the effects and microbial growth in samples packed with a combination of CO₂ and both acids was negligible even after 35 days. However, the addition of citric acid to the packages led to significant precipitation in the brine. Analysis of the bacterial flora showed that lactic-acid bacteria dominated the flora in samples packed with CO₂ while vacuum-packed samples contained high numbers of Pseudomonas sp. and yeast. As all CO₂ dissolved in the product within hours after packaging, the outer appearance of the package was that of a vacuum-package. As a result, this novel packaging method combined the advantages of modified atmosphere packaging (antimicrobial effect of CO₂) and vacuum packaging (low space requirement).     

Biobased packaging for improving preservation of fresh common mushrooms (Agaricus bisporus L.)

Freshness of common mushrooms was related to the internal atmosphere composition during modified atmosphere packaging (MAP) experiments at 20 °C and 80% RH with stretchable polyvinylchloride (PVC) film, paper, and the same paper coated with a wheat gluten solution. MAP with the stretchable film led to a detrimental deterioration of mushrooms after only one day of storage: dark brown blotches appeared and almost 30% of mushrooms exhibited open veil. This was due to the formation of condensed water at the inner surface of the material and onto mushrooms combined to a high O₂ partial pressure (16 kPa) in the headspace. Wheat gluten (WG) coated paper was the most effective to improve the shelf-life of mushrooms since it allowed the preservation of a fair colour, unbroken veils, and an acceptable texture during 3 days. This beneficial effect was attributed to the combination of a medium CO₂ (9.5 kPa) and low O₂ (2.5 kPa) partial pressure, without condensation. The main drawback of using WG-coated paper was its high water vapour permeability that led to an important weight loss (3.8 wt.% on day 3). However it did not affect the overall quality of mushrooms within the storage duration.

Industrial relevance

Even with the development of micro-perforated materials that provide the largest range of O₂ and CO₂ permeability values, several limitations are still encountered for synthetic MAP applications such as

– an insufficient perm-selectivity ratio that remains lower than 6 (value of 1 for micro-perforated material): generated atmosphere cannot reach both low O₂ and low CO₂ partial pressures and then are not adapted to CO₂-sensitive fresh produces.

– unattractive water condensation at the inner surface of the packaging that might occur due to a low water vapour permeability, favouring the development of microorganisms.

– their non biodegradability.

Previous studies reported a high selectivity ratio and a high water vapour permeability for biodegradable materials made from crops proteins (wheat gluten, for instance) that appeared well adapted for fresh fruits and vegetables preservation. However, despite low cost and such interesting functional properties, these materials exhibited poor mechanical properties and cannot be used as packaging material. Combination with other materials, such as cellulosic fibres, appeared to one way to get round this major drawback without losing its biodegradability. Indeed paper exhibits an environmental-friendliness potential (recyclability, sustainability, biodegradability, and compostability) and a high versatility in food packaging.By choosing common mushrooms, known to be sensitive to high CO₂ content, and a stretchable PVC film, commonly used to over-wrap mushrooms in tray (on European market), we demonstrate that this material was greatly less effective than a new biobased material (wheat gluten film coated onto paper) developed in collaboration with Smurfit Worldwide Research Center. This work confirms the interest in developing functionalised paper based packaging material with agro-based polymers adapted to the storage of fresh fruits and vegetable storage in ambient temperature.     

Retail Shelf-Life of Pork Dipped in Organic Acid before Modified Atmosphere or Vacuum Packaging

Modified atmosphere packaging (MAP) is increasingly popular for meat, but raw, chilled pork in vacuum or anoxic environments has a purple color. The retail shelf‐life of pork chops dipped in 500 ppm ascorbic acid, 250 ppm citric acid, or no acid dip and stored at 1 °C before simulated retail display in MAP with gas exchange or air‐permeable packaging after vacuum pouch storage was determined. The 80% N₂:20% CO₂ in MAP was exchanged with 80% O₂:20% CO₂, and chops were removed from vacuum packages and overwrapped with permeable film (VP‐PVC) on the 7th day before simulated retail display at 4 °C. Shelf‐life traits were determined at 1, 7, 8, 10, 12, and 14 d postpackaging. The pH values changed with time, but returned to post‐dipped, prepackaged levels at the end of simulated retail storage. Weight loss of chops increased (P < 0.05) in VP‐PVC compared with MAP. The a* values increased (P < 0.05) and L* and b* values decreased during simulated retail display, with higher L*, a*, and b* color values for chops in MAP than VP‐PVC. Log numbers of psychrotrophic microorganisms were higher (P < 0.05) on VP‐PVC samples than for chops in MAP on days 12 and 14. Psychrotrophic counts on ascorbic acid‐treated samples were decreased compared with citric acid or no dipping on pork during simulated retail display. Pork chops in MAP with gas exchange had lighter and redder color, increased weight retention, decreased psychrotrophic counts, and increased lipid oxidation compared with conventional vacuum and overwrap packaging systems.     

Evaluation of antimicrobial effects of lauric arginate on reduction of Salmonella spp. in ground chicken

The efficacy of lauric arginate (LAE) on Salmonella survivability in ground chicken containing 9.8% fat was determined under refrigerated storage. The effect of LAE treatments on total aerobes, pH and objective colour were also assessed in ground chicken. LAE was highly effective against Salmonella in 0.1% peptone with no detectable survivors following treatment with 200 ppm and 400 ppm of LAE. No difference existed (P > 0.05) in the growth of Salmonella and total aerobes after treatment with 200 and 400 ppm of LAE in ground chicken inoculated with a four strain mixture of Salmonella. At these concentrations, LAE did not exhibit any treatment effect on the pH and colour of ground chicken (P > 0.05). In conclusion, although LAE possesses strong inhibitory (P < 0.05) effect against Salmonella in suspension in 0.1% peptone water, no inhibitory (P > 0.05) effect on growth of Salmonella was observed in ground chicken at the currently approved levels of 200 ppm of LAE.     

Colour of hot paprika from the La Vera and Murcia regions packaged in different atmospheres during storage

This study compared the behaviour of hot paprika (Capsicum annuum L.) samples from the district of La Vera and the region of Murcia packaged in five different conditions during storage. The following five different packaging conditions were used in this study: modified atmosphere packaging with three different conditions (100% N₂; 50% N₂ and 50% CO₂; and 100% CO₂), vacuum packaging and traditional packaging (product packaging system without modifying the atmosphere). After the samples were packaged, they were stored for 8 months at room temperature (normal storage conditions). The following parameters were used to indicate the quality of the samples: Aw, ASTA colour, CIE_L*a*b* colour parameters, and the composition of red and yellow compounds. The results indicate that the modified atmosphere packaging and vacuum packaging exerted a protective effect on the paprika quality characteristics regardless of the paprika origin. However, no clear differences were detected between the effect of vacuum packaging and the different modified atmosphere packaging conditions.     

Preparation of alcalase hydrolysed rice bran protein concentrate and its inhibitory effect on soybean lipoxygenase activity

Rice bran protein concentrate (RBPC) was prepared from defatted rice bran and hydrolysed by alcalase at different hydrolysis times. As the hydrolysis times increased, the degree of hydrolysis (DHs) increased. RBPC hydrolysate obtained at 50 min (RBPCH‐50) had the highest inhibitory efficiency on soybean lipoxygenase (LOX) activity (66%). The inhibition kinetics of the reaction analysed by Lineweaver–Burk plots indicates that RBPCH‐50 is a competitive inhibitor. RBPCH‐50 inhibited soybean LOX with an IC₅₀ of 11.73 μg μL^?1 RBPCH‐50, and the obtained K_I was 4.59 μg μL^?1 RBPCH‐50. LOX inhibitory activity of RBPCH‐50 was significantly higher than that of 50 and 100 ppm butylated hydroxyanisole (BHA) and 50, 100, and 200 ppm butylated hydroxytoluene (BHT) (P ≤ 0.05); however, LOX inhibitory activity of RBPCH‐50 was similar to that of 200 ppm BHA (P > 0.05). Therefore, RBPCH might potentially be used as a natural LOX inhibitor.     

Reduction of trimethylamine oxide byShewanellaspp. under modified atmospheresin vitro

Two strains ofShewanellaspp. were isolated from cod fillets packed in modified atmosphere (60% CO₂, 30% O₂, 10% N₂). One of the strains was identified asShewanella putrefaciens. The other strain could not be fully identified but was determined as aShewanellaspp. different fromS. putrefaciens. The effect of modified atmosphere (CO₂, O₂) on the growth of the two strains and on the reduction of TMAO to TMA was studied using solid medium from fish extract packed under variable mixtures of CO₂, O₂and N₂. All the samples were incubated at 7°C for 7 days. TheShewanella-like strain was shown to be a stronger TMAO reducer and was more resistant to CO₂thanS. putrefaciens per se. Modified atmosphere packaging of marine fish can inhibit the growth and TMAO-reducing activity ofS. putrefacienswhen 50% of CO₂together with 10% of O₂are introduced into the packaging atmosphere. The growth and TMAO-reducing activity of theShewanella-like strain can be inhibited when higher proportions of CO₂together with as high as possible proportions of O₂are introduced into the packaging atmosphere. It is suggested that a combination of 60–70% CO₂and 30–40% O₂is introduced into the packaging atmosphere in order to prevent TMA production byShewanellaspp.     

Combined effect of MAP and active compounds on fresh blue fish burger

The combined effects of three essential oils [thymol, lemon extract and grapefruit seed extract (GFSE)] and modified atmosphere packaging conditions (MAP) on quality retention of blue fish burgers was studied and discussed. In particular, samples were packaged in air and in three different gas mix compositions: 30:40:30 O₂:CO₂:N₂, 50:50 O₂:CO₂ and 5:95 O₂:CO₂. During a 28-day storage period at 4 °C, the nutritional, microbiological and sensorial quality of the packed products was assessed. The potential development of biogenic amines was also evaluated.The obtained results highlight the possibility to improve the microbial quality of blue fish burgers by using very small amount of thymol (110 ppm), GFSE (100 ppm) and lemon extract (120 ppm) in combination with MAP. Based primarily on microbiological results, the combined use of the tested natural preservatives and a packaging system characterized by a high CO₂-concentration, was able to guarantee the microbial acceptability of fish burgers until the 28th day of storage at 4 °C. On the other hand, results from sensory analyses showed that sensorial quality was the sub-index that limited the burgers shelf life (to about 22–23 days), even if the proposed strategy was also effective in minimizing the sensory quality loss of the product having no effect on its nutritional quality.     

Enhancement of the nutritional status and quality of fresh pork sausages following the addition of linseed oil,fish oil and natural antioxidants

Fresh pork sausages (pork shoulder, pork back fat, water, rusk and seasoning) were manufactured where 15% of the pork back fat was substituted with linseed oil (LO) or fish oil (FO). Green tea catechins (GTC) and green coffee antioxidant (GCA) were added to both LO (LGTC 200 and LGCA 200) and FO (FGTC 200 and FGCA 200) substituted sausages at a level of 200 mg/kg. Raw and cooked pork sausages were either over-wrapped with oxygen permeable film (aerobic storage) or stored in modified atmosphere packages (MAP) containing 80% O₂:20% CO₂ or 70% N₂:30% CO₂, respectively for 7 days at 4 °C. Effects on fatty acid profiles, lipid oxidation, colour and sensorial properties were investigated. α-Linolenic acid increased from 1.34% (control) to 8.91% (LO) and up to 11.2% (LGTC 200 and LGCA 200). Addition of fish oil increased levels of EPA from 0.05% (control) to 2.83% (FO), 3.02% (FGTC 200) and 2.87% (FGCA 200) and DHA levels increased from 0.04% (control) to a maximum of 1.93% (FGTC 200). Lipid oxidation was low in raw and cooked linseed oil containing sausages. GTC (200 mg/kg) significantly (P < 0.05) reduced lipid oxidation in raw fish oil containing sausages after 7 days of storage. Colour parameters in raw pork sausages were unaffected by the packaging atmosphere. L¹ lightness values were lower (P < 0.05) in LGTC 200 and a¹ redness values lower (P < 0.05) in LGTC 200 and FGTC 200 after 7 days of storage. Sensory scores of cooked pork sausages were unaffected by linseed oil addition. Flavour and overall acceptability scores in cooked fish oil containing sausages were improved by GTC addition. Results obtained demonstrate potential for the production of nutritionally enhanced fresh pork sausages.     

Shelf life extension of fresh ginseng roots using sanitiser washing,edible antimicrobial coating and modified atmosphere packaging

Fresh American ginseng roots were washed with sanitiser solution (200 ppm sodium hypochlorite), surface‐coated with a coating solution consisting of 0.5% chitosan and three organic acids (lactic, levulinic and acetic acids) and then placed in modified atmosphere packaging (MAP) with 5% O₂, 10% O₂ or ambient air. Total aerobic bacteria, yeasts and moulds, weight loss and quality changes (texture, colour and appearance) of roots were monitored during storage at 4 °C. Throughout the 38‐week study, there were no significant changes in microbial loads, texture, colour and appearance of samples after sanitiser washing and coating treatments and packaged with air, 5% O₂ or 10% O₂. The weight loss of roots after 38 weeks was approximately 3%. The results demonstrate that the unique coating formulation (0.5% chitosan and multiple organic acids) and combination of sanitiser washing, coating treatment and MAP extend the shelf life of fresh ginseng roots to at least 38 weeks.     

Influence of hot‐air treatment,superatmospheric O2 and elevated CO2 on bioactive compounds and storage properties of fresh‐cut pomegranate arils

The impact of heat treatment using hot air (HT 45 °C and 55 °C for 1 h) and two active modified atmosphere packaging (MAP) conditions of high oxygen atmosphere (HOA: 80 kPa O₂, 20 kPa N₂) and high CO₂ atmosphere (HCA: 20 kPa CO₂, 80 kPa N₂), individually or combined, on the antioxidant capacity, polyphenols, vitamin C content, total anthocyanins, polyphenoloxydase (PPO) activity and shelf life of fresh‐cut (FC) pomegranate arils stored for 14 days at 4 °C was studied. The results indicate that HT 45 °C along with HOA inhibited PPO activity and prevented loss of antioxidant capacity, vitamin C and phenolic compounds in arils, in comparison with control and HT 55 °C. All treatments reduced the accumulation of anthocyanins, but HCA‐treated arils lost more anthocyanins besides having worse a* colour parameter values. No significant differences in titrable acidity (TA) and total soluble solids (TSS) were observed between treatments. The combination of HOA and HT 45 °C enhanced the benefits of applying each treatment separately and could be useful to improve and extend postharvest life of pomegranate FC arils.     

Effect of muscle,ageing time and modified atmosphere packaging conditions on the colour,oxidative and microbiological stability of packed beef

The objective of this study was to evaluate the influence of two different vacuum ageing times (7 and 14 days) and the impact of the modified atmosphere packaging (MAP) configuration (gas/product ratios: 0.5 and 1 and gas composition: 70% O₂ + 30% CO₂ and 40% O₂ + 30% CO₂ + 30% N₂) on the quality of fresh beef during subsequent storage at 4 °C. For this purpose, three separate experiments were performed. For each experiment, two different muscles (Longissimus dorsi and Biceps femoris) were sampled from four double‐muscled Belgian Blue beef carcasses. Next to colour, also the evolution in microbial load, pH, O₂ and CO₂ in the headspace and lipid oxidation at the meat surface were evaluated. A vacuum ageing for 14 days compared with 7 days resulted in a higher initial microbial load on the day of MAP packaging, which resulted finally in a significantly shorter shelf life. This ageing effect was less pronounced on the colour stability and lipid oxidation of the meat samples. No significant influence of the packaging configuration on any of the analysed parameters (colour, microbial load, pH and lipid oxidation at the meat surface) was observed.     

Controlled and modified atmospheres influence chilling injury,fruit quality and antioxidative system of Japanese plums (Prunus salicina Lindell)

Our objective was to compare the effects of controlled atmosphere (CA) and modified atmosphere packaging (MAP) on fruit quality, chilling injury (CI) and pro‐ and antioxidative systems in ‘Blackamber’ Japanese plums. Matured fruit were stored for 5 and 8 weeks at 0–1 °C in normal air, CA‐1 (1% O₂ + 3% CO₂), CA‐2 (2.5% O₂ + 3% CO₂) and MAP (~10% O₂ and 3.8% CO₂). CA was more effective than MAP in retention of flesh firmness and titratable acidity during cold storage. Fruit stored in CA‐1 showed reduced CI and membrane lipid peroxidation after 5 and 8 weeks of cold storage. Low O₂ atmospheres appeared to limit the generation of reactive oxygen species (ROS) and their efficient scavenging through the concerted action of superoxide dismutase and peroxidase. The role of ascorbate–glutathione (AsA–GSH) cycle in the regulation of oxidative stress was also studied during and after storage in different atmospheres. In conclusion, optimum CA conditions delayed fruit ripening and CI through augmentation of antioxidative metabolism and suppression of oxidative processes.     

Modified atmosphere influences aflatoxin B1 contamination and quality of peanut (Arachis hypogaea L.) kernels cv. Khon Kaen 84-8

Storage of ‘Khon Kaen 84-8’ peanut kernels in laminated bags (Low density polyethylene (LDPE)/Nylon) (20×30 cm; 120 μm thickness) under different packaging atmospheres had effect on quality, fungal occurrence and aflatoxin B₁ (AFB₁) contamination. During fifteen week storage, peanuts (6.4% moisture content) were kept under different packaging atmospheres with some inoculated (Inoc.) and without (Non-Inoc.) aflatoxin producing fungus Aspergillus flavus. The treatments include; 100% CO₂+Inoc., 100% N₂+Inoc., vacuum + Inoc., Air + Inoc., and Air + Non-Inoc. packed with only ambient air. The storage room conditions were a temperature of 29±2 °C and 70 ± 5% r. h. Mycobiota occurrence, AFB₁ level, moisture content, lipase activity, free fatty acids and rancidity (Thiobarbituric acid; TBA value) were investigated. A total of five major fungi were identified with four storage fungi and one field fungus; Rhizopus stolonifer, Aspergillus niger, A. flavus, Penicillium spp., and Fusarium spp., respectively. Packaging in 100% CO₂+Inoc. significantly repressed the fungal occurrence especially A. niger while all other packaging atmospheres suppressed proliferation of both R. stolonifer and Penicillium spp. The peanuts kept in vacuum + Inoc. package revealed AFB₁ level below detection limit (0.4 μg/kg). Peanut kernels in 100% CO₂+Inoc. packaging atmosphere maintained an acceptable color indicated by L* and a* values, as well as the color change (ΔE) compared to other treatments. Different packaging atmospheres showed variable results in relation to the free fatty acids level with packaging under 100% N₂ revealing the lowest. Subsequently, 100% N₂ packaging atmosphere relatively inhibited rancidity occurrence in peanut kernels during storage. The results of this study portray that 100% CO₂, 100% N₂ and vacuum packaging atmosphere could have a potential to suppress occurrence of mycobiota, maintain peanut kernel quality in relation to color and lipid oxidation, and as well curtail AFB₁ contamination respectively, for fifteen weeks or more given the quality of kernels at the end of storage.